Biometrical and morphological description of Trypanosoma evansi among one-humped camel (Camelus dromedarius) in Oman

Abstract Camel trypanosomosis is an important parasitic disease, caused by Trypanosoma evansi (T. evansi). The present study aims to study the prevalence of trypanosomosis, morphometric of T. evansi and its morphological forms among camels in Oman. A total of 501 camel blood samples were microscopically examined during 2017, 2018, and 2019. Trypanosomosis was found in 2.6% (13/501) of examined samples, where 0.54% (1/186), 1.13% (2/177) and 7.25% (10/138) of camels were infected with T. evansi during 2017, 2018 and 2019; respectively. Biometrically, the investigated T. evansi were frequently characterized by slender body, centrally located nucleus, and sub-terminal kinetoplast with total length including free flagellum of 24.9 µm (16.9–31.3 µm), the body length of 16.4 µm (7.9–25.1 µm) and width 2.8 µm (0.1–5.7 µm). The free flagellum is 8.6 µm long (1.1–14.1 µm). Some divisional features of T. evansi were observed i.e.; presence of two kinetoplast along with two flagella, two nuclei, vacuoles near to the posterior ends, and absence kinetoplast. Also, long slender form with dark stained sub-terminal or terminal kinetoplast, short stumpy form, and sphaeromastigote form were observed. The current study is the first to describe the morphological profile of T. evansi infecting camels in Sultanate of Oman.