Prevalence of Neospora caninum antibodies in dairy cattle and water buffaloes and associated abortions in the plateau of Southern Peninsular India

Serosurvey and associated risk factors for Neospora caninum infection in Egyptian water buffaloes (Bubalus bubalis)

Neosporosis is a parasitic disease that causes reproductive disorders in animals, making it a barrier to maximum efficiency. The purpose of this study was to determine the seroprevalence of Neospora caninum (N. caninum) antibodies in water buffaloes from four governorates in northern Egypt. A commercial indirect-ELISA test was used to detect antibodies against N. caninum in the serum of 450 water buffaloes. The total seroprevalence of N. caninum in water buffaloes from Egypt was 31.3%, and the highest prevalence was observed in Gharbia governorate. The identified risk factors for N. caninum infections in water buffaloes were sex (OR = 1.96, 95%CI: 1.22-4.17), buffaloes more than 4 years of age ( OR = 5.80, 95%CI: 2.26-14.86), abortion in second trimester (OR = 16.48, 95%%CI: 2.99-34.03), history of abortion (OR = 3.45, 95%CI: 1.58-7.52) and contact with dogs (OR = 2.55, 95%CI: 1.51-4.32). Thus, more studies are needed to determine the role of buffaloes in the epidemiology of neosporosis in Egypt.

Serological and molecular detection of Toxoplasma gondii and Neospora caninum in free-ranging rats from Nagpur, India

Toxoplasma gondii and Neospora caninum are cyst-forming coccidian parasites that infect both wild and domestic non-felids as intermediate hosts, with rodents serving as important reservoir hosts during their life cycles. This study was aimed at investigating T. gondii and N. caninum infections and identifying factors favouring T. gondii infection in free-ranging rats from India. A total of 181 rodents were trap-captured, and blood and brain samples were subsequently collected for serological and molecular examination of T. gondii and N. caninum. Antibodies against T. gondii and N. caninum were detected by MAT/NAT and IFAT in 13.8% (25/181) and 1.65% (3/181) of rodents, respectively. All three N. caninum samples positive by NAT/IFAT were also positive for ELISA, while for T. gondii, 19 of 25 MAT/IFAT positive samples were also positive for ELISA. The antibody titers (MAT/NAT/IFAT) of rodents seropositive for T. gondii ranged from 25 to 400, while those of rats seropositive for N. caninum ranged from 25 to 100. Also, using PCR, DNA from T. gondii (B1 gene) and N. caninum (NC5 gene) was found in 2.76% (5/181) of brain samples and 0.55% (1/181) of brain samples. All PCR positive samples were also seropositive. No mixed infections were observed in the serological and molecular detections. A Chi-square analysis revealed that older rats and rats living in urban areas are significantly associated with T. gondii infection; however, rodent species, gender, location, habitat types, and seasonality were statistically nonsignificant. Overall, this study demonstrated that T. gondii was widely distributed while N. caninum was less prevalent among free-ranging rats in the studied area.

Neospora caninum Infection in Cattle in the Province of Kohgiluyeh and Boyer Ahmad, Southwest of Iran: Seroprevalence and Molecular Assessment

Introduction

Among the protozoa of veterinary importance, Neospora caninum is responsible for large economic and productive losses in cattle herds. Dogs are being considered the definitive hosts of the parasite. Neospora caninum has gained considerable attention through its role in the etiology of bovine abortion. The current study aimed at assessing the status of Neospora infection in cattle in Boyer-Ahmad County in Kohgiluyeh and Boyer-Ahmad province, southwest of Iran.

Methods

In this cross-sectional study, 150 cattle blood samples were collected and samples were screened for N. caninum antibodies using a modified direct agglutination test (MAT). For the same samples, 130 buffy coats were collected and tested, by PCR, for the presence of N. caninum DNA, targeting the Nc-5 gene.

Results

Anti-N. caninum antibodies were detected in the sera of 49 out of 150 cattle which is corresponding to a seroprevalence rate of 32.7%. Neospora DNA was detected in buffy coats of 26 out of 127 (20.47%) cattle. Even though Neospora infection was more common in females and in five-year-old cattle by serology and molecular methods, yet there was no statistically significant difference between age, sex, and Neospora infection in both molecular and serological methods (p > 0.05).

Conclusion

Findings of the current study indicate a high rate of N. caninum infection in cattle of Boyer-Ahmad region in the southwest of Iran. This issue should be further investigated and the prevention and control of this parasite in livestock, due to the high financial burden of this parasite in the livestock industry, should be considered.

Serosurveillance and risk factors for Neospora caninum infection in water buffaloes (B. bubalis) from central and southern Mexico

The water buffalo (B. bubalis) is an alternative to cattle ranching in several regions of southern Mexico. Here we report seroprevalence and risk factors associated with the protozoan parasite, Neospora caninum, in water buffaloes in six buffalo production units, in municipalities from central and southern Veracruz, Mexico. Antibodies to N. caninum were assessed in serum samples of 543 buffaloes by a commercial ELISA-kit, and 44.8% (243/543; 95% CI 40.5-49.0) were seropositive. Questionnaires were used to collect epidemiological data and to identify risk factors associated with N. caninum infection. Data analysis indicated that older buffaloes (≥7 year) exhibited the highest seroprevalence for neosporosis 62.3% (38/61; 95% CI 49.7-73.4) (P ≤ 0.05). Buffaloes that were in close contact with cattle had higher seroprevalence 47.6% (168/353; 95% CI 42.3-52.9) (P < 0.01) than those that were not in contact 36.8% (70/190; 95% CI 30.0-44.1). Our findings provide important information to implement preventive measures in the buffalo farms.

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.

A Review of Toxoplasmosis and Neosporosis in Water Buffalo (Bubalus bubalis)

Toxoplasmosis and neosporosis are diseases with worldwide distribution that are associated with reproductive problems in livestock and responsible for economic losses. This review presents an overview of the current knowledge relative to these diseases in water buffalo (Bubalus bubalis). In general, buffalo are considered resistant to clinical toxoplasmosis because there are studies only reporting serological evidence of natural infection in these animals. Studies have described age, poor hygienic status of the farm, and presence of cats as risk factors for the development of Toxoplasma gondii infection in buffalo. It must be highlighted that buffalo meat, which does not receive adequate freezing treatment, could be a potential source for toxoplasmic human infection as well as the importance of raw buffalo milk in the transmission of toxoplasmosis to human beings. Neospora caninum is considered one of the major causes of abortion and responsible for huge economic losses in cattle. Vertical transmission is the main route to infect calves, and is responsible for maintaining the parasite within a herd. In buffalo, vertical transmission is also described; moreover, although there are indications that N. caninum may be associated with abortion in dairy buffalo, the reproductive importance of neosporosis is apparently lower in buffalo relative to cattle. Most studies have identified a higher time of exposition to N. caninum oocysts relative to age. The household system was also described as a risk factor for infection, possibly due to persistent contact between the home-raised buffalo and canids. The fetal immune competence of buffalo is similar to bovine, and buffalo fetus are highly susceptible to infection during the first trimester of pregnancy, indicating that N. caninum may be an abortigenic agent in buffaloes. Alternatively, it is interesting to note there is evidence that the inflammatory response in pregnant buffalo infected with N. caninum is mild enough to avoid abortion in most cases. It is proposed that the possible transmission of toxoplasmosis through unprocessed milk and buffalo meat may occur, which is important in terms of public health. Additionally, there is strong evidence to suggest that N. caninum may be associated with abortion in buffalo.

Meta-analysis of the prevalence and risk factors associated with bovine neosporosis

Neospora caninum is one of the main infectious agents that cause reproductive disorders in cattle. However, knowledge about the prevalence and causal factors of bovine neosporosis is needed in order to establish control measures. The purpose of this study was to estimate the pooled prevalence and determine the risk factors of bovine neosporosis using meta-analytic methods. Searches for data on N. caninum seroprevalence and potential risk factors were conducted in the PubMed, LILACS, and SciElo databases. The random effects model was used for the meta-analysis of the included studies. The pooled prevalence of N. caninum in cattle was 24% (95% confidence interval (CI), 19-29) in North and Central America, 24% (95% CI, 20-28) in South America, 18% (95% CI, 14-21) in Asia, 15% (95% CI, 12-18) in Europe, 13% (95% CI, 11-16) in Africa, and 8% (95% CI, 4-14) in Oceania. A significant correlation was found between N. caninum infection and abortion in cows (odds ratio (OR) = 2.66, 95% CI, 1.97-3.59). The following risk factors were signicantly associated with N. caninum seroprevalence: presence of dogs on the farm (OR = 2.84; 95% CI, 1.40-5.80) and the type of cattle production system, with dairy cattle being more susceptible to bovine neosporosis (OR = 1.60; 95% CI, 1.16-2.19) than beef cattle. The adoption of measures to prevent the dissemination of N. caninum in cattle herds is suggested, aiming to reduce the economic losses incurred to the dairy and beef industry.

Prevalence and associated factors with Neospora caninum infection in female water buffaloes (Bubalus bubalis) from Pernambuco, Brazil

Neosporosis is one of the major parasitic diseases that causes reproductive problems, making it a limitation for optimal efficiency in livestock. The aim of the present study was to conduct a seroepidemiological survey for bubaline neosporosis and to analyse associated factors associated with N. caninum infection in female water buffaloes in the State of Pernambuco, northeast Brazil. The prevalence of N. caninum infection in the bubaline herds examined was 35.4% (122/345; 95% CI: 30.4%-40.7%), at least 1 Neospora-positive animal was found in each farm. Associated factors for N. caninum infection identified in this study were exclusive pasture feeding (OR: 5.91, p <0.001) and purchase of animals of free fair and from reputable sellers (OR: 1.85; p =0.045). In this survey, we document the occurrence of neosporosis in female water buffaloes. Associated factors should be controlled in order to reduce the risk of N. caninum infection in these herds.

Serological survey of Neospora caninum and Toxoplasma gondii in cattle (Bos indicus) and water buffaloes (Bubalus bubalis) in ten provinces of Brazil

The objective of this study was to determine the prevalence of antibodies to Neospora caninum and Toxoplasma gondii among 500 cattle (Bos indicus) and 500 buffaloes (Bubalus bubalis) using the indirect fluorescent antibody test (IFAT) technique. Blood samples from were collected from water buffalo and cattle in 10 municipalities in the northern region of Brazil. The frequency of cattle and water buffaloes seropositive for Neospora caninum in Pará state, Brazil, was 55% and 44%, respectively, and the frequency of cattle and water buffaloes seropositive for Toxoplasma gondii was 52% and 39%, respectively. Seropositivity for both N. caninum and T. gondii was detected in 10.6% of the cattle samples and 14.8% of the buffalo samples. The frequency of cattle positive for N. caninum and T. gondii was significantly (p<0.05) higher than that of buffalo in two and three provinces, respectively. Buffaloes had a lower seroprevalence for N. caninum or T. gondii in all of the provinces studied. These results suggest that both species, when exposed to the same risks for N. caninum and T. gondii infection, have a high serological prevalence. Cattle showed a higher probability of being seropositive when exposed to the same risks for N. caninum and T. gondii. Our study, which included an extensive number of blood samples, provides important epidemiological information pertinent to buffalo production in tropical countries that can be used as a basis for disease-management practices in Latin America.

Investigations into the role of rats as intermediate hosts for Neospora caninum in Chennai, India

Attempts were made to detect Neospora caninum in rats (Rattus rattus) in and around Chennai, India. During the study, 112 feral rats were trapped and blood, brain, heart, lungs and diaphragm samples were collected for serological, parasitological and molecular identification of N. caninum. Out of 112 rats, cyst-like structures were identified in 16 brain squash samples. However, the identity of the cysts could not be confirmed as N. caninum. A total of 12 sera samples were positive for N. caninum by indirect fluorescence antibody test (IFAT). Four of the 'cyst' positive samples were also positive by IFAT. None of the above samples showed amplification of N. caninum (Nc5) or toxoplasmatiid (ITS-1) fragments by PCR. In conclusion, the present study showed 10.71% seroprevalence of N. caninum among feral rats, which is a first report in India. Low prevalence of the organism in the environment and the consequent low chance of exposure of rats to N. caninum might explain the failure to detect the DNA in any of the samples tested in the study.

A review of Neospora caninum in water buffalo (Bubalus bubalis)

A number of countries in the world have reported infections with Neospora caninum in water buffalo (Bubalus bubalis), from Africa to Asia, Europe and South America and recently Australia. In general, clinical manifestations (such as abortion) seem rare, which has raised the prospect that buffalo may be inherently resistant to clinical effects of N. caninum infection. Worldwide, the seroprevalence of N. caninum infection (as a measure of exposure determined by the detection of antibody) in buffalo is high, at approximately 48%. This reported seroprevalence is three or four times higher than that reported from the world's cattle populations, which have collective seroprevalence rates of 16.1% for dairy cattle and 11.5% for beef cattle. However, there is a lack of standardisation in seroprevalence studies and some studies may well under-estimate the true level of infection. Epidemiologic evidence supports post-natal transmission, and in utero transmission has also been demonstrated. The causes for water buffalo to have markedly higher seroprevalence but apparently lower neosporosis abortion rates than cattle warrant further investigation.

Prevalence and distribution of Neospora caninum in water buffalo (Bubalus bubalis) and cattle in the Northern Territory of Australia

The seroprevalence of Neospora caninum infection in water buffalo (Bubalus bubalis) and domestic cattle in the Northern Territory (NT) of Australia has never been determined. A total of 480 serum samples from water buffalo and 192 serum samples from cattle, collected by the NT Government from 1993 through to 2001, at 18 different survey sites throughout the Northern Territory were tested by commercial ELISA for anti-N. caninum antibodies. The water buffalo samples demonstrated a seroprevalence of 88.3% (95% CI ± 2.9%), while 31.8% (±6.1%) of the cattle sera tested positive for N. caninum antibodies. Individual buffalo from the same herd, sampled over years, showed considerable fluctuations in S/P ratios. Overall, seropositivity was consistent across buffalo herds, and showed a slight decline over the years. The study presents evidence for the first time that N. caninum infection in water buffalo in the Northern Territory is a highly endemic and that infection rates are higher than those for cattle. This is important for an understanding of any potential sylvatic life cycle of N. caninum in Northern Australia. This survey also tests cattle from that territory for the first time for evidence of N. caninum infection and makes an important contribution to the understanding of disease management issues for the beef industry in the region.

Neospora caninum serostatus is affected by age and species variables in cohabiting water buffaloes and beef cattle

The aim of this study was to investigate how Neospora caninum serostatus may be affected by variables such as host species (water buffaloes or cattle) and age in animals cohabiting in the same ranch. A convenience cross-sectional study was performed on four ranches in the Northeast of Argentina, where water buffalo are cohabitating with beef cattle. Blood samples were collected from 1350 female water buffaloes (Bubalus bubalis) and 880 female beef cattle (Bos taurus and Bos indicus crossbreeds) from four ranches. Calving and weaning percentages at herd level for each ranch were also recorded. N. caninum antibody levels were measured by an indirect fluorescent antibody test (IFAT) (reciprocal antibody titers ≥ 100). Serological results were classified into 2 categories (0: negative; 1: positive). A logistic regression model was used to describe the relationship between N. caninum serostatus and specie (water buffalo or cattle), age or ranch and their interactions. Likelihood ratio tests were used to assess the significance of the model and their terms. Odds ratios were estimated and 95% profile likelihood (LR) and Wald confidence intervals (CI) obtained. Overall, specific antibody titers were found in 43.3% (584/1350) of water buffaloes and 28.6% (252/880) of cattle. Seropositive water buffaloes and cattle were observed on all ranches. Age was statistically significant (p=0.01) with an overall estimate of logit (log odds) of age of 0.03 for both species. This indicates that for every one year increase in age, the expected change in log odds of being seropositive increased by 0.03. On three of four ranches a water buffalo was 4.48, 1.54 and 2.25 times more likely to be seropositive than cattle for animals of the same age. The N. caninum serostatus was affected by age in the first place, but also by species on at least three of the four ranches. Calving and weaning percentages were higher in water buffaloes than in beef cattle (p<0.05). Even though the low pathogenicity that N. caninum seems to have in water buffaloes, this study reinforces the importance of this specie as maintenance of the disease.

Variables Associated with Infections of Cattle by Brucella abortus., Leptospira spp. and Neospora spp. in Amazon Region in Brazil

The frequency of Neospora spp., Leptospira spp. and Brucella abortus infections in adult cattle was determined in herds of the State of Pará, Brazil, which is an important region for cattle production located in the Amazon region. A total of 3466 adult female cattle from 176 herds were tested, leading to a frequency of seropositive animals of 14.7%, 3.7% and 65.5% and a herd positivity of 87.4%, 41.3% and 98.8% for infections caused by Neospora spp., B. abortus and Leptospira spp., respectively. The five most frequently diagnosed serologic responses to Leptospira spp. were those against serovars hardjo, wolfii, grippotyphosa, hebdomadis and shermani. The following associations were found: practice of artificial insemination, large farm size, large herd size, large number of dogs and high number of total abortions per year with the presence of antibodies against serovar hardjo; positive results to serovar grippotyphosa with the presence of dogs; inappropriate disposal of aborted foetuses with positivity to serovar hebdomadis. Serovar grippotyphosa was also associated with number of episodes of abortions. Neospora spp. positive herds were associated with episodes of abortion and B. abortus infection with the disposal of dead animals and aborted foetuses on pastures and with the use of artificial insemination. In conclusion, the high frequency of brucellosis, leptospirosis and neosporosis in the region may be a consequence of social, natural and raising conditions as: (i) climate conditions that favour the survival and spread of pathogens in the environment; (ii) farms located in regions bordering forest areas; (iii) farms in areas of difficult access to the veterinary service; (iv) extensive beef herds raised at pastures with different age and productive groups inter-mingled; and (v) minimal concerns regarding hygiene practices and disease prevention measures.

Prevalence and risk factors associated with Neospora caninum infection in dairy herds in Jordan

A cross-sectional study was carried out to determine the seroprevalence and to identify risk factors associated with Neospora caninum infection in 62 dairy herds (n = 671 cows) in Jordan between January and June 2007. Information regarding herd management was recorded through personal interviews with farmers. Antibodies against N. caninum were detected using an indirect ELISA test. Chi-square analysis and multivariable logistic regression model were used to identify risk factors associated with N. caninum seropositivity. The true prevalence of antibodies against N. caninum in individual cows and cattle herds was 35 and 66.5 %, respectively. There was no significant difference in the percentage of seropositive animals between different age groups. Multivariable logistic regression model revealed workers frequently visiting nearby farms as a risk factor for seropositivity to N. caninum, while presence of a calving pen was suggested as a protective factor. Amman, Balqa, and Mafrak governorates had significantly lower seroprevalence to N. caninum compared to other Jordanian governorates. Results of this study indicated that N. caninum infection may be widespread in Jordan.