Prevalence of Dichelobacter nodosus in western Austrian sheep flocks: Comparison of bacterial cultures, clinical foot rot and lameness with PCR and analysis of sample pooling for PCR diagnosis.

INTRODUCTION: Ovine foot rot is a highly contagious and multifactorial claw disease, caused by Dichelobacter nodosus (D. nodosus) and is the main cause of lameness in sheep. The aim of this cross-sectional study was to determine the prevalence of D. nodosus in western Austria both at animal and farm levels. Real-time PCR was evaluated in comparison with clinical and bacteriological investigations from interdigital foot swabs to detect D. nodosus-infected animals. In addition, the use of pooled four-foot swabs to detect foot rot was determined. In course of the study a total of 3156 sheep from 124 farms were examined for lameness and clinical signs of foot rot. The found flock prevalence of D. nodosus was 30,65 % with bacterial culture showing a sensitivity of 75,0 % and a specificity of 100,0 % (p < 0,001) respectively, compared with PCR. Furthermore, clinical foot rot scores (Ckorr = 0,87; p < 0,001) and lameness scores (Ckorr = 0,71; p < 0,001) highly correlated with the detection of D. nodosus by PCR. The result showed that the clinical examination can be used to identify animals infected with D. nodosus in flocks, but PCR must be used to confirm the diagnosis. D. nodosus could be detected equally well with risk-based pools-of-five samples as with undiluted samples (p < 0,001), suggesting that a pool-of-five samples might be a suitable and cost-effective method for detecting D. nodosus in sheep flocks. This study provides an overview of foot rot in Tyrolean sheep flocks and outlines the possibilities and limitations of the various diagnostic tools for D. nodosus. Further studies to investigate possible influencing factors, including alpine pasturing, management factors and biosecurity predisposing to foot rot are necessary for the design of effective future control programs in alpine regions.

INTRODUCTION: Le piétin ovin est une maladie des onglons hautement contagieuse et multifactorielle, causée par Dichelobacter nodosus (D. nodosus) qui constitue la principale cause de boiterie chez les ovins. L'objectif de cette étude transversale était de déterminer la prévalence de D. nodosus dans l'ouest de l'Autriche, tant au niveau de l'animal que de l'exploitation. La PCR en temps réel a été évaluée en comparaison avec les examens cliniques et bactériologiques effectués à partir d'écouvillons des espaces interdigités pour détecter les animaux infectés par D. nodosus. En outre, l'utilisation d'un pool d'écouvillons des quatre membres pour détecter le piétin a été déterminée. Au cours de l'étude, un total de 3156 moutons provenant de 124 fermes ont été examinés pour détecter des boiteries et des signes cliniques de piétin. La prévalence de D. nodosus dans les troupeaux était de 30,65 %, la culture bactérienne montrant une sensibilité de 75 % et une spécificité de 100 % (p < 0,001), respectivement, par rapport à la PCR. En outre, les scores cliniques de piétin (Ckorr = 0,87; p < 0,001) et les scores de boiterie (Ckorr = 0,71; p < 0,001) étaient fortement corrélés avec la détection de D. nodosus par PCR. Les résultats montrent que l'examen clinique peut être utilisé pour identifier les animaux infectés par D. nodosus dans les troupeaux mais que la PCR doit être utilisée pour confirmer le diagnostic. D. nodosus a pu être détecté aussi bien avec des pools de cinq échantillons basés sur le risque qu'avec des échantillons non dilués (p < 0,001), ce qui suggère qu'un pool de cinq échantillons pourrait être une méthode appropriée et rentable pour détecter D. nodosus dans les troupeaux de moutons. Cette étude donne un aperçu du piétin dans les troupeaux de moutons tyroliens et souligne les possibilités et les limites des différents outils de diagnostic pour D. nodosus. D'autres études visant à examiner les facteurs d'influence possibles, y compris les pâturages alpins, les facteurs de gestion et la biosécurité prédisposant au piétin, sont nécessaires pour la conception de futurs programmes de contrôle efficaces dans les régions alpines.

Management and housing factors associated with paratuberculosis-positive herds in small structured alpine cattle husbandry.

Paratuberculosis (Johne´s disease) is a world-wide cattle disease caused by Mycobacterium avium subsp. paratuberculosis (MAP), associated with substantial economic losses. Purchase of subclinically infected animals or contact with animals and equipment of infected farms are known risk factors for disease transmission among herds. The aim of the present study was to identify specific management factors in Austria that triggered a MAP-positive herd status and to evaluate known risk factors for the transmission in cattle in small structured alpine agricultural systems. The agriculture in the Austrian province of Tyrol is characterized by smallholder structures, including shared alpine pastures and traditional barn management techniques. The data from an extensive survey with 50 questions in 2013/2014 and the development of the MAP herd status of 5592 cattle farms by taking feces and blood samples were examined and statistically evaluated. MAP herd status was determined by combining the results of boot swab samples, manure samples, pooled and individual feces samples as well as serological antibody testing by ELISA. The statistical analysis (odds ratio; OR) showed that the use of milk replacers for calf feeding (p = 0.047, OR=0.472) and the use of straw as bedding material for cows (p = 0.032, OR=0.625) were associated with a decreased chance of being a MAP-positive herd. Further, housing cows in deep litter systems (p = 0.028, OR=2.232), the presence of slurry channels (p = 0.028, OR=1.411) and the use of solid manure in young cattle (p = 0.041, OR=1.744) were associated with an increased OR for being MAP-positive. Surprisingly, sharing of lowland pastures (p = 0.564, OR=1.080), alpine pastures (p = 0.419, OR=1.143) or farm equipment (p = 0.733, OR=0.963) and farm size (p = 0.425) had no significant influence on the MAP herd status. The identified differences compared with previously published results in respect of MAP spread in cattle might be attributed to the traditional agricultural structures, including small family-based farms and common pasture during summer in alpine regions. Results of this study contribute to the understanding of the spread of MAP in cattle farming in alpine regions.

Evaluation of a handheld device for the measurement of beta-hydroxybutyrate in capillary blood obtained by the puncture of the vulva as well as in venous whole blood in cattle.

A negative energy balance is a common condition in high yielding dairy cows causing the production of ketone bodies (KB), including beta-hydroxybutyrate (BHB), defined as subclinical ketosis (SCK) if clinical signs are missing. The aim of the present study was to evaluate a handheld electronic device for the detection of SCK (BHB-concentration > 1.2 mmol/l), in capillary blood and venous whole blood in cows (WellionVet BELUA, MED TRUST Handels GmbH, Marz, Austria) as well as the feasibility of the puncture of the external vulva with a single use lancet. For this purpose, the blood BHB-concentration was tested in 250 venous and capillary blood samples and compared to the results of a certified laboratory. The majority (76.3%) of the animals displayed no signs of discomfort related to the puncture and in 74.2% the procedure was successful on the first attempt. The BHB-concentrations detected in capillary blood showed good agreement with the reference method, both in capillary (correlation coefficient 0.94 (p⟨0.001), Kappa-value 0.89) and venous whole blood (correlation coefficient of 0.95 (p⟨0.001), Kappa-value 0.89). Altogether, 98% of all the samples were correctly classified as SCK or non-SCK by the handheld device in capillary blood (sensitivity 0.96, specificity 0.98) and 97.4% in venous whole blood (sensitivity 0.889, specificity 0.991), respectively. An increase in the correlation by the adaptation of the cut off level could not be achieved for both sampling sites.

Prevalence of Mycobacterium avium subspecies paratuberculosis and hepatitis E in New World camelids in Austria.

Mycobacterium avium subspecies paratuberculosis (MAP) is the causative agent of paratuberculosis in domestic ruminants and New World Camelids (NWC). Hepatitis E virus (HEV) is an important public health concern worldwide. The virus has been identified in several species, some of them serving as a reservoir for zoonotic HEV strains. Husbandry and breeding of llamas and alpacas have increased in Austria in recent years. Therefore, the aim of the present study was to evaluate the prevalence of MAP and HEV in NWC in Austria. Altogether 445 animals, originating from 78 farms were enrolled in the study. Of the animals sampled, 184 (41.35%) were llamas and 261 (58.65%) were alpacas. 443 blood samples for MAP-ELISA and 399 faecal samples for quantitative PCR (qPCR) and culture for MAP as well as for HEV detection by RT-qPCR have been collected. All of the 399 animals tested for shedding of MAP were negative by faecal solid culture. Using qPCR, 15 (3.8%) of the animals were MAP positive and 384 (96.2%) negative. Out of the 443 serum samples examined for specific antibodies against MAP by ELISA, 6 (1.4%) were positive, 1 (0.2%) was questionable and 436 (98.4%) samples were negative. All faecal samples were tested negative for HEV.

[Time point and methods for emergency killing in cattle]. / Zeitpunkt und Durchführung der tierschutzkonformen Nottötung beim Rind.

Emergency killing is defined as the killing of injured or ill animals to avoid excessive pain or harm. Decision-making for emergency killing or a prolonged therapy can be difficult and has to be based on the case history and results of the clinical examination contributing to the prognosis, particularly in downer cows. Evaluation of enzyme activities and total bilirubin can be used as additional factors pointing to a guarded prognosis; however, none of these parameters provides a clear cut-off value indicating a poor prognosis and mandatory emergency killing. Euthanasia by intravenous drug application is seen as the least stressful method of killing and should therefore always be the first method of choice for emergency killing in cattle. Drugs containing pentobarbital as well as a combination of three different drugs (T61-Injektionslösung, MSD Animal Health) are available for euthanasia in cattle. All drugs must be administered by a veterinarian. Before application of pentobarbital, an animal should be deeply sedated. The administration of T61 requires anaesthesia of the animal and it is not licensed for use in pregnant animals. Alternative methods for emeragency killing, including captive bolt stunning and the use of firearms, although not regularly performed by veterinarians, should be assessed concerning their correct application and performance. When captive bolt stunning or emergency killing using firearms is performed, the correct position of the device is crucial as well as a quick exsanguination or the application of a pithing rod for the actual killing of the animal after captive bolt stunning. In addition to medical considerations, economic and personal factors contribute to the decision about emergency killing in cattle. Therefore, veterinarians should aim to evaluate each case thoroughly based on personal knowledge and experience, case history, clinical findings and laboratory parameters to avoid prolonged suffering of the animal.

Long-term detection of Mycobacterium avium subspecies paratuberculosis in individual and bulk tank milk from a dairy herd with a low prevalence of Johne's disease.

Mycobacterium avium ssp. paratuberculosis (MAP) causes Johne's disease (JD) in ruminants and is shed into the milk of infected cows, which contributes to the controversial discussion about a possible link between MAP and Crohn's disease in humans. The aim of the study was to investigate the risk for the entry of MAP in the food chain via milk from dairy farms with subclinical JD. Therefore, the occurrence of MAP in the milk of a dairy herd with a low prevalence of JD was studied in single and bulk tank milk samples over a period of 23 mo and compared with MAP shedding into feces. Milk, fecal, and blood samples were taken from all cows older than 1.5 yr of age at the beginning and the end of the trial and analyzed for MAP or specific antibodies. In addition, 63 cows (33 MAP infected and 30 MAP noninfected) were selected for monthly sampling. Raw and pasteurized bulk tank milk samples were collected on a monthly basis. The milk samples were tested for MAP by real-time quantitative PCR (qPCR), and the fecal samples were tested for bacterial shedding by qPCR or solid culture. Based on the results of the herd investigations, the prevalence of cows shedding MAP was around 5%; no cases of clinical JD were observed during the study period. The results of the ELISA showed high variation, with 2.1 to 5.1% positive milk samples and 14.9 to 18.8% ELISA-positive blood samples. Monthly milk sampling revealed low levels of MAP shedding into the individual milk samples of both MAP-infected and noninfected cows, with only 13 cows shedding the bacterium into milk during the study period. Mycobacterium avium ssp. paratuberculosis was not detected by qPCR in any raw or pasteurized bulk tank milk sample throughout the study. A significant positive association could be found between MAP shedding into milk and feces. From the results of the present study, it can be concluded that MAP is only shed via milk in a small proportion of cows with subclinical JD for a limited period of time and is diluted below the detection level of qPCR within the bulk tank milk of these herds. These findings indicate that dairy herds subclinically infected with JD pose only a minor source for human MAP consumption with milk and milk products.

Outcome of three commercial serum ELISAs and faecal detection of Mycobacterium avium subsp. paratuberculosis in consecutive samples from a cattle herd with low prevalence of paratuberculosis (Johne's disease).

Paratuberculosis (Johne's disease) in ruminants is caused by Mycobacterium avium subsp. paratuberculosis (MAP). Owing to the lack of accurate laboratory tests, diagnosis is challenging in subclinically infected cattle. To evaluate the long-term performance of serum ELISAs for the detection of paratuberculosis in a dairy herd with low MAP-prevalence, three investigations of all the cows and the consecutive testing of 33 cows suspected to be infected with MAP and 30 cows classified as MAP free were performed over a period of 22 months. Blood samples were tested by three commercial serum ELISAs, MAP shedding was detected by bacteriological culture and polymerase chain reaction (PCR). The ELISA results varied in a wide range in the herd investigations with 1.2% to 18.8% positive samples, the faecal samples were positive for MAP between 1.8% and 4.9% in the three herd investigations. Over the study period, ELISA-positive serum samples varied between 0.0% and 69.7% in MAP-suspicious and 0.0% and 17.6% in MAP-unsuspicious cows with a poor correlation between ELISAs and faecal shedding. The correlation coefficient of the optical density values of the three ELISAs varied between 0.348 and 0.61. Evidence of cow specific variations of residuals was found in all linear models. The linear mixed models showed relevant contribution of cow specific variation in explanation of the residual variances. They also showed significant effects of the explanatory ELISA, the group (MAP-suspicious or MAP-unsuspicious) and the time of sampling. It can be concluded that the choice of the laboratory test significantly influences the outcome of the testing for MAP and that none of the three ELISAs can be thoroughly recommended as single test for the early diagnosis of paratuberculosis in cattle. Test results should always be interpreted with caution to avoid erroneous decisions and the disappointment of those engaged in the abatement of paratuberculosis.

Closed reduction of coxofemoral luxation in a goat: case report.

Hip luxations have been reported in many ruminants, and several treatments have been described for them. However, successful closed reduction of hip joint luxation has not been reported in goats to date. This case report describes the closed reduction of coxofemoral luxation in a three-month-old male Saanen dairy goat. The goat showed non-weightbearing lameness and abnormal mobility of the proximal right hindlimb. Luxation of the right coxofemoral joint in craniodorsal direction was diagnosed by radiography. The femoral head was repositioned under sedation, and physiotherapy including non-weightbearing hindlimb movement and supported walking exercise was performed. Fifteen days after closed reduction the animal was discharged from the clinic. At that time the animal was sound at a slow walk but lameness was still present at faster gaits. Follow-up examinations revealed normal development of the animal, which subsequently showed no lameness and served successfully as a breeding goat.

Paratuberculosis, a notifiable disease in Austria--current status, compulsory measures and first experiences.

Paratuberculosis (Johne's disease) is one of the most important diseases in ruminants today. Its contribution is worldwide and the disease is causing severe financial losses among cattle producers in some countries [Hasanova, L., Pavlik, I., 2006. Economic impact of paratuberculosis in dairy cattle herds: a review. Vet. Med.-Czech. 51, 193-211]. Paratuberculosis is untreatable; diagnosis limited to the early stages of the infection and control of the disease is difficult. The prevalence of serologically positive Austrian cattle farms rose significantly to 19.0% during the past years [Baumgartner, W., Damoser, J., Khol, J.L., 2005. Comparison of two studies concerning the prevalence of bovine paratuberculosis (Johne's disease) in Austrian cattle in the years 1995-1997 and 2002/2003 (Article in German with extended English summary). Vet. Med. Austria/Wien. Tierärztl. Mschr. 92, 274-277]. Based on these findings clinical paratuberculosis in ruminants was declared a notifiable disease in Austria in April 2006. A survey of the current situation in Austria, the most important parts of the new compulsory measures and their practical implementation and impacts are presented in this short communication.

Longterm investigation in an Austrian dairy herd with low prevalence of paratuberculosis detection of antibodies in blood and milk.

Paratuberculosis (Johne's disease), which is widely distributed throughout the world, is caused by Mycobacterium avium subspecies paratuberculosis (MAP). Diagnosis of subclinically infected cattle is challenging and is especially problematic in herds with low prevalence of MAP. The aim of this long-term study was the comparison of different diagnostic tests for MAP and specific antibodies in a herd with low prevalence of MAP. Three different commercially available serum-ELISA (Svanovir-ELISA, Svanova, Uppsala, Sweden; IDEXX-ELISA, IDEXX Laboratories, Maine, USA; Pourquier-ELISA, Institut Pourquier, Montpellier, France) and two milk ELISA (Svanovirm-ELISA Svanova, Uppsala, Sweden; Pourquier-ELISA, Institut Pourquier, Montpellier, France) were compared. Apart from these indirect diagnostic tests, two methods for the detection of the etiologic agent (bacteriologic culture and real-time PCR of faecal samples) were performed. In January 2005 the first and in April 2005 the second herd investigation of all animals older than 2 years (n=335) were carried out. Blood, milk and faecal samples were taken. From November 2005 until April 2006 follow up investigations were performed. For this purpose, blood-, milk- and faecal samples were monthly taken from 63 selected animals. The highest number of blood- and milk samples with a detectable antibody-level was found by the Svanovir-ELISA. There was a significant correlation between serum- and milk- Svanovir-ELISA results, whereas the agreement between ELISA and faecal culture/PCR was low. Significant correlations between Svanovir-serum-ELISA results and milk somatic cell counts could be registered. Moreover, there was significant agreement between IDEXX-serum-ELISA results with the age and number of lactations of the cows, as well as the mother's MAP-status.

Serological, bacteriological and molecularbiological survey of paratuberculosis (Johne's disease) in Austrian cattle.

Paratuberculosis (Johne's disease) is a chronic infectious disease of ruminants, caused by Mycobacterium avium subspecies paratuberculosis (MAP). Because of its long incubation period, high economic losses, difficulties in diagnosis and possible links to Morbus Crohn in humans, paratuberculosis is one of the most important diseases of ruminants today. An abattoir-based nationwide survey on the occurrence of MAP in the Austrian cattle population was performed using serology (SVANOVIR-ELISA) as well as culture, ZN-stain and IS900-PCR on faeces and lymph node samples. A total of 756 Austrian slaughter cattle were serologically, bacteriologically and molecularbiologically tested for the occurrence of MAP and specific antibodies respectively. Samples were collected following a statistical plan to obtain balanced specimens from the whole country. Nineteen per cent of the animals tested were serological positive, 10.1% gave an inconclusive result and 70.9% showed no specific antibodies against MAP. Only in four individuals MAP could be detected by stain, bacteriology or Polymerase Chain Reaction. The calculated prevalence of 19.0% positive cattle, each representing one farm, showing specific antibodies against MAP is rather high in terms of animal-level but low in herd level prevalence compared with other countries. When this study is compared with a similar study performed in Austria 1999, a significant increase of positive cattle and farms could be seen in Austria.