Seroprevalence of Neospora caninum, paratuberculosis and Q fever in cattle in Belgium in 2009-2010

Seroprevalence and Risk Factors for Toxoplasma gondii and Neospora caninum in Cattle in Portugal

Simple Summary

Neospora caninum and Toxoplasma gondii are apicomplexan parasites with a worldwide distribution and both infect cattle. While the importance of N. caninum is mainly linked to reproductive losses, concern has been raised about the role of beef as a source of food-borne toxoplasmosis in humans. Little is known about the prevalence of these parasites in cattle in Portugal. This study aimed to evaluate the seroprevalence and risk factors for N. caninum and T. gondii in naturally exposed cattle from different geographical areas in the country. Results point to a low but widespread seroprevalence of T. gondii, while that of N. caninum was found to be in the same range as reported in other Mediterranean countries. Distribution of both parasites may be explained by common climate factors and management practices identified as significant predictors of infection in the study.

Abstract

Neospora caninum has a worldwide economic impact as an important cause of abortion in cattle, while Toxoplasma gondii, another abortifacient pathogen, is globally a major foodborne zoonotic threat. The study aimed to evaluate the seroprevalence and risk factors for the two parasites in cattle in Portugal. A total of 612 sera from 35 farms were tested by an in-house p30 ELISA for T. gondii and p38 ELISA for N. caninum. T. gondii positive and suspicious sera were confirmed by p30 Western blot or IFAT. T. gondii and N. caninum animal seroprevalence was 9.2% (95%CI 7.1–11.7) and 17.2% (95% CI 14.4–20.4) and herd seroprevalence was 51.4% (95% CI 35.6–67.0) and 68.6% (95% CI 52.0–81.5), respectively. At the univariable level, climate area and precipitation of wettest month, driest month, driest quarter, and warmest quarter were significant predictors of seropositivity for both. N. caninum seropositivity was more likely in the region Norte, densely populated areas, and intensive production, and the probability of T. gondii seropositivity decreased with herd size. Results confirm the need to consider neosporosis in the differential diagnosis of cattle reproductive disorders in Portugal and may be valuable to inform source attribution models for human toxoplasmosis.

Retrospective study of factors associated with bovine infectious abortion and perinatal mortality

Abortion and perinatal mortality, leading causes of economic loss in cattle industry, are the consequence of both non-infectious and a wide range of infectious causes. However, the relative contribution of pathogens to bovine abortion and perinatal mortality is poorly documented, since available studies involved only a limited number of pathogens. Therefore, the objectives of the present monitoring study were to determine the prevalence of infectious agents associated with bovine abortion and perinatal mortality, and to identify differences in production type, gestation length, parity and seasonality by using mixed effect models (logistic regression). A pre-established sampling protocol based on the collection of the aborted fetus/calf and a corresponding maternal blood sample, involving diagnostic testing for 10 pathogens, was performed. At least one potential causal agent of the abortion or perinatal mortality was detected in 39 % of cases. In these diagnosed cases, Neospora caninum was the most detected pathogen, followed by Trueperella pyogenes, BVDv, Escherichia coli, and Aspergillus fumigatus. Neospora caninum [odds ratio (OR): 0.4; 95 % confidence interval (CI): 0.3-0.7] and Aspergillus fumigatus (OR: 0.1; 95 % CI: 0.1-0.3) were detected less in late versus early gestation. Aspergillus fumigatus was less common in dairy in comparison to beef abortion cases (OR: 0.2; 95 % CI: 0.1-0.6). Winter was associated with a lower positivity for Neospora caninum and BVDv in comparison to warmer seasons. Despite extensive diagnostic testing, an etiological diagnosis was not reached in 61 % of cases, highlighting the need for even more extensive (non-)infectious disease testing or more accurate tests.

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.

Q Fever Serological Survey and Associated Risk Factors in Veterinarians, Southern Belgium, 2013

A sero-epidemiological survey was organized among veterinarians working in Southern Belgium to estimate the seroprevalence of Q fever and the risk factors associated with exposure. A total of 108 veterinarians took part to this cross-sectional study, with a majority practicing with livestock animals. The overall seroprevalence was 45.4%, but it increased to 58.3% among veterinarians having contact with livestock. Three main serological profiles were detected (relatively recent, past and potentially chronic infections). The contact with manure during the prior month was the risk factor associated with seropositivity after multivariate logistic regression analysis. Classification and regression tree analysis identified the age as the most predictive variable to exclude potentially chronic infection in apparently healthy seropositive veterinarians. In conclusion, livestock veterinarians practicing in Southern Belgium are highly exposed to Q fever, a neglected zoonosis for which serological and medical examinations should be envisaged in at risk groups.

Serologic screening for 13 infectious agents in roe deer (Capreolus capreolus) in Flanders

Introduction

In order to investigate the role of roe deer in the maintenance and transmission of infectious animal and human diseases in Flanders, we conducted a serologic screening in 12 hunting areas.

Materials and methods

Roe deer sera collected between 2008 and 2013 (n=190) were examined for antibodies against 13 infectious agents, using indirect enzyme-linked immunosorbent assay, virus neutralisation, immunofluorescence, or microagglutination test, depending on the agent.

Results and discussion

High numbers of seropositives were found for Anaplasma phagocytophilum (45.8%), Toxoplasma gondii (43.2%) and Schmallenberg virus (27.9%), the latter with a distinct temporal distribution pattern following the outbreak in domestic ruminants. Lower antibody prevalence was found for Chlamydia abortus (6.7%), tick-borne encephalitis virus (5.1%), Neospora caninum (4.8%), and Mycobacterium avium subsp paratuberculosis (4.1%). The lowest prevalences were found for Leptospira (1.7%), bovine viral diarrhoea virus 1 (1.3%), and Coxiella burnetii (1.2%). No antibodies were found against Brucella sp., bovine herpesvirus 1, and bluetongue virus. A significant difference in seroprevalence between ages (higher in adults >1 year) was found for N. caninum. Four doubtful reacting sera accounted for a significant difference in seroprevalence between sexes for C. abortus (higher in females).

Conclusions

Despite the more intensive landscape use in Flanders, the results are consistent with other European studies. Apart from maintaining C. abortus and MAP, roe deer do not seem to play an important role in the epidemiology of the examined zoonotic and domestic animal pathogens. Nevertheless, their meaning as sentinels should not be neglected in the absence of other wild cervid species.

Single Nucleotide Polymorphism Genotyping and Distribution of Coxiella burnetii Strains from Field Samples in Belgium

The genotypic characterization of Coxiella burnetii provides useful information about the strains circulating at the farm, region, or country level and may be used to identify the source of infection for animals and humans. The aim of the present study was to investigate the strains of C. burnetii circulating in caprine and bovine Belgian farms using a single nucleotide polymorphism (SNP) technique. Direct genotyping was applied to different samples (bulk tank milk, individual milk, vaginal swab, fetal product, and air sample). Besides the well-known SNP genotypes, unreported ones were found in bovine and caprine samples, increasing the variability of the strains found in the two species in Belgium. Moreover, multiple genotypes were detected contemporarily in caprine farms at different years of sampling and by using different samples. Interestingly, certain SNP genotypes were detected in both bovine and caprine samples, raising the question of interspecies transmission of the pathogen.