zika virus epidemic

The first major epidemic outside Africa occurred in Yap Island of the Federated States of Micronesia in 2007.
Another major epidemic occurred in the western Pacific islands of French Polynesia and New Caledonia in 2013-2014.

Countries and territories Population countries (Number) Sporadic cases/epidemics Seroprevalence survey Comments
Number of cases(n) Year Percentage Year
Australia 21,527,000 1 2013 Imported cases (ex–Thailand)
Cambodia 14,701,717 1 2010 Sporadic human cases
Ivory Coast 23,202,000 1 1999 Sporadic human cases Isolation in mosquitoes
Indonesia 244,968,342 1 2013 Exported cases in Australia in 2013
17 1977-1978 1977-1978 Serologic study
  13% 1963 Serologic study
Malaysia 28,250,000 1 1969 Serologic study Isolation in mosquitoes
Micronesia, Yap 7391 185 including 108 confirmed and probable 2007 73% (in population) 2007 Epidemic Study seroprevalence in population
Nigeria 170,123,740 2 1975 31% 1968 Study serologic Isolation in mosquitoes sporadic human cases
New-Caledonia 254,000 114 2014 Autochthonous cases (Dumbea)
32 2013–2014     Imported cases (e.g. FP)
Uganda 34,131,400 6.1% 1952 Serologic study
French Polynesia(FP) 268,270 8510 clinical cases 29,000 estimated cases (preliminary figures) 2013–2014 Epidemic

ZIKV was reported in mosquitoes, primates, and humans in 14 countries over three continents (Africa, Asia, Oceania).

The virus had been the object of few published studies because of the frequency of pauci/asymptomatic presentations before 2013 and because there were no documented severe presentations. Some data is available from prevalence surveys. The prevalence was 6.1% in a standard population of 99 individuals in Uganda, in 1952. The virus was isolated twice in Nigeria, from samples collected in 10,778 febrile patients, between 1971 and 1975. The authors of a serological study of 130 Nigerian symptomatic patients, performed in 1979, reported that 52 (%) had neutralizing antibodies. The authors of a study conducted in Java (Indonesia), between 1977 and 1978, reported that out of 219 patients admitted to the Java island hospital emergency unit for fever, ZIKV prevalence was 7.1%. Sporadic cases were reported in travellers between 2007 and 2013 (Thailand,Cambodia, Indonesia).

The authors of a retrospective study conducted in 2014, demonstrating a Zika virus epidemic in Gabon in 2007, proved the difficulty of detecting this epidemic in areas of dengue and chikungunya virus circulation.

A Zika virus epidemic has been reported in FP since October 2013. This is the first time such a large epidemic has been described. Cases imported from FP were reported in New Caledonia and, since January 2014, autochthonous cases have been reported there. Cases imported from FP have also been reported in Japan, Norway, Easter Island, and continental France.

Zika virus epidemic related reference

1, S. Ioos et al. / Médecine et maladies infectieuses 44 (2014) 302–307
2, Yap census; 2000 [consulté le 14 janvier 2014].
3, Duffy, et al. Zika virus outbreak on Yap Islands. Federated States of Micronesia. N Engl J Med 2009;360:24.
4, Marchette NJ, Garcia R, Rudnick A. Isolation of Zika virus from Aedes aegypti mosquitoes in Malaysia. Am J Trop Med Hyg 1969;18:411–5.
5, Dick GWA. Epidemiological notes on some viruses isolated in Uganda: yellow fever, Rift Valley fever, Bwamba fever, West Nile, Mengo, Semliki Forest, Bunyamwera, Ntaya, Uganda S. and Zika viruses. Trans R Soc Trop Med Hyg 1953;47:13–43