Protection Against Zika Virus Just as Important During Winter, Expert Says

Locally acquired infection reported in Texas

Just because temperatures are cooling down as winter approaches, it’s no time to let your guard down when it comes to mosquitoes that can carry the Zika virus, according to James Diaz, MD, DrPH, Program Director of Environmental/Occupational Health Sciences at Louisiana State University (LSU) Health New Orleans School of Public Health. Dr. Diaz details characteristics of the mosquitoes capable of transmitting the Zika virus in the United States, their habitats and biting behaviors, and control measures in an article published in the December 2016 issue of Wilderness & Environmental Medicine.

“Not only can the eggs of Aedes species mosquitos survive winter, wide variations in daytime temperatures can stimulate egg-laying and shorten the time it takes for mosquitoes to become infective after biting a person with Zika,” Dr. Diaz said. “What’s more, researchers have shown that, while relatively rare, Aedes aegypti mosquitoes are able to transmit Zika to their offspring, a mechanism allowing the virus to survive from one season to the next.”

Eggs of the Aedes species can survive in conditions that adult mosquitoes cannot. Even when their source of water has evaporated, eggs can survive desiccation, remaining environmentally stable and viable for up to a year and easily spreading to new locations. All it takes is a little rain for them to hatch.

Dr. Diaz dispelled an often-repeated misconception about the biting behaviors of mosquitoes. “It’s not just dawn and dusk when people must take precautions. Aedes mosquitoes are primarily daytime biters and sip feeders, preferring multiple small-sip human blood meals when they can sense, see, and repeatedly attack their hosts best, but they can also bite at night in well-lit areas.”

In his article, Dr. Diaz rates the effectiveness of various methods of control and protection, including physical, chemical, biologic, and genetic control of the mosquitoes, as well as personal protective strategies to prevent being bitten—from wearing long sleeves, long pants, and clothing impregnated with insecticides to a comparison of mosquito repellents.

“With a probable case of locally transmitted Zika reported in Texas in November, we now have Zika on both sides of Louisiana,” Dr. Diaz said. “As we learn more about the consequences of Zika infection, including the recent revelation that babies of Zika-infected mothers who had normal head sizes at birth have been diagnosed with microcephaly months later, it is vital that we know this enemy and remain vigilant in protecting ourselves. Moreover, the defensive lessons learned now combined with ongoing research in flaviviral immunology and genetic mosquito vector control will better prepare us for the next arthropod-borne pandemic in our changing world ecosystem.”

Source: Medical Xpress; December 8, 2016.