Parasitological and molecular investigation of Trypanosoma evansi in dromedaries from Greater Cairo, Egypt

Abstract

In Egypt, camel trypanosomiasis is widespread. From October 2021 to March 2022, we collected 181 blood samples from apparently healthy one-humped camels (Camelus dromedarius) in Cairo and Giza Governates. The objective of this study was to assess infection rates of trypanosomes using blood smear examination and PCR-sequencing assays. Trypanosomes were detected in 8.3% (15/181) of camels by blood smear and in 23.8% (43/181) by PCR targeting the internal transcribed spacer (ITS). Based on blood smear and ITS-PCR results, and the absence of tsetse flies in the study area, we hypothesized that the Trypanosoma species was likely T. evansi. Validation using PCR based on the variant surface glycoprotein (VSG) of T. evansi Rode Trypanozoon antigen type (RoTat) 1.2 (RoTat 1.2 VSG gene) on ITS-PCR-positive samples (n=43) confirmed that 88.4% (38/43) were RoTat 1.2 T. evansi, while 11.6% (5/43) were non-RoTat 1.2 T. evansi. This marks the second report of non-RoTat 1.2 T. evansi in dromedary camels in Egypt. Considering the underestimated zoonotic risk of T. evansi in Egypt, there is a potential threat to humans, underscoring the need for a "One Health" approach to safeguard animal and human health.