Refractoriness to Leishmania donovani and L. major in experimentally infected domestic and wild birds

Abstract

In the first of a series of experiments, a wild rock pigeon (Columba guinea), a wild guinea fowl (Numidia meleagris), a domestic chicken (Gallus gallus) and a domestic feral pigeon (Columbia livia) were subcutaneously challenged each with 1´107 culture-derived stationary phase Leishmania major (NLB-144) promastigotes. No parasites were recovered from any of the birds during a weekly sampling over a period of eleven weeks from both smears and cultures and neither was a lesion or nodule suggestive of a cutaneous infection observed. All the birds except the guinea fowl were sacrificed at twelve weeks post L. major-infection and cultures and smears prepared from the liver, heart, bone marrow and blood were negative for parasites. In a second series of experiments, uninfected birds that included a rock pigeon, a chicken, and a feral pigeon together with the guinea fowl previously infected with L. major were challenged subcutaneously with an inoculum dose of 1´108 culture derived L. donovani promastigotes. At fours weeks post challenge, the animals were sacrificed and touch smears and cultures prepared from the liver, heart, bone marrow and blood were negative for parasites. Serum from all the experimental groups when assayed for Leishmania specific antibodies using the Direct Agglutation Assay showed evidence of humoral response to infection. However, as it is not possible to experimentally infect these birds with even high doses of either L. major or L. donovani parasites, it is logical to conclude that domestic and wild birds may not be reservoirs of Leishmania infection.


Zimbabwe Vet. J. Vol.33(2) 2002: 73-78