EuroSurveillance.org released an interesting report of the cases of Chikungunya Virus in Italy. The outbreak appears to be over, due to the change in weather. The outbreak, which was centered in the Ravenna province in north-eastern Italy, has not had a reported case since September 28, 2007. Of the suspected 334 cases of Chikungunya virus, 204 were confirmed by lab results.
Chikungunya virus is a common illness, spread by mosquito bite (Aedes Albopictus species), and found in tropical countries. The initial source of this particular outbreak in Italy is believed to be a traveler from India, who imported the virus. Chikungunya is generally a self-limited infection that causes influenza like symptoms such as fever, muscular aches and fatigue.
There are several important learning points, from this outbreak. A virus that has previously never been a problem in Europe, can now run rampant. This underscores the ease of transmission, with a traveler being infected in India, only to continue to spread that tropical illness at their new destination. Several things had to be in place for this to occur. First, there needs to be a suitable vector, to carry the disease. The vector in the Chikungunya Italy outbreak was the Aedes mosquito.
The presence of this unique mosquito species in Italy has multiple causes but climate change is one of the leading ideas. http://woodshedenvironment.wordpress.com/ is a very good blog that addresses some of these factors. The blog centers on the fight against Dengue fever (another mosquito spread virus) in the Carribean. However, the author clearly addresses the factors of mosquito spread and the role of the vector in transmission.
Lastly, the change in the weather, from summer to winter, has effectively killed all the mosquitoes. No mosquitoes, no disease spread. If a person has the virus and is bitten by a mosquito, the mosquito carries the virus until it bites another person. This is how the virus spreads quickly and is difficult to control. For some tips on controlling mosquito bites and basic protection: http://adventuredoc.net/2007/11/06/mosquito-bite-prevention/