ABSTRACT
Balance between the immuno-pathological reactions of the host and the response of the infecting parasite towards these reactions determine the final outcome of an infection. Different immuno-pathogenic mechanisms could be expected in infections caused by a variant parasite. There are only a few studies addressing the in situ host response, humoral response, and host genetics in local Leishmania donovani infection. Cutaneous leishmaniasis–induced immunological protection against subsequent visceral infection in Sri Lankan parasites has been demonstrated using a mouse model. Authors have suggested this cross-immunity as a reason for rarity of visceral leishmaniasis in Sri Lanka. Variable in situ immune response patterns that are dependent on the treatment response and duration of the lesions have been demonstrated. The limited value of many rapid antigen detection tools in Sri Lanka indicates possible antigenic variation between dermotropic and visceralizing L. donovani. In spite of this, local crude antigen–based serological studies have reported high sero-conversion rates in L. donovani–induced cutaneous leishmaniasis in Sri Lanka. Sri Lankan studies on human host have failed to draw major conclusions and the findings were not similar to those already available for other populations.
