Zika virus disease is caused by the bite of an infected Aedes species mosquito. The most common symptoms are fever, rash, conjunctivitis and joint pain. Most people infected with the virus won’t know they have it because they don’t experience the symptoms. The incubation period for Zika virus is currently unknown, but it is surmised to be a few days to a week. The illness is usually mild and people generally do not get sick enough to seek hospitalization. The virus usually remains in the blood of the person infected for about a week.
Zika virus was first discovered in 1947 and is named for the Zika forest in Uganda. In 1952, the first human cases of Zika were detected and since then outbreaks have been noted in tropical Africa, Pacific Islands and Southeast Asia. In May, 2015 the Pan American Health Organization issued an alert regarding the first confirmed virus infection in Brazil. Local transmission has been reported in many other countries and territories. Zika virus will likely continue to spread to other areas.
How is the disease transmitted?
- A pregnant woman can pass Zika virus to her fetus during pregnancy. Zika is the cause of microcephaly and other severe fetal brain defects. The CDC is studying the full range of other potential health problems that Zika virus infection during pregnancy may cause.
- A pregnant woman already infected with Zika virus near the time of delivery can pass on the virus to her newborn around the time of birth.
- To date, there have been no reports of infants getting Zika virus through breastfeeding. Because of the benefits of breastfeeding, mothers are encouraged to breast feed even in areas where Zika virus is not found.
- Zika virus can be spread by a man to his sex partners.
- In known cases of sexual transmission, the men developed Zika virus symptoms. From these cases we know the virus can be spread when the man has symptoms, before symptoms start, and after symptoms resolve. In one case, the virus was spread a few days before symptoms developed.
- The virus is present in semen LONGER than in blood.
- As of February 1, 2016, there have not been any confirmed blood transfusion transmission cases in the United States.
- There have been multiple reports of blood transfusion transmission cases in Brazil. These reports are currently being investigated.
During the French Polynesian outbreak, 2.8% of blood donors tested positive for Zika and in previous outbreaks the virus has been found in blood donors.
What we know:
- No Vaccine exists to prevent Zika virus disease.
- Prevent Zika by avoiding mosquito bites.
- Mosquito’s that spread Zika bite mostly during the day.
- Mosquito’s that spread Zika virus also spread dengue and chikungunya viruses.
- Prevent sexual transmission of Zika by using condoms or abstain from sex.
What measures should be taken to prevent Zika virus infection?
Prevention involves reducing mosquito populations and avoiding bites, which occur mainly in daylight. Eliminating and controlling the Aedes mosquito breeding sites reduces the chances that Zika will be transmitted. An integrated response is required, involving action in several areas, including health, education, and the environment.
To eliminate and control the mosquito, it is recommended to:
- Avoid standing water in outdoor containers (flower pots, bottles and containers that collect water) so that they do not become mosquito breeding sites.
- Cover domestic water tanks so mosquitos can’t enter the container.
- Avoid accumulating garbage: Put it in closed plastic bags and keep it in closed containers.
- Unblock drains that could accumulate standing water.
- Use screens and mosquito nets in windows and doors to reduce contact between mosquito’s and people.
To prevent mosquito bites, it is recommended that you take the following steps:
- Wear long- sleeved shirts and long pants.
- Stay in places with air conditioning and window and door screens to keep mosquitos outside.
- Sleep under a mosquito net if you are overseas or outside and are not able to protect yourself from mosquito bites.
- Use repellents that contain Deet or other EPA registered insect repellents and apply them as indicated on the label.
Zika virus is an emerging mosquito borne flavivirus. Travel-associated cases of Zika virus disease have been reported in the United States. Zika virus infection during pregnancy has been causally linked to congenital microcephaly and has been associated with other adverse pregnancy outcomes, including pregnancy loss. On February 12, 2016, the CDC recommended that health care providers offer testing for Zika virus to asymptomatic pregnant women with possible exposure to Zika virus.
CDC, Pan American Health Organization and World Health Organization