A long-term study of Neospora caninum infection in a Swedish dairy herd (original) (raw)
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Veterinary Parasitology, 2002
The purpose of this paper is to investigate the high rate of seroconversion for Neospora caninum in a dairy herd. Forty-five of 95 (47%) of the seronegative animals seroconverted within a period of 6 months. Seropositive animals were not equally distributed among age-groups. A high seroprevalence age-group of 8-30 months was housed together during a period of 4 months, indicating a point source infection within this period. A lack of association between the serological status of daughters and mothers also indicated horizontal transmission of the infection. Low avidity indices in the seroconverted animals confirmed a recent infection in this herd. However, there was no increased abortion rate in connection with the seroconversion, which indicates that mass seroconversions in dairy herds may remain unnoticed. There was circumstantial evidence that the farm dog played a role in the transmission of the infection to the cattle. However, also evidence was found for an unexplained ongoing horizontal transmission after the initial point source exposure.
Theriogenology, 2004
This study was carried out to determine the prevalence of neosporosis in an area of intensive dairy production, in Portugal. Sera samples were obtained in a random basis from 114 cows in 49 herds (group A), and from 1237 cows in 36 herds with a history of abortion outbreaks (group B). All sera samples were tested for neosporosis by direct agglutination test (DAT). Additionally, attempts to isolate Neospora caninum in 42 aborted bovine fetuses from 38 dairy herds (group C) were carried out, utilizing a bioassay with immuno-depressed Swiss Webster mice. Parasitological confirmation was done by indirect fluorescent antibody test (IFAT). The prevalence of neosporosis in the group A was 28%. Group B had a significantly (P < 0:001) higher prevalence (46%) and Neospora caninum was isolated in 36% of the aborted fetuses (group C). These results indicate that neosporosis, a disease only recently (2001) diagnosed in Portugal, has a high prevalence in the country, particularly in populations with a story of abortion. Thus, neosporosis should systematically be considered in the differential diagnosis of abortion. In the context of embryo transfers, the importance of selecting Neospora-free embryo recipients is discussed, as well as the pertinence of assessing the Neospora status of traded and imported cattle.
Neospora caninum infection dynamics in dairy cattle
Parasitology Research, 2012
Neospora caninum is considered in many countries as one of the key abortion agents in cattle. This study aims to investigate the parasite behavior in dairy cattle in the municipality of Avaré, SP, Brazil, where abortions frequently occur. An ELISA was performed to compare two samplings on a total of 615 animals; tests were performed in the same herds with a gap of 3 years. An increase in the percentage of reactive animals was observed, ranging from 21.6% at the first sampling to 38.9% at the second sampling. Of the 176 animals tested at both samplings, 61.93% retained a non-reactive status, 15.9% retained a reactive status, 19.88% switched from non-reactive to reactive and 2.27% switched from reactive to non-reactive. Of the 100 animals with reproductive disturbances, 50% presented anti-Neospora antibodies, thereby indicating the presence of the protozoa. When comparing cows and their respective female offspring, a predominance of horizontal infection was observed. Moreover, considering the significant percentage of animals that switched from non-reactive to reactive and the abundant presence of dogs among the herds, the N. caninum transmission may be attributed to presence of carnivores.
AgroLife Scientific Journal, 2023
Neospora caninum is an apicomplexan protozoa parasite that causes reproductive disorders in cattle worldwide. Despite the high seroprevalence reported in Romania, there are limited data on N. caninum infection in dairy cattle, and no studies have evaluated the presence of infection over time in a limited area. Therefore, this study aimed to assess the seroprevalence of N. caninum in a dairy cattle farm in Southeastern Romania where a previously study reported about the cattle exposure to N. caninum infection. A total of 85 cattle, assigned in four groups, according to the reproductive status (repeated breeding syndrome, history of abortion, pregnant cows, and fresh cows) were tested for the presence of N. caninum antibodies, using an indirect ELISA test. The overall seroprevalence was 28.23% (95% CI: 18.67-37.80). According to the reproductive groups, the seroprevalence varied between 19.04% (95% CI: 2.25-35.84) in fresh cows to 38.09% (95% CI: 17.32-58.87) in cows with repeated breeding syndrome. By these findings new information is provided about the disease's presence in the studied farm, implying that infection with N. caninum may be the primary cause of reported reproductive disorders, as well as about the infection's persistent nature.
Evidence of post-natal transmission of Neospora caninum in Dutch dairy herds
International Journal for Parasitology, 2001
Eighteen dairy herds with neosporosis-associated abortions were analysed for antibodies against Neospora caninum. Blood samples of all cows, heifers and calves were collected on the same day for each farm. A total of 2430 heads of cattle were examined. For each herd, the seropositive and seronegative animals were plotted against month of birth. Analysis of seroprevalence in relation to age
Prevalence and transmission of Neospora caninum within infected Swedish dairy herds
Veterinary parasitology, 2005
In this long-term study, the changes in within-herd Neospora caninum seroprevalences and the relative importance of horizontal and vertical parasite transmission in Swedish dairy herds were investigated. The within-herd prevalences varied between 5.8% and 65.0% when the herds were first sampled. Comparing the prevalences of year 2000 with those found 2-3 years later, nine out of 14 investigated herds had a similar or lower within-herd prevalence while five herds had an increased portion of seropositive individuals. Three herds were free or almost free from infection at their last sampling. Changes in prevalence were not related to the level of prevalence that each herd had when first sampled. Antibody avidity measurements revealed that the majority of seropositive individuals in all herds were chronically infected. Dam-calf pair investigations and inspection of genealogic trees supplemented with antibody test results showed that vertical transmission was by far the dominant transmis...
Seroprevalence of Neospora caninum in dairy cows in Belgrade city area, Serbia
Journal of the Hellenic Veterinary Medical Society, 2018
The protozoan parasite Neospora caninum is one of the most important abortifacient pathogen in cattle. Serological investigations are often used in order to estimate seroprevalence in herds. Aims of our study were to determine the seroprevalence among aborting and non-aborting dairy cattle in Belgrade city area as well as epidemiological factors that are important for N. caninum infection. Using commercial ELISA kit, we examined 188 sera. Out of 188, 142 samples originated from pregnant (non-aborting) cows from five farms, while 46 were from cows who had aborted. Overall seroprevalence was 25% (48/188). Seroprevalence was significantly higher (p≤0.05) in aborting than in non-aborting group of cows (37% and 21.1% respectively). At least one positive sample was detected on four (80%) out of five examined farms while seroprevalence among farms varied from 0 to 43.5%. On all examined farms crucial epizootiological factors (presence of dogs and low biosecurity measures) that favor the ma...
Microbial pathogenesis, 2015
Neosporosis is a parasitic disease cause by Neospora caninum, a parasite of great importance in livestock. This study aimed to evaluate the presence of antibody against N. caninum in dairy cattle with history of abortion, as well as to identify associated risk factors for neosporosis. Animals suspected of neosporosis (n = 130) after clinical examination were randomly selected. Sera samples from 29 farms were submitted to indirect immunofluorescence technique (IFA) in order to detect antibodies against N. caninum, and animals were considered positive if ≥IFA 1:200. An epidemiological questionnaire was used to verify probable risk factors for neosporosis and their cause-effect relation. Serological results showed that 43.8% of the animals were seropositives for N. caninum. The univariate statistical analysis found a significant relation between neoporosis and age. The number of pregnancies and the number of years that the farms had been producing milk were found as associated risk fac...