
 
 The Aedes aegypti mosquito carries the Zika virus, which has been linked to suspected brain damage in thousands of Brazilian newborns. (AFP/Getty Images) 
 
 This post has been updated. 
 
 U.S. and Brazilian health officials are investigating whether there may be an association between the mosquito-borne Zika virus that is spreading in the South American country and an increase in cases of a rare syndrome that causes paralysis. 
 
 The Centers for Disease Control and Prevention has sent a four-member team to Brazil to help the health ministry in its investigation of the growing number of cases of Guillain-Barré syndrome and a potential connection to the Zika outbreak there. 
 
 Spokeswoman Christine Pearson said Thursday that the CDC team, dispatched at Brazil’s request, has been on the ground for less than a week. It includes a neuroepidemiologist and a medical epidemiologist. 
 
 [Zika's alarming spread: More than a million infected with virus globally] 
 
 Guillain-Barré syndrome occurs when individuals’ own immune system damages their nerve cells, causing muscle weakness and sometimes paralysis. Symptoms usually last for a few weeks. Most people recover fully from it, but some have long-term nerve damage. In rare cases, people have died, usually from difficulty breathing. 
 
 Brazilian officials have identified hundreds of cases of Guillain-Barré syndrome. A number of states have reported significant increases. Rio Grande do Norte state had reported 33 by August, compared to 23 in the whole of 2014, TV Globo said last month. 
 
 Brazil’s Ministry of Health said in December that it was investigating whether the syndrome could be caused by Zika. The ministry said the symptoms being seen start in the legs, before radiating through the trunk, arms and face. The condition is most dangerous when it involves respiratory muscles. “In this case, the syndrome can cause death if respiratory support measures are not adopted,” the ministry said. 
 
 ["I could move my fingers but within days I'd probably be totally paralyzed"] 
 
 Earlier this week, the Pan American Health Organization and World Health Organization announced an “increase of congenital anomalies, Guillain-Barré syndrome, and other neurological and autoimmune syndromes in areas where Zika virus is circulating.” PAHO warned member states to step up detection, prepare for a possible increase in neurological cases and reduce mosquito transmission. 
 
 Zika is carried by mosquitoes and typically causes only mild symptoms, but health officials globally have recently been alarmed because of a possible link between the virus and nearly 3,900 children born with suspected microcephaly in Brazil since October. The rare condition, marked by an abnormally small head, is associated with incomplete brain development. 
 
 (This video was updated on Feb. 2, 2016.) Authorities have confirmed more than 30 cases of Zika virus in the United States. Here's what you need to know. (Gillian Brockell/The Washington Post) 
 
 Last week, CDC issued an advisory warning pregnant women against travel to Brazil or more than a dozen other countries and territories in South America, Central America and the Caribbean where local transmission of the virus has been confirmed. 
 
 The agency then followed up with guidelines for doctors who care for pregnant women, advising that they be tested for Zika infection if they show symptoms after visiting any of those areas. The guidelines note: “Guillain-Barré syndrome has been reported in patients following suspected Zika virus infection.” 
 
 [How climate change could help the spread of Zika virus and other infectious diseases] 
 
 In recent days, several countries have taken drastic measures to try to combat the Zika virus, with Brazil, Colombia, El Salvador and Jamaica all calling on women to consider delaying becoming pregnant. 
 
 In the United States, Florida, Illinois, New Jersey, Texas and Hawaii have confirmed Zika infections involving returning travelers who were likely bitten by mosquitoes while abroad. The CDC said there have been at least “a dozen or so” cases. 
 
 Ariana Eunjung Cha and Dom Phillips in Rio de Janeiro contributed to this report. 
 
 Read more: 
 
 CDC: 'Dozens or so' cases of Zika virus among U.S. residents 
 
 Brazilians panic as mosquito-borne virus is linked to brain damage in thousands of babies ||||| Fears over the Zika virus have intensified after El Salvador warned women not to get pregnant for the next two years, as the mosquito-borne virus could cause birth defects among newborns. 
 
 The virus is thought to cause severe brain damage in new-born babies and may also be behind rising instances of a separate potentially fatal illness that can leave patients paralysed, doctors say. 
 
 It is already suspected of being responsible for a dramatic increase in cases of microcephaly, where babies are born with abnormally small heads, in Latin America. 
 
 Zika Virus is associated with a 20x increase of Guillain-Barré in Brazil. @nytimes https://t.co/cQJCQLuR3e 
 
 Nearly 4,000 cases have been recorded in Brazil since October , a trend specialists are attributing to Zika, although they concede the link is not 100 per cent certain. 
 
 Now doctors in the country believe the virus - which was previously virtually unknown on the American continent - may also be causing a sudden surge in a potentially fatal condition known as Guillain-Barre. 
 
 Brazil now fears #Zika may be causing rise in Guillain-Barré (also observed after 2013 outbreak in French Polynesia) https://t.co/CGS6ILaWtz — Jennifer Yang (@jyangstar) January 21, 2016 
 
 North-eastern Brazil, the area hardest hit by the Zika virus, recorded 554 cases of Guillain-Barre last year, leading doctors to suspect a link, although that too is still unproven. 
 
 Guillain-Barre syndrome, also known as Landry's Paralysis, is defined as a rapid onset of muscle weakness caused by damage to the peripheral nervous system. 
 
 It can be life-threatening in its acute phase and leaves sufferers unable to move and dependent on life support. 
 
 @CMichaelGibson That"s correct! Three patients with Guillain Barre syndrome have appeared in Venezuela where the Zika cases are high. — Monica Cedeno (@CedenoMonica) January 21, 2016 
 
 The United States Centres for Disease Control and Prevention (CDC) is helping authrorities in Brazil to conduct studies aimed at establishing if Guillain-Barre is connected to Zika, the New York Times reported. 
 
 The CDC last week advised pregnant women against travelling to 13 Latin American countries, as well as Puerto Rico, where Zika has become prevalent. 
 
 More than half-a-dozen Zika cases have been reported in the US, most recently a woman in Texas who had returned from a trip to El Salvador 
 
 America's first case of a baby born with an unusually small head and brain was recorded last week in Hawaii. The mother had visited Brazil while pregnant. Although the CDC says the link between Zika and microcephaly is not definite, no other explanation has been offered. 
 
 First discovered in Uganda's Zika forest in 1947, the virus is said to be related to dengue, yellow fever and the West Nile virus. While common in Africa and Asia, it only started spreading in the Western hemisphere last May following an outbreak in Brazil. 
 
 Increased foreign travel and rising temperatures caused by global warming are two common theories given to explain its sudden spread. 
 
 There is no separate test for the infection and symptoms can be relatively mild, with only 20 per cent of sufferers reporting signs such as rashes, fever, joint pain and red eyes. 
 
 It is thought to be most commonly spread by mosquitoes, which breed in or near stagnant water pools.
– There's more bad news regarding the Zika virus wreaking havoc in South America and the Caribbean: The mosquito-borne virus—which can cause birth defects and has been linked to 46 infant deaths—may also cause Guillain-Barré syndrome, a potentially life-threatening condition that can cause weeks-long paralysis, reports the New York Times. The syndrome attacks a patient's immune system, and though there is no proof of a link, Guillain-Barré was thought to be rare in Brazil until last year when 554 cases were reported in areas worst hit by the Zika virus, per the Telegraph. Colombia, Venezuela, and El Salvador—where women have been warned not to get pregnant—have also seen an increase in Guillain-Barré cases as the Zika virus spreads. Many patients had symptoms of Zika one to two weeks before experiencing paralysis. "I estimate that Zika increases by about 20 times the probability that an individual can get Guillain-Barré," says a doctor who's treated the "nightmare" condition, which strikes about 1 in 100,000. "It felt like I was drowning in a sea of mud," says one patient. "I became motionless and thought I would die. All of this happened just a few days after I had Zika." Another patient had to be put on a ventilator for 40 days once the paralysis reached her breathing muscles. Most people recover from the condition, though some suffer long-term nerve damage, per the Washington Post. The condition, which has previously been associated with mosquito-borne diseases like dengue fever and the West Nile virus, can also lead to heart attacks and comas. The CDC is now researching whether Zika and Guillain-Barré are indeed linked. (A baby born in Hawaii has brain damage linked to Zika.)