Chronic Neospora caninum infection and repeat abortion in dairy cows: A 3-year study (original) (raw)
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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.
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.
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...
The incidence of Neospora caninum in dairy cows with abortion and infertility problems
Kocatepe veteriner dergisi, 2021
The contribution of animal husbandry to the national economy cannot be ignored. The causes of infertility are various and complex. Economic losses are increasing in dairy cattle breeding due to infectious and non-infectious causes. The percentage of abortion due to infectious agents is not fully known, but infectious agents lie in about 90% of the cases whose etiology can be determined. Neospora caninum is considered to be one of the most important abortion factors of cattle. Although, this protozoa is always ignored. It causes abortion in cows. In this study, it was aimed to detect N. caninum from the blood serum obtained from 137 dairy cattle brought to Aksaray University Faculty of Veterinary Medicine between 2017-2019 and suffering from abortion and infertility problems. For serological diagnosis, ELISA (Enzyme-Linked ImmunoSorbent Assay) test was performed. As a result, N. caninum agent was detected in 37.22 % (51/137) of the samples that belong to cattle with abortion and infertility problems. It was concluded that economic loss due to infertility in dairy cattle and protozoa, which are one of the infection factors, should be given importance.
Risk factors associated with Neospora caninum abortion in Ontario Holstein dairy herds
Veterinary parasitology, 2005
The objective of this epidemiological study was to identify risk factors for Neospora caninum-related abortions in Ontario Holstein dairy herds. A total of 88 herds, consisting of 5080 cattle, and utilizing Dairy Herd Improvement (DHI) services, were divided into three groups. Case (n = 30) and first control (n = 31) herds were selected from 1998 and 1999 fetal abortion submissions to the Animal Health Laboratory, University of Guelph, that were histopathologically positive or negative, respectively, for N. caninum. A second control group (n = 27) was selected from multiple sources of herds sampled within the previous 4 years that had a low seroprevalence (<7%) to N. caninum. Between May and December 1999, all available cows on all farms, in parity one or greater, were blood sampled. The sera were then analyzed for antibody to N. caninum using a kinetic ELISA. A survey administered at the time of sampling recorded information on housing, animal species present, manure management,...
Dairy cow abortion associated with Neospora caninum and other infectious agents
Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 2005
[Aborto em vacas leiteiras associado a Neospora caninum e a outros agentes infecciosos] Dairy cow abortion associated... Arq. Bras. Med. Vet. Zootec., v.57, n.4, p.545-547, 2005 547 RESUMO Trinta e cinco vacas de rebanhos leiteiros da região Norte do estado do Paraná, com histórico de abortamento, foram pesquisadas sorologicamente para verificar a presença de anticorpos contra Neospora caninum, Toxoplasma gondii, Leptospira spp., Brucella abortus, BHV-1 e BVDV. Vinte e uma vacas apresentaram títulos sorológicos compatíveis com infecção. Todas elas, soropositivas para N. caninum, foram também soropositivas para outros agentes infecciosos, sugerindo a possibilidade de associação desses agentes nos problemas reprodutivos de bovinos, no estado do Paraná. Palavras-chave: bovino, aborto, Neospora caninum, problema reprodutivo
Controlling Endemic Neospora caninum-Related Abortions in a Dairy Herd From Argentina
Frontiers in Veterinary Science, 2019
After diagnosis of endemic abortions due to neosporosis in a commercial dairy farm, routes of Neospora caninum-transmission were evaluated in order to choose the best strategy for reducing its seroprevalence and related abortions. Fifty two dam-calf pairs were bled at parturition. Additionally, 22 female calves were also sampled at regular 3 month intervals until 18–22 months. N. caninum specific antibodies were assayed by IFAT. Serum samples were tested at a dilution 1:25 for calves before colostrum intake and heifers before mating and 1:100 for multiparous cows. Only serum samples from IFAT seropositive cattle involved in the evaluation of the routes of transmission were assessed by a commercial IgG avidity ELISA. Seropositive cows or heifers were artificially inseminated with semen from Hereford bulls. The progenies from these female animals were sent to a feed lot to produce meat. Different generalized linear models (GLM) were used to study the relationship between abortion, age category, and serostatus. Seropositive heifers were more likely to have a record of abortion (OR 2.7; 95% CI 1.6–4.7). Vertical transmission frequency was 55.5% (5 seropositive calves/9 seropositive cows). Horizontal transmission was 22.7% (5 female calves seroconverted at least one time/22 females calves sampled during 24 months) and these 5 female calves had low avidity. In heifers, both seroprevalence and abortion rates decreased from 22.1 and 8.4% of 475 in 2009 to 6.1 and 4.3% of 578 in 2015, respectively (p < 0.01). Over 5 years, N. caninum-seroprevalence and the related abortions in heifers decreased after the control strategy was assessed.
Seroprevalence ofNeospora caninuminfection following an abortion outbreak in a dairy cattle herd
Australian Veterinary Journal, 2000
Neosporosis in cattle is a globally important disease, causing abortions and significant economic losses if epidemic abortions occur. In Serbia, however, studies of Neospora caninum infection in cattle are few and are based on limited samples and/or from limited areas. We thus performed a nationwide study to examine the seroprevalence of N. caninum infection in a sample of cows randomly selected from dairy farms in 12 epidemiological units from throughout Serbia, as well as the possible transmission risk factors. Sera from a total of 1496 cattle were tested by competitive ELISA, and N. caninum-specific antibodies were shown in 7.2% animals (95% confidence interval CI, 6.6-7.9%), ranging from 2.2 to 12% across the epidemiological units. At least one seropositive animal was detected on 10.7% (95% CI, 9.7-11.8%) of farms, with a range of 5.9-25.9%. Logistic regression analysis showed that the single risk factor for infection in individual animals was keeping cows in loose-stalls (OR = 3.31, 95% CI = 1.95-5.60, P < 0.001). Risk factors for the presence of infection on farms also included housing in loose-stalls (OR = 18.49, 95% CI = 5.40-63.36, P < 0.001), and herd size > 100 animals (OR = 24.08, 95% CI = 3.85-150.50, P = 0.001). In view of the relatively low prevalence of infection showed at both the individual and farm level, this is the perfect time to undertake appropriate preventive measures to improve animal health and reduce economic losses.
Veterinary Parasitology, 2001
Neospora caninum is one of the most frequent infectious organisms causing abortion in cattle worldwide. The present case-control study was designed to assess the importance of bovine neosporosis for causing abortion in Swiss cattle and to identify selected risk factors. Infection was primarily diagnosed by a N. caninum-specific PCR and serology, complemented with histopathology and immunohistochemistry. A total of 113 case and 113 corresponding control-farms were studied for 1.5 year. During this time period, 242 abortions were reported and referred for bacteriological, virological, parasitological and pathohistological examinations. N. caninum was detected by PCR in the brains of 21% of all aborted fetuses. Microscopic lesions indicative for cerebral protozoa infection were detected in 84% of PCR-positive fetal brains. Bovine viral diarrhea virus (BVDV) was demonstrated in 7% of the cases, and bacterial infections were detected in 4% of the abortions. One or more N. caninum-abortions occurred in 20% of the herds (41 case-farms and 3 control-farms). Serological examination of aborting mother cows revealed a significantly higher percentage of N. caninum-seropositive animals (44%) in comparison to the prevalence in a randomly selected population (12%). However, in eight cases (4% of all investigated abortions) seronegative cows aborted N. caninum PCR-positive fetuses, and in 50 cases the fetus remained negative although the respective mother cow was N. caninum-seropositive. Repetitive serological investigations (at a 3-12 months interval) of 3551 cows from case-and control-farms showed a decrease of the overall N. caninum-seroprevalence from 17 to 12%. Ninety out of 3008 seronegative animals were converted to N. caninum-seropositivity. Conversely, 212 out of 543 initially