Seroprevalence of Neospora caninum antibodies in cattle and water buffaloes in India

Neospora caninum is now recognized as a major cause of abortion in cattle worldwide, but there is no report of N. caninum infection in cattle in India. Serum samples from 427 dairy cattle and 32 dairy water buffaloes from 7 organized dairy farms located in Punjab, India, were tested for N. caninum antibodies using a commercial monoclonal antibody-based competitive enzyme-linked immunosorbent assay (ELISA). Antibodies to N. caninum were found in 35 of 427 cattle from 6 of the 7 farms; 9.6% of cows, 5.1% of heifers, and 5.0% of calves were seropositive, suggesting postnatal transmission of N. caninum on the farm. Antibodies to N. caninum were found in 16 of 32 buffaloes tested from 2 dairy farms. In total, 64 cattle and 16 buffalo sera already tested by ELISA were also evaluated by an indirect fluorescent antibody test (IFAT) to verify ELISA results. Of the 64 cattle samples, 29 sera were negative by both tests and of the 35 ELISA-positive sera, 12 had IFAT titers of 1:100 or higher (1 had IFAT titer of 100, 2 had IFAT titer of 200, and 9 had IFAT titers of 400 or higher). Of the 16 buffalo sera positive by ELISA, 1 had an IFAT titer of 1:400. Thus, antibodies to N. caninum were demonstrated in cattle sera by 2 serologic methods. To our knowledge this is the first report of N. caninum infection in cattle and buffaloes in India.     

Seroprevalence of Neospora caninum infection in dairy cattle of Southern China

A seroepidemiological survey of Neospora caninum infection in dairy cattle was carried out in China's southern Guangdong Province between July 2009 and March 2010. A total of 370 serum samples of dairy cattle was collected from 5 farms and examined for antibodies to N. caninum by enzyme-linked immunosorbent assay. The overall seroprevalence of N. caninum in dairy cattle was 18.9% (70/370). The seroprevalence of N. caninum in aborting cows (22.7%) was higher than that in nonaborting cows (16.3%), but the difference was not statistically significant (P > 0.05). Five-yr-old dairy cattle had the highest seroprevalence (27.8%), followed by those that were 6-yr-old (20.4%). Dairy cattle with 4 pregnancies had the highest seroprevalence (29.2%). There was no apparent association of N. caninum seropositivity with age or number of pregnancies (P > 0.05). The results of the present survey indicated that the infection with N. caninum is prevalent in dairy cattle of all ages in southern China, which may be one of the causes of bovine abortion. This is the first report of seroprevalence of N. caninum in dairy cattle in southern China.     

Seroprevalence of Neospora caninum infection in dairy and beef cattle in Spain

In recent years, neosporosis has been identified as a major cause of abortion in dairy and beef cattle. Although the disease has been described worldwide, there is a Jack of information concerning the prevalence of this infection in different cattle production systems. The aim of this study was to investigate the seroprevalence of Neospora caninum infection in a representative area of beef and dairy cattle production in Spain. A cross-sectional study was undertaken in which herds constituted the initial sampling unit and two strata (dairy and beef herds) were considered. Using a 95% level of confidence and setting 5% (beef) and 5.4% (dairy) error limits, 216 beef and 143 dairy herds were randomly selected and sampled. Nine animals (> 1 year old) were randomly sampled in each herd to detect the presence of the infection. A herd was considered infected when at least one animal was seropositive. In total, serum samples from 1121 dairy and 1712 beef animals were collected and tested for specific anti-N. caninum IgG using an ELISA. Specific antibodies were detected in 55.1% (119/216) beef and 83.2% (119/143) dairy herds. Individual prevalences obtained were 17.9% (306/1712) for beef and 35.9% (402/1121) for dairy animals. Presence of N. caninum infection was higher in dairy than in beef herds and the association between infection and the cattle production system (dairy or beef) was statistically significant [(chi2)Y= 29.21, P < 0.001, OR = 4.04 (2.35-6.99)]. Herd size of dairy cattle did not appear to be associated with N. caninum infection. On the contrary, infection was associated with herd size in beef cattle (chi2 = 12.79, P < 0.01). Finally, no association was found between replacement or pasture management and infection in beef herds.     

Seroprevalence of Neospora caninum infection on dairy cattle in farms from southern Romania

Neospora caninum, a coccidian parasite closely related to Toxoplasma gondii, is one of the major causes of abortion in cattle worldwide. Conventional serological techniques, such as the indirect fluorescent antibody test and enzyme-linked immunosorbent assay (ELISA), are routinely used in adult animals and aborted fetuses for the detection of anti- N. caninum antibodies. In Romania, infection with N. caninum in cattle has been reported recently, but only in limited areas from the north and central parts of the country. Therefore, the aim of this study was to obtain additional seroepidemiological data on infection with N. caninum on dairy farms from the south of Romania. A total of 258 blood samples was analyzed from 230 dairy cows and 28 calves from 9 dairy farms in southern Romania; the presence of specific IgG antibodies against N. caninum was determined using an indirect ELISA test. The average seroprevalence was 40.3%, but the within-herd prevalence ranged between 11.5 and 80.0%; the seroprevalence in dairy cows was 41.7%, while in calves it was 28.6%. Of the positive samples, 74.0% (77/104) had a high positive reaction (S/P ratio more than 1.0), while 26.0% (27/104) had a low positive reaction (S/P ratio between 0.5 and 1.0). This study indicates that N. caninum infection is widespread in the south of Romania, which could explain the causes of abortions registered in some herds in the studied area. However, a serological screening across the country is planned in order to assess the actual national prevalence of N. caninum infection, followed by implementation of a prevention and control program.     

Seroprevalence of Neospora caninum and Brucella abortus in dairy cattle herds with high abortion rates

The protozoan Neospora caninum and the bacterium Brucella abortus are well-recognized causes of abortion in dairy cattle. Serum samples (n = 240) from aborting (n = 141) and at-risk (n = 99) animals from 5 herds with high abortion rates in Punjab Province, Pakistan, were tested for antibodies to N. caninum using monoclonal antibody-based ELISA and for antibodies to B. abortus using the serum agglutination test. Antibodies to N. caninum and B. abortus were detected in 105 (43.8%) and 135 (56.3%) cattle, respectively. Prevalences of antibodies to N. caninum and B. abortus were higher in aborting cows (46.8% and 76.6%, P < 0.05) than in animals at risk (39.4% and 27.3%, P > 0.05). Sixty-six animals (27.5%) were seropositive to both N. caninum and B. abortus , and results showed no significant difference (P > 0.05) with respect to geographical district, breed, and age. This is the first report of N. caninum infection among dairy cattle herds in Pakistan.     

Seroprevalence of Neospora caninum antibodies in dogs in India

Neospora caninum is one of most important causes of abortion in cattle worldwide, and dogs are an important risk factor for N. caninum infection in cattle. Antibodies to N. caninum were determined in 184 (126 rural, 58 urban) dogs from the Punjab State, India, using commercial monoclonal antibody-based competitive ELISA and found in 16.8% of the animals. The prevalence of N. caninum antibodies was significantly higher in rural dogs (21.4%, 27 of 126) than city dogs (6.9%, 4 of 58). To our knowledge this is the first report of N. caninum infection in canines from India.     

Seroprevalence of antibodies to Neospora caninum in dogs from Spain

The prevalence of Neospora caninum antibodies was determined in sera of 139 dogs from Catalonia (northeastern Spain) using the indirect immunofluorescence antibody test (IFAT). Antibodies in the IFAT were found in 17 of 139 dogs (12.2%) with titers ranging from 1:50 to 1: 1,600. Seroprevalence was higher in dogs over 1 yr old compared with dogs younger than 1 yr (P < 0.05). No statistical difference was observed when sex, breed, purpose, or modus vivendi was compared with seropositivity. Most dogs had low antibody titers, which indicated subclinical infection in the area studied. No neosporosis-related disease was reported from any dog, although a German shepherd with an antibody titer of 1:800 showed pododermatitis. All sera were also screened using a commercial direct agglutination test (DAT). The DAT showed a similar specificity but a lower sensitivity when compared with IFAT as a reference technique.     

Prevalence of Neospora caninum antibodies in sheep and goats in Pakistan

The purpose of the present study was to obtain seroepidemiological information on the Neospora caninum infection status of sheep and goats in different areas of Punjab Province and Azad Kashmir (Pakistan). A cross-sectional study, with the use of a competitive ELISA, showed an overall 27.7% (35 of 128) (95% confidence interval [CI] ± 7.7%) and 8.6% (13 of 142) (95% CI ± 4.6%) seroprevalence of N. caninum antibodies in sheep and goats, respectively. The difference in seroprevalence between sheep and goat populations was statistically significant (P < 0.05). The highest prevalence (37.4% ± 13.2%) was recorded in the tailless breed of sheep.     

Seroprevalence of antibodies to Neospora caninum in dogs and raccoon dogs in Korea

Neospora caninum is an important cause of abortion in cattle, and dogs are its only known definitive host. Its seroprevalence among domestic urban and rural dogs and feral raccoon dogs (Nyctereutes procyonoides koreensis) in Korea was studied by indirect fluorescent antibody test (IFAT) and by the neospora agglutination test (NAT), respectively. Antibodies to N. caninum were found in 8.3% of urban dogs and in 21.6% of dogs at dairy farms. Antibody titers ranged from 1:50 to 1:400. Antibodies to N. caninum were found in six (23%) of 26 raccoon dogs. However, the potential role of raccoon dogs as a source of horizontal transmission of bovine neosporosis needs further investigation. The results of this study suggest that there is a close relationship between N. caninum infection among dairy farm dogs and cattle in Korea. This study reports for the first time upon the seroprevalence of N. caninum infection in raccoon dogs in Korea.     

Evidence of post-natal transmission of Neospora caninum in Dutch dairy herds

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 showed an equal distribution of seropositives in all age-groups in 10 herds. In contrast, in eight herds an age-group could be identified which had a significantly higher seroprevalence than the other animals in the herd. Most seropositive animals in the high seroprevalence age-groups had either seronegative dams or seronegative offspring, whereas there was a strong relationship between the serostatus of dams and offspring in the other animals in the herd. Aborting animals were mainly part of the high seroprevalence age-group. These findings strongly indicate a post-natal infection of the animals in the high seroprevalence age-groups, probably due to a point source exposure to N. caninum.     

Seroprevalence of Toxoplasma gondii and Neospora caninum in slaughtered pigs in the Czech Republic

In the Czech Republic, sera from 551 clinically healthy adult slaughtered pigs (females, 6-8 months old) were collected during the first half of June in 2010. Sera were tested for Toxoplasma gondii-specific IgG antibodies by an enzyme-linked immunosorbent assay; samples with more than 50% S/P were considered as positive. The same samples were also analysed for Neospora caninum antibodies using a commercial competitive-inhibition enzyme-linked immunosorbent assay; samples with more than 30% inhibition were considered as positive. Antibodies against T. gondii were found in 198 pigs (36%) in all districts with prevalences ranging from 18% to 75%. Antibodies against N. caninum were found in 16 pigs (3%); positive animals were found in 4 districts with prevalences ranging from 1% to 20%. Indication of mixed infections (concurrent presence of both N. caninum and T. gondii antibodies) was found in 8 (1·5%) pigs. The results of our study indicate that pigs in the Czech Republic have a relatively high seroprevalence for T. gondii, while they have only a low seroprevalence for N. caninum. Therefore, natural infection with T. gondii seems to be very common in Czech pigs. It is the first evidence of N. caninum antibodies in pigs in the Czech Republic. These results complete data about N. caninum infection in pigs in Europe.     

Neospora caninum infection does not affect early pregnancy in dairy cattle

This study was designed to evaluate the relationship between Neospora caninum infection prior to pregnancy, as determined through maternal serology, and the subsequent occurrence of abortion in dairy cattle. Special emphasis was placed on pregnancy losses in the first trimester of pregnancy. Neospora caninum antibodies were analyzed by commercial ELISA in 2773 pregnant animals (2022 parous cows and 751 heifers) from six herds. The mean seroprevalence of antibodies to N. caninum in the herds was 15.1% (n = 419). From gestation Day 34 to the 90th day of pregnancy, there were 183 abortions (6.6% of all pregnancies) (23 in Neospora positive animals). After 90 days of pregnancy, the number of abortions was 146 (5.3%); 126 occurring during the second and 20 during the third trimester of pregnancy (105 in Neospora positive animals). Multiple logistic regression analyses were performed on data from each animal using abortion before or after 90 days of pregnancy as the dependent variable, and Neospora positivity, herd, pregnancy season, and parity (parous or nonparous) as independent factors. No significant effects of Neospora positivity and herd were found on the abortion rate before 90 days of pregnancy. Based on the odds ratio, the abortion rate was 4 times higher (P < 0.0001) in animals that became pregnant in the warm than in the cool period, and 3.7 times higher (P < 0.0001) in parous than in nonparous animals. Neospora positivity was the only variable included in the logistic regression model for abortions occurring after 90 days of pregnancy. Seropositivity in an animal increased the probability of abortion by an odds ratio of 18.9 (P < 0.0001; 95% confidence interval 12.9-27.8). Season, parity, and herd showed no effect. The results of the present study suggest that chronic N. caninum infection prior to pregnancy appears not to affect the early fetal period, but does have a significant abortive effect after 90 days of gestation.     

Fetal infection with Neospora caninum in dairy and beef cattle in Belgium

Neospora caninum is a protozoan parasite, which causes fetal and neonatal mortality in livestock and companion animals. In 224 abortions in Belgian cattle, different diagnostic methods were used to demonstrate infection, and the presence of N. caninum. An indirect fluorescent antibody test (IFAT) was used to analyze fetal and maternal sera and immunohistochemistry (IHC) was performed when lesions consistent with neosporosis were observed in the brain, heart or liver. Twenty dairy cattle sera out of 70 (29%) and 13 beef cattle sera out of 93 (14%) were positive by IFAT. A positive titer to N. caninum was found in seven and three fetuses born to beef and dairy cows, respectively. Lesions consistent with N. caninum infection were observed in 17 fetuses. Of nine positive beef fetuses, five were confirmed by IHC while, all but one dairy fetus were confirmed using the same technique.Age had no influence on the serological status of the mother (P = 0.486) whereas husbandry system had a borderline influence (P = 0.082). However, a strong association (P = 0.004) between the level of antibodies in the dam and the occurrence of lesions in the fetus was observed and lesions were more prominent in dairy than in beef fetuses. Additionally, the distribution of intra-cerebral lesions was more extensive in dairy than in beef fetuses (P < 0.0001). Age and serological status of the fetus were found to influence the occurrence of lesions in beef fetuses (both P < 0.001) but no such significant relationships could be demonstrated in dairy fetuses. The study indicated that N. caninum must be considered as an important cause of bovine abortion in Belgium.     

Neospora caninum in wildlife

Neosporosis, which is caused by the coccidian parasite Neospora caninum, is recognized as a major disease of domestic animals that causes high abortion rates in cattle and fatal neurological disease in dogs. A life cycle of N. caninum in wild animals (i.e. sylvatic) has long been suspected because neosporosis has been detected in several wildlife species. Recently, the transmission of N. caninum has been confirmed in coyotes and white-tailed deer. The newly confirmed wild hosts and other wild animals are probably involved in the sylvatic cycle of the parasite. Control measures for neosporosis could now become more complicated, given the participation of wildlife in the life cycle of N. caninum.     

Prevalence of Neospora caninum antibodies in dogs from dairy cattle farms in Parana,Brazil

Serum samples from 134 dogs from 22 cattle dairy farms in the northern region of Parana State, Brazil, were tested for antibodies to Neospora caninum in an indirect fluorescent antibody test. Antibodies (> or = 1:50) to N. caninum were found in 29 (21.6%) of the 134 dogs, and seropositive dogs were found on 14 (63.6%) of the 22 dairy cattle farrms. The antibody titers of dogs were 1:50 (3 dogs), 1:100 (7 dogs), 1:200 (7 dogs), 1:400 (6 dogs), and > or = 1:800 (6 dogs). The low prevalence (9%) in < 1-yr-old dogs compared with the 2- to 3-fold higher prevalence in older dogs (17-29%) suggests postnatal exposure to N. caninum infection.     

Neospora caninum infections in bovine foetuses and dairy cows with abortions in Argentina

Antibodies to Neospora caninum were measured in bovine foetuses, dairy cows and beef cows in Argentina using the IFAT, the N. caninum agglutination test, and the recombinant NCDG1 and NCDG2 ELISA. Serum antibodies (IFAT titre 1:80) were found in 20 of 82 (24.4%) dairy cow foetuses and one of 22 (4.5%) beef cow foetuses. Microscopic lesions suggestive of neosporosis were seen in brains of seven of eight foetuses with IFAT titres of 1:80. Antibodies (IFAT) were found in 122 of 189 (64.5%) dairy cows that aborted. Serum antibody titres (IFAT) of 189 dairy cows that aborted were: < 1:25 (67 cows), 1:25 (four cows), 1:50 (16 cows), 1:200 (seven cows), 1:> or = 800 (95 cows). Of the 87 sera with IFAT titres of < or = 1:50, 57 had no antibodies in 1:40 dilution and 30 had titres of 1:40 in the N. caninum agglutination test. Thus, sera from at least 56 dairy cows which had aborted were seronegative both in the N. caninum agglutination test and the IFAT. The distribution of positive and negative sera was similar when measured by ELISA, except that, depending on cut-off titre, the ELISA indicated a greater number of seropositive cows that were negative by the IFAT and N. caninum agglutination test. These results suggest that transplacental transmission of N. caninum in dairy cows in Argentina is frequent.     

Estimation of vertical and horizontal transmission parameters of Neospora caninum infections in dairy cattle

Transmission parameters of Neospora caninum infections in dairy cattle were determined in six herds with a history of Neospora-associated abortions, using an antibody-detection ELISA to detect evidence of infection. A total of 124 seropositive dams and their calves were tested at calving to estimate vertical transmission, and 154 seronegative heifers were monitored prospectively from birth for evidence of post-natal infection. The probability of vertical transmission was very high; 95.2% (95% confidence interval: 89.8%, 98.2%) of the seropositive dams produced calves that were seropositive prior to consumption of colostrum. In the prospective study, three heifers seroconverted, by 1, 8 and 16 months of age, and the overall incidence rate of seroconversion was 1.9 per 100 heifer-years at risk, ranging from 0 to 4.1 per 100 heifer-years at risk within herds. If heifers with inconclusive ELISA results were included in the analysis, the incidence rate of seroconversion was 3.8 per 100 heifer-years at risk, ranging from 0 to 8.3 per 100 heifer-years at risk within herds. This study showed that vertical transmission was the major route involved in the spread of N. caninum in these herds, and that there was only a low detectable level of horizontal transmission. However, further studies are needed to provide parasitological evidence of infection in those heifers that seroconverted.     

Prevalence of Neospora caninum infection in dairy cows and its consequences for reproductive management

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.     

Seroprevalence and associated risk factors of Toxoplasma gondii and Neospora caninum infections in cattle in Central India

Toxoplasma gondii and Neospora caninum are closely related cyst-forming parasites identified as important causes of reproductive failures in ruminants. While these parasites have been reported worldwide, seroprevalence and associated risk factors for cattle infections have not been determined in India. A total of 576 serum samples of cattle were analyzed for antibodies to T. gondii and N. caninum using enzyme-linked immunosorbent assay (ELISA), modified/Neospora agglutination test (MAT/NAT), and an indirect fluorescent antibody test (IFAT-tachyzoite and bradyzoite). Additionally, general information about cattle, movement of cats and dogs, the menace of rodents, management, and reproductive disorders were assessed to identify the potential risk factors. Overall, 32.9% (190/576) serum samples reacted positively to T. gondii and 24.8% (143/576) to N. caninum. The performance of the diagnostic tests showed excellent agreement between IFAT and ELISA (kappa [κ] = 0.98) and between MAT/NAT and ELISA (κ = 0.97). Combining both infections on avidity test, 94% sera had high-IgG avidity, and 3% had low-IgG avidity antibodies, indicating chronic infection in the majority of the cases. The identified risk factors (p < 0.05) for exposure to T. gondii were: increasing age (Odds Ratio [OR]: 2.02), movement of cat (OR: 4.8) and rodents (OR: 1.57) in the farm; and for N. caninum: increasing age (OR: 1.6), movement of dogs in the farm (OR: 2.07), drinking pond water (OR: 1.64) and abortion (OR: 1.82). These findings revealed that T. gondii and N. caninum infections are widespread in the study area and suggest conducting nationwide epidemiological studies owing to their economic importance.