Parasitological, serological and molecular survey of camel trypanosomiasis in Somalia

Abstract

BackgroundCamel trypanosomiasis or surra is of great concern in Somalia, since the country possesses the largest one-humped camel (Camelus dromedarius) population in the world. Civil war in Somalia has resulted in the destruction of educational, research, economic and social structures, making the country scores very low for most humanitarian indicators. Previous studies on detection of Trypanosoma species in Somali camels have only been performed during the 1990s using standard trypanosome detection methods (STDM). Considering the lack of state-of-the-art knowledge on camel trypanosomiasis in Somalia, the present study aimed to assess the prevalence of Trypanosoma spp. in three districts of Somalia.MethodsA total of 182 blood samples from C. dromedarius from nomadic and dairy farms were evaluated using STDM, serological (CATT/T. evansi) and molecular (ITS1-PCR) methods.ResultsAll samples were negative for Trypanosoma spp. by STDM. A total of 125/182 (68.7%, 95% CI: 61.4–75.3%) camels were seropositive for T. evansi by CATT/T. evansi. Camels reared in nomadic system were more likely to be seropositive for T. evansi than those under dairy production system (OR: 5.6, 95% CI: 2.1–15.2, P = 0.0001). Five out of 182 (2.7%, 95% CI: 0.9–6.3%) camels tested positive for Trypanosoma sp. by ITS1-PCR. Sequencing of the ITS1 region of the Trypanosoma species detected herein revealed that camels were infected with T. evansi and T. simiae.ConclusionsTrypanosoma evansi is highly prevalent in camels from the Banadir region of Somalia, particularly in nomadic herds. To our knowledge, this is the first study to confirm infections with T. evansi and T. simiae in Somali camels through DNA sequencing. Our data highlight the need for implementation of adequate control measures aiming to reduce the impact on camel production in the country.

Camel Trypanosomosis in Yabelo and Gomole Districts in Ethiopia: Prevalence and Associated Risk Factors Based on Parasitological Examinations

“…However, the present prevalence was lower compared to the findings of Hagos et al 24 12.1% and Megersa 25 10.5% and Abdurkadir et al 26 10.2% in Ethiopia and prevalence of 8.3% Swai et al 27 from Tanzania and 11.5% in Bhutto et al 28 from Pakistan. Similarly, a higher prevalence of trypanosomosis than the present finding was also reported 21% in Ethiopia, 29 28% in Kenya, 30 68.7% in Somalia, 31 and 20.6% in Egypt. 32 This difference may be related to the difference in the ecosystem, distribution, and uses of the trypanocidal drug and the seasons when the studies were conducted in which distribution of biting flies are either increase or decrease.…”

Seroprevalence and risk factors for Trypanosoma evansi, the causative agent of surra, in the dromedary camel (Camelus dromedarius) population in Southeastern Algeria

“…In most cases, these within country differences can be explained by the observed variation in ecological factors (e.g., pastoral camel densities, hottest, most humid and wettest districts in the region) that affect vector densities and therefore infection prevalence (Hagos et al 2009 ). Interestingly, geographical variation was not considered in some recent animal-level studies of Trypanosoma seroprevalence (Ghaemi, Zavarib & Jannati Pirouz 2019 ; Hassan-Kadle et al 2019 ; Salah et al 2019 ). The geographical distribution of the parasite and vectors, and thus the occurrence of trypanosomosis, is largely dependent on the nature of the agro-ecological environment.…”

Parasitological and molecular detection of Trypanosoma spp. in cattle, goats and sheep in Somalia

“…The PCR primers used in this study are shown in Table 1. A camel sample is known to be positive for T. evansi (Hassan-Kadle et al ., 2019) was used as a positive control, in all ITS1, TBR and TSM PCR runs, while brucei rhodesiense DNA (kindly donated by Dr Enock Matovu, Makerere University, Uganda) was used in SRA-PCR assay. Nuclease-free water was used as a negative control in all reactions.…”

“…However, these direct parasitological techniques lack sensitivity and specificity (Mattioli and Faye, 1996; Picozzi et al ., 2002). Therefore, molecular methods provide multi-species-specific detection of trypanosomes in a single polymerase chain reaction (PCR) (Salim et al ., 2011) and have been used in epidemiological studies (Desquesnes and Dávila, 2002; Picozzi et al ., 2002; Kouadio et al ., 2014; Hassan-Kadle et al ., 2019). Moreover, the pan-PCR techniques for Trypanosomes would reduce the cost of PCR three to five times (Njiru et al ., 2005).…”

“…Both Trypanosome species have also been reported in cattle from southern Somalia (Moggridge, 1936; Dirie et al ., 1988 a ). Additionally, a recent study has confirmed infections with Trypanosoma evansi and Trypanosoma simiae in camels through DNA sequencing (Hassan-Kadle et al ., 2019). Moreover, the human African trypanosomiasis (sleeping sickness) is unknown in Somalia, despite the presence of Glossina pallidipes , a known vector of the disease in other areas of East Africa with the practice of transhumance (Harberd, 1988).…”