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Changing climate could help the invasive Asian tiger mosquito (Aedes albopictus) spread north

By Dave Armstrong - 25 Apr 2012 21:23:8 GMT
Changing climate may help invasive Asian tiger mosquito spread north

This mosquito vector uses human or animal skin to pass on parasitic viruses and roundworms; Image Credit and Copyright; The Earth Times - Asian tiger mosquito on a flower

In the Top 100 of invasive species, a multi-infective, resilient Asian mosquito (Aedes albopictus, as opposed to the malaria mosquito , Aedes aegypti) seems likely to spread even further than it has already. North and South America, Japan, Africa, the Middle East and southern Europe have already been conquered by the Asian tiger mosquito.

The biting mouthparts are a hazard, but the number of diseases it has carried are beyond belief. The virus, chikungunya fever, is infamous recently for being carried by the mosquito to Reunion, southern Italy and the south of France. Related to this virus, dengue fever has also caused tourists to panic in tropical and now, European locations, just as in the chikungunya fever.

Neither virus causes fatalities in healthy people, but there are several other arboviral infections (various encephalitis viruses, yellow fever, west Nile fever and Rift Valley fever) carried by the insect as well as a dog roundworm that also infects wild animals and cats. This is Dirofilia immitis, a "heartworm" to dog veterinarians. Human infection would probably cause little damage, but zoonoses (conditions caused by animal diseases) have been caused by less dangerous parasites.

As global warming changes many climates and habitats throughout Europe, with wetter and warmer conditions favouring the mosquito and its aquatic larva, the authors have modelled many climate patterns.

European distribution of Aedes albopicta

The European distribution of Aedes albopicta; Credit: Journal of the Royal Society Interface

The red parts show recently observed occurrence of the species(within 5 years)

The mosquito lays eggs on rubber, hence the northern red indications are at used tyre storage centres!

The green parts show absence; while the Ukraine is shown as unknown

At the University of Liverpool, Cyril Caminade and his many confederates have synthesised a total assessment of future trends, then fitted the presence/absence of the mosquito to the different models, as shown in the map above. Their full research was published today in the Journal of the Royal Society Interface.

Further in the future, they have progressed to 2050 to investigate how mosquitoes are suited to various climates then. Surviving the European winter in ponds is critical for the larvae. Mean annual rainfall above 700mm and January temperatures above 2°C are basic to their survival.

Between 1960 and 1989, A.albopictus became established in some of the red areas on the map. Since then, the five month period that the southern French and neighbouring climates can afford the animal has given it a sound base from which to expand for two decades.

The south of England is now suitable, given several introductions, while Greece has few introductions and has only had a record since 2005. In the future, The UK, the Balkans, Germany, Benelux and northern France and Spain are expected to be very suitable for increased activity while drought conditions in the south of Spain and Sardinia are likely to restrain the spread. The threats are lessened by risk factors concerning all of the data.

Optimists will say that all of this work is wasted if the models predictions are slightly inaccurate. However the models cover a multitude of possibilities and one will possibly convey exactly "how it is." The authors warn that we must be watchful, as all the entomologists who contributed data are. Watching ports and harbours and even those tyre stores (see map) would be fruitful, with northern American and Asian locations possibly just as watchful.

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Topics: Insects / Invasive Species