by Dr. Jennifer Coates, DVM
Zika is all over the news these days. While evidence that the virus is linked to severe birth defects in some babies is understandably alarming, getting an accurate picture of all the virus’s effects is important.
Zika in People
Zika virus is transmitted primarily through Aedes aegypti mosquitos. A mosquito bites a person carrying the Zika virus (who may or may not have symptoms) and when it subsequently bites someone else, passes the virus on to this person. Evidence is mounting that Zika can also be transmitted through sexual intercourse. The virus has been found in saliva, but whether it can be passed through contact like kissing is not known.
Most people who are infected with Zika do not become sick. The 1 in 5 people with Zika who do fall ill generally report symptoms like headaches, light sensitivity, joint pain, rashes, and eye inflammation.
But, strong evidence now exists linking Zika virus infection in pregnant women and the birth of babies with microcephaly (abnormally small heads and brain defects) and eye abnormalities. The Centers for Disease Control (CDC) has found the virus in the brains of two babies from Brazil that died of microcephaly.
People in the United States have been diagnosed with Zika, but all of them have recently travelled overseas to endemic areas. In the western and northern parts of the U.S., large outbreaks of Zika are extremely unlikely since the climate is too cold and dry and Aedes aegypti mosquitos are not prevalent. People living in the southeastern part of the U.S. are most at risk for a Zika outbreak.
Treatment for Zika virus is limited to symptomatic care. There is no form of direct treatment for babies born with birth defects resulting from Zika virus infection. A vaccine is not available. The best forms of prevention in endemic areas are aggressive measures to prevent mosquito bites (keeping windows closed or screened, using nets over sleeping areas, wearing long pants and long-sleeved shirts, using mosquito repellant, environmental control measures, etc.).
Talk to your doctor if you are planning to travel to a Zika-endemic part of the world and consider postponing your trip if you will or might be pregnant at the time.
Zika in Pets and Other Animals
We know very little about the possible effects of Zika in pets or livestock. The virus causes only relatively mild illness in a fraction of people bitten by an infected mosquito, and it seems likely that a similar outcome would be seen in animals.
At this point, mosquito control measures and the use of repellants labeled for animals are the best preventative measures available should you have to travel to a Zika endemic area with your pet or if natural transmission through mosquito bites does become a problem locally in the future.
To my knowledge, there have been no reports of illness or birth defects related to Zika virus infection in animals. That does not necessarily mean that it does not occur, however. It simply means that the research has not been done.
Interestingly, a virus that is related to Zika (Bovine Viral Diarrhea Virus, or BVDV) is known to cause birth defects in calves, including microcephaly and eye deformities, when their mothers are infected during pregnancy.