Avian influenza, also known as avian flu, is a bird flu caused by the influenza A virus, which can infect people.  It is similar to other types of animal flu in that it is caused by a virus strain that has adapted to a specific host. The type with the greatest risk is highly pathogenic avian influenza (HPAI).

Though influenza A is adapted to birds, it can also stably adapt and sustain person-to-person transmission. Recent influenza research into the genes of the Spanish flu virus shows it to have genes adapted from both human and avian strains. Pigs can also be infected with human, avian, and swine influenza viruses, allowing for mixtures of genes (reassortment) to create a new virus, which can cause an antigenic shift to a new influenza A virus subtype which most people have little to no immune protection against.

Avian influenza strains are divided into two types based on their pathogenicity: high pathogenicity (HP) or low pathogenicity (LP). The most well-known HPAI strain, H5N1, was first isolated from a farmed goose in Guangdong Province, China in 1996, and also has low pathogenic strains found in North America. Companion birds in captivity are unlikely to contract the virus and there has been no report of a companion bird with avian influenza since 2003. Pigeons can contract avian strains, but rarely become ill and are incapable of transmitting the virus efficiently to humans or other animals.

History
The type of influenza known informally as avian or bird flu is caused by viruses adapted to birds. The most widely quoted date for the beginning of recorded history of avian influenza (initially known as fowl plague) was in 1878 when it was differentiated from other diseases that caused high mortality rates in birds. Fowl plague or Avian Flu also included Newcastle disease until as recently as the 1950s. Between 1959 and 1995, there were 15 recorded occasions of the emergence of HPAI viruses in poultry, but losses were minimal. Between 1996 and 2008, HPAI outbreaks in poultry have occurred at least 11 times and 4 of these outbreaks have involved millions of birds.

In the 1990s, the world's poultry population grew 76% in developing countries and 23% in developed countries, contributing to the increased prevalence of avian influenza. Before the 1990s, HPAI caused high mortality in poultry, but infections were sporadic and contained. Outbreaks have become more common due to the high density and frequent movement of flocks from intensive poultry production.

Influenza A/H5N1 was first isolated from a goose in China in 1996. Human infections were first reported in 1997 in Hong Kong. Since 2003, more than 700 human cases of Asian HPAI H5N1 have been reported to the WHO, primarily from 15 countries in Asia, Africa, the Pacific, Europe, and the Middle East, though over 60 countries have been affected.

Between early 2013 and early 2017, 916 lab-confirmed human cases of H7N9 were reported to the World Health Organization (WHO). On 9 January 2017, the National Health and Family Planning Commission of China reported to the WHO 106 cases of H7N9 which occurred from late November through late December, including 35 deaths, 2 potential cases of human-to-human transmission, and 80 of these 106 persons stating that they have visited live poultry markets. The cases are reported from Jiangsu (52), Zhejiang (21), Anhui (14), Guangdong (14), Shanghai (2), Fujian (2) and Hunan (1). Similar sudden increases in the number of human cases of H7N9 have occurred in previous years during December and January.

United States 2014–15 outbreak
From 2014 through 2015, United States poultry and egg producers experienced the largest outbreak of H5N2 in recorded history with approximately 51 million birds depopulated to control the spread of the disease. From May to June 2015, 25 million birds were culled, equating to 409,836 birds per day, or 284 birds per minute. In total, the 2014-2015 H5N2/H5N8 outbreak cost US$879 million in public expenditures and the United States egg and poultry industry more than US$3 billion to eradicate the disease from poultry production. This was the most costly United States HPAI outbreak to date.

2020

By the end of 2020, several outbreaks of various bird flus were reported in Europe. Since mid-October several European countries, including Belgium, Denmark, France, Germany, Ireland, the Netherlands, Sweden, and the United Kingdom have reported outbreaks of highly pathogenic avian influenza (HPAI) viruses, mostly in wild birds. Positive tests were also among poultry and captive birds. According to a report by the European Centre for Disease Prevention and Control (ECDC), three varieties of HPAI viruses were found, A(H5N8), A(H5N5) and A(H5N1), with H5N8 being the most commonly found. In Germany, 29,000 chickens were killed to halt the spread of H5N8. In Belgium, H5N5 was found on a poultry farm according to the World Organization for Animal Health (OIE). The outbreak was reported in Menen, near the border with France, and killed 600 birds and the culling of an additional 151,000 chickens from the flock.

United States 2022–23 outbreak
Since early 2022, more than 58 million birds in 47 states have died either directly from a bird flu virus infection or been culled (killed) as a result of possible exposure to infected birds. The recent strain has cost the government $661 million with no end to the outbreak in sight despite severe mitigation measures put in place by the industry after the 2015 outbreak.
Iowa, the biggest egg producer in the United States, has been the most affected, with almost 16 million birds slaughtered.

In January 2023, in Tijuana, a dozen eggs were priced at about $2.30, yet $7.37 in California, and border crossers who declare the eggs at the inspection stations are told the items aren't allowed and must be turned over.

Africa 2023 outbreak
In March 2023 Senegal reported an outbreak of the disease on a poultry farm in the village of Potou near the northwestern town of Louga. The disease has killed 500 birds at the farm in Potou, while 1,229 bird deaths have been recorded at the Langue de Barbarie Park and surrounding areas. A week later, in Gambia authorities detected H5N1 bird flu on a wild bird reserve.  During September and October 2023 South Africa reported one of its worst outbreaks of bird flu. Millions of chickens were killed over the first few weeks and supplies of poultry meat were threatened and supermarkets across the country were short of eggs.

Genetics
Genetic factors in distinguishing between "human flu viruses" and "avian flu viruses" include:
PB2 (RNA polymerase) Amino acid (or residue) position 627 in the PB2 protein encoded by the PB2 RNA gene. Until H5N1, all known avian influenza viruses had a Glu at position 627, while all human influenza viruses had a Lys.
HA (hemagglutinin) Avian influenza HA viruses bind alpha 2-3 sialic acid receptors, while human influenza HA viruses bind alpha 2-6 sialic acid receptors. Swine influenza viruses have the ability to bind both types of sialic acid receptors. Hemagglutinin is the major antigen of the virus against which neutralizing antibodies are produced, and influenza virus epidemics are associated with changes in its antigenic structure. This was originally derived from pigs, and should technically be referred to as "pig flu".

The evolution of avian influenza virus has been influenced by genetic variation in the virus population due to genome segment reassortment and mutation. Also homologous recombination occurs in viral genes, suggesting that genetic variation generated by homologous recombination has also played a role in driving the evolution of the virus and potentially has affected virulence and host range.

Subtypes
Out of the three types of influenza viruses (A, B, and C), influenza A virus can cause zoonotic infections, with a natural reservoir almost entirely in birds. There are many subtypes of avian influenza viruses, but only some strains of five subtypes have been known to infect humans: H5N1, H7N3, H7N7, H7N9, and H9N2. At least one person, an elderly woman in Jiangxi Province, China, died of pneumonia in December 2013 from the H10N8 strain. She was the first human fatality confirmed to be caused by that strain.

Most human cases of the avian flu are a result of either handling dead infected birds or from contact with infected fluids. It can also be spread through contaminated surfaces and droppings. While most wild birds have only a mild form of the H5N1 strain, once domesticated birds such as chickens or turkeys are infected, H5N1 can potentially become much more deadly because the birds are often in close contact. H5N1 is a large threat in Asia with infected poultry due to low hygiene conditions and close quarters. Although it is easy for humans to contract the infection from birds, human-to-human transmission is more difficult without prolonged contact. Public health officials believe strains of avian flu may mutate to become easily transmissible between humans.

Spreading of H5N1 from Asia to Europe is much more likely caused by both legal and illegal poultry trades than dispersing through wild bird migrations, being that in recent studies, there were no secondary rises in infection in Asia when wild birds migrate south again from their breeding grounds. Instead, the infection patterns followed transportation such as railroads, roads, and country borders, suggesting poultry trade as being much more likely. While there have been strains of avian flu to exist in the United States, they have been extinguished and have not been known to infect humans.

Examples of avian influenza A virus strains:

Transmission

Avian influenza is most often spread by contact between infected and healthy birds, though can also be spread indirectly through contaminated equipment. The virus is found in secretions from the nostrils, mouth, and eyes of infected birds as well as their droppings. HPAI infection is spread to people often through direct contact with infected poultry, such as during slaughter or plucking. Though the virus can spread through airborne secretions, the disease itself is not an airborne disease. Highly pathogenic strains spread quickly among flocks and can destroy a flock within 28 hours; the less pathogenic strains may affect egg production but are much less deadly.

Although it is possible for humans to contract the avian influenza virus from birds, human-to-human transmission is much more difficult without prolonged contact. Public health officials believe strains of avian flu may mutate to become easily transmissible between humans. Some strains of avian influenza are present in the intestinal tract of large numbers of shore birds and water birds, but these strains rarely cause human infection.

Five manmade ecosystems have contributed to modern avian influenza virus ecology: integrated indoor commercial poultry, range-raised commercial poultry, live poultry markets, backyard and hobby flocks, and bird collection and trading systems including cockfighting. Indoor commercial poultry has had the largest impact on the spread of HPAI, with the increase in HPAI outbreaks largely the result of increased commercial production since the 1990s.

In the early days of the HPAI H5N1 pandemic, village poultry and their owners were frequently implicated in disease transmission. Village poultry, also known as backyard and hobby flocks, are small flocks raised under extensive conditions and often allowed free range between multiple households. Further research suggested these flocks pose less of a threat than intensively raised commercial poultry with homogenous genetic stock and poor biosecurity. Backyard and village poultry also do not travel great distances compared to transport of intensively raised poultry and contribute less to the spread of HPAI.

H5N1

The highly pathogenic influenza A virus subtype H5N1 is an emerging avian influenza virus that is causing global concern as a potential pandemic threat. It is often referred to simply as "bird flu" or "avian influenza", even though it is only one of many subtypes.

H5N1 has killed millions of poultry in a growing number of countries throughout Asia, Europe, and Africa. Health experts are concerned that the coexistence of human flu viruses and avian flu viruses (especially H5N1) will provide an opportunity for genetic material to be exchanged between species-specific viruses, possibly creating a new virulent influenza strain that is easily transmissible and lethal to humans. The mortality rate for humans with H5N1 is 60%.

Since the first human H5N1 outbreak occurred in 1997, there has been an increasing number of HPAI H5N1 bird-to-human transmissions, leading to clinically severe and fatal human infections. Because a significant species barrier exists between birds and humans, the virus does not easily spread to humans. Some cases of infection were researched to discern whether human-to-human transmission occurred. More research is necessary to understand the pathogenesis and epidemiology of the H5N1 virus in humans. Exposure routes and other disease transmission characteristics, such as genetic and immunological factors that may increase the likelihood of infection, are not clearly understood.

The first known transmission of H5N1 to a human occurred in Hong Kong in 1997, when there was an outbreak of 18 human cases; 6 deaths were confirmed. None of the infected people worked with poultry. After culling all of the poultry in the area, no more cases were diagnosed. In 2006, the first human-to-human transmission likely occurred when seven members of a family in Sumatra became infected after contact with a family member who had worked with infected poultry.

Although millions of birds have become infected with the virus since its discovery, 359 people have died from H5N1 in twelve countries according to World Health Organization reports as of August 10, 2012.

The H5N1 outbreak in Thailand caused massive economic losses, especially among poultry workers. Infected birds were culled and slaughtered. The public lost confidence with the poultry products, thus decreasing the consumption of chicken products. This also elicited a ban from importing countries. Several factors enhanced the virality, including bird migration, cool temperature (increases virus survival) and several festivals at that time.

A mutation in the virus was discovered in two Guangdong patients in February 2017 which rendered it more deadly to chickens, inasmuch as it could infect every organ; the risk to humans was not increased.

Research
A study published in 2012 in Science Magazine reported on research findings that allowed for the airborne transmission of H5N1 in laboratory ferrets. The study in question created airborne H5N1 via amino acid substitutions that largely mitigated the devastating effects of the disease. This fact was underscored by the 0% fatality rate among the ferrets infected via airborne transmission, as well as the fundamental biology underlying the substitutions. Flu viruses attach to host cells via the hemagluttinin proteins on their envelope. These hemagluttinin proteins bind to sialic acid receptors on host cells, which can fall into two categories. The sialic acid receptors can be either 2,3 or 2,6-linked, with the species of origin largely deciding receptor preference. In influenzas of avian origin 2,3-linkage is preferred, vs. influenzas of human origin in which 2,6-linkage is preferable. 2,3-linked SA receptors in humans are found predominantly in the lower respiratory tract, a fact that is the primary foundation for the deadliness of avian influenzas in humans, and also the key to their lack of airborne transmission. In the study that created an airborne avian influenza among ferrets it was necessary to switch the receptor preference of the host cells to those of 2,6-linkage, found predominantly in humans' upper respiratory tract, in order to create an infection that could shed aerosolized virus particles. Such an infection must occur in the upper respiratory tract of humans, thus fundamentally undercutting the fatal trajectory of the disease.

H7N9

Influenza A virus subtype H7N9 is a novel avian influenza virus first reported to have infected humans in 2013 in China. Most of the reported cases of human infection have resulted in severe respiratory illness. In the month following the report of the first case, more than 100 people had been infected, an unusually high rate for a new infection; a fifth of those patients had died, a fifth had recovered, and the rest remained critically ill. The WHO has identified H7N9 as "...an unusually dangerous virus for humans." As of June 30, 133 cases have been reported, resulting in the deaths of 43.

Research regarding background and transmission is ongoing. It has been established that many of the human cases of H7N9 appear to have a link to live bird markets. As of July 2013, there is no evidence of sustained human-to-human transmission. A study group headed by one of the world's leading experts on avian flu reported that several instances of human-to-human infection were suspected.
It has been reported that H7N9 virus does not kill poultry, which will make surveillance much more difficult. Researchers have commented on the unusual prevalence of older males among H7N9-infected patients. While several environmental, behavioral, and biological explanations for this pattern have been proposed, as yet, the reason is unknown. Currently no vaccine exists, but the use of influenza antiviral drugs known as neuraminidase inhibitors in cases of early infection may be effective.

The number of cases detected after April fell abruptly. The decrease in the number of new human H7N9 cases may have resulted from containment measures taken by Chinese authorities, including closing live bird markets, or from a change in seasons, or possibly a combination of both factors. Studies indicate that avian influenza viruses have a seasonal pattern, thus it is thought that infections may pick up again when the weather turns cooler in China.

In the four years from early 2013 to early 2017, 916 lab-confirmed human cases of H7N9 were reported to the WHO.

On 9 January 2017, the National Health and Family Planning Commission of China reported to the WHO 106 cases which occurred from late November through December. 29, 2016. The cases are reported from Jiangsu (52), Zhejiang (21), Anhui (14), Guangdong (14), Shanghai (2), Fujian (2) and Hunan (1). 80 of these 106 persons have visited live poultry markets. Of these cases, there have been 35 deaths. In two of the 106 cases, human-to-human transmission could not be ruled out.

Affected prefectures in Jiangsu province closed live poultry markets in late December 2016, whereas Zhejiang, Guangdong and Anhui provinces went the route of strengthening live poultry market regulations. Travellers to affected regions are recommended to avoid poultry farms, live bird markets, and surfaces which appear to be contaminated with poultry feces. Similar sudden increases in the number of human cases of H7N9 have occurred in previous years during December and January.

Domestic animals

Several domestic species have been infected with and shown symptoms of H5N1 viral infection, including cats, dogs, ferrets, pigs, and birds.

Birds

Attempts are made in the United States to minimize the presence of HPAI in poultry through routine surveillance of poultry flocks in commercial poultry operations. Detection of a HPAI virus may result in immediate culling of the flock. Less pathogenic viruses are controlled by vaccination, which is done primarily in turkey flocks (ATCvet codes:  for the inactivated fowl vaccine,  for the inactivated turkey combination vaccine).

Cats
Avian influenza in cats can show a variety of symptoms and usually lead to death. Cats are able to get infected by either consuming an infected bird or by contracting the virus from another infected cat.

Global impact
In 2005, the formation of the International Partnership on Avian and Pandemic Influenza was announced in order to elevate the importance of avian flu, coordinate efforts, and improve disease reporting and surveillance in order to better respond to future pandemics. New networks of laboratories have emerged to detect and respond to avian flu, such as the Crisis Management Center for Animal Health, the Global Avian Influenza Network for Surveillance, OFFLU, and the Global Early Warning System for major animal diseases. After the 2003 outbreak, WHO member states have also recognized the need for more transparent and equitable sharing of vaccines and other benefits from these networks. Cooperative measures created in response to HPAI have served as a basis for programs related to other emerging and re-emerging infectious diseases.

HPAI control has also been used for political ends. In Indonesia, negotiations with global response networks were used to recentralize power and funding to the Ministry of Health. In Vietnam policymakers, with the support of the Food and Agriculture Organization of the United Nations (FAO), used HPAI control to accelerate the industrialization of livestock production for export by proposing to increase the portion of large-scale commercial farms and reducing the number of poultry keepers from 8 to 2 million by 2010.

Stigma
Backyard poultry production was viewed as "traditional Asian" agricultural practices that contrasted with modern commercial poultry production and seen as a threat to biosecurity. Backyard production appeared to hold greater risk than commercial production due to lack of biosecurity and close contact with humans, though HPAI spread in intensively raised flocks was greater due to high density rearing and genetic homogeneity. Asian culture itself was blamed as the reason why certain interventions, such as those that only looked at placed-based interventions, would fail without looking for multifaceted solutions.

Indonesia
Press accounts of avian flu in Indonesia were seen by poultry farmers as conflating suspected cases while the public did see the accounts as informative, though many became de-sensitized to the idea of impending danger or only temporarily changed their poultry-related behavior. Rumors also circulated in Java in 2006. These tended to focus on bird flu being linked to big businesses in order to drive small farmers out of the market by exaggerating the danger of avian influenza, avian flu being introduced by foreigners to force Indonesians to purchase imported chicken and keep Indonesian chicken off the world market, and the government using avian flu as a ploy to attract funds from wealthy countries. Such rumors reflected concerns about big businesses, globalization, and a distrust of the national government in a country where "the amount of decentralization here is breathtaking" according to Steven Bjorge, a WHO epidemiologist in Jakarta in 2006.

In the context a decentralized national government that the public did not completely trust, Indonesian Health Minister Siti Fadilah Supari announced in December 2006 that her government would no longer be sharing samples of H5N1 collected from Indonesian patients. This decision came as a shock to the international community as it disrupted the Global Influenza Surveillance Network (GISN) coordinated by the WHO for managing seasonal and pandemic influenza. GISN is based on countries sharing virus specimens freely with the WHO which assesses and eventually sends these samples to pharmaceutical companies in order to produce vaccines that are sold back to these countries. Though this was initially seen as an attempt to protect national sovereignty at all costs, it was instead used for a domestic political struggle. Prior to Indonesia's dispute with the GISN, the Ministry of Health, already weak due to the decentralized nature the government, was experiencing further leakage of funding to state and non-state agencies due to global health interventions. By reasserting control over public health issues and funding by setting itself up as the sole Indonesian representative to the WHO, the Ministry of Health made itself a key player in the management of future international funds relating vaccine production and renegotiated benefits from global surveillance networks.

Economic
Approximately 20% of the protein consumed in developing countries come from poultry. In the wake of the H5N1 pandemic, millions of poultry were killed. In Vietnam alone, over 50 million domestic birds were killed due to HPAI infection and control attempts. A 2005 report by the FAO totaled economic losses in South East Asia around US$10 billion. This had the greatest impact on small scale commercial and backyard producers relative to total assets compared to industrial chains which primarily experience temporary decreases in exports and loss of consumer confidence. Some governments did provide compensation for culled poultry, it was often far below market value (close to 30% of market value in Vietnam), while others such as Cambodia provide no compensation to farmers at all.

As poultry serves as a source of food security and liquid assets, the most vulnerable populations were poor small scale farmers. The loss of birds due to HPAI and culling in Vietnam led to an average loss of 2.3 months of production and US$69–108 for households where many have an income of $2 a day or less. The loss of food security for vulnerable households can be seen in the stunting of children under five in Egypt. Women are another population at risk as in most regions of the world, small flocks are tended to by women. Widespread culling also resulted in the decreased enrollment of girls in school in Turkey.

Prevention

People who do not regularly come into contact with birds are not at high risk for contracting avian influenza. Those at high risk include poultry farm workers, animal control workers, wildlife biologists, and ornithologists who handle live birds. Organizations with high-risk workers should have an avian influenza response plan in place before any cases have been discovered. Biosecurity of poultry flocks is also important for prevention. Flocks should be isolated from outside birds, especially wild birds, and their waste; vehicles used around the flock should be regularly disinfected and not shared between farms; and birds from slaughter channels should not be returned to the farm.

With proper infection control and use of personal protective equipment (PPE), the chance for infection is low. Protecting the eyes, nose, mouth, and hands is important for prevention because these are the most common ways for the virus to enter the body. Appropriate personal protective equipment includes aprons or coveralls, gloves, boots or boot covers, and a head cover or hair cover. Disposable PPE is recommended. An N-95 respirator and unvented/indirectly vented safety goggles are also part of appropriate PPE. A powered air purifying respirator (PAPR) with hood or helmet and face shield is also an option.

Proper reporting of an isolated case can help to prevent spread. The Centers for Disease Control and Prevention (US) recommendation is that if a worker develops symptoms within 10 days of working with infected poultry or potentially contaminated materials, they should seek care and notify their employer, who should notify public health officials.

For future avian influenza threats, the WHO suggests a three-phase, five-part plan.
 Phase 1: Pre-pandemic
 Reduce opportunities for human infection
 Strengthen the early warning system
 Phase 2: Emergence of a pandemic virus
 Contain or delay spread at the source
 Phase 3: Pandemic declared and spreading internationally
 Reduce morbidity, mortality, and social disruption
 Conduct research to guide response measures
Vaccines for poultry have been formulated against several of the avian H5N1 influenza varieties. Control measures for HPAI encourage mass vaccinations of poultry though The World Health Organization has compiled a list of known clinical trials of pandemic influenza prototype vaccines, including those against H5N1. In some countries still at high risk for HPAI spread, there is compulsory strategic vaccination though vaccine supply shortages remain a problem.

For village poultry farmers
During the initial response to H5N1, a one size fits all recommendation was used for all poultry production systems, though measures for intensively raised birds were not necessarily appropriate for extensively raised birds. When looking at village-raised poultry, it was first assumed that the household was the unit and that flocks did not make contact with other flocks, though more effective measures came into use when the epidemiological unit was the village.

Recommendations involve restructuring commercial markets to improve biosecurity against avian influenza. Poultry production zoning is used to limit poultry farming to specific areas outside of urban environments while live poultry markets improve biosecurity by limiting the number of traders holding licenses and subjecting producers and traders to more stringent inspections. These recommendations in combination with requirements to fence and house all poultry, and to limit free ranging flocks, will eventually lead to fewer small commercial producers and backyard producers, costing livelihoods as they are unable to meet the conditions needed to participate.

A summary of reports to the World Organisation for Animal Health in 2005 and 2010 suggest that surveillance and under-reporting in developed and developing countries is still a challenge. Often, donor support can focus on HPAI control alone, while similar diseases such as Newcastle disease, acute fowl cholera, infectious laryngotracheitis, and infectious bursal disease still affect poultry populations. When HPAI tests come back negative, a lack of funded testing for differential diagnoses can leave farmers wondering what killed their birds.

Since traditional production systems require little investment and serve as a safety net for lower income households, prevention and treatment can be seen as less cost-effective than letting poultry die. Effective control not only requires prior agreements to be made with relevant government agencies, such as seen with Indonesia, they must also not unduly threaten food security.

Culling

Culling is used in order to decrease the threat of avian influenza transmission by killing potentially infected birds. The FAO manual on HPAI control recommends a zoning strategy which begins with the identification of an infected area (IA) where sick or dead birds have tested positive. All poultry in this zone are culled while the area 1 to 5 km from the outer boundary of the IA is considered the restricted area (RA) placed under strict surveillance. 2 to 10 km from the RA is the control area (CA) that serves as a buffer zone in case of spread. Culling is not recommended beyond the IA unless there is evidence of spread. The manual also provides examples of how control was carried out between 2004 and 2005 to contain H5N1 where all poultry was to be stamped out in a 3 km radius beyond the infected point and beyond that a 5 km radius where all fowl was to be vaccinated. This culling method was indiscriminate as a large proportion of the poultry inside these areas were small backyard flocks which did not travel great enough distances to carry infection to adjacent villages without human effort and may have not been infected at all. Between 2004 and 2005, over 100 million chickens were culled in Asia to contain H5N1.

The risk of mass culling of birds and the resulting economic impact led to farmers who were reluctant to report sick poultry. The culls often preempted actual lab testing for H5N1 as avian flu policy justified sacrificing poultry as a safeguard against HPAI spread. In response to these policies, farmers in Vietnam between 2003 and 2004 became more and more unwilling to surrender apparently healthy birds to authorities and stole poultry destined for culls as it stripped poultry of their biosocial and economic worth. By the end of 2005, the government implemented a new policy that targeted high-risk flock in the immediate vicinity of infected farms and instituted voluntary culling with compensation in the case of a local outbreak.

Not only did culling result in severe economic impacts especially for small scale farmers, culling itself may be an ineffective preventative measure. In the short-term, mass culling achieves its goals of limiting the immediate spread of HPAI, it has been found to impede the evolution of host resistance which is important for the long-term success of HPAI control. Mass culling also selects for elevated influenza virulence and results in the greater mortality of birds overall. Effective culling strategies must be selective as well as considerate of economic impacts to optimize epidemiological control and minimize economic and agricultural destruction.

People-poultry relations
Prevention and control programs must take into account local understandings of people-poultry relations. In the past, programs that have focused on singular, place-based understandings of disease transmission have been ineffective. In the case of Northern Vietnam, health workers saw poultry as commodities with an environment that was under the control of people. Poultry existed in the context of farms, markets, slaughterhouses, and roads while humans were indirectly the primary transmitters of avian flu, placing the burden of disease control on people. Farmers saw their free ranging poultry in an environment dominated by nonhuman forces that they could not exert control over. There were a host of nonhuman actors such as wild birds and weather patterns whose relationships with the poultry fostered the disease and absolved farmers of complete responsibility for disease control.

Attempts at singular, place-based controls sought to teach farmers to identify areas where their behavior could change without looking at poultry behaviors. Behavior recommendations by Vietnam's National Steering Committee for Avian Influenza Control and Prevention (NSCAI) were drawn from the FAO Principles of Biosecurity. These included restrictions from entering areas where poultry are kept by erecting barriers to segregate poultry from non-human contact, limits on human movement of poultry and poultry-related products ideally to transporters, and recommendations for farmers to wash hands and footwear before and after contact with poultry. Farmers, pointed to wind and environmental pollution as reasons poultry would get sick. NSCAI recommendations also would disrupt longstanding livestock production practices as gates impede sales by restricting assessment of birds by appearance and offend customers by limiting outside human contact. Instead of incorporating local knowledge into recommendations, cultural barriers were used as scapegoats for failed interventions. Prevention and control methods have been more effective when also considering the social, political, and ecological agents in play.

See also

 H7N9
 Global spread of H5N1
 H5N1
 Health crisis
 Influenza
 Influenza A virus
 Influenza pandemic
 Influenza Genome Sequencing Project
 Influenza research
 Influenza vaccine
 International Partnership on Avian and Pandemic Influenza
 OIE/FAO Network of Expertise on Animal Influenza
 Pandemic Preparedness and Response Act
 Subtypes of Influenza A virus
 Transmission and infection of H5N1
 Yarding - fenced in yard in poultry farming

Notes

References

Sources
 Orent, Wendy (2006) The Science of Avian Flu, Answers to Nine Frequently Asked Questions (Discover Magazine. Health & Medicine. February 20, 2006. 59–61)
 Haugan, Salomon   (2012) Avian Influenza: Etiology, Pathogenesis and Interventions (Nova Science Publishers, Inc.)
 Riley M. Seeger, Amy D. Hagerman, Kamina K. Johnson, Dustin L. Pendell, Thomas L. Marsh (2021)When poultry take a sick leave: Response costs for the 2014–2015 highly pathogenic avian influenza epidemic in the USA (Food Policy, 2021, 102068.)

External links

World Health Organisation (WHO)
WHO Avian influenza resource
The United Nation's World Health Organization's Avian Flu Facts Sheet for 2006
In-depth analysis of bird flu Symptoms & in-depth analysis on avian flu

Food and Agriculture Organization of the UN (FAO)
FAO Avian Influenza portal Information resources, animations, videos, photos
FAO Bird Flu disease card

World Organisation for Animal Health (OIE)
Current status of HPAI worldwide at OIE. WAHID Interface – OIE World Animal Health Information Database
Disease card
 Avian influenza resource By Dr. Nati Elkin – Atlases, vaccines and information.

United States
 PandemicFlu.Gov U.S. Government avian and pandemic flu information
 CIDRAP Avian Flu Overview "Avian Influenza (Bird Flu): Agricultural and Wildlife Considerations"
 US Avian Influenza Response U.S. Agency for International Development (USAID)
 Avian influenza research and recommendations National Institute for Occupational Safety and Health
 Influenza Research Database Database of influenza sequences and related information.
 Species Profile- Avian Influenza (Orthomyxoviridae Influenza Type A, subtype H5N1), National Invasive Species Information Center, United States National Agricultural Library. Lists general information and resources for Avian Influenza.
 Strategic Health Communication for Avian and Pandemic Influenza Prevention Johns Hopkins Bloomberg School of Public Health Center for Communication Programs Global Program on Avian and Pandemic Influenza.
 NIOSH Alert: Protecting Poultry Workers from Avian Influenza (Bird Flu) CDC/NIOSH recommendations for poultry workers

Europe
 European Commission Avian Influenza control measures
 Avian Influenza: Questions & Answers European Centre for Disease Prevention and Control – Official website
 FluTrop: Avian Influenza Research in Tropical Countries French Agricultural Research Center for Developing Countries (CIRAD), Avian Influenza website

Bird diseases
Poultry diseases
Agricultural health and safety

Avian influenza


Janusz A. Zajdel () a fost un scriitor polonez de science fiction, precursor al literaturii de ficțiune, specialist în fizică nucleară, autor de articole, broșuri, manuale și cărți științifice.

Premiul literar polonez în domeniul ficțiunii (în pl. Nagroda im. Janusza A. Zajdla) a fost numit în cinstea numelui lui. A absolvit Facultatea de Fizică a Universității din Varșovia. A publicat 83 de povestiri în diverse reviste.

Publicații

Colecții de povestiri
 Jad mantezji (Nasza Księgarnia, 1965)
 Przejście przez lustro (Iskry, 1975)
 Iluzyt (Nasza Księgarnia, 1976)
 Feniks / Fenix (Nasza Księgarnia, 1981)
 Ogon diabła / Coada diavolului (KAW, 1982)

Romane
 Lalande 21185 (Nasza Księgarnia, 1966)
 Prawo do powrotu / Dreptul la întoarcere (Nasza Księgarnia, 1975)
 Cylinder van Troffa / Cilindrul lui Van Troff (Czytelnik, 1980)
 Limes inferior (Iskry, 1982)
 Wyjście z cienia (Czytelnik, 1983)
 Cała prawda o planecie Ksi / Întregul adevăr despre planeta Ksi (KAW, 1983)
 Paradyzja (Iskry, 1984)

Altele
 Izotopy promieniotwórcze (IW CRZZ, 1973)
 Wybrane zagadnienia z fizyki jądrowej (współaut. Bożena Gostkowska, Ośrodek Informacji o Energii Jądrowej, 1975)
 Promieniowanie jonizujące (PAN, NOT, 1976)
 Ogólne zasady ochrony przed promieniowaniem jonizującym (coautor. Tadeusz Majle, PZWL, 1976)
 Bezpieczeństwo i higiena pracy przy użytkowaniu promieniowania jonizującego (Stowarzyszenie Inżynierów i Techników Mechaników Polskich, 1975)

Note

Legături externe
  Twórczość Janusza Zaldla
  Janusz Andrzej Zajdel

Nașteri_în_1938
Nașteri_pe_15_august
Decese_în_1985
Decese_pe_19_iulie
Absolvenți_ai_Universității_din_Varșovia
Scriitori polonezi de literatură științifico-fantastică

Janusz Zajdel


Audrey Rose este un film de groază psihologic american din 1977 regizat de Robert Wise. Rolurile principale sunt interpretate de actorii Marsha Mason și Anthony Hopkins. Este bazat pe un roman omonim de Frank De Felitta.

Rezumat

Distribuție
 Marsha Mason -  Janice Templeton
 Anthony Hopkins -  Elliot Hoover
 John Beck -  Bill Templeton
 Susan Swift -  Ivy Templeton
 Norman Lloyd -  Dr. Steven Lipscomb
 John Hillerman -  Prosecutor Scott Velie
 Robert Walden -  Brice Mack

Primire
A avut încasări de 2 milioane $.

Note

Vezi și
 Listă de filme de groază din 1977

Filme din 1977
Filme de groază din anii 1970
Filme psihologice
Filme în limba engleză
Filme regizate de Robert Wise
Filme americane
Filme United Artists
Filme cu fantomeFilme despre reîncarnare

Audrey Rose (film)


Voice junior sæson 4 er en musikkonkurrence for børn hvor der er 3 coaches Wafande, Oh Land og Joey Moe. Værterne er Mikkel Kryger og Amelia Høy . Fjerde sæson af Voice Junior sendes i efteråret 2016

  Vinder
  Andenplads
  Udstemt i Semifinalen
  Udstemt i  kvartfinalen
  Udstemt i SuperBattle

Statistik
Farvekoder:

Kvartfinalen (8. oktober)

Semifinalen (15. oktober)

Finalen (22. oktober)

Eksterne kilder og henvisninger

 Kluddermutter: Traileroptagelser var tæt på at gå galt for Oh Land tv2.dk 6. september 2016

Sæsoner af tv-serier
Tv-programmer fra TV 2 Danmark

Voice Junior (Sæson 4)


19162 Wambsganss este un asteroid din centura principală de asteroizi.

Descriere
19162 Wambsganss este un asteroid din centura principală de asteroizi. A fost descoperit pe  la Tautenburg de Lutz Dieter Schmadel și Freimut Börngen. Asteroidul prezintă o orbită caracterizată de o semiaxă mare de 2,72 ua, o excentricitate de 0,09 și o înclinație de 2,3° în raport cu ecliptica.

Vezi și
 Lista planetelor minore: 19001-20000
 Centura de asteroizi

Referințe

Obiecte astronomice descoperite în 1990
Centura de asteroizi

19162 Wambsganss


An Steinchisma stenophyllum in uska species han Liliopsida nga syahan ginhulagway ni Eduard Hackel, ngan ginhatag han pagkayana nga asya nga ngaran ni Fernando Omar Zuloaga och Osvaldo Morrone. An Steinchisma stenophyllum in nahilalakip ha genus nga Steinchisma, ngan familia nga Poaceae. Waray hini subspecies nga nakalista.

Mga kasarigan

Steinchisma

Steinchisma stenophyllum


Podsavezna nogometna liga Sisak (također i kao Liga Nogometnog podsaveza Sisak) je bila liga četvrtog stupnja nogometnog prvenstva Jugoslavije u sezoni 1962./63.
Sudjelovalo je 12 klubova, a prvak je bio "Radnik" iz Petrinje.

Ljestvica

 Kostajnica – tadašnji naziv za Hrvatsku Kostajnicu
 Novo Pračno – tada dio naselja Sisak, također nazivano i Pračno
 Odra – skraćeni naziv za naselje Odra Sisačka

Rezultatska križaljka

 Izvori:

Unutrašnje poveznice
 Zagrebačka zona 1962./63.

Vanjske poveznice

Izvori

 "Godišnjak FSJ 1962-63", Beograd, 1963., ISSN: 0351-2894, str. 255

1962-63 Sisak
1962-63 Sisak
Sisak

Podsavezna nogometna liga Sisak 1962./63.


جامعة سنغافورة الوطنية  هي أقدم وأكبر جامعة في سنغافورة. تنتمي إلى التحالف الدولي لبحوث الجامعات.

تاريخ
تأسست جامعة سنغافورة كمدرسة طب عام 1905 تحت اسم «كلية طب مستوطنات المضائق وحكومة ولايات ماليزيا الاتحادية»، وفي عام 1913 باسم مدرسة الملك إدوارد السابع للطب، وفي عام 1921 غُير اسمها إلى كلية الملك إدوارد السابع للطب. في عام 1928 أسس السير توماس ستامفورد رافلز «كلية رافلز» التي تم دمجها عام 1942 مع كلية الملك إدوارد السابع للطب إلى اتحاد مالايا (جامعة مالايا).

وفي سياق تزايد الاستقلال في سنغافورة تحول اسمها إلى (جامعة سنغافورة)، وفي عام 1980 تم دمجها إلى جامعة وطنية مع جامعة نانيانغ التي تأسست عام 1955 وأصبح اسمها (جامعة سنغافورة الوطنية).

جامعة سنغافورة الوطنية هي الآن واحدة من الجامعات الرئيسية في جنوب شرق آسيا. يوجد بها أكثر من 31.000 طالب في 13 كلية (إحصائيات عام 2005) كما تشمل أيضا معهد للموسيقى.

احتلت جامعة سنغافورة الوطنية وفقا لترتيب الجامعات التي أعدته صحيفة «الوقت العالي» في أكتوبر 2005 المركز الخامس والعشرون كأحسن جامعات العالم.

وفي عام 2017 حققت جامعة سنغافورة الوطنية مركز متقدم جدا حيث احتلت الترتيب الثاني عشر عالميا حسب تصنيف QS Ranking للجامعات العالميت وايضا احتلت الترتيب لافضل 10 اقسام مثلا هندسة الاكهرباء والاتصالات والهندسة الكيمائية.

وتعتبر جامعة سنغافورة الوجهة الاولي للطلاب في اسيا.

مراجع

وصلات خارجية
 موقع جامعة سنغافورة الوطنية (باللغة الإنجليزية)

جامعات وكليات أسست في 1980
التعليم في سنغافورة
تأسيسات سنة 1980 في سنغافورة
جامعات وطنية
هيئات تعليمية أسست في 1905
هيئات تعليمية أسست في 1980

جامعة سنغافورة الوطنية


Brabantse Pijl Dames Gooik (tidligere Pajot Hills Classic) er et endags elitelandevejsløb i Belgien for kvinder, der klassificeres som et 1.2 løb af UCI as a 1.2 race.

Vindere

Referencer

Cykelløb i Belgien
Cykelløb for kvinder
Etableret i 2016

Brabantse Pijl Dames Gooik


Colostrum, or first milk, is the first form of milk produced by the mammary glands of humans and other mammals immediately following delivery of the newborn. It may be called beestings when referring to the first milk of a cow or similar animal.  Most species will begin to generate colostrum just prior to giving birth. Colostrum has an especially high amount of bioactive compounds compared to mature milk to give the newborn the best possible start to life. Specifically, colostrum contains antibodies to protect the newborn against disease and infection, and immune and growth factors and other bioactives that help to activate a newborn's immune system, jumpstart gut function, and seed a healthy gut microbiome in the first few days of life. The bioactives found in colostrum are essential for a newborn's health, growth and vitality.  Colostrum strengthens a baby's immune system and is filled with white blood cells to protect it from infection.

At birth, the surroundings of the newborn mammal change from the relatively sterile environment in the mother's uterus, with a constant nutrient supply via the placenta, to the microbe-rich environment outside, with irregular oral intake of complex milk nutrients through the gastrointestinal tract. This transition puts high demands on the gastrointestinal tract of the neonate, as the gut plays an important part in both the digestive system and the immune system. Colostrum has evolved to care for highly sensitive mammalian neonates and contributes significantly to initial immunological defense as well as to the growth, development, and maturation of the neonate's gastrointestinal tract by providing key nutrients and bioactive factors. Bovine colostrum powder is rich in protein and low in sugar and fat. Bovine colostrum can also be used for a range of conditions in humans, and can boost a neonate's immunity.

Colostrum also has a mild laxative effect, encouraging the passing of a baby's first stool, which is called meconium.  This clears excess bilirubin, a waste-product of dead red blood cells which is produced in large quantities at birth due to blood volume reduction from the infant's body and which is responsible for jaundice.

Bioactive components in colostrum
Newborns have very immature and small  digestive systems, and colostrum delivers its bioactives in a very concentrated low-volume form.  Colostrum is known to contain immune cells (as lymphocytes) and many antibodies such as IgA,  IgG, and IgM.  These are some of the components of the adaptive immune system. Other immune components of colostrum include the major components of the innate immune system, such as lactoferrin, lysozyme, lactoperoxidase, complement, and proline-rich polypeptides (PRP). A number of cytokines (small messenger peptides that control the functioning of the immune system) are found in colostrum as well, including interleukins, tumor necrosis factor, chemokines, and others.

Colostrum also contains a number of growth factors, such as insulin-like growth factors I (IGF-1), and II, transforming growth factors alpha, beta 1 and beta 2, fibroblast growth factors, epidermal growth factor, granulocyte-macrophage-stimulating growth factor, platelet-derived growth factor, vascular endothelial growth factor, and colony-stimulating factor-1.

Human colostrum

Colustrum, which is produced for the first two to four days after childbirth, enhances immunity and is believed to have anti-inflammatory properties. It is suggested infants fed with human colostrum have lower incidence of gastrointestinal infections.

Human consumption of bovine colostrum
While it has long been understood that the colostrum a mother produces is vital to a newborn's health in the first few days of life, research has shown that bovine (cow) colostrum and its components can continue to support important biological activities when given to more mature children and adults, so that the benefits of colostrum can extend well beyond the neonatal period of development.

Bovine colostrum and human colostrum are highly similar in their makeup, both containing many of the same antibodies, immune and growth factors, and other nutrients. Because they share so many of the same components, the way they work in the body is also highly similar. The benefit of bovine colostrum for human health has been studied in many areas including:

 Immune health: Colostrum is composed of bioactives that support immune health, including immunoglobulins, immune modulators, and oligosaccharides. These bioactives have been shown to work together to support not only the immune system but also respiratory health in adults and children.
 Digestive health: Colostrum is composed of bioactives that support digestive health, including immunoglobulins, growth factors, and oligosaccharides. These bioactives work together to maintain and support intestinal integrity and improve nutrient absorption, while its naturally occurring prebiotics feed beneficial bacteria and support a balanced gut in adults and children
 Early life nutrition: While colostrum and breast milk are a critical part of newborn nutrition, research has shown that colostrum has continued benefits in children over the age of one. As a component in early life nutrition, colostrum can help to support children's immune systems, soothe digestive upsets, and otherwise support children's digestive health.
 Sports nutrition: Bovine colostrum contains several bioactives that help support sports nutrition, including immunoglobulins and growth factors. These bioactives combine to help maintain a healthy immune system during the stress during athletic training, while supporting cellular proliferation and restitution as well as protein synthesis and soft tissue repair.
There is also research suggesting that a large proportion of colostrum is not fit for human consumption "due to tremendous bacterial loads". Salmonella was also detected in 15% of unpasteurised samples. Pasteurisation reduces the bioactive proteins many of the benefits rely upon, however.

Colostrum use in animal husbandry
Colostrum is crucial for newborn farm animals.  They receive no passive transfer of immunity via the placenta before birth, so any antibodies that they need have to be ingested (unless supplied by injection or other artificial means). The ingested antibodies are absorbed from the intestine of the neonate. The newborn animal must receive colostrum within 6 hours of being born for maximal absorption of colostral antibodies to occur. Recent studies indicate that colostrum should be fed to bovines within the first thirty minutes to maximize IgG absorption rates.

The role of colostrum for newborn animals is to provide nutrition, and essential protection against infection while the immune and digestive systems are developing and maturing. Bovine colostrum provides macro- and micro-nutrients, as well as growth factors, cytokines, nucleosides, oligosaccharides, natural antimicrobials, antioxidants; and a range of immunoglobulins such as IgG, IgA, IgD, IgM and IgE. It is well established that minimal levels of IgG are essential to prevent failure of passive transfer. The iron-binding glycoproteins lactoferrin and transferrin in bovine colostrum assist in attacking pathogens by impacting their cell membrane and making them more susceptible to the immune systems attack by neutrophils. Cytokines present in bovine colostrum enhance B and T cell maturation and increase endogenous antibody production. They also play a major role in regulation of epithelial cell growth and development, proliferation, and restitution. Transfer factors enhance the activity of T cells. Other growth and immune factors such as IGF-1, IGF-2, FGF, EGF, TGF, PDGF, etc.

Bovine colostrum's components benefit the immune and digestive health of animals of all ages and species. Bovine colostrum's vast array of bioactive components collectively increase resistance to infection and disease caused by a wide range of pathogens including bacteria and viruses. The quality of the colostrum is essential in providing the essential benefits. Both contaminated early bovine colostrum at the farm level or late transition milk or milk are poor sources of the important colostral components necessary to maintain life and achieve and maintain healthy animal maturation and homoeostasis. Bovine colostrum also is beneficial in repairing or healing intestinal damage as well as increasing the absorption of nutrients from the GI tract. These properties and benefits are consistent among human and animal species.

The transition from fetal to neonatal and shift from maternal to environmental reliance requires an abrupt immunological change. In calves, for example, colostrum provides a significant benefit in neonatal intestine development. This includes villus area, circumference, height and height/crypt ratio. Colostrum is critically important to calves and foals in order to prevent failure of passive transfer and death. Calves, foals and piglets with low IgG levels have an increased risk of morbidity and mortality. Bovine colostrum can be used to reduce the duration and severity of infections so it can be a useful tool to include in the reduction of antibiotic use. Finally, another important and valuable benefit of colostrum is in the reduction in scours and increase in average daily weight gain all of which have a significant farmer and ultimately consumer benefit.

Colostrum use in companion animals

Much like in humans and production animals, companion animal survival in the newborn stage of life is largely dependent upon colostrum. Companion animal immune systems require several weeks to several months in order to fully develop. Maternal antibodies provide benefit for a relatively short period of time so a gap exists with immune sufficiency where an animal is at risk of infection. Like humans, companion animal immune response changes with age where early life and later in life have similarities. That is, an immune bias whereby the animal has less of an ability to fend off infections and greater prevalence of allergy at both ends of the age spectrum. Stress also affects a companion animal's immune system including changes in environment, diet, etc. Maintaining gut microbial balance is key to maintaining a healthy immune system as well as mucosal integrity, similar to humans. Bovine colostrum has been demonstrated to benefit companion animal immunity and digestive health.

Bovine colostrum plays a role in increasing Ig levels, increasing lymphocyte proliferation stimulating activity and increasing phagocytosis activity. These are supported by other components of colostrum which further enhance the activity of the immune response. The iron binding glycoproteins lactoferrin and transferrin in bovine colostrum assist in attacking pathogens by impacting their cell membrane and making them more susceptible to the immune systems attack by neutrophils. Cytokines present in bovine colostrum enhance B and T cell maturation and increase endogenous antibody production. They also play a major role in regulation of epithelial cell growth and development, proliferation, restitution. Transfer factors enhance the activity of T cells. Other growth and immune factors such as IGF-1, IGF-2, FGF, EGF, TGF, PDGF, etc. Colostrum contains glycomacropeptides which help to regulate appetite.

Bovine colostrum has been shown to enhance immune response in animal models including canine, feline and equine animals including maintaining a higher level of vaccine antibody response over time and for a longer period than the vaccine alone. Animals fed colostrum had a significantly higher local immune status resulting in higher IgA through GALT stimulation. Colostrum also plays a key role in reduction or prevention of diarrhea and reduction in respiratory illness.

Bovine colostrum history of study and potential future applications

Dairy cattle are naturally exposed to pathogens and produce immunoglobulins against them. These antibodies are present in the cow's bloodstream and in the colostrum. These immunoglobulins are specific to many human pathogens, including Escherichia coli, Cryptosporidium parvum, Shigella flexneri, Salmonella species, Staphylococcus species, and rotavirus (which causes diarrhea in infants). Before the development of antibiotics, colostrum was the main source of immunoglobulins used to fight bacteria. In fact, when Albert Sabin made his first oral vaccine against polio, the immunoglobulin he used came from bovine colostrum. When antibiotics began to appear, interest in colostrum waned, but, now that antibiotic-resistant strains of pathogens have developed, interest is once again returning to natural alternatives to antibiotics, namely, colostrum.

Although bovine colostrum has been consumed by humans for centuries,  only in recent decades have we seen an increase in randomized clinical trials to support assertions of health benefits. It is probable that little absorption of intact growth factors and antibodies into the bloodstream occurs, due to digestion in the gastrointestinal tract. However, the presence of casein and other buffering proteins does allow growth factors and other bioactive molecules to pass into the lumen of the small intestine intact, where they can stimulate repair and inhibit microbes, working via local effects. This provides a probable mechanism explaining reductions in gut permeability after colostrum administration in some published studies, while another study found colostrum promising as treatment for distal colitis. Evidence for the beneficial effect of colostrum on extra-gastrointestinal problems is less well developed, due in part to the limited number of randomised double-blind studies published, although a variety of possible uses have been suggested.

The gut plays several important roles including acting as the main pathway for fluid, electrolyte and nutrient absorption while also acting as a barrier to toxic agents present in the gut lumen including acid, digestive enzymes and gut bacteria. It is also a major immunological defence mechanism, detecting natural commensals and triggering immune response when toxic microbes are present. Failure of homeostasis due to trauma, drugs and infectious microbes not only damages the gut but can lead to influx of damaging agents into the bloodstream. These mechanisms have relevance for multiple conditions affecting all areas of the world and socioeconomic groups such as ulcers, inflammation, and infectious diarrhea. There is currently much interest in the potential value of colostrum for the prevention and treatment of these conditions as it is derived from natural sources and can influence damaging factors through multiple pathways including nutritional support, immunological intervention (through its immunoglobulin and other anti-microbial factors) and growth/healing factor constituents. As pointed out by Kelly, inconsistency between results in some published studies may be due in part to variation in dose given and to the timing of the colostrum collection being tested (first milking versus pooled colostrum collected up to day 5 following calving).

Some athletes have used colostrum in an attempt to improve their performance, decrease recovery time, and prevent sickness during peak performance levels. Supplementation with bovine colostrum, 20 grams per day (g/d), in combination with exercise training for eight weeks may increase bone-free lean body mass in active men and women.

Low IGF-1 levels may be associated with dementia in the very elderly, although causation has not been established. Malnutrition can cause low levels of IGF-1, as can obesity. Supplementation with colostrum, which is rich in IGF-1, can be a useful part of a weight reduction program. Although IGF-1 is not absorbed intact by the body, some studies suggest it stimulates the production of IGF-1 when taken as a supplement whereas others do not.

Colostrum also has antioxidant components, such as lactoferrin and hemopexin, which binds free heme in the body.

The Isle of Man had a local delicacy called "Groosniuys", a pudding made with colostrum.
In Finland, a baked cheese called Leipäjuusto is traditionally made with either cow colostrum or reindeer milk.

A sweet cheese-like delicacy called 'Junnu' or 'Ginna' is made with colostrum in the south Indian states of Karnataka, Andhra Pradesh and Telangana. It is made with both cow and buffalo milk; in both cases it is the milk produced on the second day after giving birth which is considered best for making this pudding-like delicacy. Colostrum is in very high demand in these states, resulting in product adulteration.

Hyperimmune colostrum
Hyperimmune colostrum is natural bovine colostrum collected from a population of cows immunized repeatedly with a specific pathogen. The colostrum is collected within 24 hours of the cow giving birth. Antibodies towards the specific pathogens or antigens that were used in the immunization are present in higher levels than in the population before treatment.  Although some papers have been published  stating that specific human pathogens were just as high as in hyperimmune colostrum, and natural colostrum nearly always had higher antibody titers than did the hyperimmune version. Clinical trials have shown that if the immunization is by surface antigens of the bacteria, the Bovine Colostrum Powder  can be used to make tablets capable of binding to the bacteria so that they are excreted in stools. This prevents the successful colonization of the gut, which would otherwise lead to bacteria releasing enterotoxigenic materials.

Proline-rich polypeptides
These small immune signaling peptides (PRPs) were independently discovered in colostrum and other sources, such as blood plasma, in the United States, Czechoslovakia and Poland. Hence they appear under various names in the literature, including Colostrinin, CLN, transfer factor and PRP. They function as signal transducing molecules that have the unique effect of modulating the immune system, turning it up when the body comes under attack from pathogens or other disease agents, and damping it when the danger is eliminated or neutralized. At first thought to actually transfer immunity from one immune system to another, it now appears that PRPs simply stimulate cell-mediated immunity.

References

External links
 Maryland Cooperative Extension

Usage of Bovine Colostrum

Animal products
Biotechnology
Breastfeeding
Breast milk
Milk
Dietary supplements

Colostrum


In mathematics, the Iwahori–Hecke algebra, or Hecke algebra,  named for Erich Hecke and Nagayoshi Iwahori, is a deformation of the group algebra of a Coxeter group.

Hecke algebras are quotients of the group rings of Artin braid groups. This connection found a spectacular application in Vaughan Jones' construction of new invariants of knots. Representations of Hecke algebras led to discovery of quantum groups by Michio Jimbo. Michael Freedman proposed Hecke algebras as a foundation for topological quantum computation.

Hecke algebras of Coxeter groups
Start with the following data:

 (W, S) is a Coxeter system with the Coxeter matrix M = (mst),
 R is a commutative ring with identity.
 {qs | s ∈ S} is a family of units of R such that qs = qt whenever s and t are conjugate in W
 A is the ring of Laurent polynomials over Z with indeterminates qs (and the above restriction that qs = qt whenever s and t are conjugated), that is A = Z [q]

Multiparameter Hecke Algebras
The multiparameter Hecke algebra HR(W,S,q) is a unital, associative R-algebra with generators Ts for all s ∈ S and relations:
 Braid Relations: Ts Tt Ts ... = Tt Ts Tt ..., where each side has mst < ∞ factors and s,t belong to S.
 Quadratic Relation: For all s in S we have: (Ts - qs)(Ts + 1) = 0.

Warning: in later books and papers, Lusztig used a modified form of the quadratic relation that reads  After extending the scalars to include the half integer powers q the resulting Hecke algebra is isomorphic to the previously defined one (but the Ts here corresponds to q Ts in our notation). While this does not change the general theory, many formulae look different.

Generic Multiparameter Hecke Algebras
HA(W,S,q) is the generic multiparameter Hecke algebra. This algebra is universal in the sense that every other multiparameter Hecke algebra can be obtained from it via the (unique) ring homomorphism A → R which maps the indeterminate qs ∈ A to the unit qs ∈ R. This homomorphism turns R into a A-algebra and the scalar extension HA(W,S) ⊗A R is canonically isomorphic to the Hecke algebra HR(W,S,q) as constructed above. One calls this process specialization of the generic algebra.

One-parameter Hecke Algebras
If one specializes every indeterminate qs to a single indeterminate q over the integers (or q to q½ respectively), then one obtains the so-called generic one-parameter Hecke algebra of (W,S).

Since in Coxeter groups with single laced Dynkin diagrams (for example groups of type A and D) every pair of Coxeter generators is conjugated, the above-mentioned restriction of qs being equal qt whenever s and t are conjugated in W forces the multiparameter and the one-parameter Hecke algebras to be equal. Therefore, it is also very common to only look at one-parameter Hecke algebras.

Coxeter groups with weights
If an integral weight function is defined on W (i.e. a map L:W → Z with L(vw)=L(v)+L(w) for all v,w ∈ W with l(vw)=l(v)+l(w)), then a common specialization to look at is the one induced by the homomorphism qs ↦ qL(s), where q is a single indeterminate over Z.

If one uses the convention with half-integer powers, then weight function L:W → ½Z may be permitted as well. For technical reasons it is also often convenient only to consider positive weight functions.

Properties
1. The Hecke algebra has a basis  over A indexed by the elements of the Coxeter group W. In particular, H is a free A-module. If  is a reduced decomposition of w ∈ W, then . This basis of Hecke algebra is sometimes called the natural basis. The neutral element of W corresponds to the identity of H: Te = 1.

2. The elements of the natural basis are multiplicative, namely, Tyw=Ty Tw whenever l(yw)=l(y)+l(w), where l denotes the length function on the Coxeter group W.

3. Elements of the natural basis are invertible. For example, from the quadratic relation we conclude that T = q Ts + (q-1).

4. Suppose that W is a finite group and the ground ring is the field C of complex numbers. Jacques Tits has proved that if the indeterminate q is specialized to any complex number outside of an explicitly given list (consisting of roots of unity), then the resulting one parameter Hecke algebra is semisimple and isomorphic to the complex group algebra C[W] (which also corresponds to the specialization q ↦ 1) .

5. More generally, if W is a finite group and the ground ring R is a field of characteristic zero, then the one parameter Hecke algebra is a semisimple associative algebra over R[q±1]. Moreover, extending earlier results of Benson and Curtis, George Lusztig provided an explicit isomorphism between the Hecke algebra and the group algebra after the extension of scalars to the quotient field of R[q±½]

Canonical basis

A great discovery of Kazhdan and Lusztig was that a Hecke algebra admits a different basis, which in a way controls representation theory of a variety of related objects.

The generic multiparameter Hecke algebra, HA(W,S,q), has an involution bar that maps q½ to q−½ and acts as identity on Z. Then H admits a unique ring automorphism i that is semilinear with respect to the bar involution of A and maps Ts to T. It can further be proved that this automorphism is involutive (has order two) and takes any Tw to

 Kazhdan - Lusztig Theorem: For each w ∈ W there exists a unique element  which is invariant under the involution i and if one writes its expansion in terms of the natural basis:

one has the following:
 Pw,w=1,
 Py,w in Z[q] has degree less than or equal to ½(l(w)-l(y)-1) if y<w in the Bruhat order,
 Py,w=0 if

The elements  where w varies over W form a basis of the algebra H, which is called the dual canonical basis of the Hecke algebra H. The canonical basis {Cw | w ∈ W} is obtained in a similar way. The polynomials Py,w(q) making appearance in this theorem are the Kazhdan–Lusztig polynomials.

The Kazhdan–Lusztig notions of left, right and two-sided cells in Coxeter groups are defined through the behavior of the canonical basis under the action of H.

Hecke algebra of a locally compact group

Iwahori–Hecke algebras first appeared as an important special case of a very general construction in group theory. Let (G,K) be a pair consisting of a unimodular locally compact topological group G and a closed subgroup K of G. Then the space of K-biinvariant continuous functions of compact support, Cc(K\G/K), can be endowed with a structure of an associative algebra under the operation of convolution. This algebra is denoted by H(G//K) and called the Hecke ring of the pair (G,K).

Example: If G = SL(n,Qp) and K = SL(n,Zp) then the Hecke ring is commutative and its representations were studied by Ian G. Macdonald. More generally if (G,K) is a Gelfand pair then the resulting algebra turns out to be commutative.

Example: If G = SL(2,Q) and K = SL(2,Z) we get the abstract ring behind Hecke operators in the theory of modular forms, which gave the name to Hecke algebras in general.

The case leading to the Hecke algebra of a finite Weyl group is when G is the finite Chevalley group over a finite field with pk elements, and B is its Borel subgroup. Iwahori showed that the Hecke ring H(G//B) is obtained from the generic Hecke algebra Hq of the Weyl group W of G by specializing the indeterminate q of the latter algebra to pk, the cardinality of the finite field. George Lusztig remarked in 1984 (Characters of reductive groups over a finite field, xi, footnote):

I think it would be most appropriate to call it the Iwahori algebra, but the name Hecke ring (or algebra) given by Iwahori himself has been in use for almost 20 years and it is probably too late to change it now.

Iwahori and Matsumoto (1965) considered the case when G is a group of points of a reductive algebraic group over a non-archimedean local field K, such as Qp, and K is what is now called an Iwahori subgroup of G. The resulting Hecke ring is isomorphic to the Hecke algebra of the affine Weyl group of G, or the affine Hecke algebra, where the indeterminate q has been specialized to the cardinality of the residue field of K.

Work of Roger Howe in the 1970s and his papers with Allen Moy on representations of p-adic GL(n) opened a possibility of classifying irreducible admissible representations of reductive groups over local fields in terms of appropriately constructed Hecke algebras. (Important contributions were also made by Joseph Bernstein and Andrey Zelevinsky.) These ideas were taken much further in Colin Bushnell and Philip Kutzko's theory of types, allowing them to complete the classification in the general linear case. Many of the techniques can be extended to other reductive groups, which remains an area of active research. It has been conjectured that all Hecke algebras that are ever needed are mild generalizations of affine Hecke algebras.

Representations of Hecke algebras
It follows from Iwahori's work that complex representations of Hecke algebras of finite type are intimately related with the structure of the spherical principal series representations of finite Chevalley groups.

George Lusztig pushed this connection much further and was able to describe most of the characters of finite groups of Lie type in terms of representation theory of Hecke algebras. This work used a mixture of geometric techniques and various reductions, led to introduction of various objects generalizing Hecke algebras and detailed understanding of their representations (for q not a root of unity). Modular representations of Hecke algebras and representations at roots of unity turned out to be related with the theory of canonical bases in affine quantum groups and combinatorics.

Representation theory of affine Hecke algebras was developed by Lusztig with a view towards applying it to description of representations of p-adic groups. It is different in many ways from the finite case. A generalization of affine Hecke algebras, called double affine Hecke algebra, was used by Ivan Cherednik in his proof of the Macdonald's constant term conjecture.

See also
 Abstract algebra

References
David Goldschmidt Group Characters, Symmetric Functions, and the Hecke Algebra ,
Iwahori, Nagayoshi; Matsumoto, Hideya On some Bruhat decomposition and the structure of the Hecke rings of p-adic Chevalley groups. Publications Mathématiques de l'IHÉS, 25 (1965), pp. 5–48.
 Alexander Kleshchev, Linear and projective representations of symmetric groups, Cambridge tracts in mathematics, vol. 163. Cambridge University Press, 2005. ,
 George Lusztig, Hecke algebras with unequal parameters, CRM monograph series, vol.18, American Mathematical Society, 2003. ,
 Andrew Mathas, Iwahori-Hecke algebras and Schur algebras of the symmetric group, University Lecture Series, vol.15, American Mathematical Society, 1999. ,
 Lusztig, George, On a theorem of Benson and Curtis, J. Algebra 71 (1981), no. 2, 490–498. ,
 Colin Bushnell and Philip Kutzko, The admissible dual of GL(n) via compact open subgroups, Annals of Mathematics Studies, vol. 129, Princeton University Press, 1993. ,

Algebras
Representation theory

Iwahori–Hecke algebra


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