Monday, February 29, 2016

Zika virus: what do family physicians need to know?

- Jennifer Middleton, MD, MPH

Zika virus continues to make headlines as researchers study both its spread and its possible connections with Gullian-Barre disease and microcephaly. Family physicians are likely to come across questions related to travel and the Zika virus, and we are also potentially the first source of contact for a returning infected traveler.

The Zika virus is a single-stranded RNA virus that is primarily transmitted via mosquito bite, but reports of sexual and mother-to-child transmission have also been described. The only documented cases in the mainland United States (not including Puerto Rico or other Caribbean U.S. territories) thus far are in travelers returning from affected countries. Many individuals with Zika virus are asymptomatic, but the 1 in 5 who do exhibit symptoms complain of fever, maculopapular rash, arthralgia, myalgia, conjunctivitis, and/or headache. The CDC provides a lengthy list of diagnoses to consider in the differential, and obtaining a detailed travel history is crucial to narrowing the list. Typically, Zika illness is not life-threatening, but correlations with an increased rate of microencephaly to infants born to infected mothers in Brazil and surrounding countries may worry parents-to-be. While the CDC has advised pregnant women to "consider postponing travel to any area where Zika virus transmission is ongoing," they have not yet advised pregnant women to completely avoid travel to Zika-affected areas. For travelers to affected areas, however, they do recommend that:
[P]rotection from mosquito bites is required throughout the day. Prevention of mosquito bites includes wearing long-sleeved shirts, pants, permethrin-treated clothing, and using United States Environmental Protection Agency (EPA)-registered insect repellents. Insect repellents containing ingredients such as DEET, picaridin, and IR3535 are safe for use during pregnancy when used in accordance with the product label
Family physicians should contact their local or state health department if they have a patient returning from a Zika-affected area who should be tested for Zika virus; all pregnant women, symptomatic or not, returning from affected areas should be offered testing, as should all potentially symptomatic individuals. Only the CDC and a few state health departments are currently equipped to test for Zika virus, and their expertise is necessary in interpreting the results since other flaviviruses like dengue and yellow fever can also give a positive result. Full instructions for sending samples to the CDC for testing can be found on this website, but, again, family physicians should consult with their local or state health department prior to doing so.

The above information is important for us to share with patients who come to see us for pretravel consultation, especially for pregnant women, women of child-bearing age, and their partners. Up-to-date travel health notices can be found on the CDC website, and they also have patient information resources here.

Under the Featured Content section of the AFP website's homepage are several useful resources about Zika virus from the AAFP, CDC, and others that are continually updated as new information becomes available. If you'd like to read more on travel medicine in general, there's an AFP By Topic on Travel Medicine which includes this useful 2009 article on pretravel consultation.