Friday 2 September 2016

ZIKA

Zika virus (ZIKV) is a member of the virus family Flaviviridae and the genusFlavivirus. It is spread by daytime-active Aedes mosquitoes, such as A. aegyptiand A. albopictus. Its name comes from the Zika Forest of Uganda, where the virus was first isolated in 1947.Zika virus is related to the dengue, yellow fever, Japanese encephalitis, and West Nile viruses. Since the 1950s, it has been known to occur within a narrow equatorial belt from Africa to Asia. From 2007 to 2016, the virus spread eastward, across the Pacific Ocean to the Americas, leading to the 2015–16 Zika virus epidemic.

The infection, known as Zika fever or Zika virus disease, often causes no or only mild symptoms, similar to a very mild form of dengue fever. While there is no specific treatment, paracetamol (acetaminophen) and rest may help with the symptoms. As of 2016, the illness cannot be prevented by medications orvaccines. In January 2016, the United States Centers for Disease Control and Prevention(CDC) issued travel guidance on affected countries, including the use of enhanced precautions, and guidelines for pregnant women including considering postponing travel. Other governments or health agencies also issued similar travel warnings, while Colombia, the Dominican Republic, Puerto Rico, Ecuador, El Salvador, and Jamaica advised women to postpone getting pregnant until more is known about the risks. Zika is pronounced /ˈziːkə/

The vertebrate hosts of the virus were primarily monkeys in a so-calledenzootic mosquito-monkey-mosquito cycle, with only occasional transmission to humans. Before the current pandemic began in 2007, Zika "rarely caused recognized 'spillover' infections in humans, even in highly enzootic areas". Infrequently, however, other arboviruses have become established as a human disease and spread in a mosquito–human–mosquito cycle, like the yellow fever virus and the dengue fever virus (both flaviviruses), and the chikungunyavirus (a togavirus). Though the reason for the pandemic is unknown, dengue, a related arbovirus that infects the same species of mosquito vectors, is known in particular to be intensified by urbanization and globalization. Zika is primarily spread by Aedes aegypti mosquitoes, and can also be transmittedthrough sexual contact or blood transfusions. The basic reproduction number (R0, a measure of transmissibility) of Zika virus has been estimated to be between 1.4 to 6.6.

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