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.

Cattle tick fever (CTF), caused by Anaplasma marginale, Babesia bovis and Babesia bigemina, remains a sanitary and economic challenge for cattle farming in Brazil. Thus, this study evaluated the prevalence, regional distribution, co-infection patterns, and risk factors associated with CTF causative agents in cattle the semi-arid region of Paraíba, the semi-arid region of Ceará, and the Tropical Humid region of Paraíba, Northeast Brazil. Blood samples were collected from 336 cattle, from 60 farms, and analyzed by means of conventional PCR and nested-PCR, while epidemiological data were obtained through questionnaires applied to producers. The overall infection prevalence by at least one pathogen was 82.7% (278/336), with higher rates in the tropical humid region of Paraíba at 94.8% (109/115), followed by the semi-arid region of Ceará, with 88.1% (89/101) and the semi-arid region of Paraíba with 66.6% (80/120). Co-infections were frequent, especially the association between A. marginale and B. bigemina, detected in 23.2% (78/336) of the animals, while triple infections occurred in 15.8% (53/336) and were most frequent in the semi-arid region of Ceará at 21.8% (22/101). The semi-arid region of Paraíba had the fewest entirely positive properties (7/20) and the highest number of entirely negative properties (2/20). The tropical humid region of Paraíba had the highest number of entirely positive properties (17/21), with no properties entirely free of CTF agents. Multivariate analysis identified the presence of horn fly (OR = 7.23; CI 3.05–18.86; 95% CI), needle reuse (OR = 5.8; CI: 2.62–13.90; 95% CI), animal purchase and introduction without quarantine (OR = 5.4; CI: 2.17–14.93; 95% CI), and pasture sharing (OR = 3.21; CI: 1.08–11.25; 95% CI) as risk factors, while beef herds showed lower susceptibility (OR = 0.28; CI: 0.15–0.52; 95% CI). These findings demonstrate that infections by CTF causative agents are endemic but exhibit region-specific epidemiological patterns, reflecting the combined effects of climate and management practices, and localized transmission foci that may be intensified by commercial cattle movement.

This study aimed to determine the prevalence and risk factors associated with Toxoplasma gondii infection in blood donors from the Brazilian Semiarid region, and to explore its implications for transfusion safety. Samples were collected from 646 donors at blood donation centers in the states of Ceará and Paraíba. Serological diagnosis was performed using BIOLISA TOXOPLASMOSE ELISA kits for anti-T. gondii IgM and IgG antibodies, and molecular diagnosis was conducted by conventional PCR targeting a 529-bp noncoding repetitive fragment. Epidemiological questionnaires on variables associated with infection were administered, and statistical analysis was performed in univariate and multivariate stages, using multiple logistic regression. Among the 646 donors, 43.4% (281/646) were positive for anti-T. gondii IgG antibodies, 0.3% (2/646) for IgM antibodies, and none tested positive by PCR. In the univariate analysis, age, family income, educational level, salad washing practices, water source, raw milk consumption, and duration as a donor were significantly associated, whereas in the multivariate analysis only “age” and “salad washing practices” remained significant. A substantial IgG seroprevalence was observed among blood donors in the Brazilian Semiarid. The low IgM frequency, concurrent IgG positivity, and negative PCR results are consistent with a low transfusion risk in the region. However, these findings should be interpreted cautiously, as negative PCR results do not completely rule out the presence of circulating parasites. Age was identified as a risk factor, whereas proper salad washing showed a protective effect.

Cattle tick fever (CTF) is the most important tick-borne disease complex affecting cattle production in tropical and subtropical regions. This study evaluated the enzootic status of CTF in cattle herds from two contrasting climatic regions of Paraíba State, Northeast Brazil, and identified epidemiological factors associated with herd immune status. A cross-sectional serological survey was conducted in 32 cattle herds from two contrasting climatic regions of Paraíba State. All herds were tested for Babesia bovis and Babesia bigemina, whereas 28 herds (14 per region) were evaluated for A. marginale. Herds were classified according to the proportion of seropositive animals for each pathogen as non-immune (≤12.5%), unstable (>12.5% to <75%), or stable (≥75%), and epidemiological factors associated with enzootic status were subsequently investigated using logistic regression models. Antibodies against at least one pathogen were detected in 55.4% (97/175) of the evaluated cattle, with higher overall seroprevalence in the Tropical Humid region (56/85; 65.9%) than in the Semi-arid region (41/90; 45.6%). Antibodies anti-B. bovis showed the lowest prevalence (24/175; 13.7%), whereas anti-A. marginale (60/155; 38.7%) and anti-B. bigemina (58/175; 33.1%) were more frequently detected. No herd was classified as enzootically stable for anti-B. bovis, whereas 6/32 (18.8%) and 3/28 (10.7%) herds achieved enzootic stability for anti-B. bigemina and anti-A. marginale, respectively. Herds composed predominantly of cattle older than five years were 97% less likely to develop protective seropositivity against B. bovis. Dairy production and animal purchase increased the odds of protective seropositivity against B. bigemina by approximately 74-fold and 10-fold, respectively, whereas needle reuse reduced the likelihood of protective seropositivity against A. marginale by 97%. These findings demonstrate that enzootic instability predominates in cattle herds from Paraíba State, indicating that natural pathogen circulation alone has been insufficient to establish consistent herd immunity against the cattle tick fever pathogens.