Supranational comparison of Neospora caninum seroprevalences in cattle in Germany, The Netherlands, Spain and Sweden

Herd, within-herd and animal prevalences for Neospora caninum in beef and dairy cattle were compared between four countries. In randomly selected herds from regions of Germany, The Netherlands, Spain and Sweden that were representative for the cattle production of these countries, all animals > or = 2 years were examined serologically by enzyme-linked immunosorbent assays (ELISAs) with high test specificity (> 98.0%). In a previous study, the ELISAs had been validated against each other. Single reacting animals within a herd were confirmed by immunobloting. At the time of sampling, animal (age, breed, herdtype, sex, lactation stage) and herd data (region) were collected. Considerable differences in N. caninum herd, within-herd, and overall animal prevalence estimations were observed between countries, regions, herdtype, age categories and breeds. Herd prevalences, based on confirmation of single reactors, for dairy herds were estimated to be 16% (95%CI: 10-24%) in Sweden, 49% (95%CI: 39-59%) in Germany, 63% (95%CI: 57-69%) in Spain and 76% (95%CI: 67-84%) in The Netherlands and for beef herds 41% (95%CI: 31-50%) in Germany, 46% (95%CI: 41-51%) in Spain and 61% (95%CI: 50-72%) in The Netherlands. No beef herds were examined in Sweden. The lowest animal true prevalence was estimated in dairy cattle in Sweden (0.5% (95%CI: 0.1-0.8%)) while the highest animal true prevalence was estimated for dairy cattle in Spain (16.2% (95%CI: 14.9-17.5%)). Within-herd prevalences varied greatly, with very few farms in Sweden having more than 10% seropositive animals while in Spain more than 10% of the herds had within-herd prevalences between 50 and 100%. Seropositivity was significantly associated with herdtype (beef versus dairy), age, breed and region within countries. The results of this supranational comparative study showed that the importance of N. caninum infection varied greatly within in Europe. Estimates of prevalence can be used to calculate the economic impact of N. caninum infection as well as to evaluate the effect of prevention and control strategies over time.     

Seroepidemiology of Neospora caninum and Toxoplasma gondii in cattle and water buffaloes (Bubalus bubalis) in the People's Republic of China

A seroepidemiological survey of Neospora caninum and Toxoplasma gondii in cattle and water buffaloes was carried out in the People's Republic of China. Serum samples were obtained from dairy (n=262, 9 herds in 9 provinces) and beef cattle (n=10, 1 herd) and water buffaloes (n=40) in China. All sera were tested for antibodies to N. caninum and T. gondii by an enzyme-linked immunosorbent assay (ELISA) and an indirect agglutination test (IAT), respectively. The overall seroprevalence of N. caninum in dairy cattle was 17.2% (45/262), and the herds seroprevalence of N. caninum was 88.9% (8/9), and antibodies to T. gondii were present in 6 cows (2.3%). None of the cows had antibodies against both T. gondii and N. caninum. Antibodies to T. gondii or N. caninum were not found in beef cattle or water buffaloes. The seroprevalence of N. caninum in aborting cows (20.2%) was higher than that in non-aborting cows (16.6%) with an odds ratio of 1.26 (95% CI, 0.54-2.95), but the difference was not statistically significant (P>0.05). There was no apparent association of N. caninum seropositivity with age or number of pregnancies. This is the first report on the seroprevalence of N. caninum in cattle and water buffaloes in China.     

A nationwide survey on seroprevalence of Neospora caninum infection in beef cattle in Uruguay

Bovine abortions due to Neospora caninum infection have been reported worldwide and its economic impact on the beef industry has been acknowledged as a problem. Uruguay has the largest export value of beef per acre in South America. However, no data on the prevalence of N. caninum infection have been available in this country. The objective of this study was to estimate the prevalence and distribution of N. caninum infection in beef cattle in Uruguay through a nationwide survey. A two stage sampling design was used with farms being selected in stage one and animals being selected in stage two. A brief questionnaire was administered on each farm. Seroprevalence of N. caninum in 4444 beef cattle from 229 farms in all the counties, except Montevideo, of Uruguay was determined by an ELISA. The data were then analyzed to identify associations between infection and variables such as type of animal (cow or heifer), herd size, use of veterinary advice, productivity of the soil in relation to the national average, use of improved grass, use of mineral salts, use of supplemental feed, and presence of a dog(s) on the farm. The estimated proportion of positive farms for all the beef cattle operations was 69.2% (95% confidence interval [CI], 53.7-84.7). The overall cattle seroprevalence was estimated as 13.9% (95% CI, 11.6-16.3). The prevalence estimation by animal category was 14.3% (95% CI, 11.4-17.2) for beef cows and 12.9% (95% CI, 10.0-15.8) for beef heifers. There was no significant difference in the estimated prevalence between the two animal types. There was no significant difference in the animal level prevalence of N. caninum infection among different herd sizes. None of the herd demographic or management variables was significantly associated with the seropositivity to N. caninum infection. In conclusion, these results show that N. caninum infection is common among beef herds across Uruguay. Since the beef industry is one of the key industries in Uruguay, the economic effect and risk factors of N. caninum infection among beef cattle in this country should be further evaluated in the near future.     

Epidemiology and impact of Neospora caninum infection in three Queensland tropical dairy herds

This study investigated the epidemiology of Neospora caninum in three tropical dairy herds in North Queensland, Australia. All animals in the herds were bled, and the sera were tested by ELISA for N. caninum antibodies. Herd records were examined, and the number of calves carried to term and the number of abortions which occurred over the lifetime of each animal were recorded to determine the abortion rate for each animal. Pedigrees were constructed for two of the herds to investigate whether vertical transmission was occurring. The seroprevalence of N. caninum ranged from 23% to 34%. The abortion rate in seropositive animals was significantly (p < 0.001) higher than in seronegative animals in all three herds (12-20.1% cf. 3.6-7%). Overall, the probability of a calf being seropositive was 3.5 times higher when the dam was also seropositive than when the dam was seronegative. Subsequent selective breeding employed by one herd reduced the N. caninum seroprevalence from 23% to 5% over a 9-year period. This study shows that N. caninum infection is prevalent in North Queensland dairy cattle, and both post-natal infection and vertical transmission are common.     

Seroprevalence and associated risk factors of neosporosis in beef and dairy cattle in Italy

A cross-sectional serological survey for Neospora caninum was carried out on beef and dairy cattle in southern and northern Italy. A total of 111 herds and 1140 animals were tested using an ELISA assay (CHEKIT-Neospora) to detect anti-N. caninum antibodies. Management and individual data were collected and analysed both by linear and logistic multiple-regression models in order to find good predictors of the cattle seroprevalence and anti-N. caninum antibody level. At least one seropositive animal was found in 49 herds (44.1%), of which 31 (39.7%) from southern Italy and 18 (54.5%) from northern Italy. A total of 126 head of cattle (11%) were found to be seropositive and the seroprevalence was lower in southern (8.7%) than in northern Italy (16%). One of the best predictors of neosporosis seroprevalence in this study was the practice of self-rearing replacement heifers. Further risk factors were linked to higher stocking density, i.e. animals farmed in large herds and with no summer or permanent grazing practices were more likely to be seropositive than others. Farms with two or more dogs had higher herd seropositivity than farms with one or no dogs and this factor interacted significantly with the farm size and presence of poultry. Among individual characteristics, seropositivity was higher in animals sampled in mid- or late-pregnancy compared to animals either in early pregnancy or not pregnant. There was a significant interaction between the factors for pregnancy status and grazing practices. None of the epidemiological data recorded was a good predictor of the anti-N. caninum antibody level.     

Prevalence of anti-Neospora caninum antibodies in cattle and dogs from Western Amazon, Brazil, in association with some possible risk factors

For evaluation of the prevalence of anti-Neospora caninum antibodies and its associated risk factors, serum samples from 2109 cattle (11 beef, 50 dairy and 25 mixed farms) and 174 dogs were examined in the State of Rond?nia, Western Amazon, Brazil. An inquiry was applied in each farm. Sera were examined by the Indirect Fluorescence Antibody Test (IFAT) using cut off dilution of 1:25 for cattle and 1:50 for dogs. Statistical association between the serologic status and several variables were analyzed by linear and logistic regression. The overall herd prevalence of anti-N. caninum antibodies for 86 farms was 72% (61.3-81.2%). Prevalence values were 100, 70 and 64% in beef, dairy and mixed herds, respectively. Herd prevalence in beef herds was significantly different (P<0.05) from dairy and mixed herds. The overall animal prevalence of N. caninum in cattle was 8.8%. Prevalence values by animal were similar in different production types (P>0.05), with values of 9.5, 11.2 and 9.7% for beef, dairy or mixed cattle, respectively. Antibodies were found in 12.6% of the 174 examined dogs. Sixteen (22.8%) out of 70 farms with dogs had at least one dog with anti-N. caninum antibodies. The occurrence of antibodies in cattle was statistically associated with farms having more than 25 cows (OR 9.7, 95% IC 2.9-32.2; P=0.0002). There was no significant association between the presence of the dogs, jungle contact or reproductive variables with the occurrence of antibodies in cattle.     

Herd-level seroprevalence and risk-mapping of bovine hypodermosis in Belgian cattle herds

Our objective was to determine the seroprevalence of Hypoderma spp. and to develop a spatial model describing the risk surface of warble-fly infection in Belgian cattle herds (adjusting for herd size, herd type, local temperature, rainfall, relative air humidity and land-cover). This survey was carried out in 390 selected herds of all types (dairy, mixed and beef) from December 1997 to March 1998, which were included in a national infectious bovine rhinotracheitis and paratuberculosis (Johne's-disease) survey. All animals >24 months old were blood sampled and an ELISA was used on pooled serum samples (10 animals per pool). The herd seroprevalence was 48.7% (95% confidence interval: 43.6-53.8); positive herds were mainly in the south of the country and along the North Sea coast. The logistic multiple-regression model of herd-level seropositivity indicated that mixed-type and beef-cattle herds have more than four-fold and two-fold increases in the odds of being Hypoderma-positive, respectively, compared with dairy herds.     

Estimation of Neospora caninum seroprevalence in dairy cattle from Normandy, France.

An epidemiological study was conducted in Orne (France) on randomly selected dairy herds (42 herds including 1,924 cows and heifers, which were at least 15 months old). The aim was primarily to estimate the seroprevalence of Neospora caninum infection from two blood samples per cow, using an enzyme-linked immunosorbent assay (ELISA) for N. caninum (one positive result indicating infection). The second aim was to test the association between some individual and herd factors and N. caninum seropositivity with a logistic model including a random term effect. The prevalence was estimated at 5.6% (107 seropositive animals). At least 27 of the 42 herds had one seropositive cow or heifer. The intra-herd seroprevalence varied from 1.1 to 8% for 18 positive herds (66.7%). Dogs were present in 36 farms and 104 of the 107 seropositive animals were exposed to them. The factors associated with individual seropositivity were the presence of cats (OR = 0.17; P < 0.001), dogs (OR = 4.35; P = 0.02), rabbits and/or ducks (OR = 2.10; P = 0.04), long calving periods (12 months) (OR = 0.44; P = 0.007), tethered housing (OR = 2.50; P = 0.01), somatic cell counts (200-400 x 10(3) cells/mL) (OR = 0.24; P < 0.001) and pond water supply (OR = 2.43; P = 0.04). In conclusion, the animal and intra-herd seroprevalences were low in dairy cows from Normandy, France.     

Prevalence of serum antibodies to Mycobacterium avium subsp. paratuberculosis in cattle in Galicia (northwest Spain)

Prior to establishing a control and prevention program for Johne's disease in cattle in Galicia (northwest Spain), a survey was conducted to estimate the prevalence of the disease. For this survey, 61,069 animals of at least 1-year of age from 2735 randomly selected herds were bled and samples analyzed with a commercial ELISA. The estimated true individual-level prevalences – assuming the manufacturer's reported test sensitivity of 48.5% and specificity of 98.9% – were 3.02% in dairy cattle, 1.03% in beef cattle and 2.83% in animals from farms with both dairy and beef cattle. True herd prevalences (with herds declared positive if one or more animals tested positive) were 10.69% for dairy herds, 0% for beef herds and 2.71% for mixed herds. When herds were declared positive if at least two animals tested positive, true herd prevalences were 14.75% for dairy herds, 1.47% for beef herds and 12.01% for mixed herds. Assuming a higher specificity of 99.4%, true individual-level prevalences increased to 4.03% in dairy herds, 2.07% in beef herds and 3.84% in mixed herds. Herd prevalences were 27.77%/18.79%, 2.78%/2.40% and 5.70%/12.24% (using the one/two-animal cut-offs) in dairy, beef and mixed herds, respectively. In conclusion, these results seem to indicate that a small percentage of cows and a rather high percentage of dairy herds in this region are MAP-seropositive.     

Vertical and horizontal transmission of Neospora caninum in dairy herds in Québec

Neospora caninum is an important cause of abortion in dairy cattle. The objective of this observational study was to estimate the rate of vertical transmission of N. caninum in dairy herds in Québec and to investigate horizontal transmission in the same herds. The genealogy of cows from 23 dairy herds were examined. Prevalence of seropositive animals in herds studied varied from 4.3% to 61.8% (average, 21.9%). The overall rate of vertical transmission was estimated to be 44.4%, varying from 0% to 85.7%. Seven cases of horizontal transmission were identified in 6 of the 23 herds studied. Estimated vertical transmission rate varied from herd to herd, but appeared to be higher in herds with a high prevalence of seropositive animals. Although horizontal transmission was identified in 6 herds, it does not appear to be the major route of infection for N. caninum.     

Prevalence of paratuberculosis (Johne's disease) in the Belgian cattle population

The national bovine paratuberculosis (PTB) seroprevalence (apparent prevalence) in the Belgian cattle population was determined by a serological survey that was conducted from December 1997 to March 1998. In a random sample of herds (N=556, 9.5%), all adult cattle of 24 months of age or older (N=13,317, 0.4%) were tested for the presence of antibodies using a commercially available absorbed ELISA test kit. The PTB median within-herd seroprevalence (proportion of detected animals within the seropositive herds) and the PTB individual-animal seroprevalence (proportion of detected animals) were, respectively, 2.9% (quartiles=1.6-5.6) and 0.87% (95% confidence interval (CI)=0.71-1.03). The PTB herd seroprevalence (proportion of detected herds) was 18% (95% CI=14-21).Assuming a test sensitivity and specificity of 45 and 99% [Sweeney et al., 1995. J. Vet. Diagn. Invest. 7 (4), 488; Sockett et al., 1992. J. Clin. Microbiol. 30 (5), 1134], respectively, the median true within-herd prevalence and the true individual-animal were estimated to be 7 and 2%, respectively. The true herd prevalence of Mycobacterium paratuberculosis infection was first estimated according to currently accepted methodology. This calculation revealed that the specificity of the used test has a dramatic effect on the estimation; assuming a test sensitivity of 45% and a true within-herd prevalence of 7%, the true herd prevalence estimation decreased from 36 to 0.8% if the test specificity decreased from 99. 9 to 99%, respectively. This sensitivity analysis showed that the practical limits of the accuracy of the used screening test jeopardize the estimation of the true herd prevalence within reasonable confidence limits, because the within-herd PTB true prevalence was low.For this reason we augmented the herd specificity for herds with larger adult herd size (>5). This was done by increasing the cut-off number of positive cattle required (>/=2) to classify a herd truly positive and including herds with one positive test result if there was historical evidence of PTB (previous diagnosis and/or clinical signs). This approach resulted in an estimated true herd prevalence of M. paratuberculosis infection of 6%. The true herd prevalence for dairy, mixed and beef herds was, respectively, 10, 11 and 3%.     

Herd-level risk factors for Neospora caninum seroprevalence in dairy farms in southern Brazil

A cross-sectional study was used to test the relationship between herd seroprevalence to Neospora caninum and various potential herd-level risk factors in 60 dairy farms located in two distinct regions in southern Brazil. Thirty farms were randomly selected from within each region. A questionnaire was designed to summarize each farm's production system as it might relate to N. caninum transmission. The questionnaire contained 105 closed questions relating to general characteristics of the farms, farm facilities, management, source of food and water, herd health, environment and biosecurity, which included questions relevant to N. caninum transmission, including presence and number of dogs and other animals, purchase of animals and contact with man. Serum samples were collected from 40% of animals in each farm and N. caninum antibodies were detected by immunofluorescent antibody test (IFAT). The association between potential risk factors and the probability of an animal being seropositive was modeled using a generalized estimation equations (GEE) logistic regression model. The model accounted for multilevel correlation of data from multiple animals within herds. The mean (+/-S.D.) number of animals in the 60 herds was 64.5 (+/-45.6), ranging from 20 to 280 females. Blood samples were collected from 1549 animals. The size of the farms varied from 4 to 100 ha (mean 30.1+/-25.9 ha). At least one dog was found in 57 of the 60 dairy farms (95%). The mean number of dogs was 3.1 (+/-1.9), ranging from 0 to 10. All females were raised on pasture. For all cattle sampled, N. caninum seroprevalence was 17.8%. Overall, 93.3% of herds (56/60) had at least one seropositive animal identified. Four variables were significantly associated with N. caninum sero-response in the 57 dairy farms, which were included in the final multivariable model: the number of dogs on the farm, farm area (hectares), feeding pooled sources of colostrum and region. The odds of a cow being seropositive increased 1.13 times for each additional dog present on the farm (P=0.021). Cattle from farms that fed calves colostrum pooled from multiple cows had 1.79 times greater odds for being seropositive for N. caninum (P<0.003). The probability of being seropositive was inverse to the area of the farms, such that cattle had 0.92 times the odds to be seropositive (P=0.014) for each additional 10 ha of farmland. Finally, cattle from farms in region one had 0.71 times the odds to be seropositive than cattle from region two (P=0.035). Results of this study suggest that several risk factors may explain why dairy cattle in Brazil may become exposed to N. caninum. However, further investigation of these factors is necessary because the purpose of this study was to refine and generate hypotheses on N. caninum transmission.     

Seroepidemiology of beef and dairy herds and fetal study of Neospora caninum in Argentina

The purpose of the present work was to study the epidemiology of Neospora caninum in beef and dairy herds in the Humid Pampas of Argentina. The seroprevalence of N. caninum was evaluated in 2414 serum samples of cows from beef and dairy farms. An indirect fluorescent antibody test (IFAT) was used to determine specific antibodies. The sera was screened at a dilution >or=1:200 and >or=1:600 in cows with reproductive disease antecedents and without them, respectively. Cows without history of reproductive diseases from nine beef and fifteen dairy farms were grouped according to the percentage (> or or 相似文献   

A longitudinal study of seroprevalence and seroconversion of Neospora caninum infection in dairy cattle in northeast Thailand

A long-term study was carried out in 11 dairy herds in the Khon Kaen province of northeast Thailand between August 2001 and November 2004. The objective was to investigate seroprevalence dynamics of Neospora caninum infection in the herds and to demonstrate patterns of seroconversion in individual cattle. Each herd was visited once a year, in total four times, and sera from cattle > 3 months of age and farm dogs as well as a sample from the bulk milk were collected. All samples were analysed for presence of specific antibodies by an N. caninum iscom ELISA. The overall percentage of antibody-positive cattle was constant and varied only between 10 and 13% over the 4 years, but the variation in within-herd seroprevalence between herds was substantial. Two herds had > or = 20% seropositive animals at all samplings and consistently high bulk milk OD, whereas two herds had no seropositive animal at the last two samplings and low bulk milk OD. Five herds had a decreasing trend of within-herd seroprevalence, whereas the remaining six herds had a higher portion of test-positive individuals at the end of the study. A total of 424 individuals were sampled more than once; 344 (81%) and 32 (8%) were consistently antibody-negative and antibody-positive, respectively. The proportions of animals that changed from being seronegative to seropositive and from being seropositive to seronegative between the years were 3.9-4.6% and 19-39%, respectively. Apparent vertical and horizontal transmission rates were 58% (95% CI; 44-71%) and 5% (95% CI; 3-7%), respectively. In conclusion, the overall percentage of N. caninum antibody-positive cattle was constant over the years, but the within-herd seroprevalence varied substantially between the herds. Seroconversions were likely to occur in individual cattle although most animals had consistent serological status throughout the study.     

Risk factors for epidemic respiratory disease in Norwegian cattle herds

An epidemic of acute respiratory disease associated with bovine respiratory syncytial virus (BRSV) occurred during the winter and spring of 1995 in two neighbouring veterinary districts in the south-eastern part of Norway.The objective of this study was to describe the time course of the outbreak associated with BRSV in the cattle herds, and to determine the association between selected herd factors and the risk of experiencing a herd outbreak of acute respiratory disease.Data from 431 cattle herds on the dates of disease occurrence, location of the farms, herd size, age profile and production type were collected retrospectively for 1995. The risk of acute respiratory disease occurring in a cattle herd was related to the herd size as well as the type of production, with an expressed interaction between these two variables. From the Cox proportional-hazards model, the risk of a herd outbreak in a mixed herd of 20 animals was estimated to be 1.7-times greater than in a dairy herd and 3.3-times greater than a beef herd (reference category) of a comparable size. On increasing the herd size to 50 animals, the risk increased 1.3-fold for a mixed herd, 3.3-fold for a dairy herd, and 2.1-fold for a beef herd, compared to the risk for a corresponding type of herd of 20 animals.     

Neospora caninum seroprevalence and associated risk factors in beef cattle in the northwestern United States

A Neospora caninum seroprevalence and risk factor survey of 2585 cows was conducted in 55 beef cow-calf herds located in five northwestern states of the USA. Blood samples were collected by private veterinary practitioners and management practices were surveyed using a mail questionnaire. Producers were randomly selected from those that employed these veterinarians to perform annual herd pregnancy examinations. Questions were asked about animal management, grazing and feeding, immunization and record keeping practices. Blood was collected from a systematically selected sample of cows in each herd, and age, origin, and pregnancy status were recorded. Blood samples were analyzed for antibodies against N. caninum antigen using a monoclonal antibody-based competitive inhibition (CI) ELISA. Overall seroprevalence was 24% and within herd seroprevalence ranged from 3 to 67% with a median of 19%. Within herd seroprevalence and mean inhibition percentage were different between the five states. Herds that managed their cows on range for summer grazing had lower seroprevalence than those that did not, while increased seroprevalence was associated with higher winter stocking density. Cows less than 3 years of age had higher CI ELISA inhibition percent values than cows greater than 6 years of age. No relationship was noted between serologic status and individual cow origin (purchased or raised), or pregnancy status at the time of sampling.     

Seroprevalence of and agroecological risk factors for Mycobacterium avium subspecies paratuberculosis and neospora caninum infection among adult beef cattle in cow-calf herds in Alberta, Canada

A province-wide cross-sectional seroprevalence and agroecological risk factor study of Mycobacterium avium subspecies paratuberculosis (MAP) and Neospora caninum (NC) infection among cattle in 100 cow-calf herds in Alberta was conducted. The seroprevalence of MAP in adult cattle was 1.5% across all herds. Using a widely accepted herd test cutpoint of 2 or more seropositive cows out of 30 animals tested, 7.9% of herds were estimated to be infected (95% confidence interval (CI): 2.3-23.4%). Seroprevalence of MAP differed by agroecological region; specifically, cattle and herds in areas with high soil pH (> 7.0), southern latitudes, and arid climates had a moderately reduced risk of infection (P < 0.10). Seroprevalence of NC infection was 9.7% among adult beef cattle province-wide--these levels also varied by agroecological region--with 91.0% of herds infected overall.     

Prevalence and distribution of paratuberculosis (Johne's disease) in cattle herds in Ireland

A simple random survey was conducted in Ireland during 2005 to estimate the ELISA-prevalence of paratuberculosis, commonly called Johne's disease (JD), in the cattle population. Serum samples were collected from all 20,322 females/breeding bulls over 12 months-of-age in 639 herds. All samples were tested using a commercially available absorbed ELISA. The overall prevalence of infected herds, based on the presence of at least one ELISA-positive animal, was 21.4% (95% CI 18.4%-24.9%). Herd prevalence levels amongst dairy herds (mean 31.5%; 95% CI: 24.6%, 39.3%) was higher than among beef herds (mean 17.9%; 95% CI: 14.6%-21.8%). However, the animal level prevalence was similar. The true prevalence among all animals tested, was calculated to be 2.86% (95%CI: 2.76, 2.97) and for animals >= 2 yrs, it was 3.30% (95%CI: 3.17, 3.43). For animals in beef herds, true prevalence was 3.09% (95%CI: 2.93, 3.24), and for those in dairy herds, 2.74% (95%CI: 2.59, 2.90). The majority of herds had only one ELISA-positive infected animal. Only 6.4% (95% CI 4.7%-8.7%) of all herds had more than one ELISA-positive infected animal; 13.3% (CI 8.7%-19.7%) of dairy herds ranging from two to eight ELISA-positive infected animals; and, 3.9% beef herds (CI 2.4%-6.2%) ranging from two to five ELISA-positive infected animals. The true prevalence of herds infected and shedding Mycobacterium avium subspecies paratuberculosis is estimated to be 9.5% for all herd types; 20.6% for dairy herds; and 7.6% for beef herds. If ELISA positive animals <2-years-of-age are excluded, the true herd prevalene reduces to: 9.3% for all herd types; 19.6% for dairy herds; and 6.3% for beef herds based on a test specificity (Sp) of 99.8% and test sensitivity (Se) (i.e., ability to detect culture-positive, infected animals shedding at any level) of 27.8-28.9%.     

Seroprevalence of Toxoplasma gondii and Neospora caninum infections in goats in Poland

In 2007 a survey on herd-level seroprevalence of Toxoplasma gondii and Neospora caninum infections in goats in Poland was carried out. Sera were collected from all 49 breeding goat herds, scattered over the entire country, with the vast majority of them located in the western, central and northern provinces. Only adult females (≥12 months of age) were included in the study. A herd was recorded as infected if at least one seropositive female was detected. In each herd, simple random sampling was applied and sample size was determined in a way, which allowed to evaluate serological status of a herd at expected individual-level seroprevalence 10% and level of confidence 95%. In total, 1060 sera were tested using two commercial indirect ELISA kits. Sera positive to N. caninum were subsequently confirmed with IFAT. The true herd-level seroprevalence was 100% for T. gondii and 9.0% for N. caninum infection. Three herds positive to T. gondii infection were randomly selected and all adult goats were tested with an ELISA. Individual-level true seroprevalence in these herds ranged from 30.2% to 100%. This is the first time that antibodies to N. caninum have been detected in goats in Poland.     

Seroprevalence of Neospora caninum in dairy and beef cattle with reproductive disorders in Japan

Serum samples from 145 dairy and 65 beef cattle with reproductive disorders and 54 normally calving dairy cattle (controls) in Japan were tested for presence of Neospora caninum antibodies by use of an indirect fluorescent antibody test (IFAT, titer 1:200). Overall, seroprevalence of N. caninum was significantly higher (P < 0.001) in dairy cattle (20.0%, 29/145) than in beef cattle (1.5%, 1/65). In cattle which aborted, seroprevalence of N. caninum was significantly higher (P = 0.041) in dairy cattle (26.1%, 23/88, compared with controls (3.7%, 2/54)) than in beef cattle (5.0%, 1/20), indicating that neosporosis might be a more common problem in dairy cattle than in beef cattle in Japan. Seropositive cattle were 9.2 times more likely to abort compared to seronegative cows. Abortions associated with N. caninum seropositivity in this study were most frequently observed in the second trimester, and the mean gestational age of the fetuses aborted from seropositive dams was 5.7 months. In conclusions, N. caninum seems to be causing serious economic losses in the dairy industry in Japan. This is the first report on an objective comparison of seroprevalence of dairy and beef cattle with reproductive disorders in Asia.