A female Aedes aegypti mosquito flies away after a blood meal.
The Centers for Disease Control and Prevention gathered more than 300 local, state and federal authorities and experts at its headquarters in Atlanta on Friday to prepare for clusters of mosquito-borne Zika infections in the U.S. mainland.
“The mosquitoes that carry the Zika virus are already active in the US territories, hundreds of travelers with Zika have already returned to the mainland US, and we could very well see clusters of Zika virus in the mainland US in the coming months.” US can see,” said CDC Director Tom Frieden. said in a statement ahead of today’s meeting. “Urgent action is needed, especially to minimize the risk of exposure during pregnancy.”
Zika, a virus that has been sweeping through Central and South America since last year, is mainly transmitted by mosquitoes, but can also be transmitted through sexual contact. In general, the virus causes only mild illness, with symptoms such as fever, rash, pink eye, and pain. But in recent outbreaks, Zika has been linked to rare cases of a crippling autoimmune disease, Guillain-Barré syndrome. Most concerning, it’s also linked to devastating birth defects, including microcephaly, in which babies are born with small, misshapen heads and brains.
While researchers are still studying the link between Zika and microcephaly, health experts fear that microcephaly is just one of the potential problems for the unborn child.. “Perhaps one of the most important unknowns is the range of fetal abnormalities beyond microcephaly,” Frieden said at a press conference at the summit. Microcephaly may be the extreme, he and others noted. Babies exposed to the virus in the womb may also suffer from less obvious developmental and cognitive problems, he speculated.
The fear is heightened by recent data that has only strengthened the link between the virus and the birth defect, with some studies showing that the virus kills developing brain cells. In a study published this week in the New England Journal of Medicineresearchers report that they have followed the development of a fetus whose mother was infected with the virus during a trip to Central America while she was three months pregnant.
Using blood tests and magnetic resonance imaging (MRI), researchers watched as the baby’s brain essentially turned to fluid over the course of nine weeks. The woman aborted the fetus at week 21.
Friday’s one-day summit covered such groundbreaking scientific data on the virus and provided training to authorities on how to prevent, treat and talk to the public (particularly pregnant women) about Zika and its health implications. Experts also focused on coordinating efforts to eradicate mosquito populations.
There’s a hodgepodge of practices in different communities to address mosquito control, and many of them are very effective, according to Amy Pope, White House deputy homeland security adviser and deputy assistant to the president who spoke at the news conference. “The goal of today’s summit is to bring all of those practices together in one place, give people a kind of menu of options so they can develop a comprehensive plan well before we see mosquito bites in the continental United States,” she said.
While health experts do not foresee large-scale outbreaks of mosquito-borne Zika in the US, there is reason to expect small clusters of transmission. Zika is transmitted by Aedes mosquitoes, in particular Aedes aegypti and to a lesser extent Aedes albopictus. These mosquitoes, which are found in some parts of the US, can also transmit yellow fever, dengue, and chikungunya viruses. Small outbreaks of chikungunya and dengue pop up every year in certain areas, particularly Texas and Florida. Health experts suspect Zika may behave similarly.
Frieden emphasized how difficult it is to hit back Aedes populations, which are diurnal biters that can breed in very small amounts of standing water. Coordinated, sustained and well-funded efforts are needed to control these populations, he said.
So far, there is no vaccine or specific treatment for Zika. Well, in another scientific report in the journal Science this week, researchers report getting the first detailed 3D image of the virus using cryo-electron microscopy. While the viral close-up is unsurprisingly similar to that of dengue, a related virus, there are slight differences. Those findings may provide clues about how researchers can beat the virus with a vaccine.
New England Journal of Medicine2015. DOI: 10.1056/NEJMoa1601824 (About DOIs).
Science2015. DOI: 10.1126/science.aaf5316