Mwacha, D.; Collins, D. A.; Raphael, J.; Wambura, P.; Hoza, A.

Treponema pallidum subsp. pertenue (TPE) causes yaws, a chronic, nonvenereal Treponematosis characterized by contagious cutaneous lesions in early stages and destructive bone involvement in the tertiary stage. In the latency stage, the infection is asymptomatic with only serologic markers. A retrospective analysis of health, demographic, and behavioral records using a Generalized Linear Mixed Model (GLMM) with binomial distribution, conducted through R software to assess disease risks and trends from January 2019 to December 2024 of wild baboons at Gombe, revealed an overall clinical prevalence of 11.24% (2018/17946) across the eight studied troops. Age was a strong predictor where infants (OR = 0.05, p < 0.001), juveniles (OR = 0.27, p < 0.001), and subadults (OR = 0.65, p < 0.01) had significantly reduced odds of displaying Treponema signs compared to adults. Troops B.C and D.D exhibited elevated infection risk (OR = 2.74 and 2.63, respectively). Pregnant females (OR = 0.19, p < 0.001), wounded baboons (OR = 0.45, p < 0.001), and male immigrants (OR = 0.47, p < 0.001) were less likely to show signs. Infection signs were also lower during wet seasons (OR = 0.81, p < 0.001). Notably, the odds of infection increased consistently over time (Year OR = 1.73, p < 0.001). Understanding the ecological and demographic determinants of Treponema transmission is essential for disease surveillance, conservation, and One Health initiatives. This study presents the first long-term dataset on (TPE) infection in wild baboons from Tanzania and East Africa.