First Chikungunya Case Acquired in US Reported in Florida

Mark Crane

July 17, 2014

The first case of locally acquired mosquito-borne chikungunya virus in the United States has been confirmed in a Florida man, the Centers for Disease Control and Prevention (CDC) announced today.

The man had not recently traveled outside the country. The newly reported case represents the first time that mosquitoes in the continental United States are thought to have spread the virus to a nontraveler, the CDC said in a statement.

Since 2006, the US has averaged 28 imported cases of chikungunya per year in travelers returning from countries where the virus is common, the CDC said. To date this year, 243 travel-associated cases have been reported in 31 states and 2 US territories in the Caribbean Sea.

As of July 11, the CDC reports that local transmission of the virus had been transmitted in 23 countries or territories in the Caribbean, Central America, or South America, with a total of 5037 laboratory-confirmed cases.

"The arrival of chikungunya virus, first in the tropical Americas and now in the United States, underscores the risks posed by this and other exotic pathogens," Roger Nasci, PhD, chief of the CDC's Arboviral Diseases Branch, said in the statement. "This emphasizes the importance of CDC's health security initiatives designed to maintain effective surveillance networks, diagnostic laboratories and mosquito control programs both in the United States and around the world."

The chikungunya virus is transmitted to people by 2 species of mosquitoes, Aedes aegypti and Aedes albopictus. Both species are found in the southeastern United States and limited parts of the southwest; Aedes 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 said.

The CDC and the Florida Department of Health are assessing whether there are additional locally acquired cases and are "providing consultation to the public on ways to prevent further spread of the virus by controlling mosquitoes and educating people about personal and household protection measures to avoid mosquito bites. CDC has asked state health departments to report cases of chikungunya to help track the virus in the United States. Local transmission occurs when a mosquito bites someone who is infected with the virus and then bites another person."

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

People infected with chikungunya virus typically develop fever and joint pain. Other symptoms can include muscle aches, headaches, joint swelling or rash, the CDC said. Travelers returning from areas with chikungunya activity and those living in areas where the virus has been reported in the US should seek medical care if they experience chikungunya symptoms.

Healthcare 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 agency said.

"Infection with chikungunya virus is rarely fatal, but the joint pain can often be severe and debilitating. This virus is not spread person to person. There is no vaccine and no specific treatment for infection, but research is underway in both areas. Patients recover in about a week, although long-term joint pain occurs in some people. Infection is thought to provide lifelong immunity," the CDC said.


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