Molecular detection of Trypanosoma evansi in camels (Camelus dromedarius) in southwestern Saudi Arabia

This cross-sectional study aimed to determine the prevalence of Trypanosoma evansi infection and its associated risk factors in camels in the Jazan region, southwestern Saudi Arabia. A total of 679 blood samples were collected from three local breeds of camel - Awadia, Awarkia and Sawahelle - in 11 randomly selected governorates of Jazan region. Blood samples were screened by Giemsa-stained blood film (GSBF) and polymerase chain reaction (PCR) techniques. The overall prevalence of T. evansi was 30.9% (210/679, CI: 27.6-34.5%) by PCR, whereas a prevalence of 22.2% (151/679, CI: 19.3-25.5%) was revealed by GSBF. The highest prevalence was identified in Ad-Darb (55.6%) followed by Farasan (44.4%) and Alarda (42.1%) while the lowest prevalence was found in Samtah (10.6%). A significant association between the infection and the location of the camels was found (P = 0.023); a high infection rate was recorded in the northern governorates which declined gradually in the central and southern governorates, regardless of the sex, breed or age of the camels. Moreover, a significant interaction of breed and age on disease prevalence was found (P = 0.012). Camels of the Awadia breed aged below 5 years were 3.6 times more likely to harbour T. evansi than those of the Awarkia breed aged over 15 years. This study demonstrates that T. evansi infection is prevalent among camels in southwestern Saudi Arabia. Further studies should be conducted to focus on vectors and hosts, and to evaluate the potential risk factors in order to plan and implement effective control programmes.