Warming Weather Brings Heightened Concerns About Zika

After the long dark and cold days of winter, typically we welcome the return of warmer weather and increased outdoor activities.

Unfortunately, warm weather also means increased outdoor activities for mosquitoes! In turn, this may be cause for increased concerns about mosquito-borne infections. A leading worry is whether or not Zika virus will become more widespread and cause an epidemic in the United States. The Zika virus swept through much of Latin America and the Caribbean with terrible consequences, but it only established a toehold in Florida and Texas in 2016. What will 2017 bring?

The good news is that usually Zika infection brings very little in terms of consequences. The vast majority of infections (in 80 percent, or in 4 out of 5, cases) are asymptomatic, meaning that people do not even realize that they were infected. The remaining 20 percent, or 1 in 5 cases, are typically associated with mild symptoms, such as fever, rash, joint pain, muscle discomfort and redeye, that resolve on their own over several days to a week. There are rare cases of more serious Zika infection, sometimes causing significant weakness, paralysis and other serious neurological symptoms, but these are distinctly uncommon.

The bad news is that Zika virus is an entirely different infection during pregnancy, where it poses very significant risks for the fetus. Newly released studies tell just how devastating Zika virus can be during pregnancy. Nearly half (46%) of all pregnancies in woman infected with Zika were adversely affected by stillbirths, miscarriages and identifiable birth defects in surviving infants. Thus, the toll that Zika virus takes on pregnancies appears to be even higher than was previously estimated.

Importantly, Zika virus poses a risk to the developing fetus across the entirety of pregnancy and not just in early or late periods. Adverse outcomes, such as pregnancy losses or birth defects, were found in 55 percent of first trimester infections, 52 percent of pregnancies of second trimester infections, and 29 percent of pregnancies in which infection occurred in the third trimester.

Luckily, only 3 percent of Zika infection pregnancies result in abnormally small heads and underdeveloped brains, known as microcephaly. However, the rate of microcephaly is 50 times greater than the rate of microcephaly in non-Zika infected pregnancies.

With these devastating consequences, clearly Zika infection during pregnancy is truly worrisome. The question on everyone’s minds is “Will we see widespread Zika virus transmission in the United States?” The answer is maybe yes. The reasons are two-fold. First and foremost is that the mosquitoes that preferentially transmit Zika virus infection are currently living and thriving in the United States. Secondly, there is so much travel between areas where Zika virus is widespread and the continental United States that we fully expect visitors and returning travelers to come to the United States carrying Zika infection. These persons could be bitten by local mosquitoes, which in turn can become infected and then transmit Zika virus to the next person they bite.

In 2016, less than 221 of people in the United States were believed to have acquired Zika virus via local transmission from infected mosquitoes – and this was only in very limited locations in Florida and Texas. Yet, the toll of Zika infection on pregnant Americans was much greater. In fact, on March 3, the CDC reported on more than 1,500 pregnant women in the U.S. with possible evidence of Zika virus infection, and over 50 infants and fetuses have been born in the U.S. with Zika-related birth defects.

Unfortunately there is still no effective treatment, nor commercialized vaccine, to combat Zika infection.To prevent being infected with Zika virus and having a child born with a birth defect, the CDC continues to recommend prevention as the only remedy. The two pillars of prevention include that pregnant avoid unnecessary travel to areas where Zika virus is endemic, and that all persons take generic measures to mitigate the risks from mosquito-borne infections. This includes reducing mosquito populations, maintaining barriers to mosquito exposures, and reducing the risk of secondary transmission (persons who are infected with Zika should avoid contact with mosquitoes, so additional mosquitoes do not get infected and spread the chain of infection).

Homeowners should eliminate areas of standing water around the property, such as flowerpots, birdbaths, baby pools and grill covers. Mosquitoes need only about a half an inch of water to breed. It’s also recommended to screen all windows and doors, and patch up even the smallest tear. People can also protect themselves by wearing long-sleeved shirts and long pants. It’s also crucial to apply insect repellent when spending time outside, as these products have been shown to be effective deterrents. Multiple agents are available, such as DEET, picaridin, oil of lemon eucalyptus or para-menthane-diol, and IR3535. Pregnant and breastfeeding women can use all EPA-registered insect repellents, including DEET, according to the product label. Most repellents, including DEET, can be used on children older than 2 months.

Additionally, we cannot forget concerns with sexual transmission of Zika. Men infected with Zika may sexually transmit Zika for up to six months. Thus, men with Zika should wait at least six months after symptoms start before couples try to get pregnant. Women with Zika should wait at least eight weeks after symptoms start before trying to get pregnant.

If there are concerns about mosquito activity, contact a licensed pest control company or the local mosquito abatement district.