WIKIMEDIAHow vector-borne viruses such as Zika persist in a region even when vector populations are diminished—because of environmental conditions or some other factor—is “one of the basic questions that has long puzzled arbovirologists,” researchers from the University of Texas Medical Branch in Galveston wrote in their August 29 paper in The American Journal of Tropical Medicine and Hygiene. In an effort to better understand how Zika virus sticks around when Aedes aegypti and A. albopictus mosquitoes are not in season, the researchers infected female insects with the virus before mating them. They then tested the mosquitoes’ progeny, finding 1 in every 300 offspring had inherited Zika virus, STAT News reported.
“Vertical (transovarial or transovum) transmission (VT) of a virus from female insects directly to their progeny is one mechanism for arbovirus maintenance in nature during adverse environmental conditions,” the authors wrote in their paper. “VT can also maintain a virus in a specific locality, when most of the potential vertebrate hosts are immune, either as a result of vaccination or natural infection.”
“It’s a nice strategy for the virus to hide,” entomologist Phil Lounibos of the University of Florida who was not involved in the study, told The Verge.
Finding that the virus can be passed from female mosquitoes to their offspring is unlikely to “change the epidemiology of the disease,” study coauthor Robert Tesh of the University of Texas Medical Branch told STAT. Joseph Conlon, an advisor to the American Mosquito Control Association who was not involved in the research, told STAT that Zika transmission among infected people remains a key public health problem. “We’re going to have continual reintroduction of this virus in people,” he said.