Emergence of fatal Mannheimia haemolytica infections in cattle in the Netherlands.

In the Dutch national surveillance system, outbreaks of fatal infections by Mannheimia haemolytica (M. haemolytica) in dairy cows and veal calves have become apparent in recent years. These observations prompted an in-depth analysis of available pathology data over the period 2004-2018 to investigate changes in the occurrence and/or expression of M. haemolytica-associated cattle disease. With multilevel logistic regression models, time trends were identified and corrected for farm, season, pathologist and region. Deaths associated with M. haemolytica infection increased over time with dairy cows and veal calves diagnosed with fatal M. haemolytica infections 1.5 and 1.4 times more frequently every following 3-year period between 2004 and 2018, respectively. M. haemolytica-associated disease showed two distinct disease presentations: acute pleuropneumonia in dairy cows and polyserositis in veal calves. The prevalence of both disease presentations with M. haemolytica confirmed increased in each 3-year time period between 2004 and 2018, with an odds ratio (OR) of 1.5 for acute pleuropneumonia in dairy cows and an OR of 1.7 for polyserositis in veal calves. No change was found for M. haemolytica-associated disease in dairy calves. Although M. haemolytica is considered an opportunist bovine pathogen, and the presence of primary pathogens such as BHV-1, BVDV and Mycoplasma species was not completely ruled out in our study, substantial evidence is provided to indicate infections with M. haemolytica were the most likely cause of death. M. haemolytica-associated diseases occurred more often in October-June than July-September, and were detected more often in necropsied animals from the North, South and East Netherlands than the West Netherlands.

Ovine and Bovine Congenital Abnormalities Associated With Intrauterine Infection With Schmallenberg Virus.

In December 2011, a previously unknown congenital syndrome of arthrogryposis and hydranencephaly in sheep and cattle appeared in the Netherlands as an emerging epizootic due to Schmallenberg virus (SBV). Gross lesions in 102 lambs and 204 calves included porencephaly, hydranencephaly, cerebellar dysplasia and dysplasia of the brainstem and spinal cord, a flattened skull with brachygnathia inferior, arthrogryposis, and vertebral column malformations. Microscopic lesions in the central nervous system showed rarefaction and cavitation in the white matter, as well as degeneration, necrosis, and loss of neurons in the gray matter. Brain and spinal cord lesions were more severe in lambs than in calves. Ovine and bovine cases examined early in the outbreak showed encephalomyelitis. SBV infection was confirmed by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) in brain samples in 46 of 102 lambs (45%) and in 32 of 204 calves (16%). Immunohistochemistry, performed on tissue samples from 18 RT-qPCR-positive lambs, confirmed the presence of bunyaviral antigen in neurons of the brain in 16 cases. SBV antibodies were detected by enzyme-linked immunosorbent assay in fetal blood in 56 of 61 sampled ovine cases (92%). In a virus neutralization test, all tested dams of affected newborns, 46 ewes and 190 cows, were seropositive. Compared with other teratogenic viral infections, the pathogenesis and lesions of SBV in sheep and cattle fetuses are similar to those of other ruminant orthobunyaviruses. However, the loss of spinal ventral motor neurons and their tracts, resulting in micromyelia, distinguishes SBV infection from other viral central nervous system lesions in newborn ruminants.

Epizootic of ovine congenital malformations associated with Schmallenberg virus infection.

Epizootic outbreaks of congenital malformations in sheep are rare and have, to the best of our knowledge, never been reported before in Europe. This paper describes relevant preliminary findings from the first epizootic outbreak of ovine congenital malformations in the Netherlands. Between 25 November and 20 December 2011, congenital malformations in newborn lambs on sheep farms throughout the country were reported to the Animal Health Service in Deventer. Subsequently, small ruminant veterinary specialists visited these farms and collected relevant information from farmers by means of questionnaires. The deformities varied from mild to severe, and ewes were reported to have given birth to both normal and deformed lambs; both male and female lambs were affected. Most of the affected lambs were delivered at term. Besides malformed and normal lambs, dummy lambs, unable to suckle, were born also on these farms. None of the ewes had shown clinical signs during gestation or at parturition. Dystocia was common, because of the lambs' deformities. Lambs were submitted for post-mortem examination, and samples of brain tissue were collected for virus detection. The main macroscopic findings included arthrogryposis, torticollis, scoliosis and kyphosis, brachygnathia inferior, and mild-to-marked hypoplasia of the cerebrum, cerebellum and spinal cord. Preliminary data from the first ten affected farms suggest that nutritional deficiencies, intoxication, and genetic factors are not likely to have caused the malformations. Preliminary diagnostic analyses of precolostral serum samples excluded border disease virus, bovine viral diarrhoea virus, and bluetongue virus. In December 2011, samples of brain tissue from 54 lambs were sent to the Central Veterinary Institute of Wageningen University Research, Lelystad. Real-time PCR detected the presence of a virus, provisionally named the Schmallenberg virus, in brain tissue from 22 of the 54 lambs, which originated from seven of eight farms that had submitted lambs for post-mortem examination. This Schmallenberg virus was first reported in Germany and seems to be related to the Shamonda, Aino, and Akabane viruses, all of which belong to the Simbu serogroup of the genus Orthobunyavirus of the family Bunyaviridae. These preliminary findings suggest that the Schmallenberg virus is the most likely cause of this epizootic of ovine congenital malformations, which is the first such outbreak reported in Europe.

Epizootic congenital hydranencephaly and abortion in cattle due to bluetongue virus serotype 8 in the Netherlands.

An outbreak of hydranencephaly in aborted foetuses and newborn calves occurred following the 2007 epidemic of bluetongue serotype 8 (BTV8\net2006) in the Netherlands. In total 35 aborted foetuses and 20 live-born calves, submitted from September 2007 to May 2008, were examined pathologically. Foetuses with gestational ages between 4 and 9 months (mean 6.8 month) showed varying stages of cerebral malformation. Initial stages were cavitations in the cerebral hemispheres with massive destruction of neuroparenchyma, calcium deposits, and a phagocytic inflammatory response. Later stages showed distinct hydranencephaly, the cerebral hemispheres being almost completely replaced by fluid-filled sacs. In seven cases the cerebellum was affected as well, but brainstem structures were intact. Newborn calves with clinical signs of abnormal behaviour ('dummy calves'), circling, head pressing, incoordination, and blindness were seen from the end of January 2008. The calves were born between 2nd January and 16th March 2008. The calves were euthanized after 1 day up to 14 weeks (mean 4-7 weeks). Brain malformations in these calves were confined to the cerebrum and consisted of varying degrees of hydranencephaly. Spleen tissue was PCR-positive for bluetongue virus (BTV) in 21 of 35 foetuses and in 1 of 20 calves. A higher percentage of PCR-positives was found in foetuses aborted in early gestation than in late gestation, suggesting clearance of BTV during gestation. Fifteen of 33 dams of PCR-negative hydranencephalic foetuses or calves could be traced and all were BTV-seropositive, indicating a previous BTV infection. The timing of hydranencephaly cases in live-born calves during the first months of 2008 was consistent with infection in early gestation during the prior transmission season. Vertical transmission and teratogenic potential have previously been described for modified-live vaccines for bluetongue but are highly unusual for field strains of BTV, which raises the issue whether BTV8\net2006 or its ancestor has been cell- or laboratory-adapted in the past.

[Post-mortem diagnosis of leptospirosis in two dogs]. / Twee postmortaal vastgestelde gevallen van leptospirose bij de hond.

Leptospirosis was diagnosed post-mortem in a 2-year-old male Dogo Argentino and a 7-week-old male Foxhound puppy. The two cases were unrelated. Clinical symptoms were mainly confined to the gastro-intestinal tract. Pathological lesions were suggestive of acute leptospirosis. Leptospires infection was confirmed by serological (indirect IgM/Ig6 ELISA and MAT) and immunohistochemical techniques.

[Acute zinc poisoning in a dog]. / Acute zinkintoxicatie bij een hond.

Zinc-induced haemolytic anaemia was diagnosed in a young dog. The origin of the zinc intoxication was the ingestion of a toy material which contained a high percentage of zinc. The level of zinc in the liver and kidneys was resp. 1050 and 1320 ppm.

Salmonella (sero)types and their resistance patterns in pig faecal and post-mortem samples.

The purpose of this survey was to take stock of porcine Salmonella isolates derived from faecal and post-mortem samples over a 4-year period. Salmonella was isolated by direct inoculation on BGA(NO)-plates (faeces, intestinal content) or sheep blood agar (organs). Antimicrobial susceptibility was tested by the agar diffusion method. Salmonella was isolated in 4.2% of all porcine submissions received at the Animal Health Service. A total of 1305 salmonellae were isolated from a total of 1279 submissions from 1008 different herds. Salmonella Typhimurium was the most frequently isolated serotype (88%), and Salmonella Typhimurium DT104 was the most frequently isolated phagetype (17.2% of Salmonella Typhimurium). Resistance to antimicrobials occurred in 47.3% of all isolates, mainly those of the multiresistant phagetype DT104. Other pathogens were isolated in more than 50% of the submissions. In cases of clinical diarrhoea, multiple pathogens may be involved and therapy and preventive measures should be adjusted accordingly.

Salmonella typhimurium DT104 septicaemia with meningitis in neonatal piglets.

Clinical salmonellosis in pigs in the Netherlands usually manifests itself as diarrhoea. In finishing pigs this is sometimes accompanied by peracute mortality, mainly in the last month of the finishing period. This is the first report describing Salmonella Typhimurium DT104 infection of 1-week-old suckling piglets in the Netherlands. The piglets showed nervous symptoms and died. The clinical symptoms, gross pathology, histopathological, bacteriological and phagetyping results are presented as well as the antimicrobial resistance pattern. This case is not only important as an extension of the clinical syndrome of salmonellosis in pigs in the Netherlands, but also because of the risk of human infection after consumption of pork or pork products contaminated with this pathogenic and multiple resistant Salmonella clone.

Isolation and characterization of porcine circovirus type 2 from pigs showing signs of post-weaning multisystemic wasting syndrome in The Netherlands.

Pigs with wasting syndrome were examined for macroscopic and histopathological lesions, and for porcine circovirus (PCV). Histopathological lesions were comparable to those previously documented for post-weaning multisystemic wasting syndrome (PMWS). In addition, in seven out of ten examined PMWS-affected pigs focal-to-slight mononuclear meningitis and focal cerebral mononuclear infiltrates (4 out of 10) were observed. A virus was isolated from organs and sera from pigs showing wasting syndrome. An immunoperoxidase monolayer assay and an indirect immunofluorescence assay were performed on the infected PK-15 and Dulac cell cultures, respectively, and both assays indicated the presence of PCV type 2 (PCV2). The nested-polymerase chain reaction (nPCR) technique, based on the use of PCV2 specific oligonucleotides, revealed specific amplified products of 481 bp. Nucleotide sequence analysis of the entire genome of the Dutch PCV isolate 24657 NL showed a homology with known nucleotide sequences of porcine PCV type 1 (PCV1) and PCV2 isolates of 77.1% and >96%, respectively. This is the first report of the isolation and characterization of PCV2 in PMWS-affected pigs in the Netherlands.

Light microscopic, immunohistochemical, and electron microscopic features of amyloid arthropathy in chickens.

Amyloid arthropathy has been recently recognized as a spontaneous syndrome in chickens. Predominantly, femorotibial and tarsometatarsal joints were affected, showing (peri) articular orange amyloid deposits. Immunohistochemical evaluation revealed the amyloid to be of the reactive type. Induction of amyloid arthropathy in chickens was carried out using a single intravenous injection of Enterococcus faecalis cultures. In the naturally occurring and the induced cases, amyloid deposits were found in the hypertrophic synovial villi and in the articular cartilage, particularly in the superficial layer and in the nutritional blood vessel walls. Highly sulfated glycosaminoglycans (GAGs) were found in the amyloid deposits. Ultrastructurally, bundles of amyloid fibrils were seen in invaginations of synoviocytes and chondrocytes. Immunogold electron microscopy failed to reveal signs of intracellular amyloid formation. The predilection site for amyloid deposition in the major leg joints of the chickens with reactive amyloid could be explained by the arthritic condition caused by Enterococcus faecalis bacteriaemia. The polyarthritis triggers hepatic acute phase protein synthesis and increases the vascular serum amyloid A (SAA) supply to the joint. Inflammatory and degenerative changes in the articular cartilage and adjoining tissues result in an increase of highly sulphated GAGs, which are considered to enhance deposition of SAA as amyloid.

A mare with colic caused by an ovarian tumour.

An 11-year-old Arabian mare had sudden signs of colic 10 days post partum. Rectal examination revealed a large mass in the abdomen. The mare was successfully operated on for a granulosa cell tumour of 31.5 kg. The large abdominal wound healed by primary intention.

[Viral hemorrhagic disease: an overview and personal data]. / Viral haemorrhagic disease: een overzicht en eigen bevindingen.

A review is given of current knowledge of taxonomy, clinical symptoms, pathogenesis and pathology, diagnosis, epizootiology and prevention of Viral Haemorrhagic Disease (VHD). We also report our own experiences with the (histo)pathology, laboratory diagnosis, and epizootiology of this disease. The frequency of other diagnoses in an eighteen months period.

[Postmortem findings in swine: non-selected submissions from hog cholera protection areas of 1992 versus selected submissions of 1991-1992]. / Sectiebevindingen bij varkens: niet-geselecteerde inzendingen uit varkenspest-beschermingsgebieden van 1992 versus geselecteerde inzendingen van 1991-1992.

This article presents a survey of death-causes of all spontaneously died pigs, n = 851, from a restricted area in the province of South Holland during a 2 1/2 months lasting hog-cholera epizoötic in 1992. 23 pigs from 5 submissions showed a positive IFT against hog-cholera virus. Those animals and pigs from sero-positive farms were excluded from this survey. The results of the post-mortems were compared with the post-mortem findings of the normally submitted, selected, animals in 1991 and 1992, n = 904 + 745, from the western parts of the Netherlands, in which the above mentioned province is situated. By means of classification of the animals in age-classes and of the post-mortem findings to disease or diseased organsystem, insight is gained in the prevalence of the various causes of death per age-class. No distinct differences were found between the findings in the groups of animals from 1991 and 1992. In the group of the hog-cholera-period comparatively more animals belonged to the neonatal and suckling period. In contrast to 1991-1992 the number of weaned and fattening pigs in the hog-cholera-group was lower. In both groups 40% of the death-causes was due to diseases of the digestive tract and 30% was a result of respiratory-tract infections. The third main cause of death in both groups was septicaemia and related diseases as endocarditis, pleuritis, peritonitis, polyserositis and polyarthritis. Comparison of the prevalence of infectious diseases per organsystem in successive age-classes demonstrated a similar tendency in the hog-cholera-group as in the year-groups 1991 and 1992.(ABSTRACT TRUNCATED AT 250 WORDS)

[Mortality of cattle following feeding of moldy flower bulbs]. / Sterfte van rundvee na het voederen van beschimmelde bloembollen.

Five of eight meat cattle died suddenly without showing prior symptoms of disease. The sudden death occurred in connection with the feeding of mouldy tulip bulbs. A short review is given of the use of flower bulbs as cattle feed, the use of herbicides/fungicides in bulb cultivation, and the relevant legislation. Several toxicological aspects that should be taken into consideration when flower bulbs are used as cattle feed are discussed. Both the Central Veterinary Institute and the State Institute for Public Health and Environmental Hygiene showed, in experiments with mice, the presence of a toxin in extracts of the mouldy tulip bulbs. This toxin is probably produced by moulds present in the tulip bulbs. The death of the animals was probably caused by an as yet unidentified mycotoxin.