Leptospirosis as a cause of infertility in Uruguayan beef cattle.

Leptospirosis, caused by pathogenic spirochetes of the genus Leptospira spp., is a globally significant zoonotic disease that affects humans and animals. In cattle, leptospirosis is associated not only with overt clinical manifestations but also with reproductive diseases, including infertility. This study assesses the potential correlation between leptospirosis and infertility in Uruguayan beef cattle. A case-control study involved 31 beef herds with no prior history of Leptospira vaccination. In each herd, veterinarians identified 10 non-pregnant (cases) and 25 pregnant cows (controls) using ultrasound, and blood and urine samples were collected from each cow. Serological diagnosis was performed using the Microscopic Agglutination Test (MAT), and quantitative PCR (qPCR) was used to assess Leptospira excretion. Additionally, antibodies against bovine viral diarrhea virus (BVDV) and infectious bovine rhinotracheitis (IBR) were tested. The results demonstrated an association between seropositivity to the Sejroe serogroup (cut-off 1:200) and infertility in cattle (OR=1.31; p-value=0.06). Furthermore, the level of Leptospira excretion (qPCR) in urine was associated with increased infertility risk, with cows excreting over 100 copies per mL of urine having the highest odds of infertility (OR=2.34; p-value<0.01). This study suggests a potential association between leptospirosis and infertility in Uruguayan beef cattle, emphasizing the importance of both serological and molecular diagnostics for assessing reproductive health in cattle herds. Future research should explore the impact of Leptospira serogroups on other reproductive disorders in cattle.

Seroprevalence and herd-level associated factors of pathogenic Leptospira spp. circulating locally in dairy cattle in Uruguay.

Leptospirosis is a zoonotic disease of worldwide importance. In Uruguay, it is endemic in cattle and primarily affects people with occupational exposure to livestock. The aim of this study was to determine the national seroprevalence and associated factors of local pathogen Leptospires in dairy cattle. A cross-sectional study was carried out. Herds were stratified by size (1-50, 51-250, and > 250 cattle), and up to 60 dairy cows per herd were randomly selected. A total of 4269 serum samples from 101 dairy herds were analyzed by microscopic agglutination test (MAT). A two-stage sampling design was used to estimate population seroprevalence of Leptospira spp. In order to determine the factors associated with the disease, herds with at least 1 seropositive animal were considered as case herds. Seroprevalence of Leptospira was 27.80% with a 95% CI [21.06, 34.54] at the animal level and 86.92% with a 95% CI [80.00, 93.75] at the herd level. The serology confirms the predominance of serogroups Sejroe and Pomona in our herd with the presence of incidental leptospires infection, in smaller proportion, but with a wide distribution at farm level. The population size and purchasing replacement of cows on dairy farms were associated with infection at farm level. The serologic studies confirmed that exposure to Leptospira spp. is endemic in our herds, and the spreading over dairy herds. Although the movement of purchased females and the size of the herd were associated with the disease, more studies should be conducted, to better understand the epidemiology of the disease and to highlight the possible risks to public health, especially in rural workers, farmers and veterinarians.

Epidemiological study of neosporosis in Uruguayan dairy herds.

Neosporosis is one of the leading causes of abortion in cattle worldwide, posing a great economic burden on cattle producers. The aim of this study was to determine the national seroprevalence and putative risk factors of Neospora caninum (N. caninum) in dairy cattle in Uruguay. A cross-sectional study was carried out. Herds were stratified by size (1-50, 51-250, and >250 cattle) and up to 60 dairy cows per herd were randomly selected. Four thousand two hundred twenty-three serum samples from 102 dairy herds were analyzed by indirect ELISA test, under the manufacturer's recommendations. In addition, the herdsman was surveyed and a population study was carried out. The in degree data, geographical coordinates, and seroprevalence of bovine viral diarrhea, enzootic bovine leukemia and infectious bovine rhinotracheitis were available for each herd. A sampling design was used to estimate population seroprevalence of N. caninum. In order to determine the factors associated with the disease, herds with an intra-herd seroprevalence over 20% were considered as case herds. Seroprevalence of N. caninum was 22.3% (95% CI: 18.7-25.9 %) and 96.0% (95% CI: 92.1-99.8%) at the animal and herd level, respectively. The number of dogs on the dairy farms were associated with infection levels (OR: 1.43, 95% CI: 1.02 to 2.03). It was concluded that N. caninum is endemic in the country, and is spreading over dairy herds. Although this study showed evidence that the number of dogs were associated with high levels of infection, more studies should be conducted, to better understand the epidemiology of the disease and thus develop efficient control measures.