Imported cases of the mosquito borne illness chikungunya continue to arrive in the United States. Using public health data, media reports and personal contacts, the compiled number of chikungunya cases discovered as of June 5 is 30. There have been no locally acquired chikungunya illnesses in the continental United States.
The Centers for Disease Control have begun listing a count for the number of chikungunya cases reported to them. As of June 2, their count showed 26 imported cases in the continental U.S. One imported case has been found in the U.S. Virgin Islands and one locally acquired chikungunya case in Puerto Rico.
Florida is reporting any chikungunya cases in that state in its weekly Arbovirus Surveillance report. Their May 31 report shows 18 imported cases, two more than the CDC has. WLBT in Jackson MS, reports that an imported case has been diagnosed in nearby Flowood. A U.S. aid worker in Rhode Island has confirmed to me that she has been diagnosed with chikungunya. She returned from Haiti about May 23. Those four cases, added to the CDC count, provide the current national total of 30 chikungunya cases.
The U.S. military has had troops in the Dominican Republic performing a variety of humanitarian assistance missions during the last several weeks. The exercise is named Beyond the Horizon: Dominican Republic 2014. In addition, a new exercise, Tradewinds 2014, is about to bring troops from the U.S. and 15 other countries to the Dominican Republic for maritime security and disaster response training. Both the DR and Haiti are in the midst of a severe chikungunya epidemic. Inquires about troops safety and illness prevention efforts made to the U.S. Southern Command in connection with these exercises have not yet been responded to.
Dr Jake Dunning, of the Imperial College in London, believes that predicting the potential toll from chikungunya may be impossible. In a Twitter exchange, he suggested that there are too many variables. He does believe that, in a climate with seasonal variations, vector control efforts could have some success, but less so in areas with a more stable temperature range.
John W. Belmont, M.D., Ph.D., from the Baylor College of Medicine, agrees that mosquito control is the key. He wondered, in a Twitter exchange, if locally acquired chikungunya would spread on the U.S. Gulf Coast. He noted, in another exchange, that dengue is transmitted by the same mosquito vector and it has been rare, confined to south Florida and the Rio Grande valley of Texas.
Steven Hecht, Ph.D., is an associate professor at Grand Valley State University in Michigan. He points out that life style choices such as using screens, as well as the diverse climate in the United States, “will likely limit” the number of locally acquired chikungunya cases in the U.S. He did state that he would “expect it to be bad in some areas.”