Much media attention has been given to the spread of Zika virus in South America, but the mosquito-borne virus also poses a seasonal threat to more than 192 million people living in the southern United States. Becoming educated about the virus and its potential impact is an important step toward defending against it.
Dr. Lola V. Stamm, associate professor of epidemiology at UNC’s Gillings School of Global Public Health, has offered a succinct discussion of the history, scope and impact of Zika in a “Viewpoint” article, published online May 11 in JAMA Dermatology.
[Photo: Government officials in Brasilia, Brazil, examine old tires that have collected rainwater and may serve as a breeding ground for mosquitoes. (Photo by Pedro Ventura/Agencia Brasilia)]
In the article, “Zika Virus in the Americas: An Obscure Arbovirus Comes Calling,” Dr. Stamm notes the challenges of controlling insect-borne disease in a highly globalized world. First isolated in 1947 from a monkey in Uganda’s Zika forest, Zika is similar to dengue, yellow fever, West Nile virus and Japanese encephalitis. Usually, it is transmitted by an infected female Aedes aegypti mosquito, a species well adapted to urban environments.
Confined until recently to Africa and southeast Asia, Zika caused serious outbreaks in 2007 in the Federated States of Micronesia (in which 75 percent of the population of the Yap Islands was infected) and in 2013 in French Polynesia (where about 11 percent of the population was infected). Most patients presented with mild disease, but for the first time, Guillain-Barré syndrome, an autoimmune disorder that causes paralysis, was associated with Zika.
Since 2014, outbreaks of Zika have occurred in several South Pacific islands. In early 2015, clusters of people in Brazil reported a bumpy rash, sometimes accompanied by fever, headache, joint swelling and/or muscle pain, and by May 2015, the cause was confirmed to be the virus. Since late 2015, there has been a 20-fold increase in the number of infants born with microcephaly in these areas of the country.
The virus continued to spread by way of travelers to countries in Latin America and the Caribbean. By February 1, the World Health Organization called the spread of Zika virus in the Americas a “public health emergency of international concern.”
It is nearly impossible to confirm the presence of Zika based upon clinical criteria, Dr. Stamm said, and she called for better diagnostic tests, one of which already has been developed. At present, there are no treatments for the infection or vaccines to prevent it.
“Until a vaccine becomes available,” Dr. Stamm wrote, “effective mosquito control, education of health care professionals and the public, and enhanced surveillance to detect and monitor early infection and to ensure safety of the blood supply will be key to mitigating the impact of Zika virus on the health of the U.S. population. Hopefully, what we learn while confronting Zika will be of benefit when the next obscure [insect-borne virus] comes calling.”