‘WE JUST DON’T MUCH ABOUT ZIKA’
While Zika’s connection to microcephaly has yet to be definitively proven, the presence of the virus has been found in the bodies of five of the newborns that died with the condition and in the placentas of two women who miscarried babies with microcephaly.
The Centers for Disease Control and Prevention has warned pregnant women not to travel unnecessarily to more than a dozen countries currently experiencing an outbreak of Zika virus, as well as Puerto Rico. The governments of Brazil, El Salvador, and Columbia, meanwhile, are urging women to delay any plans of pregnancy.
“People are worried that Zika may also have other, more subtle, effects on fetuses besides microcephaly,” Kitron says. “We just don’t know that much about Zika. It has not been studied extensively in the lab and field data is also limited.”
So far, the few known cases of Zika in the US mainland are linked to people who had traveled abroad and were likely infected by mosquitos elsewhere. If Zika follows the same patters as dengue fever, however, states like Texas, Florida, and Hawaii could experience small outbreaks transmitted by mosquitoes during the summer months.
The Zika virus is named after an isolated forest in Uganda where it was discovered in a monkey in 1947. Only a handful of human cases were known until 2007 when it popped up in the Yap Islands of the southwestern Pacific Ocean, sickening thousands of people. In 2013 Zika appeared in French Polynesia and the following year in other islands of the South Pacific.
Although Zika outbreaks have coincided with a slightly increased rate of Gillian-Barre’s Syndrome, none of the previous outbreaks were associated with a spike in microcephaly births.
The Brazilian Zika outbreak, first identified in May, is the largest ever. The cases are centered in the northeastern states of Paraiba, Pernambuco, and Bahia. The virus quickly spread in the region, since the population had never been exposed to it, making it highly susceptible. Given the high rate of infection, herd immunity may delay future outbreaks for several years, Kitron says.
Zika cases were initially confused with chikungunya, another virus transmitted by the Aedes aegypti mosquito that was introduced to Brazil and other parts of Latin America and the Caribbean in 2014.
Next, learn why one disease ecologist calls Aedes aegypti “the roaches of the mosquito world,” and why mosquito control is vital to beating Zika.