Preliminary investigation of trypanosomosis in exotic dog breeds from Zambia's Luangwa and Zambezi valleys using LAMP

Abstract

Abstract. Canine African trypanosomosis (CAT) is rarely reported in the literature. In this preliminary study, we evaluated the performance of loop-mediated isothermal amplification (LAMP) against microscopy to detect CAT in six exotic dog breeds naturally infected with trypanosomes from Zambia's South Luangwa National Park and Chiawa Game Management Area. To our knowledge, this is the first report of CAT in Zambia. The patients exhibited a variety of aspecific clinical signs. The LAMP did not only confirm all six parasitologically positive CAT cases detected passively between April 2010 and January 2012, but was also critical in trypanosome speciation. According to LAMP, the majority of the dogs had monolytic infections with either Trypanosoma congolense or Trypanosoma brucei rhodesiense. The LAMP is thus a potential simple and cost-effective tool for trypanosome diagnosis in endemic regions. The rare report of zoonotic trypanosomes in dogs in Zambia has public health implications and justifies further investigations of CAT.

Figure 1.

Visual appearance of representative results for the CON2 18S rRNA (CON2)-LAMP (upper row), repetitive insertion mobile element (RIME)-LAMP (middle row), and human serum resistance-associated gene (SRA)-LAMP used for confirmation of canine African trypanosomiasis (CAT). Loopamp Fluorescent detection reagent was added to the reaction mixture at the beginning of the assay. The reactions were incubated at 64°C for 30 minutes. In contrast to the light green background fluorescence in the negative samples, positive samples exhibit a bright fluorescent green color when visualized under the transilluminator. NC = negative control (distilled water); PC = positive control (Trypanosoma congolense for CON2-LAMP; Trypanosoma brucei rhodesiense for RIME-LAMP and SRA-LAMP); 1–6: dog blood sample identity.