Autochthonous foci of canine and feline infections by Dirofilaria immitis and Dirofilaria repens in central Italy

Abstract

This survey was conducted to investigate the presence of Dirofilaria immitis and Dirofilaria repens in native dogs and cats living in an area of Italy where animal and human dirofilarioses have been sporadically reported in the past few years. From May 2008 to March 2009 individual blood samples were collected from 300 native cats and 300 native dogs in the Abruzzo region of central Italy. All 600 samples were subjected to a Knott modified method, to a test for the detection of circulating D. immitis antigen and to two species-specific PCR-coupled sequencing protocols. Epidemiological data were collected and then correlated with the filarial prevalence by univariate and multivariate statistical analyses. Twenty-five dogs (8.3%) and six cats (2%) were positive for filariae in at least one diagnostic test, with an overall prevalence rate for D. immitis and D. repens of 2.3% and 5.6% in dogs and 0.3% and 1.6% in cats, respectively. Male and large sized dogs resulted more likely to be infected by Dirofilaria spp., possibly due to the fact that animals living outdoor and of large size are more exposed to mosquito bites. However these factors were not confirmed as convincing risk factors by multivariate analysis. The results are discussed, together with the origin of these new autochthonous foci in central Italy and the present expansion southward of canine and feline filariae in Italy.