Zika virus (ZIKV) is a member of the virus family Flaviviridae and the genus Flavivirus, transmitted by daytime-active Aedes mosquitoes, such as Aedes aegypti. Its name comes from the Zika Forest of Uganda, where the virus was first isolated in 1947 [Wiki].
Where is zika usually found?
The Zika virus is a tropical infection discovered in the Zika forest in Uganda in 1947. It is common in Africa and Asia, and did not begin spreading widely in the Western Hemisphere until May 2015, when an outbreak occurred in Brazil. It has since spread rapidly in the Americas, and has now been identified in most tropical and sub-tropical countries. [NYTimes]
common is zika?
For decades, after its discovery in the 1940s, Zika outbreaks were sporadic and tiny, and the disease seemed to do little harm. Prior to 2007, there were only 14 documented Zika cases. But then the first big outbreak erupted on Yap island in Micronesia, with 49 confirmed cases. The virus was first detected in the Americas in 2014. Since then, it has spread fast: in 2015, an outbreak in Brazil affected up to 1.3 million people [WHO].
How is zika transmitted?
Zika virus (ZIKV) is transmitted by daytime-active Aedes mosquitoes. The two most common mosquitoes to transmit the disease are the Aedes aegypti and Aedes albopictus species. Both are invasive species with worldwide distributions, including in the US south and south-west [Nature].
So far one case of sexually transmitted disease has been confirmed. There is also a risk to blood tranfusion recipients in some circumstances (donations are not yet screened for the virus). [CDC]
there a genetic / familial / hereditary factor?
None known; many diseases are variable in their affects because of personal variation in susceptability and resistance, which can be familial; not enough is yet know about the zika virus.
zika be spread from person-to-person?
One case of sexual transmission of the virus has been confirmed, in Texas.[CDC] It is too soon to say whether this is a change in the disease, or a major issue in the spread of the disease.
is most at risk from zika?
Pregnant women are at greatest risk, especially in the first trimester, though the risk is actually to the fetus, rather than the mother. Strong epidemiological evidence from Brazil suggests that Zika can cause brain damage - microcephaly - in developing fetuses.
Women in zika areas - or in contact with someone who has travelled there - should seek screening for the virus [CDC]
What are the
symptoms of zika?
Until recently, Zika was not considered a major threat because its symptoms are relatively mild. Only one of five people infected with the virus develop symptoms, which can include fever, rash, joint pain and red eyes. Those infected usually do not have to be hospitalized [Reuters]
There is strong epidemiological evidence that pregnant womens' fetuses can be born microcephalic, and there is circumstantial evidence that the virus can cause Guillain-Barré in some victims.
When is it necessary
to contact a doctor?
Women in affected areas, and those who may have had contact with zika - who are pregnant - or considering pregnancy - should seek medical advice [CDC].
What are the long term
effects of zika?
Those who merely contract the disease with no ill effects should have no future complications; evidence suggests that is completely cleared from the body.
Microcephaly is a permanent condition, and those who succumb to Guillain-Barré syndrome will have the same ongoing risks as others with that condition [WHO].
What is the mortality
rate for zika?
Death due to zika itself has not been reported, though death through Guillain-Barré syndrome does occur. Other potentially fatal rare nerve disorders have been linked to the disease, but not yet confirmed [BBC]
How is zika diagnosed?
There is no widely available test for Zika infection. Because it is closely related to dengue and yellow fever, it may cross-react with antibody tests for those viruses. To detect Zika, a blood or tissue sample from the first week in the infection must be sent to an advanced laboratory so the virus can be detected through sophisticated molecular testing.
there a treatment for zika?
There is no vaccine to prevent or specific medicine to treat Zika virus.
Treat the symptoms [CDC]:
- Get plenty of rest.
- Drink fluids to prevent dehydration.
- Take medicine to reduce fever and pain.
- Do not take aspirin and other non-steroidal anti-inflammatory drugs (NSAIDS) until dengue can be ruled out to reduce the risk of bleeding.
- If you are taking medicine for another medical condition, sek medical advice before taking additional medication.
If you have Zika, prevent mosquito bites for the first week of your illness.
- During the first week of infection, Zika virus can be found in the blood and passed from an infected person to a mosquito through mosquito bites.
- An infected mosquito can then spread the virus to other people.
Is there a
way to prevent infection?
If you can, avoid travel to areas where the disease in endemic.
If you are in a zika area, take normal precautions against mosquito bites.
Is there a zika
There is no zika vaccine.
research is underway to create one, testing may commence this year (2016) [NBC]
Can zika be controlled
Brazil is trying to eradicate the virus in populated areas by spraying and sterilizing breeding areas, but despite the expense of untold tons of chemical being poured into the environment, the effects are likely to be placebo and cosmetic (fears about forthcoming sports events). The American Council on Science and Health argues that the zika virus can be contained in this way [ACSH] can, but decades of experience with attempts to control Malaria have shown this to be a futile and expensive move, not to mention damage to innocent flora and fauna. But then, ACSH is part-funded by the agro-chemical industry. With currently available chemicals - such as DDT - and the huge areas where the mosqitoes can be found, attempted eradication would be hugely expensive, catastrophic for other benign species, and almost certainly futile, as cleared areas would be immediately recolonised as the clearance teams moved on.
What can be learned from
Recent experience with the Ebola epidemic in west Africa, plus the proximity of the outbreaks to the USA, has incentivised the WHO and CDC to take this disease seriously.
Where can I get more information
CDCP: Zika virus infection 'through sex' reported in US - BBC
Colombia links Zika to rare nerve disorder deaths - BBC
Zika virus, microcephaly and Guillain-Barré syndrome - WHO
Wikipedia: Zika virus - Wiki
Brazil says Zika virus outbreak worse than believed - Reuters
Zika Virus: Unlikely to Kill, Impossible to be Killed - ACSH
Short Answers to Hard Questions About Zika Virus - New York Times
Zika Virus - For Pregnant Women - CDC
Zika Virus - Symptoms and management - CDC
The global compendium of Aedes aegypti and Aedes albopictus occurrence - Nature
Could We Have a Zika Vaccine Soon? - NBC
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Article written by Andrew Heenan BA (Hons), RGN, RMN