Original article(s)

Chemical and immuno-chemical test kits are frequently used in human medicine for the detection of fecal occultblood loss. Since only limited data on the use of these test kits in equine medicine are available, the chemicalHemoccult SENSA test was evaluated for the detection of fecal occult blood loss in the horse. The results show thatthe Hemoccult SENSA test kit has a good sensitivity and specificity for the detection of distal intestinal blood lossin stabled horses. In horses at pasture, many false positive reactions were observed, probably due to the presence ofplant peroxidases in the diet. This high rate of false positive reactions could, in contrast to the human analyses, notbe eliminated by a delayed development of the test. Stabling the horses for at least four days before testing drasticallyimproved the specificity. In comparison to humans, the detection limit of the Hemoccult SENSA test appears to belower in horses. In the present study, up to 1% of the blood loss could be detected in the feces. This corresponds to120 ml blood loss a day.

An outbreak of distemper was observed in beech martens (Martes foina) in the eastern part of Flanders(Belgium) for the first time. The clinical and pathological findings were consistent with other outbreaks describedin mustelids in Europe. Using reverse transcriptase polymerase chain reaction, morbillivirus RNAwas detected in an organ homogenate inoculated on Vero.dogSLAM cells. The virus was sequenced and wasidentified as a canine distemper virus (CDV) strain, hundred percent identical to an earlier isolate from amarten from Germany. After a period of nearly complete absence of beech martens in Flanders due to intensiveprosecution, their population density has increased substantially in the last decennia. Although the exactmechanisms behind the observed population changes stay unclear, spread of CDV from central Europe followingdispersion of beech martens is indicated by our findings. Further CDV spread could negatively impacton the highly threatened pine marten (Martes martes) and the decreasing polecat (Mustela putorius) populationsin Flanders.

Swine dysentery causes severe economic losses in swine industry. Eliminating the disease at farmlevel can become problematic when resistance of the causative agent, Brachyspira hyodysenteriae,against pleuromutilins is reported. In this study, the use of tylvalosin (Aivlosin®) in eliminating the diseasein a single-site, farrow-to-finish herd was evaluated. In addition, productivity parameters andantimicrobial use were compared prior to and after implementing the elimination protocol.On a mixed farm of 200 sows and 1500 finishers with a history of chronic dysentery, the B. hyodysenteriaeisolate was resistant to pleuromutilins but had a low minimum inhibitory concentration fortylvalosin (2 μg/ml). Combined with a strict program for rodent control and hygiene, sows were treatedwith tylvalosin at a dose of 4.25 mg/kg BW daily for four weeks. The sows were washed one weekafter the start of the treatment before entering a clean stable. Piglets born from sows that had receivedthis treatment, were considered free from dysentery and were kept separated from infected, untreatedanimals on the farm. A monitoring program with monthly sampling of sows and fatteners wasinstalled to evaluate the absence of B. hyodysenteriae on the farm.After treatment, the clinical symptoms in the treated sows disappeared and remained absent in theoffspring born after the procedure. Fecal samples examined by PCR remained negative for the wholetesting period (14 months after the end of the treatment) and no clinical outbreaks were reported afterwards.The feed conversion ratio improved by 12%, the mortality rate with 37% and the antimicrobialuse decreased by 71.5%.We conclude that the elimination of swine dysentery on a single-site, farrow-to-finish herd is possibleusing tylvalosin (AivlosinR) combined with strict hygiene and rodent control. The improvementsof the technical parameters in this study are not only the result of the elimination of B. hyodysenteriae,but also changes in management practices influenced these parameters.

This study reviews the medical records of 56 dogs diagnosed with lymphoma based on thecytological and/or histological results between January 1, 2009 and December 31, 2010. Most of thedogs were middle-aged to old, and were diagnosed with multicentric lymphoma (ML) (n=36). Themajority of the dogs were presented in stages III to V (n=55) and substage b (n=43). A completeblood count and serum biochemistry, urinalysis, serum protein electrophoresis, thoracic radiographsand/or abdominal ultrasound were performed. The results correlated with previously describedresults in the literature. Therapy was initiated in 80% of the dogs (n=45). After diagnosis, the mediansurvival time of 62% of these dogs (n=28) treated with only prednisolone was 32 days (range 3 – 224days). For 24% of the dogs (n=11) treated with chemotherapy, the median survival time was 119days (range 11 - 273 days). Surgical resection of the macroscopic tumor was performed in theremaining six dogs (13%). Three of these dogs received subsequent prednisolone therapy. Themedian survival time of these six dogs was 47 days (range 0 – 669 days). The dogs that receivedchemotherapy had significantly longer survival times than those treated with only prednisolone,although negative prognostic factors were present in all of the cases treated with chemotherapy.

In this study, the effect of farm, time, season and health was evaluated on the composition ofmare’s milk sold in Flanders. The content of the analyzed components (i.e. fat, fatty acids, protein,lactoferrin, lysozyme, lactose and urea) differed signifi cantly (p < 0.0001) between farms, at a givenmoment in time. Within each farm, large month-to-month variations for most milk components (p< 0.01 to 0.0001) were observed. The variation over time between different farms was smaller. Thesefi ndings indicate that the composition of the mare’s milk consumer portions varies substantiallybetween the different farms and also over time within each farm. Season, nutrition, udder healthand worm burden are believed to contribute signifi cantly to this variation.

Parasitic infections with gastrointestinal (GI) nematodes and liver fl uke (Fasciola hepatica) arecommon causes of reduced productivity in ruminants. In this paper, the results of a voluntarymonitoring campaign on helminth infections in Belgian dairy herds are summarized and discussed.From 2009 until 2011, a bulk tank milk sample was collected in autumn and analyzed by antibodydetectingbulk tank milk ELISA’s to assess the level of exposure to GI nematodes and liver fl uke.The number of farms participating in the survey increased over the years, from 1216 in 2009 to1731 in 2011. The proportion of herds with high exposure to GI nematodes varied signifi cantlybetween the three years, from 67% in 2009 over 70% in 2010 to 63% in 2011. The proportion ofherds with high exposure to F. hepatica remained stable around 30%. Important regional variationswere observed with levels of exposure to GI nematodes increasing from the north to the south ofthe country, whereas the distribution of F. hepatica was concentrated in the province of West-Flanders, the southern part of East-Flanders, Hainaut and the northern part of Luxembourg. It canbe concluded that, when compared with surveys conducted in surrounding countries, the levels ofhelminth exposure in Belgium can be considered high, especially for GI nematodes. If the aim is todecrease levels of exposure in the future, this will likely require control methods based on alteredtimings of treatment and changes in pasture management.

Anthelmintic resistance of parasites in small ruminants, cattle and horses is increasing worldwide as a consequence of the over usage of the currently available products. In Belgium, Cooperia oncophora is the most common cattle nematode in which resistance, especially against macrocyclic lactones, occurs. Once resistance has been diagnosed, a change to another drug with a different mode of action is advised. However, effective anthelmintics will be hardly available in the near future. Therefore, it is important that farmers and veterinarians find a balance between achieving good parasite control and the sustainability of their control strategies. In this way, anthelmintic resistance may be delayed, and the effectiveness of anthelmintic drugs may be prolonged. This requires sensitive detection tools. With a sensitive detection technique, anthelmintic resistance can be diagnosed in a very early stage. Hence, the spread of resistance alleles in the parasite population may be prevented. In this review, different diagnostic assays for the detection of anthelmintic resistance are discussed, an overview is given of the current status of anthelmintic resistance in Belgian cattle, and measures are suggested to avoid or delay the development of anthelmintic resistance.