The geographic range of two type of Aedes mosquitoes known to transmit the Zika virus includes much of the United States, and according to a blog post today by NIH Director
22.7 million Americans live in parts of the country (primarily Southern Florida and Texas) where one or both of these mosquito breeds can live year round.
While the Zika virus is not currently circulating in North American mosquito populations, all it requires is for a Zika infected individual to arrive on our shores and provide a blood meal to the right kind of mosquito.
Assuming that mosquito goes on to bite another person within a reasonable period of time, they have the potential to pass on the virus.
In reality, it likely takes multiple introductions over time, and under the right conditions, before a virus like Zika (or Dengue, or Chikungunuya) can successfully establish itself (at least temporarily) in a new location. But, as we've already seen with Dengue in Florida, Texas, and Hawaii . . . when provided enough opportunities . . . it can and does happen.
According to a study sponsored by the NIH, 2.7 million travelers arrive in the United States each year from Brazil (and many more from other endemic regions), providing ample opportunities for the virus to be imported.
All of which makes it of paramount importance for researchers to determine if there is a causal link between maternal Zika infection and microcephalic birth defects, to develop better diagnostics and (hopefully) effective therapeutics, and perhaps find ways to mitigate the spread of the virus.
Credit: Kraemer et al. eLife 2015;4:e08347
For decades, the mosquito-transmitted Zika virus was mainly seen in equatorial regions of Africa and Asia, where it caused a mild, flu-like illness and rash in some people. About 10 years ago, the picture began to expand with the appearance of Zika outbreaks in the Pacific islands. Then, last spring, Zika popped up in South America, where it has so far infected more than 1 million Brazilians and been tentatively linked to a steep increase in the number of babies born with microcephaly, a very serious condition characterized by a small head and brain . And Zika’s disturbing march may not stop there.
In a new study in the journal The Lancet, infectious disease modelers calculate that Zika virus has the potential to spread across warmer and wetter parts of the Western Hemisphere as local mosquitoes pick up the virus from infected travelers and then spread the virus to other people . The study suggests that Zika virus could eventually reach regions of the United States in which 60 percent of our population lives. This highlights the need for NIH and its partners in the public and private sectors to intensify research on Zika virus and to look for new ways to treat the disease and prevent its spread.
(Continue . . . )