Trypanosoma evansi infection in Algeria: A systematic review and quantitative synthesis of prevalence, distribution, and host susceptibility.

Trypanosoma evansi, the causative agent of Surra, remains a major constraint to livestock production in arid and semi-arid regions. In Algeria, numerous studies have investigated T. evansi infection in domestic animals; however, reported prevalence estimates vary widely and are influenced by study design and diagnostic approach. Following PRISMA 2020 guidelines, we conducted a systematic review to synthesize available data and provide an updated overview of T. evansi epidemiology in Algeria. Twelve peer-reviewed studies reporting prevalence data were included. Data were extracted on host species, geographic region, diagnostic method, and number of animals examined and infected. Pooled prevalence estimates were calculated separately according to diagnostic method, and prevalence patterns were described according to host species and geographic region within each diagnostic category. Overall, 4449 animals from various host species were included. Pooled prevalence estimates varied markedly by diagnostic method: serological assays yielded a pooled prevalence of 14.29% (95% CI: 9.36-20.07%), molecular methods 6.64% (95% CI: 3.20-11.21%), and parasitological examination 2.53% (95% CI: 0.68-5.51%), confirming the well-known hierarchy of diagnostic sensitivity. Dromedary camels and equids consistently showed the highest seroprevalence, whereas lower infection rates were observed in cattle, small ruminants, and dogs. Marked regional differences were evident, with higher seroprevalence reported in southwestern and southeastern Algeria. These findings confirm that T. evansi remains endemic in Algeria and that reported prevalence is strongly influenced by the diagnostic method employed, emphasizing the need for standardized surveillance protocols using sensitive tools, particularly in camels and equids.