In 2010, imported cases of Chikungunya Fever arrived in North America for the first time. These cases were infected viremic travelers returning from India. But, the first evidence of autochthonous transmission was recorded in December 2013, in Saint Martin, a French island in the Caribbean Region. Probably, these infections are introduced in the island from people that could come from La Réunion, where the transmission has been active since 2004.
From Saint Martin, the new disease spread to several countries in the Caribbean Region. In almost 8 months autochthonous transmission has been detected in 33 countries and territories of the Americas: 27 countries and territories in the Caribbean, 3 countries in Central America, 1 country and 1 territory in South America and 1 country in North America. There were 659,367 reported cases in the region and 37 deaths.
Today, 15 months after the first autochthonous case, 44 countries and territories reported autochthonous cases, while 6 countries reported imported cases only. The incidence rate in Caribbean countries reaches 41 cases per 100.000 inhabitants and the fatality rate, 1%. In Central American countries the incidence rate was 6 cases per 100.000 inhabitants and no deaths were registered. South America reported 1 case per 100.000 inhabitants and only 3 deaths. Brazil presents a particularity: now there are two different outbreaks, one in the North caused by the Asian virus introduced in the country through the French Guiana border, and other in the Northeast caused by the African virus that a Brazilian living in Luanda, Angola transmitted to his family in Bahia.
Some aspects of the disease are important: the majority of the infected people develop symptomatic cases, some patients have a relapse after the acute illness, while others have chronic persistence of the disease for months or years. Since many countries are infested by Aedes aegypti, Chikungunya Fever will probably become endemic in Americas. Like Dengue Fever epidemics, Chinkugunya fever will be a huge challenge. The threats posed to health services and to surveillance programs require an integrated approach of prevention and vector control activities.
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PAHO/WHO Number of reported cases of Chikungunya fever in the Americas, by country or territory, 2013-2015. Epidemiological week EW10 (13 March 2015)
Teixeira MG, Andrade AMS, Costa MCN, Castro JSM, Oliveira FLS, Goes CSB, Maia M, Santana EB, Nunes BTD, Vasconcelos PFC. East/Central/South African Genotype Chikungunya virus, Brazil, 2014. Letter published by Emerging Infectious Diseases, 2015; 21(5). DOI: 10.3201/eid2105.141727.