Cryptosporidium spp. in livestock in Brazil: An underestimated threat to animal and human health

Cryptosporidium spp. infections in livestock are a significant yet underrecognized threat to both animal and human health in Brazil. This systematic review aimed to identify and synthesize available data on the geographical distribution, host species, age groups, diagnostic methods, infection rates, and Cryptosporidium species and subtypes identified, as well as to assess potential associations with diarrhea and the zoonotic impact of infections in production animals. A total of 82 articles were included, comprising 78 epidemiological investigations and 4 case reports. The majority of studies were concentrated in the Southeast region, mainly in the State of São Paulo. Cattle were the most frequently studied species (n = 49 articles), followed by sheep (n = 12), horses (n = 8), pigs (n = 6), goats (n = 5), and buffaloes (n = 2). Diagnostic methods varied, with microscopy being the predominant technique, limiting species identification. Molecular methods, including nested PCR, were employed in a smaller subset of studies, providing more precise species identification. Cryptosporidium parvum subtype IIaA15G2R1 was the most prevalent. The findings underscore the need for standardized diagnostic approaches and enhanced surveillance to better understand the epidemiology of Cryptosporidium infections in Brazilian livestock. Addressing these gaps is crucial for implementing effective control measures and mitigating the zoonotic risks associated with these infections.