Mosquito-Borne Virus Spikes in Western Hemisphere

Chikungunya virus spreading rapidly in Caribbean but not likely to cause large US outbreak

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) In the previous months, chikungunya cases have spiked in the Western Hemisphere. While locally transmitted cases have been confirmed in Florida, officials don't think the virus will spread rapidly in the US.

While the Centers for Disease Control and Prevention (CDC) reports that US territories have seen 221 chikungunya cases in 2014, only four locally acquired cases have been reported on the mainland, with the first two confirmed at the beginning of last month. All US cases have been in Florida.

But, since the first confirmed case in the Western Hemisphere in December 2013, the virus has spread quickly. The Pan American Health Organization reported more than 400,000 potential Western Hemisphere cases in late July.

"Avoid unnecessary exposure to mosquitoes."

Chikungunya is a virus spread to humans through infected mosquitoes and marked by fever and sometimes debilitating joint pain. While there isn't a cure for the disease, the symptoms usually subside within a few weeks. Some patients report lingering joint pain.

CDC epidemiologist Erin Staples, MD, PhD, told JAMA that the virus likely won't spread as far as it has elsewhere because Americans tend to spend less time outside and use screened doors and windows, reducing exposure to mosquitoes. She also said that the current outbreak is more prevalent in a type of mosquito that is not as common in the US.

Two types of mosquitoes can carry chikungunya: Aedes aegypti and Aedes albopictus. The current virus is mostly spread through the former, also known as the tiger mosquito, reports the Scientific American.

Despite the low number of locally transmitted cases in the US so far, the CDC reported 584 US cases Aug. 12. These patients likely became infected while traveling to the Caribbean or Central or South America.

Dr. Staples told JAMA that as much as 12 percent of the population of French Saint Martin in the Caribbean has been infected with chikungunya.

Ann Powers, PhD, chief of the CDC's Alphavirus Laboratory, said travelers returning to the US from high-risk areas raise the chances of a US outbreak.

"Many U.S. travelers visit countries where chikungunya virus is found," she said on the CDC website. "Therefore, we expected that chikungunya would not be restricted to regions south of the continental United States. The more American tourists return home from these areas with chikungunya virus in their blood, the higher the risk of outbreaks here."

According to a recent JAMA article, Florida typically reports one case of chikungunya from travel per year. So far this year, that number is up to more than 80.

Those living in areas where chikungunya has been reported can help prevent its spread by using insect repellent, wearing long pants and sleeves and checking window and door screens for holes, says the Florida Department of Health.

Review Date: 
August 14, 2014
Last Updated:
August 15, 2014