Identification of Leishmania tropica from micro-foci of cutaneous leishmaniasis in the Kenyan Rift Valley

We performed diagnosis and species identification of parasites in lesion samples from suspected cutaneous leishmaniasis patients in four villages, three of which are in a known Leishmania tropica endemic region in Kenya. Samples were analyzed both by microscopy and PCR for Leishmania, and typed by an assay using four ribosomal DNA-based species-identification PCRs. The lesions were demonstrated to be caused by L. tropica, which confirms the re-emergence of cutaneous leishmaniasis from this species after a period of reduced incidence in the endemic zone. Our report highlights the importance of an intervention and sustained Leishmania control program.

Recombinant expression of trypanosome surface glycoproteins in Pichia pastoris for the diagnosis of Trypanosoma evansi infection

Serodiagnosis of surra, which causes vast economic losses in livestock, is still based on native antigens purified from bloodstream form Trypanosoma (T.) evansi grown in rodents. To avoid the use of laboratory rodents in antigen preparation we expressed fragments of the invariant surface glycoprotein (ISG) 75, cloned from T. brucei gambiense cDNA, and the variant surface glycoprotein (VSG) RoTat 1.2, cloned from T. evansi gDNA, recombinantly in Pichia (P.) pastoris. The M5 strain of this yeast has an engineered N-glycosylation pathway resulting in homogenous Man5GlcNAc2 N-glycosylation which resembles the predominant Man9-5GlcNAc2 oligomannose structures in T. brucei. The secreted recombinant antigens were affinity purified with yields of up to 10mg and 20mg per liter cell culture of rISG 7529-465-E and rRoTat 1.223-385-H respectively. In ELISA, both recombinant proteins discriminated between pre-immune and immune serum samples of 25 goats experimentally infected with T. evansi. The diagnostic potential of rRoTat 1.223-385-H but not of rISG 7529-465-E was confirmed with sera of naturally infected and control dromedary camels. The results suggest that rRoTat 1.223-385-H expressed in P. pastoris requires further evaluation before it could replace native RoTat 1.2 VSG for serodiagnosis of surra, thus eliminating the use of laboratory animals for antigen production.