New article name is Zika Virus
Zika virus (ZIKV) is a member of the Flaviviridae virus family and the flavivirus genus. It is related to dengue, yellow fever, West Nile and Japanese encephalitis viruses that are also members of the virus family Flaviviridae. Along with other viruses in this family, Zika virus is enveloped and icosahedral with a non-segmented, +ssRNA genome. It is most closely related to the Spondweni virus, and is one of the two viruses in the Spondweni virus clade. [1] The virus was first isolated in 1947 from a rhesus monkey in the Zika Forest of Uganda, Africa, and was isolated for the first time from humans in 1968 in Nigeria. [2] It is transmitted by mosquitoes, and has been isolated in Ae. africanus, Ae. apicoargenteus, Ae. luteocephalus, Ae. aegypti, Ae vitattus, and Ae. furcifer, all members of the Aedes mosquito family. [2] Studies show that the extrinsic incubation period in mosquitoes is about 10 days. [2] The vertebrate hosts of the virus include monkeys and humans.
The pathogenesis of the virus is hypothesized to first infect dendritic cells near the site of inoculation, and then spread to lymph nodes and the bloodstream. [1] In terms of replication, flaviviruses generally replicate in the cytoplasm, but Zika virus antigens have been found in infected cell nuclei. Common symptoms of infection with the virus include mild headaches, maculopapular rash, fever, malaise, conjunctivitis, and arthralgia. The first well documented case of Zika virus was in 1964, beginning with a mild headache and progressing to a maculopapular rash, fever, and back pain. [2] Within 2 days, the rash was fading, and within 3 days, the fever was gone and only the rash remained. [2] There is no vaccine or preventive drug for Zika virus, and only treatment of symptoms is possible. Usually non-steroid anti-inflammatories and/or non-salicylic analgetics are used.
The first outbreak of the disease outside of Africa and Asia was began in April 2007, on Yap Island of the Federated States of Micronesia. This virus was was characterized by rash, conjunctivitis, and arthralgia, and was initially thought to be dengue. The Chikungunya and Ross River viruses were also suspected. [3] However, serum samples from patients in the acute phase of illness contained RNA of Zika virus. The virus was relatively mild, as there were 49 confirmed cases, 59 uncomfirmed cases, no deaths and no hospitalizations. [4]
Zika virus could be considered an emerging pathogen, as it spread outside Africa and Asia for the first time in 2007. [2] Thus far, it has been a relatively mild disease with limited scope, but its true potential as a virus and an agent of disease is currently unknown.
References
edit- ^ a b Fields Virology, 5th Edition
- ^ a b c d e f Center for Disease Control and Prevention <www.cdc.gov>
- ^ Altman, Lawrence K. “Little-Known Virus Challenges a Far-Flung Health System.” NY Times 3 July 2007: 21 Oct. 2009. <http://www.nytimes.com/2007/07/03/health/03virus.html>
- ^ New England Journal of Medicine; “Zika Virus Outbreak on Yap Island, Federated States of Micronesia” <http://content.nejm.org>
External links
edithttp://www.cdc.gov/eid/content/15/9/1347.htm http://www.nytimes.com/2007/07/03/health/03virus.html?_r=1 http://content.nejm.org/cgi/content/short/360/24/2536