Endemicity of Dirofilaria immitis and Dipetalonema reconditum in dogs of Pleasants Valley, Northern California.

A house-to-house survey of dogs in a 26-km2 area of Pleasants Valley (Northern California) was done to determine the prevalence of the filariids Dirofilaria immitis Leidy and Dipetalonema reconditum Grassi in the canine population. Blood samples were taken from the cephalic vein of 97 dogs (greater than or equal to 5 months of age) and were tested for the presence of microfilariae, using a modification of the Knott technique. Two dogs with autochthonous D immitis (2.1% of the dogs examined) were discovered. These dogs were outdoor-housed working or sporting dogs, 5 to 8 years old, 1 female and 1 male. Five male dogs, greater than 2 years of age (5.1%), were positive for Dip reconditum microfilariae. Mixed infections were not detected.