The US Centres for Disease Control and Prevention is asking pregnant women to avoid 22 countries that have seen outbreaks of the Zika virus. That's up eight from just yesterday. Disturbingly, the mosquito-borne virus, which may be causing abnormally small heads in newborns, has also been linked to yet another debilitating disease.
The Zika virus has been spreading rapidly over the past several months, most prominently in Brazil. Its spread has been associated with a dramatic increase in microcephaly, a rare condition in which babies are born with abnormally small heads. No definitive link has been made between Zika and microcephaly, but a recent investigation discovered traces of the virus in placentas of two women who miscarried their babies.
What's more, Brazil is in the midst of an unprecedented microcephaly epidemic, and people are pointing their fingers directly at Zika. In response, health authorities in several countries, including Brazil, Colombia, El Salvador, and Jamaica, have asked women to voluntarily consider delaying their pregnancies.
The CDC is now working with the Brazilian authorities to determine if a potential link exists between Zika and yet another condition, a rare autoimmune disorder known as Guillain-Barré syndrome. Similar to the recent surge of microcephaly, Brazilian health officials have diagnosed hundreds of cases of Guillain-Barré, which represents a significant increase. This disease, in which the body's immune system attacks nerve cells, can cause muscle weakness and sometimes paralysis.
The CDC is recommending that "all pregnant women consider postponing travel to areas where Zika virus transmission is ongoing." As of yesterday, the travel alert (Level 2-Practice Enhanced Precautions) included the following countries:
Brazil, Colombia, El Salvador, French Guiana, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Saint Martin, Suriname, Venezuela, and Puerto Rico
Today, the CDC added eight more to the travel advisory:
Barbados, Bolivia, Ecuador, Guadeloupe, Saint Martin, Guyana, Cape Verde and Samoa
These all happen to be tropical countries in which Aedes aegypti, the mosquito responsible for transmitting the virus from person to person, is able to flourish year round. A dozen cases of Zika have been confirmed in the United States, including a case in Hawaii a few days ago, but in all instances these infections occurred from mosquito bites while travelling.
Health experts are worried, however, that the virus could spread north into parts of the United States due to warming weather.
A. aegypti feeding on a human. The Zika virus is spread by mosquitoes, and cannot be transmitted from person to person. Credit: James Gathany/PHIL/CDC
Around 80 per cent of people who contract the virus show no symptoms. And for those who do, the effects are relatively mild and short-lived. Fatalities are exceptionally rare. Typical symptoms include a slight fever and rash. No vaccine currently exists for Zika, nor are there any antiviral treatments.
The CDC wants health care providers to ask all pregnant women about their recent travel history. Pregnant women who have just returned from any of the aforementioned countries should be "evaluated for Zika virus infection and tested in accordance with CDC Interim Guidance." And because other similar diseases are currently making the rounds in these regions, namely dengue and chikungunya, patients who exhibit any symptoms with the Zika virus should also be tested for these infections.
The CDC is offering this advice for pregnant women who, for whatever reason, cannot avoid a trip to a country currently experiencing Zika virus transmissions:
If a pregnant woman travels to an area with Zika virus transmission, she should be advised to strictly follow steps to avoid mosquito bites. Mosquitoes that spread Zika virus bite both indoors and outdoors, mostly during the daytime; therefore, it is important to ensure protection from mosquitoes throughout the entire day. Mosquito prevention strategies include wearing long-sleeved shirts and long pants, using U.S. Environmental Protection Agency (EPA) — registered insect repellents, using permethrin-treated clothing and gear, and staying and sleeping in screened-in or air-conditioned rooms. When used as directed on the product label, insect repellents containing DEET, picaridin, and IR3535 are safe for pregnant women.
The CDC has also posted these guidelines for using insect repellents.
Top image: Geographic Distribution of Zika Virus as of January 2016, via CDC.