Prevalence and risk factors of Neospora caninum and Toxoplasma gondii infection in breeding ewes from central western Mexico.

The objective of the study was to analyse the prevalence of infection by N. caninum and T. gondii in breeding ewes from central western Mexico. For this purpose, 184 blood samples were collected from sheep in the reproductive stage, which were analysed by ELISA and PCR tests, respectively, and the association between seroprevalence and some management factors was estimated by means of a logistic regression analysis. For N. caninum, a seroprevalence of 15.22% was identified, while the DNA detection in blood was 14.13% (26/184); positive animals were found in 75% of the farms (6/8). The variables poor placental waste management (OR 8.4), abortion history (OR 1.5) and presence of rodents (OR 1.3) were identified as risk factors for N. caninum infection. In the case of T. gondii, a seroprevalence of 61.96% was found, and antibodies were detected in eight farms included in the study; no positive samples were identified for T. gondii by the PCR test. The main identified risk factors for T. gondii were as follows: poor hygiene conditions (OR 12.5), presence of cats (OR 9.5), presence of other domestic animals (OR 5.7), urban context of the farm (OR 9.5) and public water supply (OR 5.3). The seroprevalence of co-infection of T. gondii and N. caninum in breeding ewes was 7% (13/184; 95% CI 6.92-7.20). T. gondii has a high seroprevalence while N. caninum was of lower proportion, and both may be associated with reproductive losses for these herds studied.

Prevalence, Incidence, and Risk Factors for Infection by Neospora caninum in Dairy Farm Dogs in North-Central Mexico.

The purpose of this study was to describe the prevalence and incidence of Neospora caninum infection in dogs that are in close contact with dairy cattle and to identify possible risk factors associated with the infection in this population. Twenty-four dogs located in 8 different dairy farms of Aguascalientes, Mexico, were evaluated for a 6-mo period. Once a month a sample of serum and a sample of peripheral blood was collected. The serum was used to detect antibodies against N. caninum by means of the indirect immunofluorescence technique, and the blood was used to detect parasite's DNA. The association between seroprevalence and possible risk factors was estimated using logistic regression. The prevalence of anti-N. caninum antibodies was 54% in the first month, 62% in the last month, and the incidence was 8.69%. One farm had no positive cases. Antibody titers ranged from 1:50 to 1:800. Parasite DNA was not detected in any of the samples. Only the age (>6 yr) of the dogs was identified as a risk factor for infection by N. caninum (P ≤ 0.05).

Frequency of infection by Neospora caninum in wild rodents associated with dairy farms in Aguascalientes, Mexico.

The purpose of this study was to detect the presence of Neospora caninum in tissues from wild rodents associated with dairy farms in Aguascalientes, Mexico. Individuals from Mus musculus, Rattus novergicus and Spermophilus variegatus were caught in dairy farms with history of positive status to N. caninum. A total of 33 rodents were caught from which samples were taken of brain, spinal cord, liver and heart and were tested with nested PCR and Immunohistochemistry (IHC). Results obtained with PCR showed that M. musculus had 77% (10/13) positive samples to N. caninum, S. variegatus had 71% (10/14) and R. novergicus had 50% (3/6). The results obtained with IHC showed that 15% (2/13) of M. musculus individuals were positive, while 43% (6/14) of S. variegatus and 33% (2/6) R. novergicus were also positive. This is the first report of the presence of N. caninum in S. variegatus.

Seroepidemiological study of Neospora caninum infection in dogs found in dairy farms and urban areas of Aguascalientes, Mexico.

The objective of this study was to describe the seroepidemiology of Neospora caninum infection in dogs in close contact with dairy cattle and dogs from urban areas of Aguascalientes, Mexico, as well as to estimate the possible association between age, gender and size of these groups and seroprevalence. Sera were obtained from samples of 152 dogs in dairy farms and 116 in the urban area, and were subjected to ELISA test. General seroprevalence reached 32%, while the seroprevalence in farm dogs (41%) was significantly higher than in dogs from the urban area (20%) (p<0.05). Regarding age groups, general seroprevalence was greater among dogs between 11 and 15 years of age (67%) remaining equal between males and females (32 and 31%, respectively). Nevertheless, females resident in farms had a higher seroprevalence (42%) than female resident in the urban area. Regarding size, large-sized animals had greater seroprevalence in farms (58%), while in the urban area medium-sized animals were those that had the highest seroprevalence (27%). It was found that dairy farm dogs had a higher risk of infection (OR=2.79; p=0.0004), and that in said group, the age range from <1 to 5 years of age was identified as a risk factor (OR=3.11, p=0.001).