Sero-epidemiological study of the presence of hantaviruses in domestic dogs and cats from Belgium.

Hantaviruses are worldwide rodent-borne pathogens infecting humans and other animals mainly through inhalation of aerosols contaminated with rodent excreta. Few data are available on hantavirus serology and geographical distribution in dogs and cats. We therefore screened sera from pet dogs (N=410) and cats (N=124) in two regions of Belgium, using IgG ELISA and IFA. We analysed the effect of the owner's address as well as pet gender and age on hantavirus status. Hantavirus antibodies were found in both species with a significantly higher seroprevalence in cats than in dogs (16.9% vs. 4.9%, P=0.001). More dogs were infected in highly forested southern Belgium (harbouring more rodents) than in northern Belgium (10.5% vs. 3.0%, P=0.002). In the south, hantavirus sero-positive cats were found in more densely forested localities than sero-negatives ones were (P=0.033). These results are consistent with the ecological variations of hantavirus risks in humans.

Determination of the source of increased serotonin (5-HT) concentrations in blood and peritoneal fluid of colic horses with compromised bowel.

REASONS FOR PERFORMING STUDY: Increased plasma (5-HT) concentrations are reported in horses predisposed to develop laminitis and after i.v. infusion of endotoxins. In the equine jejunum contractile 5-HT1A-like receptors show tachyphylaxia upon prolonged activation with 5-HT. Therefore, increased systemic 5-HT release in colic horses could play a possible role in the pathophysiology of ileus. OBJECTIVE: To investigate possible increased systemic release of 5-HT in colic horses with compromised bowel and to identify the source of 5-HT overload. METHODS: Concentrations of 5-HT were determined in plasma and peritoneal fluid (PF) of healthy horses (n = 10), strangulating small intestinal colic horses (n = 18), nonsurgical colic horses (n = 10) and cryptorchid stallions (n = 6). It was attempted to identify the source of 5-HT overload by comparing the blood and PF 5-HT concentrations within horses and by assessing the in vivo platelet activation through determination of the beta-thromboglobulin (beta-TG)/platelet factor 4 (PF4) ratio. RESULTS: All horses in the strangulating small intestinal colic group had plasma (P = 0.006) and PF (P = 0.01) 5-HT concentrations above those found in the control group. Plasma beta-TG/PF4 ratio in these horses exceeded 2 in all cases, indicating in vivo platelet activation. Concentrations of 5-HT in PF of colic horses with compromised bowel were significantly lower than the corresponding plasma concentrations (P = 0.005). POTENTIAL RELEVANCE: In horses with compromised bowel, significant amounts of 5-HT can be released into the systemic circulation, through massive release of platelet-stored 5-HT. 5-HT is a very potent proinflammatory, vasoconstrictive and immunomodulatory agent. In view of the rapid and prolonged tachyphylaxia, shown for the jejunal 5-HT1A-like receptors, this increased systemic 5-HT release could play a role in the pathophysiology of ileus in horses.

First diagnosis of Encephalitozoon intestinalis and E. Hellem in a European brown hare (Lepus europaeus) with kidney lesions.

Encephalitozoon intestinalis and Encephalitozoon hellem were diagnosed in the kidneys of a free-ranging European brown hare (Lepus europaeus) with multifocal wedge-shaped chronic interstitial nephritis using real-time PCR and microarray. This is the first description of these microsporidia species in a European brown hare, which are both potential zoonotic agents.

Severe alopecia due to demodicosis in roe deer (Capreolus capreolus) in Belgium.

Demodex mites are part of the normal fauna of hair follicles of many, if not all, healthy mammal species. Normally these parasites live in harmony with their host, however in states of putative immunosuppression the acarids undergo excessive proliferation and cause clinical disease, which may be localised or generalised. This paper describes four cases of demodicosis in roe deer (Capreolus capreolus) with localised to generalised alopecia.

First chronic wasting disease (CWD) surveillance of roe deer (Capreolus capreolus) in the northern part of Belgium.

Cases of chronic wasting disease (CWD) in wild cervids have yet not been reported in Europe, whereas the disease is considered enzootic in free-ranging mule deer, Rocky mountain elk and white-tailed deer in the area of Colorado, Wyoming, and Nebraska. New foci of CWD continue to be detected in other parts of the United States. However, no large-scale active epidemiosurveillance of European wild cervids is yet installed in Europe. In accordance with the opinion of the European Scientific Steering Committee, a preliminary (active) surveillance scheme was installed, in order to improve the knowledge of the CWD status of wild cervids (roe deer) in the Northern part of Belgium. Spleen samples (n=206) and brain samples (n=222) of roe deer collected in the Northern part of Belgium, were examined for CWD using the antigen-capture enzyme-linked immunoassay (EIA) of IDEXX. Afterwards, the EIA was systematically confirmed by immunohistochemistry using three antibodies, namely R524, 2G11 and 12F10. There were no indications on the occurrence of TSE in any of the samples. A Bayesian framework was used for the estimation of the true prevalence of CWD in the Northern part of Belgium that was estimated to have a median value of zero with a 95th percentile value of 0.0049 and 0.0045 for spleen and brain samples respectively.

First results of chronic wasting disease (CWD) surveillance in the south-eastern part of Belgium.

Chronic wasting disease (CWD) has not been reported in Europe, whereas it is considered to be enzootic in free-ranging mule deer, Rocky mountain elk and white-tailed deer in the area of Colorado, Wyoming, and Nebraska, and new foci of CWD have been detected in other parts of the United States. However, no large-scale active epidemiosurveillance of European wild cervids has been installed in Europe. In accordance with the opinion of the European Scientific Steering Committee, a preliminary (active) surveillance scheme was installed, in order to improve the knowledge of the CWD status of the Belgian free-ranging cervids (roe deer and red deer). Spleen samples (n=866) of roe deer and red deer collected in the south-eastern part of Belgium, were examined for CWD using a enzyme-linked immunosorbent assay of Bio-Rad. Afterwards, the ELISA was systematically confirmed by immunohistochemistry using three antibodies, namely R524, 2G11 and 12F10. There were no indications on the occurrence of transmissible spongiform enncephalopathy (TSE) in any of the samples. A Bayesian framework was used for the estimation of the true prevalence of CWD in south-eastern part of Belgium that was estimated to have a median value of zero with a 95% percentile value of 0.00115.

Detection of polymorphisms in the prion protein gene in the Belgian sheep population: some preliminary data.

The development of clinical signs of TSE/scrapie in sheep has been linked to polymorphisms in the prion protein (PRNP) gene. The most important polymorphisms appear to be at codons 136, 154, and 171. The objective of this study was to investigate the polymorphisms at these codons in the Belgian sheep population, including clinical healthy animals, healthy animals at the slaughterhouse and animals in TSE/scrapie positive farms (including a Nor98 farm).

The use of epostane in an attempt to reproduce cystic endometrial hyperplasia in the bitch.

The aetiology and pathogenesis of spontaneous cystic endometrial hyperplasia (CEH) in the bitch is not yet completely understood. Recent research based on the expression of uterine sex hormone receptors in spontaneous cases of CEH suggested that a temporary progesterone deficiency during late oestrus-early metoestrus may be responsible for the onset of CEH development. In the present study a temporary progesterone deficiency during late oestrus-early metoestrus was experimentally created using an inhibitor of progesterone synthesis, epostane. At day 49 of metoestrus, there was a significant reduction in the size of the uterine wall, mainly due to endometrial atrophy, and there was also a significant increase in the mucus-filled uterine lumen in the bitches that had been treated with epostane compared to the control bitches. No significant differences in the expression of sex hormone receptors was observed between the two groups. As no CEH developed in the epostane-treated bitches, an additional oestrogenic stimulus may be required to stimulate endometrial proliferation. Therefore, it is suggested that deficient luteinization of the corpus luteum may be the trigger in the pathogenesis of CEH, as the secretion of varying amounts of sex steroids depends on the degree of luteinization.

An outbreak of histomoniasis in free-range layer hens.

Histomonas meleagridis was held primarily responsible for an outbreak of 6% increased mortality and 11% decreased egg production between weeks 57 and 72 in a flock of free-range layer hens, concurrently infected with Brachyspira-like bacteria. This case can be considered an example of ancient diseases re-emerging in alternative housing systems that are promoted because of animal welfare considerations, but that at the same time allow rapid spread of pathogens in birds for which only few curative drugs are registered. Therefore, new housing methods should be introduced gradually to gain experience with them.

Uterine oestrogen and progesterone receptor expression in experimental pyometra in the bitch.

Pyometra was induced in five bitches by the intraluminal inoculation of a ligated uterine horn in metoestrus with an Escherichia coli suspension, the other horn serving as an uninoculated control. Histologically, the inoculated horns resembled those with naturally occurring pyometra, while the uninoculated horns had an inactive appearance instead of the normal metoestrus appearance. Immunohistochemically, the expression of sex hormone receptors in the inoculated horns corresponded with that in natural cases of pyometra. In the uninoculated horns, virtually no expression of sex hormone receptors was observed, in contrast to such expression in normal metoestrus. Bacteria-associated ovario-uterine interactions may have been responsible for the hyperplastic (inoculated horn) and inactive (uninoculated horn) uterine changes observed in this experiment.

Estrogen-alpha and progesterone receptor expression in cystic endometrial hyperplasia and pyometra in the bitch.

Estrogen-alpha receptor (ER) and progesterone receptor (PR) were examined immunohistochemically in uteri of normal bitches, in uteri of bitches with cystic endometrial hyperplasia-mucometra (CEH-M) and in uteri of bitches with endometritis-pyometra (E-P), under exogenous progesterone treatment. In the CEH-M group, the ER- and PR-scores of all uterine cell types were higher than the ER- and PR-scores of normal uteri, although these differences were not always statistically significant. The ER-scores of E-P group were significantly lower than the ER-scores of the normal uteri and CEH-M group. The PR-scores of the E-P group tended to be higher than the PR-scores of the normal uteri, except for the surface epithelium, although these differences were not statistically significant. Exogenous progesterone treated bitches with CEH-M or E-P showed reduced ER- and PR-scores in the different uterine cell types, compared with the corresponding nontreated CEH-M or E-P group. The differences in ER and PR expression between CEH-M and E-P suggest different factors in the pathogenesis of both entities. Although, these changes in ER and PR expression do not seem to be directly involved in the pathogenesis of CEH-M and E-P. It is suggested that for CEH-M and progestin induced CEH-M a hormone dependent pathway is responsible. For P, the trigger may be bacterial infection.

The effect of physical structure in maize silage-based diets for beef bulls.

To investigate the influence of physical structure on zootechnical performances, four feeding regimens were evaluated with 52 Belgian Blue double-muscled bulls starting from 327 kg until slaughter (646 kg). All diets were fed ad libitum and consisted of concentrates and maize silage in different ratios. The structural value (SV), currently used in Belgium as an evaluator of physical structure in the diet for dairy cows, amounted to 0.95 (control group), 0.74 and 0.52 per kg dry matter for the treatments with a high (HSV), medium (MSV) and low (LSV) SV, respectively. The fourth group (LSVs) received the same diet as group LSV, but additional straw was provided ad libitum, as a possible corrector for a lack of physical structure. No significant differences were found for growth rate, intake and feed conversion data. However, between 600 and 650 kg, growth rate and intake of group LSV and LSVs tended to be reduced. The influences on the carcass quality were of minor importance. Remarkably, meat tenderness of the LSV group was improved (32.3 N) in comparison (p=0.08) with the other groups (42.6 N). The height of the rumen papillae was not affected by the diets. Histological examination of the ruminal epithelium revealed that the LSV group showed the severest morphological changes. Examination of the cross-sections of the digits showed no influence of the diet on the incidence of laminitis. From these results, it is concluded that maize silage-based rations with a SV of 0.74 provide enough structure for optimal zootechnical performances of finishing Belgian Blue double-muscled bulls.

The use of a Daphnia magna bioassay for rapid screening of acute intoxications with insecticides in dogs and cats.

Sudden death due to acute insecticide intoxications occurs frequently in dogs and cats. The absence of characteristic lesions at autopsy often renders post-mortem diagnosis dependent on the analysis of samples taken from the carcase at autopsy. In the present study, a bioassay utilizing Daphnia magna was proposed and tested as a rapid screening method for acute intoxications in dogs and cats. The bioassay was shown to be highly sensitive for detecting carbamate and organophosphate insecticides in the stomach contents. Generally. the mean survival time of the waterfleas in the control group was 5.17 h (SD = 1.24) and in the intoxicated group 1.32 h (SD = 1.49). during a 6 h observation period. If a cut-off is set at 4 h, this Daphnia bioassay gave 5.5% false negative results and 18.2% false positive results. using the results of toxicological analyses as a gold standard.

Cystic endometrial hyperplasia-pyometra complex in the bitch: should the two entities be disconnected?

The uteri of 26 clinically healthy bitches and 42 bitches with a clinical suspicion of pyometra were examined histologically using a computerized image analysis system. Histologic lesions were characterised mainly by thickening or atrophy of the endometrium and by varying degrees of cystic changes of the glands. These lesions were observed in most of the clinically healthy bitches as well as in all of the clinically ill animals. In most of the ill bitches a variable degree of inflammation also was found. Some bitches with clinical signs indicative for pyometra had no inflammatory reaction in the uterus. These bitches were misdiagnosed as suffering from pyometra, confirming the difficulty of diagnosing pyometra by simple clinical examination. Determination of sex hormone serum levels revealed that all dogs in both groups were either in metestrus or in anestrus. Based on the results of this study the cystic endometrial hyperplasia-pyometra complex can be divided in two entities: a cystic endometrial hyperplasia-mucometra complex and an endometritis-pyometra complex. Both entities bear many similarities with each other, except for the inflammatory reaction in the endometritis-pyometra complex. It is concluded from this study that the latter complex probably does not necessarily follow the former, but that both can arise de novo.