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04.05.09 / MEDCON
Climate change brings Dirofilaria infections to Northern Europa
Reviewing the effects of climate on Dirofilaria infections in Europe, researchers conclude that if the actual trend of temperature increase continues, filarial infection will spread into previously infection-free areas.
MILAN/ITALY, (04 May 2009) – Reviewing the effects of climate on Dirofilaria infections in Europe, researchers conclude that if the actual trend of temperature increase continues, filarial infection will spread into previously infection-free areas.
In their study, to be published in Veterinary Parasitology, Dr. Claudio Genchi, from University of Milan, and colleagues evaluated the effects of climate and other global drivers on Dirofilaria immitis and Dirofilaria repens infections in Europe and the possible implications on the transmission and control of these mosquito-borne nematodes.
In the last several years, growing degree day (GDD) based forecast models, which use wide or local scale temperature data, have been developed to predict the occurrence and seasonality of Dirofilaria in different parts of the world. All these models are based on the fact that on the one hand there is a threshold of 14 °C and below in which Dirofilaria development will not proceed and on the other hand there is a requirement of 130 GDD for larvae to reach infectivity and a maximum life expectancy of 30 days for a vector mosquito, the Italian researchers write.
“The output of these models predicts that summer temperatures (with peaks in July) are sufficient to facilitate extrinsic incubation of Dirofilaria even at high latitudes,” they report, adding that the global warming projected by the Intergovernmental Panel on Climate Change suggests that warm summers suitable for Dirofilaria transmission in Europe will be the rule in future decades. Thus, they say, if the actual trend of temperature increase continues, filarial infection should spread into previously infection-free areas.
Apart from that, they point out that “these factors do not only favour incubation of Dirofilaria, but have also an impact on mosquito species.” Recent findings, for instance, have demonstrated that Aedes albopictus is now considered to be an important, competent vector of Dirofilaria infections. This mosquito species could spread from southern to northern European countries in the near future, changing the epidemiological patterns of dirofilariosis both in humans and animals, Genchi’s team writes.
In the last several years, growing degree day (GDD) based forecast models, which use wide or local scale temperature data, have been developed to predict the occurrence and seasonality of Dirofilaria in different parts of the world. All these models are based on the fact that on the one hand there is a threshold of 14 °C and below in which Dirofilaria development will not proceed and on the other hand there is a requirement of 130 GDD for larvae to reach infectivity and a maximum life expectancy of 30 days for a vector mosquito, the Italian researchers write.
“The output of these models predicts that summer temperatures (with peaks in July) are sufficient to facilitate extrinsic incubation of Dirofilaria even at high latitudes,” they report, adding that the global warming projected by the Intergovernmental Panel on Climate Change suggests that warm summers suitable for Dirofilaria transmission in Europe will be the rule in future decades. Thus, they say, if the actual trend of temperature increase continues, filarial infection should spread into previously infection-free areas.
Apart from that, they point out that “these factors do not only favour incubation of Dirofilaria, but have also an impact on mosquito species.” Recent findings, for instance, have demonstrated that Aedes albopictus is now considered to be an important, competent vector of Dirofilaria infections. This mosquito species could spread from southern to northern European countries in the near future, changing the epidemiological patterns of dirofilariosis both in humans and animals, Genchi’s team writes.
References
- Veterinary Parasitology, published ahead of print, 2009 March 26th