"Approximately 1.67 million undescribed viruses are thought to exist in mammals and birds, up to half of which are estimated to have the potential to spill over into humans," says a study led by researchers at the University of California, Davis. According to a report from the United Nations Environment Programme and International Livestock Research Institute large part of the causes are environmental like climate change, unsustainable agriculture, exploitation of wildlife, land use change. Others are linked to changes in human society like more mobility. The organizations propose a set of measures to stop the rise. Contamination of food or water supply The most significant zoonotic pathogens causing foodborne diseases are Escherichia coli O157:H7, Campylobacter, Caliciviridae, and Salmonella. In 2006 a conference held in Berlin focused on the issue of zoonotic pathogen effects on food safety, urging government intervention and public vigilance against the risks of catching food-borne diseases from farm-to-table dining. Many food-borne outbreaks can be linked to zoonotic pathogens. Many different types of food that have an animal origin can become contaminated. Some common food items linked to zoonotic contaminations include eggs, seafood, meat, dairy, and even some vegetables. Outbreaks involving contaminated food should be handled in preparedness plans to prevent widespread outbreaks and to efficiently and effectively contain outbreaks. Farming, ranching and animal husbandry Contact with farm animals can lead to disease in farmers or others that come into contact with infected farm animals. Glanders primarily affects those who work closely with horses and donkeys. Close contact with cattle can lead to cutaneous anthrax infection, whereas inhalation anthrax infection is more common for workers in slaughterhouses, tanneries and wool mills. Close contact with sheep who have recently given birth can lead to infection with the bacterium Chlamydia psittaci, causing chlamydiosis (and enzootic abortion in pregnant women), as well as increase the risk of Q fever, toxoplasmosis, and listeriosis, in the pregnant or otherwise immunocompromised. Echinococcosis is caused by a tapeworm, which can spread from infected sheep by food or water contaminated by feces or wool. Bird flu is common in chickens and, while rare in humans, the main public health worry is that a strain of bird flu will recombine with a human flu virus and cause a pandemic like the 1918 Spanish flu. In 2017, free-range chickens in the UK were temporarily ordered to remain inside due to the threat of bird flu. Cattle are an