Factors that can combine to produce a Zika virus outbreak are expected to be present in a number of U.S. cities during peak summer months, new research shows.
The Aedes aegypti mosquito, which is spreading the virus in much of Latin America and the Caribbean, will likely become increasingly abundant across much of the southern and eastern United States as the weather warms, according to a new study led by mosquito and disease experts at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado.
The results are published in the peer-reviewed journal PLOS Currents: Outbreaks.
The research was funded by the National Institutes of Health, NASA, and the National Science Foundation (NSF), which is NCAR’s sponsor, and was also co-authored by scientists at NASA, North Carolina State University, Maricopa County Environmental Services Vector Control Division, University of Arizona and Durham University.
This research can help us anticipate the timing and location of possible Zika virus outbreaks in certain U.S. cities,” said NCAR scientist Andrew Monaghan, lead author of the study. “While there is much we still don’t know about the dynamics of Zika virus transmission, understanding where the Aedes aegypti mosquito can survive in the U.S. and how its abundance fluctuates seasonally may help guide mosquito control efforts and public health preparedness.”
Added NCAR scientist Mary Hayden, a medical anthropologist and co-author of the study, “Even if the virus is transmitted here in the continental U.S., a quick response can reduce its impact.”
Although the study does not include a specific prediction for this year, the authors note that long-range forecasts for this summer point to a 40-45 percent chance of warmer-than-average temperatures over most of the continental United States.
In addition to looking at meteorological conditions, the researchers studied two other key variables that could influence the potential for Zika outbreaks: travel from Zika-affected areas, and socioeconomic conditions in states that may face abundant mosquito populations.
To analyze air travel, the team estimated the number of passengers arriving in U.S. cities on direct flights from airports in 22 Latin American countries and territories listed on the Centers for Disease Control and Prevention’s Zika travel advisory as of Jan. 29, 2016.
Cities that had both high potential numbers of Aedes aegypti and a large volume of air travelers included Miami, Houston and Orlando.
As the scientists were able to obtain passenger numbers for direct flights only, they could not estimate the number of passengers continuing on to smaller cities. They noted that the summertime peak in air travel coincides with the peak season in mosquito abundance.
The study also estimated that nearly five times as many people cross the U.S.-Mexico border per month than arrive by air in all 50 cities. This could indicate a high potential for transmission in border areas from Texas to California, although the Zika virus has not been widely reported in northern Mexico.
Read the Complete Research Summary (via NSF)
Read the Full Text of the Article Cited in the Summary (via PLOS Current: Outbreaks)
Includes several charts and data tables.
See Also: Additional Maps and Images via NSF