Zika virus disease is an emerging mosquito borne viral disease. It is transmitted by bite of an infected Aedes mosquito. Zika virus was first identified in Zika forest of Uganda in 1947 in rhesus monkeys. In1952, it was identified in humans, in Uganda and the United Republic of Tanzania through serological tests. The virus was isolated from human samples in Nigeria in 1968. Outbreaks of Zika virus disease have been recorded in Africa, the Americas, Asia and the Pacific.
In 2007, the South Pacific recorded its first outbreak of Zika virus in Yap Island in the Federated States of Micronesia. In October 2013, French Polynesia reported its first outbreak.
In May 2015, the public health authorities of Brazil confirmed the transmission of Zika virus in the northeast of the country. Since October 2015, other countries and territories of the Americas have reported the presence of the virus.
Along with Zika virus infection, cluster of microcephaly (condition where a baby is born with a small head or the head stops growing after birth) cases and other neurological disorders (Guillain-Barré Syndrome) (GBS) reported in Brazil and a similar cluster in French Polynesia in 2014.
World Health Organisation (WHO) strongly suspected a causal relationship between zika virus infection during pregnancy and microcephaly and recommended more investigation and research to understand any possible link. No scientific evidence to date confirms a link between Zika Virus and microcephaly or GBS.
On 1st February 2016, WHO announced that the cluster of neurological disorders and neonatal malformations reported in the Americas region constitutes a Public Health Emergency of International Concern.
Since 2007, Zika viral transmission has been documented in 46 countries and territories including 34 countries which reported autochthonous transmission, or locally acquired infection, between 2015 and 2016, six countries with indication of viral circulation, five countries where the Zika virus outbreak has ended and one country with a locally acquired case but without vector borne transmission(12th February 2016)*.
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Questions and answers about Zika virus-
National Guidelines for Zika virus disease
(a) Guidelines on Zika Virus Disease- http://www.mohfw.nic.in/media/disease-alerts/national-guidelines-zika-virus-disease
(b) Guidelines for integrated vector management for control of Ades mosquito- http://www.mohfw.nic.in/
(c) Do’s And Don’ts- http://www.mohfw.nic.in/
(d) Travel Advisory for Zika Virus Disease- http://www.mohfw.nic.in/
(e) Fact sheet on Zika virus disease (updated on 3 rd February 2016)- http://www.mohfw.nic.in/
(f) Guidelines on laboratory detection and diagnosis of Zika virus disease- http://www.mohfw.nic.in/
Zika virus referral form for laboratory diagnosis(NIV,Pune)- niv.co.in/Zika_viral_disease_CRF.pdf
http://www.who.int/emergencies/zika-virus/situation-report/ (accessed on 15th February 2016)*
A majority of those infected with Zika virus disease either remain asymptomatic (up to 80%) or show symptoms similar to other arbovirus infections such as dengue, and include fever, skin rashes, conjunctivitis, muscle and joint pain, malaise, and headache.
These symptoms are usually mild and last for 2-7 days.
The incubation period (the time from exposure to symptoms) of Zika virus disease is not clear, but is likely to be a few days.
As compared to Dengue, cases of Zika virus infection has a mild to moderate clinical picture, the onset of fever is more acute and shorter in duration.
Increased cases of Guillain-Barré syndromea (GBS) in general public and microcephalyb in newborns were reported from French Polynesia and Brazil during Zika outbreaks in 2013-2014 and 2015 respectively. Medical experts suspected an association of micocephaly and GBS with Zika virus infection. But no scientific evidence confirms a link so far*.
(a. Guillain-Barré syndrome-It is a condition in which the body’s immune system attacks part of the nervous system. It can be caused by a number of viruses and can affect people of any age. The main symptoms include muscular weakness and tingling in the arms and legs. Severe complications can occur if the respiratory muscles are affected.)
(b. Microcephaly- It is a condition where a baby is born with a small head or the head stops growing after birth.)
www.who.int/emergencies/zika-virus/situation-report/who-zika-situation- (accessed on 15th February 2016)*
Zika virus is a mosquito-borne flavivirus closely related to dengue virus.
Vector-Zika Virus is transmitted to people through the bite of an infected mosquito from the Aedes genus, mainly Aedes aegypti in tropical regions and subtropical regions. This is the same mosquito that transmits dengue, chikungunya and yellow fever.
Other species of Ades mosquito Ae. albopictus, Ae. hensilli, Ae. polynesiensis were also found as vector in spread of Zika Virus.
Some evidence suggests Zika virus can also be transmitted to humans through blood transfusion, perinatal transmission and sexual transmission.
Some facts about Ades mosquito-