There are a lot of nasty viruses out there, many with strange names that suggest they are mainly problems for remote sections of the rain forest.Since I don't go to remote sections of the rain forest they have been mostly an object of academic interest for me. One of these viruses is an arthopodborne beauty called chikungunya, which has been ably and informatively blogged by my SciBling Tara Smith at Aetiology. But every autumn I head off to a scientific meeting in northern Italy (Emilia Romagna) and now I find that chikungunya has arrived there ahead of me:
A recent outbreak of the debilitating tropical disease known as chikungunya fever in northern Italy apparently marks the mosquito-borne infection's first foothold in Europe, according to European health authorities.Europe has had scattered cases of chikungunya before, mainly in travelers from parts of Africa and Asia where the disease is established. But the outbreak this summer in Italy's Ravenna province was spread by mosquitoes, according to a report published Sep 6 by Eurosurveillance Weekly. (CIDRAP News)
The virus reaches fairly high levels in the human bloodstream, making person to person transmission via a biting mosquito possible. Sporadic imported cases have been reported in Europe and the US before (i.e., cases contracted elsewhere but with onset in Europe or the US), but the Ravenna outbreak is the first in Europe where the virus has spread to non-travelers. The disease is debilitating but usually self-limiting. Here's is Tara's (excellent) description:
After an incubation period of around a week, the patient suffers from sudden onset of a high fever, chills, and headache. Joint pain can be significant, and may persist for weeks. A rash may be present, and in rare cases (more common in children than adults), a hemorrhagic fever manifestation may occur. (Aetiology)
The vector in Italy is the tiger mosquito, Aedes albopictus, which along with another competent vector Aedes aegypti is also found in the southeaster US. Another arbovirus, West Nile virus (WNV), established a foothold in the US after its appearance in Queens, NY in 1999 and has since spread to almost every state. Whether this will hold true with chikungunya is hard to say. There are two crucial differences. One is that the only known reservoir for chikungunya is humans (although other reservoirs may exist but aren't identified), while for WNV there exists a vast endemic reservoir in many species of birds and possible some mammals. On the other hand, in humans levels of WNV aren't high enough to sustain transmission from person to person via a biting mosquito but they are for chikungunya. Of these two opposing factors, the size of the reservoir is probably more important, but there is a great deal about the dynamics of arbovirus infection we don't understand. The Italian outbreak was a great surprise, and now numbers 166 cases.
The mosquito season I hope will be over by the time I get there but I've been there at the same time of year when it has been unseasonably warm, so I am not entirely confident. Self limited or not, it sounds unpleasant, and in some cases aches and pains can last for months. Sorry, but that's not for me.
A century ago there was still a fair among of mosquito borne disease in the US, especially malaria and yellowfever. Now we have the encephalitidies (WNV, St. Louis Encephalitis, Easter Equine Encephalitis and a few more), the possibility of dengue and now chikungunya.
Globalization at its finest.
Medicine & Health
Comments
Since the CIDRAP says the Italian outbreak began with an infected Indian man travelling to Italy, I don't see any reason why it couldn't come to the U.S.
Posted by: caia | September 12, 2007 8:13 PM
caia: It clearly can come here. The question is whether it can propagate here. Imported cases of tropical diseases are not that uncommon. But what happened in Italy (or WNV in the US) is uncommon. The disease has established a foothold there.
Posted by: revere | September 12, 2007 8:19 PM
The tiger appears to be a remarkably prolific vector. I first encountered it in the jungles of Vietnam, in 1965. Very nasty creature. A bite that resembles airborne razor-wire. And it's an extremely aggressive daytime biter. It's not nocturnal, at all. That's one of the reasons that it is so very dangerous.
Posted by: Dylan | September 13, 2007 12:01 AM
The tiger appears to be a remarkably prolific vector. I first encountered it in the jungles of Vietnam, in 1965. Very nasty creature. A bite that resembles airborne razor-wire. And it's an extremely aggressive daytime biter. It's not nocturnal, at all. That's one of the reasons that it is so very dangerous.
I agree with
Posted by: wmwebtr ödüllü seo yarışması | September 13, 2007 12:17 AM
Dylan--
Thanks for the information on tiger mosquitoes. They have arrived here on the Adriatic coast of Slovenia. I noted that once the sun was down the mosquitoes disappeared. It also seems that there are no other varieties of mosquitoes around (i.e. in the past bites during sleep were a major annoyance while this year I haven't been bitten once). My question for you (or anyone) is do tiger mosquitoes eliminate all their Aedes competition? I also wonder if they can pass over the Alps and survive a continental winter. Thanks.
Posted by: slovenia | September 13, 2007 2:23 AM
With global warming we must expect that viruses will change their habitat however they are transmitted, which causes me to ponder the effect of warmth and humidity on H5N1.
Posted by: Marissa | September 13, 2007 9:18 AM
The tiger appears to be a remarkably prolific vector. I first encountered it in the jungles of Vietnam, in 1965. Very nasty creature. A bite that resembles airborne razor-wire. And it's an extremely aggressive daytime biter. It's not nocturnal, at all. That's one of the reasons that it is so very dangerous.
I agree with
Posted by: Spor | November 7, 2007 6:29 AM
With global warming we must expect that viruses will change their habitat however they are transmitted, which causes me to ponder the effect of warmth and humidity on H5N1.
Posted by: wmwebtr ödüllü seo yarışması | November 7, 2007 12:04 PM
SAKOL BACİ!
Posted by: wmwebtr ödüllü seo yarışması | November 24, 2007 1:45 AM
thanks.
Posted by: kelebek | June 19, 2008 8:12 AM