Mosquito bites are the primary way that Zika virus is transmitted. The virus can be spread from mother to child. Spread of the virus through blood transfusion and sexual contact have also been reported.
Not all mosquito types transmit the Zika virus. It is primarily transmitted through the bite of an infected Aedes mosquito (A. aegypti and possibly A. albopictus). These mosquitoes are mainly found in South Texas and along the Texas coast, but are also present in other parts of Texas, especially urban environments. They typically lay eggs on the walls of water-filled containers like buckets, bowls, animal dishes, flower pots and vases. They live indoors and outdoors.
Even if you don’t know you’re infected, mosquitoes that bite you could transmit the virus to others. Mosquitoes may pick up certain viruses, such as Zika, from biting a human who has a Zika infection. The mosquito takes a blood meal from the human and takes in the virus in the human’s blood. Then, after about 7-10 days, the mosquito may pass the Zika virus to other humans when biting them. The illness is usually mild with symptoms lasting several days to a week.
Most Texas cases of Zika are related to travel. People were bitten by an infected mosquito while traveling to areas where Zika is being spread and then diagnosed after returning home.
Although rare, the Zika virus may also be among the causes of Guillain-Barré syndrome, a condition in which your immune system attacks part of your nervous system. The Zika virus also can be spread from mother to child, if the mother is infected with the Zika virus during pregnancy.
The Zika virus has been linked to birth defects such as microcephaly, a condition where a baby’s head is much smaller than expected and can cause developmental delays.
There have not been any reports of pets or other kinds of animals spreading or contracting Zika. Read more about Zika and animals on the CDC website.
Sexual contact, blood transfusion
The Zika virus can also be spread through sexual contact and blood transfusion. In known cases of sexual transmission, people spread the virus to their sex partners. CDC recommends that all pregnant women who have a sex partner who has traveled to or resides in an area with Zika use barrier methods every time they have sex or they should not have sex during the pregnancy. Although no cases of woman-to-woman Zika transmission have been reported, these recommendations now also apply to female sex partners of pregnant women. Research shows the virus might persist in semen longer than in blood; studies to determine the duration of persistence in semen are not yet completed.
To date, there have not been any confirmed blood transfusion transmission cases in the United States. The best way to protect the U.S. blood supply is to screen blood donors using the donor history questionnaire and asking about recent travel to areas with active transmission of Zika, according to the American Association of Blood Banks. The U.S. Food and Drug Administration advises testing for Zika virus in all donated blood and blood components.
Vector control professionals can read the CDC’s Mosquito Control recommendations for more information.
More information about transmission is on the CDC website.