The weekly data on the number of chikungunya cases in the Western Hemisphere has been released by both the Pan American Health Organization (PAHO) and the European Centre for Disease Prevention and Control (ECDC). The two international public health agencies released their data July 5. The data shows that the number of cases and the number of countries or territories affected by the mosquito borne illness continue to climb.
The PAHO is reporting a total of 264,444 suspected or confirmed cases of chikungunya. The illness has been diagnosed in 22 countries or territories. The Dominican Republic and the French islands of Martinique and Guadeloupe have reported the greatest numbers.
The ECDC shows a higher number of chikungunya illnesses, 285,406. The difference is that reports to the ECDC from Martinique and Guadeloupe have a higher number of suspected cases. The ECDC is also reporting 22 chikungunya-related deaths.
Neither agency has the most accurate reporting. Paperwork is taking a backseat to other priorities in many of these small, impoverished nations. A compilation of public and media reports suggests that the actual number of chikungunya cases is well over 315,000.
How many people will catch chikungunya in this first wave of infections? Martinique and Guadeloupe have been reporting illnesses for six months. At this point in time, 11.7 percent of the population of Martinique is believed to have caught the virus. On Guadeloupe, 13.1 percent have.
The Dominican Republic has been reporting chikungunya illnesses for three months. In that time, based upon recent public announcements, 1.6 percent of the population has been infected. It is very likely that this estimate is lower than the actual number of infections.
Suspect or confirmed cases of chikungunya have recently been reported in the Cayman Islands, Brazil and Paraguay. The number of cases in El Salvador and Venezuela continue to increase.
The United States has not been immune to the increase in chikungunya cases. To date, the only locally acquired illnesses have been in the U.S. Virgin Islands and Puerto Rico. Reporting varies but that number is 20-23 for Puerto Rico and three in the Virgin Islands. The PAHO is also reporting an additional 119 suspected chikungunya cases in Puerto Rico.
In the continental United States, the latest reporting by state agencies is 141 imported cases of chikungunya in 29 states. Florida has seen 54 cases, followed by New York and Tennessee with eight each. There have been no locally acquired chikungunya illnesses yet.
Chikungunya is not contagious and does not spread from human to human. It can only be caught by being bitten by an infected mosquito and just two species are known to carry the several strains of the illness. The strain circulating in the Americas is only transmitted by the Yellow Fever mosquito, Aedes aegypti. That species has a limited habitat in the continental U.S.and can only overwinter in the sub-tropical areas of Florida and along the coast of the Gulf of Mexico.