Two days ago Eurosurveillance stated that 10 Spanish travelers returning from Haiti and Dominican Republic between April and June were infected with the chikungunya virus (CHICKV). This infectious agent, transmitted to humans by two mosquito species, Aedes aegypti and Aedes albopictus (both being found in some of the southern parts of the US), started to spread in the Caribbean in October 2013, obviously threatening the shores of North, Central and South America. Previously, in Europe, localized outbreaks were reported in Italy (2007) and France (2010). The same day (July 17), CDC reported a locally acquired human contamination in Florida which represents the first case in the continental US. Previously, from 2006 to 2013 an average of 28 people were positively diagnosed in the US every year, all being travelers returning from affected countries, mostly from Asia. As of July 15 already 357 chikungunya cases were reported from different US states and territories. Out of these cases, 120 people were locally infected in Puerto Rico and 3 in the US Virgin Islands. All other cases were travel-associated: 230 people returning from the Caribbean and South America, 3 from the Pacific Islands and 1 from Asia.
One of the features of this disease is that only 75 % of cases are symptomatic. The average incubation period is between 2-4 days (which could range between 1 to 12 in some cases) the main symptoms being fever, headache, rash and arthralgia (joint pain), quite common in other infectious diseases as well, like dengue fever or malaria. Therefore, any confirmation of the disease should be based on molecular laboratory analysis. Occasionally, complications could include myocarditis, hepatitis or encephalitis (inflammations of heart muscle, liver and brain, respectively), ocular disorders, and even hemorrhagic fever.
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WHO and CDC states that no commercial vaccine or antiviral drug is currently available. The best (and perhaps only) way to prevent the infection is by avoiding mosquito bites. This include wearing long sleeves and pants when outdoors (including daytime, the above mentioned mosquito species being considered day-biting vectors) or by using repellents and protective window screens. Special care should be taken against any potential breeding site nearby human communities, such as natural or artificial water containers/sources that could allow mosquito larvae development. Unlike Aedes aegypti, which is a mosquito that usually spreads across tropical and sub-tropical regions, Aedes albopictus occurs in temperate regions as well, populations being localized in many such areas in Europe or the Americas. This species, originally from Asia, also known as the tiger mosquito, has a high degree of adaptability, including by using apparently insignificant water breeding sources like rock pools, tree holes, vehicle tires, or even the trays beneath the flower or other decorative plant pots.