Zika virus is a member of the virus family Flaviviridae and the genus Flavivirus, transmitted by daytime-active Aedes mosquitoes, such as A. aegypti and A. albopictus, the same type of mosquito that spreads dengue, chikungunya and yellow fever. The Pan American Health Organization (PAHO) said Aedes mosquitoes are found in all countries in the Americas except Canada and continental Chile, and the virus will likely reach all countries and territories of the region where Aedes mosquitoes are found.
The infection, known as Zika fever, often causes no or only mild symptoms. Since the 1950s it has been known to occur within a narrow equatorial belt from Africa to Asia. In 2014, the virus spread eastward across the Pacific Ocean to French Polynesia, then to Easter Island and in 2015 to Mexico, Central America, the Caribbean, and South America, where the Zika outbreak has reached pandemic levels.
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The Zika virus is found in tropical locales with large mosquito populations. Outbreaks of Zika virus disease have been recorded in Africa, the Americas, Southern Asia and the Western Pacific. The virus was first identified in Uganda in 1947 in rhesus monkeys and was first identified in people in 1952 in Uganda and Tanzania, according to the World Health Organization.
The vertebrate hosts of the virus were primarily monkeys in a so-called enzootic mosquito-monkey-mosquito cycle, with only occasional transmission to humans. Before the current pandemic began in 2007, Zika virus “rarely caused recognized ‘spillover’ infections in humans, even in highly enzootic areas”. Infrequently, other arboviruses have become established as a human disease though, and spread in a mosquito–human–mosquito cycle, like the yellow fever virus and the dengue fever virus (both flaviruses), and the chikungunya virus (a togavirus)
Can Zika be transmitted through sexual contact?
Two cases of possible person-to-person sexual transmission has been described, but the PAHO said more evidence is needed to confirm whether sexual contact is a means of Zika transmission.
It is unknown whether women can transmit Zika virus to their sexual partners. As of February 2016, the CDC recommends that men “who reside in or have traveled to an area of active Zika virus transmission who have a pregnant partner should abstain from sexual activity or consistently and correctly use condoms during sex (i.e., vaginal intercourse, anal intercourse, or fellatio) for the duration of the pregnancy.” Men who reside in or have traveled to an area of active Zika virus transmission and their non-pregnant sex partners “might consider” abstinence or condom use. The CDC did not specify how long these practices should be followed with non-pregnant partners because the “incidence and duration of shedding in the male genitourinary tract is limited to one case report” and that “testing of men for the purpose of assessing risk for sexual transmission is not recommended.
The PAHO also said Zika can be transmitted through blood, but this is an infrequent transmission mechanism. There is no evidence the virus can be transmitted to babies through breast milk.
CDC issued new recommendations to those who have traveled to Zika-prone areas: Use condoms during sex or don’t have sex. – Click & See
Zika virus is related to dengue, yellow fever, Japanese encephalitis, and West Nile viruses. The illness it causes is similar to a mild form of dengue fever, is treated by rest, and cannot yet be prevented by drugs or vaccines. There is a possible link between Zika fever and microcephaly in newborn babies by mother-to-child transmission, as well as a stronger one with neurologic conditions in infected adults, including cases of Guillain–Barré syndrome.
People who get Zika virus disease typically have a mild fever, skin rash, conjunctivitis, muscle and joint pain and fatigue that can last for two to seven days. But as many as 80 percent of people infected never develop symptoms. The symptoms are similar to those of dengue or chikungunya, which are transmitted by the same type of mosquito.
The PAHO said there is no evidence that Zika can cause death, but some cases have been reported with more serious complications in patients with pre-existing medical conditions.
The virus has been linked to microcephaly, a condition in newborns marked by abnormally small heads and brains that have not developed properly. It also has been associated with Guillain-Barre syndrome, a rare disorder in which the body’s immune system attacks part of the nervous system. Scientists are studying whether there is a causal link between Zika and these two disorders.
There is no defenite treatment developed yet.Patients are adviced to take rest. Doctors sometimes prescribe few nominal medicines to get little relieve from extenal symptoms.
Defense against mosquitoes is defense against Zika. The CDC recommends long clothing and insect repellent. If you develop symptoms, go see a doctor.
Effective vaccines exist for several flaviviruses. Vaccines for yellow fever virus, Japanese encephalitis, and tick-borne encephalitis were introduced in the 1930s, while the vaccine for dengue fever only became available for use in the mid-2010s.
Work has begun towards developing a vaccine for Zika virus, according to Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. The researchers at the Vaccine Research Center have extensive experience from working with vaccines for other viruses such as West Nile virus, chikungunya virus, and dengue fever. Nikos Vasilakis of the Center for Biodefense and Emerging Infectious Diseases predicted that it may take two years to develop a vaccine, but 10 to 12 years may be needed before an effective Zika virus vaccine is approved by regulators for public use.
Indian company Bharat Biotech is working on two approaches to a vaccine: “recombinant”, involving genetic engineering, and “inactivated”, where the virus is incapable of reproducing itself but can still trigger an immune response. On 3 February 2016, the company claimed animal trials of the inactivated version would commence in two weeks.
Since April 2015, a large, ongoing outbreak of Zika virus that began in Brazil has spread to much of South and Central America and the Caribbean. In January 2016, the CDC issued a level 2 travel alert for people traveling to regions and certain countries where Zika virus transmission is ongoing. The agency also suggested that women thinking about becoming pregnant should consult with their physicians before traveling. Governments or health agencies of the United Kingdom, Ireland, New Zealand, Canada, and the European Union soon issued similar travel warnings. In Colombia, Minister of Health and Social Protection Alejandro Gaviria Uribe recommended to avoid pregnancy for eight months, while the countries of Ecuador, El Salvador, and Jamaica have issued similar warnings.
Plans were announced by the authorities in Rio de Janeiro, Brazil, to try to prevent the spread of the Zika virus during the 2016 Summer Olympic Games in that city.
According to the CDC, Brazilian health authorities reported more than 3,500 microcephaly cases between October 2015 and January 2016. Some of the affected infants have had a severe type of microcephaly and some have died. The full spectrum of outcomes that might be associated with infection during pregnancy and the factors that might increase risk to the fetus are not yet fully understood. More studies are planned to learn more about the risks of Zika virus infection during pregnancy. In the worst affected region of Brazil, approximately 1 percent of newborns are suspected of being microcephalic.
Click & see : 2007 Yap Islands Zika virus outbreak
Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.