Influenza is spread person to person but there are viruses that depend upon another intermediate host to travel from host to host. Many of these viral diseases are found in tropical climes, although they used to be common in temperate regions. The US had quite a lot of malaria and yellow fever in the 18th and 19th centuries. These are both mosquito-borne diseases. They were eliminated by eliminating the mosquito species that carried them. Lately the US has had a resurgence of encephalitis viruses, especially West Nile and Eastern Equine Encephalitis. Recently a new mosquito-borne viral disease has started to take root in Europe, chikugunya virus. Two factors were needed. One was the virus itself, the chikungunya virus. But the other is a competent mosquito vector, in this case the vicious Tiger mosquito, Aedes albopictus. We discussed its origin in a couple of posts (here and here) last fall. Now we find that Aedes albopictus is spreading out of Italy and has been found in Switzerland -- north of the Alps:
The first tiger mosquito was detected in the canton of Ticino in 2003 [3]. Monitoring was gradually intensified due to growing mosquito densities in northern Italy. As the long-distance migration of Ae. albopictus depends on passive transport, the monitoring system consisted of strategically positioned oviposition traps along main traffic axes, including parking lots within industrial complexes, border crossings and shopping centres. In 2007, this monitoring system consisted of over 70 checkpoints with a total of 300 traps.[snip]
Between 2003 and 2006, the tiger mosquito density (1.4-3.3% positive traps) detected by the monitoring system was low enough to support the hypothesis that individual adults had been introduced sporadically from Italy but had not been able to establish locally. However, the situation changed significantly in 2007. Within the border city of Chiasso, a dramatic increase of positive traps and a higher number of eggs were both observed, indicating that a local mosquito population had established (Figure 1 and 2). At the same time, based on information offered by a member of the public, the first tiger mosquito was confirmed in Switzerland north of the Alps, in the canton of Aargau. (Eurosurveillance)
A. albopictus is not only a competent vector for chikungunya infection but for dengue fever. This nasty little biter also can be found in the US southeast. I wouldn't be a bit surprised to see homegrown chikungunya and dengue in both northern Europe and the southern US in the next decade.
Maybe you didn't hear it hear first. But you heard it here.
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Have been listening to Curious Orange at radionetherlands.nl/radioprogrammes/curiousorange/ on a weekly basis. Last week they had a short discussion on the growing mosquito problem there. One fellow said, "I nearly fell off my bicycle when I saw a swarm of mosquito's last summer flying through the sky." (something close to the quote, not claiming exact words here).
As a side note, was at the doctor's recently and tried again to share H5N1 information with him, he refused and outright said he's more concerned about mosquito's.
Thats bad news for all folks north of the Alps. With the last two winters not being cold enough we have seen tick born disease (here, that is in southern Germany, thats Lyme and FSME mainly) spreading further and starting earlier in the course of the year.
We've got Tiger mosquitoes here on the Adriatic coast of Slovenia. They are daytime feeders and disappear after dusk. Over the past couple of years I have noticed an almost complete absence of nightime feeding mosquitoes. Does anyone know if the Tigers drive all other species away? Thanks.