ABSTRACT
Six hundred and eleven random-source dogs (338 male, 273 female) one year of age or older, from six sections of the city of Recife, Pernambuco, were examined antemortem for circulating microfilariae Dirofilaria immitis and Dipetalonema reconditum adult heartworm (D. immitis) antigen, and examined postmortem for adult heartworms. The prevalence of heartworm infection was 2.3 per cent (14/611), as determined by necropsy for adult worms, and 1 per cent (6/611) had circulating microfilariae of D. immitis; thus, 57.1 per cent of the heartworm-infected dogs had occult infections. The results of serological testing indicated that 1.3 per cent (8/611) of the dogs were positive for adult heartworm antigen. A total of 42 (6.9 per cent) of the dogs had microfilariae of D. reconditum; 40 of these had only D. reconditum and two additional dogs had microfilariae of both species, D. immitis and D. reconditum.