What's in this article?
What is Zika virus?
The Zika virus, first identified in Uganda in 1947, is transmitted by the same type of mosquito that carries dengue fever, yellow fever, and chikungunya virus. A mosquito bites an infected person and then passes those viruses to other people it bites. Outbreaks did not occur outside of Africa until 2007, when it spread to the South Pacific.
The CDC has confirmed Zika can spread through sex, usually after a person traveled to an area where Zika has broken out, got the virus, and gave the virus to a sex partner who did not travel. Infected women and men can both pass the virus to sex partners — even if they haven’t shown symptoms of infection, the CDC says.
The CDC is aware of a report that Brazilian scientists have found the virus in the saliva and urine of infected people, CDC Director Tom Frieden, MD, told reporters, but more information is needed.
What we know
- Zika is spread mostly by the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus). These mosquitoes are aggressive daytime biters. They can also bite at night.
- Zika can be passed from a pregnant woman to her fetus. Infection during pregnancy can cause certain birth defects.
- There is no vaccine or medicine for Zika.
- The Florida Department of Health has identified an area in one neighborhood of Miami where Zika is being spread by mosquitoes.
Symptoms of Zika virus?
The disease can cause fever, rash, joint pain, and redness in the whites of the eye. But most people won’t know they have it.
“Only about 1 in 5 people with the virus will exhibit symptoms,” says Amesh Adalja, MD, a spokesman for the Infectious Diseases Society of America. “The vast majority have no symptoms at all.”
Zika has “never been thought of as a severe infectious disease until now,” Adalja says.
Where does Zika virus occur?
While the majority of Zika virus cases occur in tropical regions such as Brazil, Colombia, Paraguay, Suriname, Venezuela and French Guiana, the possibility exists of mosquito infection in tropical-like climates in some cities, such as Houston and New Orleans in the US.
Areas within the US which are of concern for potential Zika-infected mosquitos are those with wet lowlands, warmer temperatures and higher levels of poverty.
Other countries with past or recent Zika virus infection include parts of Africa, Asia, the Americas, Oceania and the Pacific Islands. Infection in the US is currently linked to exposure of travelers who return from other countries.
Due to the fact that the species of mosquito that transmits Zika virus can be found throughout the world, the Centers for Disease Control and Prevention (CDC) believe it is likely that outbreaks of the disease will spread to new countries.
WHO expects the virus to rapidly spread through the whole of the Americas and some virologists and epidemiologists also believe that Asia will be at risk.
Prevention of Zika virus
- No vaccine exists to prevent Zika.
- Prevent Zika by avoiding mosquito bites.
- Mosquitoes that spread Zika virus bite mostly during the daytime.
- Mosquitoes that spread Zika virus also spread dengue and chikungunya viruses.
- Zika can be passed through sex from a person who has Zika to his or her sex partners. Condoms (and other barriers to protect against infection) can reduce the chance of getting Zika from sex.
- The Florida Department of Health has identified an area in one neighborhood of Miami where Zika is being spread by mosquitoes.
How is Zika virus treated?
There’s no treatment, but Adalja says most people with symptoms do well with over-the-counter medications for aches and pains. The disease usually runs its course within a week or so.
No vaccine is available, but the National Institutes of Health announced on Aug. 3 that it had begun testing a Zika vaccine in humans. At least 80 people are expected to participate.
What is the connection between Zika, microcephaly, and pregnancy?
Zika causes microcephaly in babies born to infected pregnant women, the CDC confirmed earlier this year. Microcephaly stunts a baby’s head growth, causing devastating, sometimes-fatal brain damage, and it can result in miscarriage or stillbirth.
