Seroprevalence of Trypanosoma evansi in camels using CATT/T. evansi technique in Borno and Yobe states, Nigeria

Big Six: Vertebrate host interactions as significant transmission drivers of bovine trypanosomosis in Nigeria - A systematic review and meta-analysis

Bovine trypanosomosis remains a significant challenge in Nigeria due to the widespread presence of tsetse and biting flies. Despite numerous control interventions, livestock owners continue to face the burden of high treatment costs year-round. Holistic management has been elusive, largely due to the interconnected roles of the "Big-Six" animal hosts in sustaining transmission dynamics. This study conducted a systematic review of publications from Web of Science, Ovid MEDLINE, PubMed, Google Scholar, and AJOL Online databases, following PRISMA guidelines between 2000 and 2024. Eligible studies reported trypanosomosis prevalence in cattle, small ruminants, dogs, pigs, camels, and wildlife. Subgroup analyses by breed, sex, and diagnostic techniques were performed, with point estimates evaluated at a 95 % confidence interval (CI). A total of 80 studies involving 25,171 animals were included, revealing average prevalence of 38.2 % (95 % CI: 31.4-45.3) in wildlife, pooled prevalence of 12.0 % (95 % CI: 3.0-25.1) in cattle, with 11.7 % specifically observed in trypanotolerant cattle breeds, 4.6 % (2.3-7.6) in small ruminants, 9.6 % (95 % CI: 1.9-21.5) in dogs, 10.4 % (95 % CI: 5.6-16.3) in pigs, and 28.0 % (95 % CI: 18.5-38.6) in camels. Wildlife exhibited distinct ecological patterns, while ovine and caprine data clustered closely. These findings explain the critical role of vertebrate hosts, along with bovine herd management practices, in perpetuating disease transmission within susceptible cattle populations. Effective control requires treating vertebrate hosts harbouring trypanosomes within or surrounding bovine herds and the use of insecticide-impregnated nets, alongside fencing cattle herds from forest edges. This integrated approach is essential to achieving the elimination of African animal trypanosomosis (AAT) in Nigeria and across Africa.

Parasitological, molecular, and epidemiological investigation of Trypanosoma evansi infection among dromedary camels in Balochistan province

Surra is a zoonotic disease caused by Trypanosoma evansi (T. evansi), which affects a wide variety of animals worldwide. The disease has a severe impact on the productivity, health, and working capacity of camels and causes mortality and extensive economic losses if not diagnosed early. This is the first comprehensive report on the prevalence of T. evansi infection in dromedaries in Balochistan province. In the present study, 393 blood samples (indigenous, n = 240; imported, n=153) were collected from one-humped camels (Camelus dromedarius) and were tested by molecular methods to estimate the prevalence of T. evansi in three districts (Pishin, Nushki, and Lasbella) of Balochistan province. The overall prevalence of T. evansi among examined camel samples was 28.24% (95% confidence interval (CI): 24.02-32.89%). The risk of T. evansi infection in adult camels (> 10 years) is higher than that in young ones (odd-ration (OR) = 2.7; 95% CI: 1.3357-5.3164%). Moreover, male camels were six times more likely to get an infection than female camels. The detection of T. evansi infection in camels sampled in summer and spring was 3.12- and 5.10-fold higher, respectively, than in camels sampled in winter. In conclusion, our findings showed a high rate of T. evansi infection in camels from the three districts. Our study emphasizes the need for a strict surveillance program and risk assessment studies as prerequisites for control measures.

Microscopic and serological survey of Trypanosoma evansi infection in Tunisian dromedary camels (Camelus dromedarius)

Camels are the most adapted species to the harsh ecosystems of the African continent where they represent 80% of world's population. However, they can be susceptible to many pathogens such as Trypanosoma evansi. This parasite is widely distributed in Africa and represents a real threat to animal health and production. In Tunisia, despite its importance, this disease is underestimated and only a few data are available. The present study aims to investigate the prevalence of the disease by combining microscopic and serological tests. A cross-sectional study was conducted on 307 dromedary camels randomly selected from Southern Tunisia. Collected blood samples were microscopically examined and tested with Card Agglutination Trypanosomiasis Test to detect anti-T. evansi antibodies. The microscopic and serological prevalence were estimated at 2.93 and 62.54%, respectively. Microscopic examination showed morphological features of T. evansi. All positives samples were collected from aged males (>5 years old). Seroprevalence was similar for both sexes but it was higher in dry season and in the southwest of Tunisia. The present study revealed high prevalence of T. evansi infection among dromedary camels. This highlights the need for adequate control measures based on the detection and treatment of infected animals and vector control. We recommend investigating the prevalence of infection in other domestic animals living in the same environment.

Prevalence and animal level risk factors associated with Trypanosoma evansi infection in dromedary camels

Surra is a non-cyclic parasitic disease caused by Trypanosoma evansi (T. evansi) and spread by biting flies. The disease has a severe impact on camel health, productivity, and market value, posing a significant threat to food safety and the economy. In a cross-sectional study, 370 blood samples were collected from camels in three Egyptian governorates. Samples were tested using parasitological (thin blood smear (TBS)), card agglutination test for T. evansi (CATT), and PCR to estimate the prevalence of T. evansi infection. Overall, the prevalence of T. evansi among examined camels was 17.3%, 18.9% and 22.7% using TBS, CATT and PCR methods, respectively. The risk of T. evansi infection in older camels (> 10 years) is higher than that in young ones (odds ratio (OR) = 9; 95% CI: 3.5–23.1), particularly during spring (OR = 2.5; 95% CI: 1.1–5.7). Furthermore, females and poor conditioned camels were 2.6 and four times more likely to get infection than males and good conditioned camels, respectively. The level of agreement between diagnostics tests were perfect kappa (> 0.83). Moreover, CATT showed higher sensitivity (0.83; 95% CI: 0.74–0.91) than TBS (0.76; 95% CI: 0.66–0.85) and both had perfect specificity (100%). In conclusion, our findings revealed a high rate of T. evansi infection in camels from the three Egyptian governorates. The CATT is a good test for routine use in control program of trypanosomiasis in camels.

Serological survey and associated risk factors' analysis of Trypanosomiasis in camels from Southern Tunisia

Surra (Trypanosoma evansi infection) is one of the main causes of dromedary (Camelus dromedarius) abortion, besides generating severe economic losses in herds. A sero-epidemiological survey was carried out between December 2018 and December 2019 in Southern Tunisia to estimate the seroprevalence of Trypanosoma evansi infection in camels and to determine its possible associated risk factors. Two-stage sampling was conducted to select breeders and camels targeted in our study. A total of 1205 blood samples were collected from 277 randomly selected farms belonging to six governorates of southern Tunisia. Sera were tested with the card agglutination test for Trypanosoma evansi (CATT/T. evansi) to detect the presence of anti-Trypanosoma. evansi antibodies. The overall individual and herd seroprevalence were 30.8% (95%CI 27.9–33.1%), 64.9% (95%CI 61.7–73), respectively. The seroprevalence of T. evansi infection both at the animal (26.2% (95%CI 21.4–30.9%) and herd level (84.4 (95%CI 76.3–92.5)) was higher in Kebili than in other governorates (P = 0.003). At the animal level, the infection rate with T. evansi was significantly associated to the age group among camels (P = 0.0008), production system (P = 0.006), bioclimatic stage (P = 0.02), and herd size (P = 0.04) in the univariable analysis. Multivariable logistic regression indicated that only age group and herd size were potential risk factors associated with Trypanosoma evansi infection. However, no significant variation of the seroprevalence of T. evansi with the sex of camels, farm type, and previous trypanocidal treatment were detected (P > 0.05). The findings of this study are crucial for this disease surveillance and control. Further investigations on the efficacy of the treatment against surra are needed to explain the persistence of the disease in the south of Tunisia.