A research team from Saint Louis University recently placed the St. Louis area in a high-risk zone for significant spread of the Zika virus this summer. They named the Mississippi Delta as the potential epicenter of a 2017 U.S. outbreak, adding that there also is a high likelihood of widespread Zika transmission in southern states along the Atlantic coast as well as in southern California.
To reach those conclusions, the team looked at information from 3,108 counties, pinpointing 507 of them as high-risk areas for Zika outbreaks. Because the virus is spread by bites from the Aedes aegypti mosquito and also is transmitted sexually, their analysis was based on several factors: the area’s warm, moist climate; the presence of the mosquitoes; high rates of sexually transmitted infections; the number of women of child-bearing age, and an estimate of birth rates for each county. “The purpose of this study was not to create unwarranted alarm, but rather to enhance Zika prevention methods such as mosquito control, effective prevention message dissemination, and treatment and care preparation, in advance of a Zika epidemic in the contiguous U.S.,” said the study’s lead author, Enbal Shacham, Ph.D., M.Ed., a SLU associate professor of behavioral science and health education.
About 80 percent of those infected with Zika have no symptoms during the illness, meaning many people may not know they are at risk of transmitting it to others. When a pregnant woman contracts Zika, her unborn baby may die or develop severe birth defects, such as brain damage and a smaller than expected head size called microcephaly.
Using several different transmission models to gauge the risk, the SLU researchers estimated that between 300,000 and 41.7 million people from the 507 high-risk counties could be more likely to contract Zika than those living in other areas of the U.S. Based on those same models, between 3,700 and 632,000 of those people would be pregnant women. The study was published online in the American Journal of Public Health.