Leishmaniasis occurs in two forms, both of which are present in Europe (123). Both the visceral and the cutaneous form are caused by Leishmania donovani infantum. Cutaneous leishmaniasis cases have been reported from France, Italy, Spain and countries in central Asia. Zoonotic visceral leishmaniasis (also known as kala-azar) is endemic in all countries bordering the Mediterranean Sea. It has become an important co-infection with HIV in France, Italy and Spain (124).
Leishmaniasis is transmitted by sandflies, which inhabit semiarid regions. Sandflies are very susceptible to DDT and were significantly reduced in Europe following malaria eradication campaigns in the 1960s and 1970s. As vector control declined, however, vector densities increased. The reservoirs or intermediate hosts of the pathogen are rodents, foxes and domestic or stray dogs. In endemic urban areas, the black rat may play a role in transmission.
There are two sandfly vectors of leishmaniasis in Europe. Phle-botomus perniciosus is distributed throughout the Mediterranean region (France, Portugal, Spain, Tunisia and Turkey). Ph. perfiliewi has more of a northern distribution, extending from Cyprus, Greece and Malta (but not North Africa) to eastern Europe (Azerbaijan, Hungary, Romania and the Federal Republic of Yugoslavia).
Sandfly vectors are not actively controlled in Europe. Cutaneous leishmaniasis and zoonotic visceral leishmaniasis are controlled by treating human cases. In Europe, canine leishmaniasis is a major veterinary problem, and a dog vaccine is considered highly desirable. A vaccine is currently being developed for use in humans.
The distribution of zoonotic visceral leishmaniasis in Europe is probably limited by the distribution of the sandfly vectors. Climate change is likely to extend the range of the sandfly vectors northwards.
One study on leishmaniasis in Italy (125) indicates that climate change may extend the range of Ph. perniciosus but reduce that of Ph. perfiliewi. Higher temperatures would accelerate the maturation of the protozoal parasite, thereby increasing the risk of infection (126). An important vector in southwestern Asia (including Israel), Ph. papatasi, has been mapped using climate and satellite data (127). It has been estimated that a rise in temperature of 3 °C would greatly increase both the geographical and seasonal distribution of Ph. papatasi in this region (128).
There is a risk that zoonotic visceral leishmaniasis will extend further northwards in Europe with climate change. Several imported cases of canine leishmaniasis are reported in Austria, Germany and Switzerland every year (129). Thus, imported cases are a potential source of the pathogen if the vectors expand northwards with climate change.
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