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CDC: Providers should consider Zika in returning US travelers
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Health officials are urging providers to be more aware of Zika virus in travelers returning to the United States, and to inform patients about the potential risks associated with the disease and how to reduce exposure to mosquitoes in areas with active Zika virus transmission.
Morgan J. Hennessey, DVM, an Epidemic Intelligence Service officer at the CDC’s Division of Vector-Borne Diseases, told Infectious Disease News that the risk of infected travelers returning to the U.S. and spreading the disease through local transmission has not been fully established.
Morgan J. Hennessey
“So far, we have about 400 cases or so that have been diagnosed in travelers returning to the United States, and none of those cases has led to local vector-borne transmission,” Hennessey said in an interview. “It’s a question we’re all still trying to answer right now — exactly what that risk is. So far we haven’t seen it. We know that mosquitoes that transmit the virus are present in certain areas of the U.S., but we don’t know what that risk might be.”
Hennessey and colleagues have been tracking positive Zika virus (ZIKV) test results performed at the CDC since 2010. Some of their findings, presented at the CDC’s Epidemic Intelligence Service Conference in Atlanta, show that only 11 travel-associated ZIKV disease cases (median age, 50 years; 55% male) were identified in the U.S. between 2010 and 2014. The onset of illness predominantly occurred from January to April 2014 (82%), and the majority of cases reported rash (91%), fever (90%), myalgia (80%), arthralgia (64%) and conjunctivitis (56%). All of the cases reported traveling to islands in the Pacific Ocean days before becoming ill and were potentially viremic after returning to the U.S., the researchers said.
Since 2015, imported cases of ZIKV have increased significantly in the U.S. In a recent analysis of travel patterns and weather models, researchers found that 50 cities across the country could support the Aedes aegypti mosquito, a primary vector of ZIKV, although not every city has documented populations of that species. The researchers determined that cities in southern Florida and impoverished areas of southern Texas are more susceptible to local outbreaks than anywhere else in the country.
Although the actual risk for local transmission in the U.S. is unknown, Hennessey advised clinicians to consider ZIKV in the differential diagnosis of patients — particularly pregnant women — who present with symptoms after returning from areas with active transmission.
“Zika virus is something that the clinician should be aware of and, if the clinical symptoms are compatible with it, something they should test for, and something they should report to the state or local health department,” he said. – by John Schoen
References:
Hennessey MJ, et al. Zika Virus in Returning U.S. Travelers — United States 2010-2014. Presented at: Annual Epidemic Intelligence Service Conference; May 2-5, 2016; Atlanta.
Monaghan AJ, et al. PLoS Curr. 2016;doi:10.1371/currents.outbreaks.50dfc7f46798675fc63e7d7da563da76.
Disclosure: Hennessey reports no relevant financial disclosures.