The Centers for Disease Control released the latest data on the number of chikungunya cases that have been diagnosed in the United States on July 29. New York State has reported 44 confirmed cases of chikungunya. All of the cases are imported, travel-associated.
Neighboring New Jersey has now reported 25 chikungunya cases for 2014. All of those cases are also travel-associated. The mosquito borne illness has been reported from 37 states, Puerto Rico and the U.S. Virgin Islands.
Florida continues to report the most chikungunya cases. The CDC states that the state has seen 105 imported cases as well as the only two locally acquired chikungunya cases in the continental United States. New York ranks second in cases and New Jersey third.
Locally acquired chikungunya cases are those where the patient contracted the viral illness without traveling. Florida has found two such cases. Puerto Rico has 215, according to the CDC and the Virgin Islands have had two.
It is not unusual for New York to report exotic illnesses in large numbers. Through July 20, the CDC reports that the city and state had diagnosed 26 dengue cases, more than any other state. There have been 113 cases of malaria, again ranking New York first in the nation. These are all imported, although there was one locally acquired dengue case on Long Island in 2013.
New York, and New York City in particular, is a major travel destination as well as home to a large number of immigrants. The Census Bureau states that 22 percent of New York's population is foreign born. It is no surprise that the region sees far more unusual, imported diseases than most.
Chikungunya can only be transmitted through the bite of an infected mosquito. Two species of mosquitoes are known to carry the virus, Aedes aegypti (the Yellow Fever mosquito) and Aedes albopictus (the Asian Tiger mosquito). The Yellow Fever mosquito does not inhabit New York but historical records suggest that a small population can develop in southern N.Y. for a month or two during a hot, wet summer. The Asian Tiger mosquito is new to the state and has a limited habitat in the New York City and Long Island area.
The strain of chikungunya currently circulating in the Americas can only be carried by the Yellow Fever mosquito. At this time, there has been no known instances of chikungunya infections contracted from Asian Tiger mosquitoes. Last year's locally acquired dengue illness on Long Island was most likely from a bite by that species, however.