Mapping canine leishmaniasis and phlebotomine vectors in the mt. Vesuvius area, Italy

The Mt. Vesuvius area of the Campania region (southern Italy) is an endemic zone of canine Leishmaniasis (CanL). Phlebotomus perniciosus is the main vector involved in the transmission of Leishmania infantum to susceptible hosts. Noteworthy, the Mt. Vesuvius area has been considered a stable focus of intense L. infantum zoonotic transmission. Geographical information systems (GIS) are very useful tools for mapping and monitoring the distribution of CanL and its vectors in the area in relation to environmental features. A previous entomological study conducted in the area showed a different density of P. perniciosus among the two sides of the Mt. Vesuvius. Indeed, higher densities of P. perniciosus were found on the coastal side (density = 5.8) than on the Apennine side (density = 1.4).The predominance of green vegetated environments (forest, semi-­‐natural and agricultural areas) in the coastal side, in contrast with the predominance of artificial surfaces (namely urban environment) in the Apennine side, was considered responsible for the different P. perniciosus densities between the two surveyed areas. Therefore, a serological survey was conducted using GIS in order to map the distribution of CanL along the coastal and the Apennine sides of the Mt. Vesuvius area. Sera from 505 autochthonous owned dogs were examined by IFAT to detect antibodies to L. infantum. A titre of at least 1:80 was considered a positive result. Out of the 505 dogs examined, 213 (42.2%; 95%Confidence Interval = 37.9 -­‐ 46.6%) were found to have antibodies to L. infantum. The prevalence was not different between the two sides (42.6% in the Apennine side and 41.6% in the coastal side). The findings of the present study showed that even low densities of P. perniciosus, especially when associated with an urban environment, seem sufficient to ensure Leishmania transmission among susceptible hosts. In fact, no significant differences were found in CanL seroprevalence of the two areas. Comprehensive control programs, including the use of vaccine, are discussed to prevent CanL in such endemic areas as the Mt. Vesuvius.