Travel Associated Cases of Chikungunya Fever, Rhode Island, 2014.

Large outbreaks of chikungunya fever can occur when chikungunya virus (CHIKV) is introduced into a susceptible population where the appropriate vectors are present (1). It has been long known that many countries located within the Carribean have conditions appropriate to support a CHIKV outbreak (2). On December 7, 2013, the World Health Organization reported the first local autochthonous transmission of CHIKV in the Americas. Subsequently, on December 13, 2013, the CDC released a health advisory instructing U.S. public health officials and clinicians how to recognize, manage and report CHIKV infections in travelers returning from the Caribbean. By the end of 2014, the America’s had over 1.1 million cases of chikungunya fever (3). Chikungunya fever is characterized by an acute onset of fever (typically > 102°F) and polyarthralgia. Other common symptoms may include myalgia, headache, arthritis, conjunctivitis, nausea/vomiting and a macropapular rash. Acute symptoms usually resolve in 7–10 days, but joint pains and other symptoms may persist for months to years in some individuals (4). Rare complications have been documented (5). CHIKV is an Alphavirus that is transmitted to humans by infected Aedes aegypti and Aedes albopictus mosquitoes. Humans and other primates serve as the main amplification reservoir. Individuals infected with CHIKV are viremic from the day of symptom onset up to seven days post onset, after which the virus becomes undetectable by RT-PCR (6). Once exposed to the virus, most individuals exhibit symptoms and only 3% to 28% remaining asymptomatic. The incubation period is typically 3–7 days (range, 1–12 days) (4). The human immunogenic response to CHIKV is rapid with IgM detectable as early as four days after illness onset and IgG detectable a day later on the fifth day (6).