In December 2013, the World Health Organization reported the first cases of transmission of Chikungunya virus in the Americas, on the island of St. Martin in the Caribbean (cdc.gov/travel/notices/watch/chikungunya). Since that report, >2000 cases of Chikungunya have been reported from eight different Caribbean islands. As of July 11, 2014, the Pan American Health Organization had reported 259,723 suspected and 4,721 confirmed cases of locally-acquired chikungunya fever in the Americas. With over 130 cases in over 20 states reported in the U.S., the chances of having an outbreak here are increasing.
Chikungunya is an Alphavirus transmitted by Aedes mosquitoes, the same mosquitoes that transmit dengue. The first cases of Chikungunya were reported from Africa in the 1950s; since 2004 the disease has spread through Southern Asia and Europe and caused millions of human infections. The symptoms of Chikungunya are abrupt onset of high fever accompanied by severe joint pain and stiffness (arthralgia/arthritis/tenosynovitis), particularly of the hands and feet, but other joints can be involved. The pain is often symmetric and debilitating. A maculopapular rash may develop two to three days after the onset of fever, and may be accompanied by headache, fatigue, nausea, vomiting, and myalgias (cdc.gov/travel/yellowbook/chikungunya). Symptoms usually begin within a week of an infected mosquito bite, and while the fever typically resolves after three to five days, in 10% of cases the joint pain and debility can persist for weeks or months. Accompanying laboratory abnormalities can include lymphopenia, thrombocytopenia, elevated creatinine and liver function tests. Complications and fatalities are both rare. Treatment is supportive, including analgesics, antipyretics, and intravenous fluids if needed. There is no licensed vaccine for Chikungunya, though some candidates are entering phase I human studies. The only effective prevention is mosquito avoidance.
Chikungunya virus disease cases reported by state or territory – United States, 2014 (as of July 22, 2014)
Source: http://www.cdc.gov/chikungunya/geo/united-states.html#arbonet-data
Countries and territories where chikungunya cases have been reported* (as of July 22, 2014).
*Does not include countries or territories where only imported cases have been documented. This map is updated weekly if there are new countries or territories that report local chikungunya virus transmission.
Source: http://www.cdc.gov/chikungunya/pdfs/ChikungunyaWorldMap_07-22-2014.pdf
The diagnosis of Chikungunya is based on clinical symptoms and history of recent travel (< 2 weeks) to an area reporting disease activity. Suspected cases can be tested for Chikungunya IgM and IgG antibodies in reference laboratories, or for neutralizing antibodies at the CDC. Because people with Chikungunya have high levels of virus in blood during the first two to six days of the illness, they should be advised to remain indoors behind mosquito screens to prevent further spread of the disease. As of this writing, only a few locally-acquired Chikungunya cases have been reported from the continental U.S., but give the wide prevalence of the Aedes mosquito vector and the rapid spread of this disease since 2004, clinicians should remain alert for an increasing number likely to occur. Clinicians are advised to consult the CDC website for updates on this disease, particularly if they have patients who plan travel to affected areas or if they are treating a case of fever and arthritis in a returning traveler.