The Zika virus continues to spread across the world, and medical researchers are understandably alarmed. There is strong evidence, increasing by the day, that the Zika virus is causing babies to be born with abnormally shrunken heads, called microcephaly. In the most horrific example to date, one baby was stillborn after the virus appeared to have destroyed most of its brain.
Although for most a Zika infection is relatively harmless, pregnant women are at incredible risk from this virus. Naturally, people are wondering where Zika may head to next. Unfortunately, a new study published in the journal PLOS Currents: Outbreaks has showcased just how much of the U.S. is a perfect home for this particular proliferating virus.
Zika is spread by mosquitoes of the Aedes genus – particularly the species Aedes aegypti – to all kinds of primates, including humans. Therefore, wherever this mosquito can live and reproduce, the virus can spread. As it turns out, this mosquito is happy in humid, hot climates, which would explain why it has kept its stronghold on much of South America for so long. This is epitomized by Brazil, where there have been at least 1.5 million cases of infection to date.
This also explains why cases have flared up in Hawaii, and why a previous study has predicted that humid states like Florida, Georgia, Louisiana, Mississippi and the south of California are ripe for Zika virus outbreaks. This new study reinforces these findings, confirming that these southern states are likely to suffer from spikes in A. aegypti populations.
Using disease transmission simulations driven by changes in weather, the team of researchers at the National Center for Atmospheric Research (NCAR) determined that warm summer weather above the equator would encourage Zika-carrying mosquitos to spread further northwards. This coming summer will be no exception, and the southern U.S. will be swarming with Ae. aegypti by the time July swings around – particularly Miami.
The most at-risk regions for Zika outbreaks in the United States in July. NCAR
Worryingly, major cities further north along the eastern seaboard, including New York City, will also probably see Ae. aegypti beginning to appear. This isn’t just because of the summer weather, however: Large cities are likely to have a higher influx of people traveling in from countries already experiencing severe Zika outbreaks. When they arrive, the Zika cases will register as occurring in these large metropolises. Additionally, there is a chance they will spread the disease through sex.
Areas in the U.S. rife with poverty, featuring dilapidated houses, high occurrences of stagnant water, and poor sanitation, will likely show the most rapid spread of Ae. aegypti. Consequently, the most impoverished areas of the U.S., particularly those in Florida, will be the most prone to Zika outbreaks. Fortunately, the authors note that thanks to better disease control and better overall infrastructure, outbreaks in the U.S. are likely to be far less severe than those seen across South America.
In any case, this study – and others like it – will boost the U.S. government’s attempt to stymy the spread of the virus this summer by giving officials a forewarning of Zika’s most likely transmission path. “Even if the virus is transmitted here in the continental U.S., a quick response can reduce its impact,” said Mary Hayden, a medical anthropologist at NCAR and co-author of the study, in a statement.