Surveillance of zoonotic pathogens in cattle and dromedaries sacrificed at the Grand Magal of Touba: a cross-sectional survey

Mass gatherings increase infectious disease risks through human, environmental, and zoonotic pathways. The Grand Magal of Touba (GMT) involves the annual sacrifice of animals under limited biosafety, yet data on zoonotic pathogens are scarce. This cross-sectional exploratory study aimed to detect major zoonotic agents in livestock during the GMT and to provide baseline evidence to guide One Health surveillance. From 2022 to 2024, post-mortem samples (blood, nasal and rectal swabs, skin, ticks) were collected from sacrificed animals and analyzed using molecular and culture-based methods. 88 animals were included. Borrelia spp. was detected in 28.8% of bovine blood samples, mostly in 2023 and 8.3% of dromedaries. Enterohemorrhagic Escherichia coli occurred in 64.3% of cattle and 33.3% of dromedaries’ rectal samples. Nasal swabs showed Mycobacterium spp in 54.9% bovines and 75.0% dromedaries. Among hard ticks from bovines (predominantly Hyalomma spp.), 10.2% and 11.5%) were infected with Borrelia spp. and Rickettsia spp., including R. aeschlimannii and R. sibirica mongolitimonae . and one case of Coxiella burnetii was found. In dromedaries, only Borrelia spp. (43.7%) was found in ticks. No dermatophytes were isolated. These findings demonstrate active zoonotic circulation and stress the need for continuous surveillance of zoonotic pathogens in animals involved in the GMT. Given the close proximity of humans and livestock during such events, the potential for spillover of zoonotic agents necessitates a One Health approach, integrating veterinary, environmental, and human health surveillance. Future investigations should further characterize pathogen species to better inform risk reduction strategies.