THE ROLE OF DOGS IN THE EPIDEMIOLOGY OF HUMAN VISCERAL LEISHMANIASIS IN NORTHERN PAKISTAN

Infantile visceral leishmaniasis (VL) was first reported from north Pa kistan over 3 decades ago in the remote valleys of the western Himalay as. These foci were reported as being completely devoid of domestic do gs. The later emergence of sporadic cases of infantile VL in the sub-H imalayan region of the country, where dogs are abundant, enabled us to investigate the prevalence of canine disease and study its relation w ith disease in humans. A serological survey in dogs by direct agglutin ation test (DAT) and enzyme-linked immunosorbent assay (ELISA) indicat ed that 18% (DAT) and 26.6% (ELISA) harboured anti-Leishmania antibodi es, with older dogs showing higher prevalence; 10% of the infected dog s had no clinical signs of leishmaniasis. Deoxyribonucleic acid (DNA) probing by P-32-labelled Lmet 2 cDNA probe showed high sensitivity wit h aspirates obtained from the popliteal lymph nodes of dogs but not wi th skin snips. Parasites isolated from dogs in these foci were identif ied as L. infantum by isoenzyme characterization.