Research of canine filariasis in Trapani province (western Sicily). Morphology on SEM of male Dirofilaria repens.

The prevalence of canine filariasis was investigated in 4 municipalities of Trapani province (Campobello di Mazara, Castelvetrano, Marsala and Mazara del Vallo), an area where 8 human cases of dirofilariasis due to Dirofilaria (Nochtiella) repens have occurred during the last decade. Blood samples were collected late in the afternoon, during August and September 1995, and examined by Knott technique for the presence of microfilariae. Sixtythree (29.3%) out of 215 domestic dogs (98 males, 117 females; 40 sub-adults, 175 adults) proved to be positive for microfilariae: 55 (25.6%) for D. repens, 13 (6.0%) for Dipetalonema reconditum, 1 (0.5%) for D. immitis; 6 (2.8%) mixed infections (5 D. repens + D. reconditum and 1 D. repens + D. immitis) were also found. The surface topography via SEM of an adult male specimen of D. repens found in a dog during necroscopy is also described. The relatively large number of human cases of dirofilariasis appears to be related to the high prevalence of D. repens observed in dogs of Trapani province. This matter should be investigated more extensively in this area.