Countries with active<unk>  virus transmission as of September 2016. In April 1947, as part of studies sponsored by the Rockefeller Foundation into yellow fever, 6 caged rhesus monkeys were placed in the canopy of the<unk>  Forest of Uganda. On April 18 one of the monkeys (no. 776) developed a fever and blood samples revealed the first known case of<unk> . Population surveys at the time in Uganda found 6.1% of individuals to be seropositive for<unk> . The first human cases were reported in Nigeria in 1954. A few outbreaks have been reported in tropical Africa and in some areas in Southeast Asia. Until recently there were no documented cases of<unk>  virus in the Indian subcontinent, however, the first cases were reported in 2017 from Gujarat state and Tamil Nadu, more cases were reported in Rajasthan state involving an outbreak of 153 reported cases and in a pregnant women living in Kerala state. A 1954 study assessing blood samples from several people from different states found antibodies to<unk>  in healthy people in India which could indicate past exposure, though it could also be due to cross-reaction with other flaviviruses. By using phylogenetic analysis of Asian strains, it was estimated that<unk>  virus had moved to Southeast Asia by 1945. In 1977–1978,<unk>  virus infection was described as a cause of fever in Indonesia. Before 2007, there were only 13 reported natural infections with<unk>  virus, all with a mild, self-limited febrile illness. As of July 2019, evidence of local transmission from mosquitoes to humans has been reported in a total of 87 countries from four of six WHO Regions; African, Americas, South-East Asia and Western Pacific. Yap Islands The first major outbreak, with 185 confirmed cases, was reported in 2007 in the Yap Islands of the Federated States of Micronesia. A total of 108 cases were confirmed by PCR or serology and 72 additional cases were suspected. The most common symptoms were rash, fever, arthralgia, and conjunctivitis, and no deaths were reported. The mosquito Aedes hensilli, which was the predominant species identified in Yap during the outbreak, was probably the main vector of transmission. While the way of introduction of the virus on Yap Island remains uncertain, it is likely to have happened through introduction of infected mosquitoes or a human infected with a strain related to those in Southeast Asia. This was also the first time<unk>  had been reported outside Africa and Asia. Before the Yap Island outbreak, only 14 human cases had ever been reported. Oceania In 2013–2014, several outbreaks of<unk>  were reported in French Polynesia, New Caledonia, Easter Island and the Cook Islands. The source of the virus was thought to be an independent introduction of the virus from Southeast Asia, unrelated to the Yap Islands outbreak. Americas Areas of active<unk>  virus transmission, April 2016 Genetic analyses of<unk>  virus strains suggest that<unk>  first entered the Americas between May and December 2013. It was first detected in the Western Hemisphere in February 2014, and rapidly spread throughout South and Central America, reaching Mexico in November 2015. In 2016 it established local transmission in Florida and Texas. The first death in the United States due to<unk>  occurred in February 2016. In May 2015, Brazil officially reported its first 16 cases of the illness. Although, a case of illness was reported in March 2015 in a returning traveller. According to the Brazilian Health Ministry, as of November 2015 there was no official count of the number of people infected with the virus in Brazil, since the disease is not subject to compulsory notification. Even so, cases were reported in 14 states of the country. Mosquito-borne<unk>  virus is suspected to be the cause of 2,400 possible cases of microcephaly and 29 infant deaths in Brazil in 2015 (of the 2400 or so notified cases in 2015, 2165 were under investigation in December 2015, 134 were confirmed and 102 were ruled out for microcephaly). The Brazilian Health Ministry has reported at least 2,400 suspected cases of microcephaly in the country in 2015 as of 12 December, and 29 fatalities. Before the<unk>  outbreak, only an average of 150 to 200 cases per year were reported in Brazil. In the state of Pernambuco the reported rates of microcephaly in 2015 are 77 times higher than in the previous 5 years. A model using data from a<unk>  outbreak in French Polynesia estimated the risk of microcephaly in children born to mothers who acquired<unk>  virus in the first trimester to be 1%. On 24 January 2016, the WHO warned that the virus is likely to spread to nearly all countries of the Americas, since its vector, the mosquito Aedes aegypti, is found in all countries in the region, except for Canada and continental Chile. The mosquito and dengue fever have been detected in Chile's Easter Island, some away from its closest point in mainland Chile, since 2002. In February 2016, WHO declared the outbreak a Public Health Emergency of International Concern as evidence grew that<unk>  is a cause of birth defects and neurological problems. In April 2016, WHO stated there is a scientific consensus, based on preliminary evidence, that<unk>  is a cause of microcephaly in infants and Guillain–Barré syndrome in adults. Studies of this and prior outbreaks have found<unk>  infection during pregnancy to be associated with early pregnancy loss and other pregnancy problems. In the Americas the number of cases peaked during the first half of 2016 and declined through 2017–2018, with a total of 31,587 suspected, probable, and confirmed cases of ZIKV disease were reported in the Region of the Americas. Of these, 3,473 (11%) were laboratory confirmed. In general, transmission persists at low levels in some areas and is not uniformly distributed within countries. Asia In 2016 imported or locally transmitted<unk>  was reported in all the countries of Asia except Brunei, Hong Kong, Myanmar and Nepal. Serological surveys have indicated that<unk>  virus is endemic in most areas of Asia, though at a low level. While there was a sharp rise in the number of cases of<unk>  detected in Singapore after the 2016 Summer Olympics in Brazil, genetic analysis revealed that the strains were more closely related to strains from Thailand than from those causing the epidemic in the Americas.
Zika fever
Chikungunya
Leptospirosis
Yellow fever
Dengue fever
Blackwater fever
Malaria
Trench fever