Florida man acquires first “local” chikungunya case in the U.S.: Deet, birds or bats?

March 18th, 2015

Another mosquito-borne virus threatens to establish an endemic presence in the United States, as a Florida man recently became the first American to acquire chikungunya (chik-un-GUHN-ya) without traveling to a country where its spread is common. The first “locally acquired” case of chikungunya -- which can cause severe and debilitating joint pain -- was reported July 19^th by the Centers for Disease Control and Prevention.

Though chikungunya rarely causes death, the last thing this country needs is more joint problems. There is no vaccine and no specific treatment for chikungunya, so avoiding mosquito bites and eradicating breeding areas are important. Patients recover in about a week, although long-term joint pain occurs in some people. According to the CDC, infection is thought to provide lifelong immunity.

Since 2006, the United States has averaged 28 imported cases of chikungunya annually in travelers returning from countries where the virus is common. However, this year the virus is rapidly spreading after first establishing a base in the Caribbean, with 243 travel-associated cases reported in 31 states and two territories. The virus does not spread from person to person in the traditional sense, but is transmitted by mosquitos biting an infected human and then spreading the virus while feeding on the blood of a subsequent victim.

The mosquitos that typically carry chikungunya are Aedes aegypti and Aedes albopictus, the latter described by the CDC as an “aggressive biter” and the former a “sneaky biter.” Both species are found in the southeastern United States and limited parts of the southwest. A. albopictus is also found further north up the East Coast, through the Mid-Atlantic states and is also found in the lower Midwest, the CDC reported. Both mosquitoes will bite boldly in the full light of day, with the A. albopictus “Asian Tiger” a particular threat to spread disease because it often moves from person to person in taking its blood meals.

CDC officials believe chikungunya virus will behave like dengue virus in the United States, where imported cases have resulted in sporadic local transmission but have not caused widespread outbreaks. None of the more than 200 imported chikungunya cases between 2006 and 2013 triggered a local outbreak. However, as more chikungunya-infected travelers come into the United States likelihood increases that more local transmission will occur.

Outbreaks of chikungunya have been previously reported from countries in Africa, Asia, Europe, India, and the Middle East, and on the French side of the Caribbean island of St. Martin. The virus spread quickly in St. Martin and through the Caribbean in December 2013 and into South and Central America. Local transmission has been reported in 23 countries in the hemisphere prior to the U.S. case. In addition to fever and joint pain, symptoms can include muscle aches, headaches and rash. Travelers returning from areas with chikungunya activity and those living in areas where the virus has been reported in the United States should seek medical care if they experience chikungunya symptoms. Health care providers in areas with reported cases should be on the alert for possible cases.

People infected with chikungunya should protect themselves by wearing insect repellents, using air conditioning or window and door screens to keep mosquitoes out, wearing long pants and long-sleeved shirts when possible, and emptying standing water outside your home. “Protecting yourself and others from mosquito bites during the first few days of illness can help prevent other mosquitoes from becoming infected and reduce the risk of further spread,” the CDC emphasized

Both bats and Purple Martin birds will eat mosquitos, but suggestions that these animals be employed as a natural defense against vector-borne diseases keep running into the same problem: they don’t eat mosquitos exclusively and won’t necessarily pass up a meal of something else to hunt down the insects. N,N-diethyl-3-methylbenzamide (DEET) remains an effective mosquito repellent, but more “natural” options are also available, according to the American Mosquito Control Association .