Serological response to Neospora caninum infection in goats and agreement between three diagnostic techniques to detect caprine neosporosis

Reproductive, productive and financial consequences of chronic Trypanosoma vivax infection in a dairy cattle herd in a region without a cyclic vector

This study evaluated the reproductive, productive and financial consequences of chronic Trypanosoma vivax infection in a dairy cattle herd located in a region without the cyclic vector during two years. Animals were categorized as either positive (chronically infected) or negative for T. vivax antibodies using a commercial rapid test. Additionally, serum samples from cows were analyzed for the presence of anti-Neospora caninum antibodies. Pregnancy diagnoses were performed through rectal palpation and ultrasonography after 30, 60 and every 21 days until the 144th day of pregnancy. If an abortion occurred in the final trimester, serology and cPCR were performed on calves for T. vivax and N. caninum. The breeding period, calving interval and pregnancy losses were recorded. The milk production of each animal during the 305 days of lactation was measured, and the annual financial impact of milk production was calculated using a revenue minus feed cost (RMFC) indicator. Out of 177 cows, 71.75 % were chronically infected, and 13.50 % were T. vivax-negative. No correlation (p = 0.8854) of co-infection between T. vivax and N. caninum was observed. Negative cows required fewer (p≤0.05) artificial inseminations than chronically infected ones. T. vivax was not significantly associated (p = 0.7893) with pregnancy loss up to 81 days of pregnancy. Cows chronically infected by T. vivax had 4-fold greater chance (p = 0.0280) of experiencing pregnancy loss between 82 and 144 days of gestation. Eighteen cows aborted, two were positive for T. vivax antibodies, and one for N. caninum antibodies. The calves were negative for T. vivax and N. caninum. Chronically infected cows and negative cows for T. vivax that experienced pregnancy loss (82-144 days of pregnancy) had a longer (p≤0.05) breeding period to become pregnant, and consequently a longer calving interval compared to cows that maintained pregnancy. The difference (p≤0.05) in milk production was evident when pregnancy loss occurred between 82 and 144 days of gestation in cows chronically infected by T. vivax. The RMFC indicated a negative impact of 38.2 % on the farm's annual milk revenue due to the presence of chronically infected cows.

Dynamics of natural infection by Toxoplasma gondii in goat herds in the semiarid region of northeastern Brazil: transitional antibody observation

This study aimed to describe the transmission of T. gondii in naturally infected goats in the semiarid region of northeastern Brazil, through evaluating the serological status of these animals from one to 12 months of age. Seven goat farms were selected. During the first visit, an epidemiological questionnaire was applied. Blood samples were collected from pregnant goats and from their female offspring every month, to monitor them for anti-T. gondii antibodies, using the indirect fluorescence antibody test (IFAT). Out of 66 pregnant goats evaluated, 47% (31/66) (95% CI: 34.6% - 59.7%) were positive and out of 93 female offspring, 61.3% (57/93) (95% CI: 52.4% - 69.2%) were positive, in at least one month during the evaluation period. Among the positive female offspring, 43.3% (27/57) (95% CI: 39.7% - 56.9%) presented environmental infection and 56.7% (30/57) (95% CI: 43.4% - 66.3 %) probably had only colostral antibodies or vertical transmission. It was observed that 92,6% (25/27) from environmental infections occurred until reproductive age (six months) (p<0.0001). It was also noted that there is a correlation between the titration of mothers and offspring, until four months of age (p<0.0001). Large fluctuations in the presence of antibodies were observed among the animals over the months monitored. It can be concluded that the prevalence of anti-T. gondii antibodies within the herds was greater than what has been expressed in specific prevalence studies and that most goat become infected up to the six months of life in the studied area.

Neospora caninum infection in cattle in the state of Amazonas, Brazil: seroprevalence, spatial distribution and risk factors

Livestock in the Amazon has grown significantly and, although neosporosis in cattle has been reported worldwide, there is no information about N. caninum in production systems in the state of Amazonas. The objective of this study was to determine the prevalence of anti-Neospora caninum antibodies in cattle, their spatial distribution and the risk factors associated with N. caninum infection in the state of Amazonas. Questionnaires were applied to farmers to assess risk factors associated with N. caninum infection. Blood samples were collected from 1,073 animals on 47 farms in 33 municipalities in the four Amazonian subpopulations. IgG anti-N.caninum antibodies were detected by the indirect fluorescence test, with a general prevalence of 30.2%, being seropositive in 43 farms (91.5%), with prevalence ranging from 2.2% to 69.2%. The highest number of high density points was found in subpopulation 3 (municipality of Apuí and other municipalities on the Madeira River and affluent). It was concluded that N. caninum is present with high seroprevalence values, when compared to other cattle producing states in the Amazon region of Brazil. The identified factors can be used as risk indicators so that control measures can be implemented to prevent infection by N. caninum in these herds.