Chikungunya: An exotic virus on the moveA tropical virus now endemic in a temperate climate, chikungunya is not usually a killer though it is very painfully unpleasant. The first cases on the European continent occurred in northeastern Italy in 2007. Infectious diseases, do not respect borders. Their vectors and hosts can hop a ride on a plane or a boat, and arrive in the US unexpectedly. Some of them like it just fine over here, and have adapted very well. West Nile arrived in the US in New York in just 1999. It is now endemic, and is continuing its spreading throughout the Americas killing hundreds of millions of birds and more than a thousand humans as well.http://www.cidrap.umn.edu/cidrap/content/other/news/sep1007chik.html There is a possibility that the same thing could happen in the United States, since the two mosquito species that can spread the virus are found in the Southeast, according to an official with the US Centers for Disease Control and Prevention (CDC). But he said the likelihood of that is "relatively low."Chikungunya usually causes fever, headache, fatigue, nausea, vomiting, muscle and joint pain, and a rash, according to the CDC. The disease is not life-threatening. Symptoms typically last a few days to 2 weeks, but fatigue or joint pain sometimes lingers for weeks to months, the CDC says.The name "chikungunya" is Swahili for "that which bends up," a reference to the stooped posture associated with joint pain. There is no vaccine or specific antiviral treatment for the illness, which is caused by a virus of the genus Alphavirus.The report says A albopictus is found in several other European countries, including Albania, France, Belgium, Montenegro, Switzerland, Greece, Spain, Croatia, the Netherlands, Slovenia, Bosnia, Herzegovina, and possibly more, suggesting a potential for further spread of the disease."We don't even know why West Nile disease [another mosquito-borne viral illness] became endemic in North America but not in Europe, even though the virus and the vector are present on both continents," Evelyn Depoortere, an epidemiologist at the European Centre for Disease Prevention and Control in Stockholm, told Nature."For chikungunya to be transmitted in the US, you need to have a viremic person or mosquito introduction in an area where both susceptible persons and the predominant mosquito vector are present," Hayes said. "Both those conditions exist in the US, so I think the importation of chikungunya is a concern."But the risk of indigenous transmission is "probably relatively low in the continental United States," mainly because of socioeconomic and lifestyle differences that tend to limit the spread of mosquito-borne viruses like chikungunya, dengue, and yellow fever, Hayes said. For example, air conditioning and window screens help protect people from heavy exposure to mosquitoes, he explained.However, areas where dengue transmission already occurs or is possible may be more vulnerable to chikungunya, Hayes said. Such areas include parts of Florida and Texas, plus Puerto Rico and the US Virgin Islands."It's possible, if the virus should become endemic in, say, the southeastern US, that it could provide a locus for spread to other parts of the country, but I wouldn't think it would spread like West Nile virus," he said. Birds have helped spread West Nile across the continent since the disease emerged in New York City in 1999.Here is a brief explanation for why the Aedes albopictus mosquito has now become a much better vector for the spread of the chikungunya virus. It wasn't always, but viruses evolve, and adapt. Here is what this "smart" virus did to ensure its own survival.http://www.virology.ws/2009/03/18/chikungunya-an-exotic-virus-on-the-move/The rapid global movement of chikungunya virus appears to be a consequence of a change in its mosquito vector. Some time during 2005 a virus was selected with a single amino acid change in the envelope glycoprotein which allows efficient replication in Aedes albopictus ...This mosquito was never a good host for chikungunya virus, partly because it bites so many different animal species. The amino acid change enhances viral replication in the mosquito, leading to much times higher levels of virus in the salivary gland. Consequently the virus is more likely to be transmitted upon biting a new host.To further complicate matters, not only is Aedes albopictus now a good host for chikungunya virus, but the mosquito is spreading across the globe from eastern Asia to Europe and the United States. The mosquito was first found in the New World in 1985 when it was isolated in Houston, Texas. It probably traveled there from northern Asia in ships carrying scrap tires. But there are at least five other reasons to worry about Aedes albopictus: the mosquito has also been found to carry eastern equine encephalitis, Keystone, Tensaw, Cache Valley, and Potosi viruses.Supporting public health efforts in the developing world helps to protect all of us, but our own public health system needs attention, and support too. It is underfunded, and likely to be overlooked given how bad the economy is. Maybe, the Obama administration will do the right thing by it. http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=219364The chain of chikungunya fever outbreaks from Kenya to Italy reflects a convergence of factors including: rapid international transport, previous introduction of exotic mosquito species, inadequate mosquito control, and climatic conditions. Increasingly important in vector-borne disease emergence, these factors have facilitated other recent epidemics involving imported microbes and local vectors. For high-income countries, the increasing range of vector-borne diseases suggests two major implications: First is the need to maintain vector control capabilities, and second countries should recognize that public health system weaknesses in developing countries endanger all countries.