Claude Saegerman

Brucellosis at the animal/ecosystem/human interface at the beginning of the 21st century

Following the recent discovery of new Brucella strains from different animal species and from the environment, ten Brucella species are nowadays included in the genus Brucella. Although the intracellular trafficking of Brucella is well described, the strategies developed by Brucella to survive and multiply in phagocytic and non-phagocytic cells, particularly to access nutriments during its intracellular journey, are still largely unknown. Metabolism and virulence of Brucella are now considered to be two sides of the same coin. Mechanisms presiding to the colonization of the pregnant uterus in different animal species are not known. Vaccination is the cornerstone of control programs in livestock and although the S19, RB51 (both in cattle) and Rev 1 (in sheep and goats) vaccines have been successfully used worldwide, they have drawbacks and thus the ideal brucellosis vaccine is still very much awaited. There is no vaccine available for pigs and wildlife. Animal brucellosis control strategies differ in the developed and the developing world. Most emphasis is put on eradication and on risk analysis to avoid the re-introduction of Brucella in the developed world. Information related to the prevalence of brucellosis is still scarce in the developing world and control programs are rarely implemented. Since there is no vaccine available for humans, prevention of human brucellosis relies on its control in the animal reservoir. Brucella is also considered to be an agent to be used in bio- and agroterrorism attacks. At the animal/ecosystem/human interface it is critical to reduce opportunities for Brucella to jump host species as already seen in livestock, wildlife and humans. This task is a challenge for the future in terms of veterinary public health, as for wildlife and ecosystem managers and will need a One Health approach to be successful.

Infection of cattle with Yersinia enterocolitica O:9 a cause of the false positive serological reactions in bovine brucellosis diagnostic tests

During the last four years, an increasing number of cattle herds were classified positive by brucellosis screening tests in areas of Belgium and France free of the disease. No clinical symptom of brucellosis was reported in these animals and no Brucella abortus strains were isolated. After two years, no brucellosis outbreak was registered in all of the herds concerned. On this basis, all the serological reactions observed were classified as false positive. An ELISA using Yersinia Outer membrane Proteins (YOPs) as antigens was developed in order to discriminate between a Yersinia enterocolitica O:9 infection and a Brucella abortus infection. Antibodies against YOPs were detected in sera from Y. enterocolitica O:9 experimentally infected cattle (n = 4) but not in sera from B. abortus experimentally infected cattle (n = 4). In a field study, 66.7% of the 174 serum samples from cattle presenting false positive serological reactions showed anti-YOPs antibodies whereas only 10% of 454 sera, classified negative by the brucellosis screening tests, showed anti-YOPs antibodies. Our results suggest that infections with Y. enterocolitica O:9 may cause false positive reactions in brucellosis testing.

Decision support tools for clinical diagnosis of disease in cows with suspected bovine spongiform encephalopathy.

ABSTRACT Reporting of clinically suspected cattle is currently the most common method for detecting cases of bovine spongiform encephalopathy (BSE). Improvement of clinical diagnosis and decision-making remains crucial. A comparison of clinical patterns, consisting of 25 signs, was made between all 30 BSE cases, confirmed in Belgium before October 2002, and 272 suspected cases that were subsequently determined to be histologically, immunohistochemically, and scrapie-associated-fiber negative. Seasonality in reporting suspected cases was observed, with more cases being reported during wintertime when animals were kept indoors. The median duration of illness was 30 days. The 10 most relevant signs of BSE were kicking in the milking parlor, hypersensitivity to touch and/or sound, head shyness, panic-stricken response, reluctance to enter in the milking parlor, abnormal ear movement or carriage, increased alertness behavior, reduced milk yield, teeth grinding, and temperament change. Ataxia did not appear to be a specific sign of BSE. A classification and regression tree was constructed by using the following four features: age of the animal, year of birth, number of relevant BSE signs noted, and number of clinical signs, typical for listeriosis, noted. The model had a sensitivity of 100% and a specificity of 85%. This approach allows the use of an interactive decision-support tool, based entirely on odds ratios, a statistic independent of disease prevalence.

Multidisciplinary and Evidence-based Method for Prioritizing Diseases of Food-producing Animals and Zoonoses

To prioritize 100 animal diseases and zoonoses in Europe, we used a multicriteria decision-making procedure based on opinions of experts and evidence-based data. Forty international experts performed intracategory and intercategory weighting of 57 prioritization criteria. Two methods (deterministic with mean of each weight and probabilistic with distribution functions of weights by using Monte Carlo simulation) were used to calculate a score for each disease. Consecutive ranking was established. Few differences were observed between each method. Compared with previous prioritization methods, our procedure is evidence based, includes a range of fields and criteria while considering uncertainty, and will be useful for analyzing diseases that affect public health.

European outbreaks of atypical myopathy in grazing equids (2006-2009). Spatiotemporal distribution, history and clinical features

REASONS FOR PERFORMING STUDYnImproved understanding of the epidemiology of atypical myopathy (AM) will help to define the environmental factors that permit or support the causal agent(s) to exert toxicity.nnnOBJECTIVESnThis European survey of AM aimed to describe spatiotemporal distribution, survival, clinical signs, circumstances in which AM develops and its different expressions between countries and over time.nnnMETHODSnThe spatiotemporal distribution, history and clinical features of AM cases reported to the Atypical Myopathy Alert Group from 2006 to 2009 were described. Comparisons of data from the most severely affected countries and from the large outbreaks were made with Fishers exact and Welchs tests with Bonferroni correction.nnnRESULTSnOf 600 suspected cases, 354 met the diagnostic criteria for confirmed or highly probable AM. The largest outbreaks occurred during the autumns of 2006 and 2009 in Belgium, France and Germany. For the first time, donkeys, zebras and old horses were affected, and clinical signs such as gastrointestinal impaction, diarrhoea, penile prolapse, buccal ulceration and renal dysfunction were observed. Affected horses spent >6u2003h/day on pastures that almost always contained or were surrounded by trees. The latency period was estimated at up to 4 days. Overall survival rate was 26%. Although differences between countries in affected breeds, body condition, horse management and pasture characteristics were recognised, the common presenting clinical signs and mortality were similar between countries.nnnCONCLUSIONS AND POTENTIAL RELEVANCEnThis study describes new data on case details, history and clinical course of AM that is of preventive, diagnostic and therapeutic value. However, the true impact of the findings of this study on the development of or severity of AM should be tested with case-control studies.

Field veterinary survey on clinical and economic impact of Schmallenberg virus in Belgium.

We implemented a questionnaire-based methodology targeting veterinary field practitioners to evaluate clinical and economic impact of Schmallenberg virus in Belgium. First suspicious cases were detected as soon as July 2011. The mean cost for individual symptomatic treatment was 65 or 107 Euros, in case of fatal outcome or apparent recovery, respectively.

Is evidence-based medicine so evident in veterinary research and practice? History, obstacles and perspectives

Evidence-based medicine (EBM) refers to the conscientious, explicit and judicious use of current best evidence from research for the care of an individual patient. The concept of EBM was first described in human medicine in the early 1990s and was introduced to veterinary medicine 10 years later. However, it is not clear that the EBM approach promulgated in human medicine can be applied to the same extent to veterinary medicine. EBM has the potential to help veterinarians to make more informed decisions, but obstacles to the implementation of EBM include a lack of high quality patient-centred research, the need for basic understanding of clinical epidemiology by veterinarians, the absence of adequate searching techniques and accessibility to scientific data bases and the inadequacy of EBM tools that can be applied to the busy daily practise of veterinarians. This review describes the development of EBM in the veterinary profession, identifies its advantages and disadvantages and discusses whether and how veterinary surgeons should further adopt the EBM approach of human medicine.

Preliminary survey on the impact of Schmallenberg virus on sheep flocks in south of Belgium.

Between late February and May 2012, a preliminary anonym survey was conducted among sheep farmers in south of Belgium in order to contribute to future estimations of the economic losses caused by Schmallenberg virus (SBV). Based on clinical signs consistent with SBV infection, this survey involved 13 meat sheep flocks considered as positive flocks with subsequent SBV detection by RT-qPCR [SBV-positive flocks (PF); total of 961 animals], and 13 meat sheep flocks considered as negative flocks (NF; total of 331 animals). These preliminary results indicated several significant characteristics that were more present in PF than in NF. These include an increased rate of abortions (6.7% in PF versus 3.2% in NF), of lambs born at term but presenting malformations (10.1% in PF versus 2.0% in NF) and of dystocia (10.1% in PF versus 3.4% in NF). Lamb mortality during the first week of life was reported more frequently in PF (8 of 13 PF, 61.5%) than in NF (1 of 13 NF, 7.7%). In PF, the observed prolificacy rate was 2-fold lower (93%) than expected (186%). The implementation of a survey at larger scale, including a high number of breeders, is necessary to allow a more detailed analysis of the SBV impact in the sheep sector.

Bovine Tuberculosis Prevalence Survey on Cattle in the Rural Livestock System of Torodi (Niger)

Background Bovine tuberculosis (BTB) is a widespread zoonosis in developing countries but has received little attention in sub-Saharan Africa, especially in Niger. Recent investigations confirmed the high incidence of the disease in cattle slaughtered in an abattoir in Niamey. The fact that most of the animals in which M. bovis has been identified were from the rural area of Torodi implied the existence of a probable source of BTB in this region. This study aimed to determine the prevalence of BTB infection in cattle and to identify risk factors for infection in human and cattle populations in Torodi. Methods and Principal Findings A survey was carried out at the level of households keeping livestock (nu200a=u200a51). The questionnaire was related to the potential risk factors and the presence of clinical signs of TB both in animals and humans. Comparative Intradermal Tuberculin Test was conducted to determine the TB status in cattle (nu200a=u200a393). The overall apparent individual animal prevalence of tuberculin reactors was 3.6% (CI: 95%, 1.9–5.9), whereas the individual true prevalence was estimated at 0.8% (CI: 95%, 0.0–5.0). Using a multivariate logistic regression analysis and a classification tree analysis, the only household level risk factor that significantly influenced the presence of BTB in cattle was the presence of animals coughing in the herd (ORu200a=u200a4.7, 95% CI: 1.12–19.71, p-valueu200a=u200a0.034). The lack of the practice of quarantine was borderline significant (ORu200a=u200a4.2, 95% CI: 0.96–18.40, p-valueu200a=u200a0.056). Conclusion/Significance The study confirmed that BTB is endemic in cattle in Torodi and the risk of the transmission of the disease to humans is potentially high. For the control of the disease in livestock, slaughtering of infected animals and the compensation of the owners is needed. Collaboration between the veterinary and the medical sectors, in the diagnosis, monitoring, prevention and control of BTB is strongly encouraged.

Apparent prevalence of antibodies to Coxiella burnetii (Q fever) in bulk tank milk from dairy herds in southern Belgium

In 2006, a cross-sectional survey was carried out in 206 herds in southern Belgium to estimate the proportion of herds with Q fever-seropositive bulk tank milk (BTM), i.e. herds with an intra-herd seroprevalence >10%. Of the tested herds, 119 (57.8%; 95% CI: 51.1-64.4%) were seropositive. Most had a low antibody titre. Of these herds, 50 were randomly subjected to a real time Coxiella burnetii PCR analysis. The proportion of herds excreting Coxiella in BTM was 30.0% with only 2.0% of herds having a high level of shedding. An additional questionnaire and logistical regression identified some factors which increased the risk of BTM seroconversion (in heifers, drinking water from watercourse or well water) and some which decreased it (in heifers, tie- and free-stalling, and animals of all age in the same shed; in heifers and cows, shed disinfection).