Detection of Leishmania donovani Status in Dogs (Canis familiaris, Linnaeus, 1758) in the Karamoja Subregion of Uganda

Abstract

To date, the reservoir host for visceral leishmaniasis, a neglected tropical disease caused by Leishmania donovani, is unknown, although studies pointing to dogs, domestic animals, and rodents are emerging. We aimed to investigate whether the dog (Canis familiaris, Linnaeus, 1758) is a potential reservoir for L. donovani in the Karamoja subregion of Uganda. Blood and lymph node aspirates were purposively collected from dogs (n = 139) in disease endemic villages of Amudat and Moroto districts in August 2023. An indirect enzyme-linked immunosorbent assay was used to detect anti-Leishmania IgG antibodies in serum. DNA extracted from lymph node aspirates was subjected to a polymerase chain reaction (PCR) targeting the rRNA internal transcribed spacer region of Leishmania species. The sera from 139 dogs did not demonstrate any evidence of circulating antibodies against Leishmania, as the optical density (OD) values were all below 0.25, lower than the threshold value of 0.45. Similarly, all the dog lymph node DNAs (n = 139) were negative for Leishmania parasites. Although our results found no evidence to support dogs as reservoirs for L. donovani, in this study, further research utilizing larger sample sizes is recommended to confirm this finding. Furthermore, the presence of L. donovani in sand flies and other suspected reservoirs, such as domestic animals and wild rodents, requires further investigation.