Warming U.S. temperatures, the resumption of travel, and new knowledge about Zika’s long-term effects on children signal that Zika prevention and vaccine development should be on public health officials’, doctors’, and communities’ radar, even when community infection is not occurring.
“Although we haven’t seen confirmed Zika virus circulation in the continental United States or its territories for several years, it’s still something that we are closely monitoring, particularly as we move into the summer months,” Erin Staples, MD, PhD, medical epidemiologist at the Arboviral Diseases Branch of the Centers for Disease Control and Prevention in Fort Collins, Colo., told this news organization.
“This is because cases are still being reported in other countries, particularly in South America. Travel to these places is increasing following the pandemic, leaving more potential for individuals who might have acquired the infection to come back and restart community transmission.”
How Zika might reemerge
The Aedes aegypti mosquito is the vector by which Zika spreads, and “during the COVID pandemic, these mosquitoes moved further north in the United States, into southern California, and were identified as far north as Washington, D.C.,” said Neil Silverman, MD, professor of clinical obstetrics and gynecology and director of the Infections in Pregnancy Program at UCLA Medical Center in Los Angeles.
“On a population level, Americans have essentially no immunity to Zika from prior infection, and there is no vaccine yet approved. If individuals infected with Zika came into a U.S. region where the Aedes aegypti mosquito was present, that population could be very susceptible to infection spread and even another outbreak. This would be a confluence of bad circumstances, but that’s exactly what infectious disease specialists continue to be watchful about, especially because Zika is so dangerous for fetuses,” said Dr. Silverman.
How the public can prepare
The CDC recommends that pregnant women or women who plan to become pregnant avoid traveling to regions where there are currently outbreaks of Zika, but this is not the only way that individuals can protect themselves.
“The message we want to deliver to people is that in the United States, people are at risk for several mosquito-borne diseases every summer beyond just Zika,” Dr. Staples said. “It’s really important that people are instructed to make a habit of wearing EPA [U.S. Environmental Protection Agency)–registered insect repellents when they go outside. Right now, that is the single best tool that we have to prevent mosquito-borne diseases in the U.S.
“From a community standpoint, there are several emerging mosquito control methods that are being evaluated right now, such as genetic modification and irradiation of mosquitoes. These methods are aimed at producing sterile mosquitoes that are released into the wild to mate with the local mosquito population, which will render them infertile. This leads, over time, to suppression of the overall Aedes aegypti mosquito population – the main vector of Zika transmission,” said Dr. Staples.
Monica Gandhi, MD, MPH, professor of medicine and associate chief of the division of HIV, infectious diseases, and global medicine at the University of California, San Francisco, encourages her patients to wear mosquito repellent but cautioned that “there’s no antiviral that you can take for Zika. Until we have a vaccine, the key to controlling/preventing Zika is controlling the mosquitoes that spread the virus.”