LEISHMANIA-INFANTUM IN THE HIMALAYAS

Visceral leishmaniasis (VL) was first reported in Pakistan over 30 years ago from the remote north-eastern Himalayan region. Sporadic cases are now widely reported from the Northern Areas, parts of North-West Frontier Province (NWFP) and Punjab Province, together with Azad Jammu and Kashmir (AJK). Two hundred and thirty-nine cases, mostly young children, have been reported in the last decade; 52% were under 2 years old, and 86% were aged less than 5 years; the male:female ratio was 3:1. In a cross sectional study of the population in 14 endemic villages, 1938 individuals of all ages were randomly skin-tested with leishmanin and 27.4% gave a positive result. The leishmanin response rate increased with age. In some areas, almost 70% of the adults over 40 years old were positive. Leishmanin positivity appeared to cluster among households (P=0.0003), but clinical cases among households did not (P=0.472). The leishmanin response pattern in the foci of Chilas and AJK reflected an endemic pattern of disease, whereas that seen in the Baltistan foci suggested interrupted transmission. Human sera collected in endemic villages were tested for anti-leishmania antibodies, 580 by enzyme-linked immunosorbent assay and direct agglutination test (DAT), and another 1403, as blood samples on filter paper, were tested by DAT alone. Isolations of Leishmania were made from 15 patients, 11 from bone marrow, 3 from normal skin and one from spleen. The parasites were typed as Leishmania infantum zymodeme LON-49 (=MON-1).