Chikungunya (CHKV) is a mosquito-borne virus that - up until a decade ago - was only seen in central Africa. In 2005 it jumped to Reunion Island in the Indian Ocean, where it sparked a major epidemic infecting tens of thousands. Since then it has spread rapidly to counties such as India, Thailand, Vietnam, Indonesia, Myanmar, Pakistan, and others in Asia and the Western Pacific.
While rarely fatal, the CDC describes the symptoms of infection as lasting a few days to a few weeks, producing `debilitating illness, most often characterized by fever, headache, fatigue, nausea, vomiting, muscle pain, rash, and joint pain’, although some may experience `incapacitating joint pain, or arthritis which may last for weeks or months.’
About 10 days ago the CDC held a COCA Call On Chikungunya to inform clinicians of the recent arrival of the Chikungunya virus to the Americas (see ECDC Epidemiological Update: Chikungunya Spreads In Caribbean And Into South America), and to advise them on how to diagnose, report, and treat the illness should it show up in the United States.
Date: Tuesday, February 18, 2014
J. Erin Staples, MD, PhD
Arboviral Diseases Branch
National Center for Emerging and Zoonotic Infectious Diseases
Centers for Disease Control and Prevention
Chikungunya virus is a mosquito-borne virus that can cause fever and severe polyarthralgia. Outbreaks of the chikungunya have occurred in countries in Africa, Asia, Europe, and the Indian and Pacific Oceans. In late 2013, the first local chikungunya virus transmission in the Americas was reported on islands in the Caribbean. Travelers to areas with ongoing outbreaks are at risk of becoming infected and spreading the virus to new areas, including the United States. During this COCA call, a CDC subject matter expert will provide information on chikungunya virus epidemiology, clinical findings, diagnosis, treatment, and prevention. Additionally, they will describe the importance of early recognition and reporting of suspected cases to mitigate the risk of local transmission.
At the conclusion of the session, the participant will be able to accomplish the following:
- Describe which patients to test for the infection
- Explain testing, treatment and prevention measures for chikungunya
- Understand the importance of early recognition and reporting of cases
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The ECDC’s most recent Communicable Disease Threats Report (Feb 28th) indicates that the transmission of the virus in the Caribbean continues unabated, with more than 8,000 suspected and confirmed cases over the past several months.
Chikungunya outbreak - The Caribbean, 2013
Opening date: 9 December 2013 Latest update: 14 February 2014
Cases reported as of 28 February 2014:
- Virgin Islands (UK), 6 confirmed cases;
- Saint Martin (FR), 2 030 suspected and 765 confirmed or probable cases;
- Sint Maarten (NL), 115 confirmed autochthonous cases;
- Martinique, 3940 suspected and 1058 confirmed or probable cases;
- Saint Barthélemy, 380 suspected and 127 confirmed or probable cases;
- Guadeloupe, 1 460 suspected and 476 confirmed or probable cases;
- Dominica, 45 confirmed cases (imported) and 44 autochthonous cases;
- French Guiana, 17 confirmed cases, 10 of which are autochthonous cases;
- Anguilla, 11 confirmed cases on the island with one case probably originating from Saint Martin;
- Aruba, one imported case originating from Sint Maarten;
- St. Kitts and Nevis one confirmed case.
ECDC assessmentEpidemiological data indicate that the outbreak, which started in Saint Martin (FR), is expanding. An increasing number of cases have been observed from most of the affected areas. The vector is endemic in the regions, where it also transmits dengue virus. Vigilance is recommended for the occurrence of imported cases of chikungunya in tourists returning to the EU from the Caribbean, including awareness among clinicians, travel clinics and blood safety authorities. The autochthonous cases in French Guyana are the first autochthonous chikungunya cases in mainland South America.
Although we’ve seen imported cases of Chikungunya into the United States, thus far onward transmission via local mosquito vectors has not been documented. Of course, the same could have been said about the West Nile Virus prior to the late 1990s, and Dengue before 2009.
The most competent vector for the virus is the Aedes Albopictus mosquito (followed by the Aedes aegypti), which arrived in the United States in the 1980s, and can now be found across a wide swath of the country.
Aedes albopictus (Asian Tiger) Mosquito - Wikipedia
Dark blue: Native range
Dark green: introduced (as of December 2007)
The risks of CHKV introduction was considered great enough that in 2011, the CDC and PAHO (Pan American Health Organization) put together a 161-page guide on preparing for the arrival of Chikungunya to the Americas (see Preparedness and Response for Chikungunya Virus Introduction in the Americas).
Now, with the virus literally on our doorstep, officials worry that it is only a matter of time before we begin to see outbreaks here in the United States (see WSJ report Approach of Mosquito-Borne Virus Has U.S. on Alert).
With no vaccine available, and limited treatment options, the best strategy is prevention. For public health officials, that means stepping up mosquito control projects and launching public awareness campaigns to reduce transmission.
Between the increasingly common West Nile Virus, and rare reports of Dengue or EEE (Eastern Equine Encephalitis), and the prospect of having Chikungunya arrive, this advice from the Florida health department remains very much worth heeding.