title: Can heartworm prevalence in dogs be used as provisional data for assessing the prevalence of the infection in cats?
abstract: Cats are considered a susceptible host for Dirofilaria immitis; however, increased host resistance is reflected by relatively low adult worm burdens in natural and experimental infections; the prolonged prepatent period (8 months); the low level and short duration of microfilaremia; and the short life span of adult worms (2-3 years). From April to September 2006, 212 cats and 608 dogs, all exposed for at least one transmission season, were screened for D. immitis infection in a multi-center study in the Po River Valley in northern Italy. Cats were initially evaluated by antibody testing; positive subjects were followed up by antigen testing and echocardiography (and necropsy if death occurred). The prevalence in dogs was 29% by a modified Knott test and antigen testing compared with a prevalence of 4.7% in cats by an antibody test; six of these infections (2.8%) were confirmed by the follow-up evaluations. This field study demonstrated that the prevalence of heartworm infection in cats in this area is within the expected limits of 9-18% of the prevalence in dogs. Antibody testing likely underestimates the real prevalence of D. immitis infection in cats. These results also emphasize the importance of preventive treatment in cats.
authors.affiliation: Veterinary Hospital Città di Pavia, 27100 Pavia, Italy. luigivenco@libero.it
authors.forename: L
authors.initials: L
authors.lastname: Venco
authors.forename: M
authors.initials: M
authors.lastname: Genchi
authors.forename: C
authors.initials: C
authors.lastname: Genchi
authors.forename: D
authors.initials: D
authors.lastname: Gatti
authors.forename: L
authors.initials: L
authors.lastname: Kramer
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology; D002371:Cat Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000469:parasitology; D002415:Cats; D004183:Dirofilaria immitis / Q000276:immunology* / Q000472:pathogenicity; D004184:Dirofilariasis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000469:parasitology; D004283:Dog Diseases / Q000453:epidemiology* / Q000469:parasitology; D004285:Dogs; D004452:Echocardiography / Q000662:veterinary; D005260:Female; D007558:Italy / Q000453:epidemiology; D008017:Life Expectancy; D008297:Male; D015995:Prevalence
chemical_list: D000947:Antigens, Helminth