Toxoplasmosis, caused by Toxoplasma gondii, poses a significant threat to sheep flocks, affecting reproductive performance and meat quality, and leading to economic losses. This study aimed to evaluate the correlation between anti-T. gondii IgG antibodies in the serum and colostrum of naturally infected ewes and to assess passive immunity in newborn lambs. Blood and colostrum samples were collected from 162 ewes and 182 lambs across 20 sheep farms in Paraíba, Brazil. Samples were tested for anti-T. gondii and anti-Neospora caninum IgG using indirect fluorescence antibody tests (IFATs), with titers ≥ 1:64 considered positive. Among the ewes, 45.1% tested positive for anti-T. gondii IgG in serum, with titers ranging from 1:64 to 1:16,384. The colostrum from 94.6% of the ewes also tested positive, although 74% had higher titers in their serum than in their colostrum. Concordance between serum and colostrum was high, with a kappa coefficient of 0.950. Lamb serum showed a perfect agreement with maternal colostrum (kappa = 0.962), demonstrating effective passive transfer of antibodies. This study confirms that colostrum is a reliable matrix for detecting anti-T. gondii antibodies and assessing passive immunity in lambs. The high concordance between serum, colostrum, and lamb titers suggests that IFATs on colostrum can be a practical tool for monitoring maternal antibody transfer, contributing to the better management of T. gondii infections in sheep flocks.

Cryptosporidiosis is a zoonotic disease of medical and veterinary importance caused by Cryptosporidium spp. This study conducted a systematic review to assess the occurrence and distribution of Cryptosporidium spp. in humans in Brazil, with emphasis on C. parvum. Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) protocol and using five databases, 3689 articles were screened, and 48 met the inclusion criteria. Most studies were concentrated in the Southeast Region, particularly São Paulo, while major gaps were identified in the North and Midwest Regions. The mean prevalence was 8.9% using direct methods and 52.2% using indirect methods, with the highest positivity reported in the Northeast Region. Microscopy was the most frequently employed diagnostic tool, although it showed limited ability to differentiate species. When combined with molecular approaches, C. parvum and C. hominis were identified as the predominant species. Infection was most common among children and immunocompromised individuals, especially those with HIV and kidney diseases. Overall, the findings highlight substantial research gaps regarding cryptosporidiosis in Brazil and its disproportionate impact on vulnerable populations. Expanding regional studies, integrating molecular methods for species characterization, and implementing targeted public health strategies are essential to improve epidemiological knowledge and guide prevention and control measures.