Detection of bovine herpesvirus type 4 antibodies and bovine lymphotropic herpesvirus in New Zealand dairy cows

AIM: To detect the presence of bovine herpesvirus (BoHV) type 4 in New Zealand dairy cows with clinical metritis.

METHODS: Serum samples taken from 92 dairy cows with clinical metritis, each from a different farm, were tested for the presence of antibodies against BoHV-4 using a commercially available, indirect ELISA. Peripheral blood mononuclear cells (PBMC) were collected from 10 BoHV-4 seropositive cows, and PBMC were examined by a pan-herpesvirus nested PCR to detect herpesvirus. PCR products were sequenced directly and a proportion of the PCR products were cloned and sequenced to identify the virus present.

RESULTS: Antibodies to BoHV-4 were detected in 23/92 (25%) serum samples. The pan-herpesvirus PCR was positive in 8/10 PBMC samples. Cloning and sequencing identified that all of the eight PCR-positive PBMC contained bovine lymphotropic herpesvirus (BLHV); no BoHV-4 DNA was detected.

CONCLUSIONS: This study reports the finding of the presence of apparent antibodies to BoHV-4, and BLHV DNA in New Zealand dairy cows affected by metritis.

CLINICAL RELEVANCE: Bovine herpesvirus type 4 and BLHV are reported to have the potential to cause reproduction failure in cows. This is the first report of apparent BoHV-4 antibodies, and BLHV in New Zealand. The importance and epidemiology of these viruses in cattle in New Zealand requires further investigation.     

Experimental tuberculosis in red deer (Cervus elaphus)

This study was designed to investigate experimental Mycobacterium bovis infection of red deer (Cervus elaphus). Three intravenously inoculated deer (dose 10µg–1000µg) developed miliary tuberculosis of the lungs and all died within 28 days of being infected. No clinical illnesses were observed in four subcutaneously (dose 1 uµg–100uµg) and three intratracheally (dose lµg–100µg) inoculated deer. At the conclusion of the experiment six weeks post inoculation, these seven animals reacted to 2 mg/ml of bovine purified protein derivative. The principal lesions in the intravenously inoculated deer were in the lungs which had multiple foci of necrosis containing very large numbers of acid fast bacilli. A gradation of changes was seen in the subcutaneously inoculated deer. The animal receiving the 1µg dose only had lesions at the injection site and the draining prescapular lymph node. Deer receiving higher doses also had histopathological changes in the lungs and liver. Microscopic changes in the intratracheally infected animals were restricted to the thoracic cavity. The ability of the deer to control infection was related to the route of inoculation.     

Equine multisystemic eosinophilic epitheliotropic disease: A case report and review of literature

CASE HISTORY: A 2-year-old Standardbred gelding presented with a history of fever over 1 week, anorexia and skin lesions on all four legs. The lesions were associated with severe pruritus and oedema, and there was no response to therapy.

CLINICAL FINDINGS: The horse was in poor body condition, was lethargic and severely pruritic. Skin lesions consisted of diffuse alopecia and crusting of the distal extremities. Initially it was slightly febrile, but subsequently its temperature increased up to 40°C. Ten days after admission it developed profuse watery diarrhoea and the skin lesions progressed. Skin biopsies revealed superficial and deep perivascular dermatitis with lymphoplasmacytic and eosinophilic predominance. Based on the poor prognosis the horse was subject to euthanasia.

PATHOLOGICAL FINDINGS: The most notable lesions included ulcerative gastritis, typhlitis and colitis with prominent oedema of the intestines, marked subcutaneous oedema and severe thickening of the large bile ducts. Histopathology showed marked eosinophilic and lymphoplasmacytic infiltration of various tissues including the skin, gastrointestinal tract, mesenteric lymph nodes, large bile ducts, pancreatic duct and kidney. Immunohistochemistry revealed a clear predominance of CD3-positive cells in the lymphocytic infiltrations.

DIAGNOSIS: Based on the clinical findings and histopathology a diagnosis of multisystemic eosinophilic epitheliotropic disease (MEED) was made.

CLINICAL RELEVANCE: Multisystemic eosinophilic epitheliotropic disease is rare in horses, and usually chronic. In the current case the horse showed an apparently acute onset with high fever and rapid clinical deterioration. A diagnosis of MEED should be considered in horses presenting with weight loss and skin lesions with or without fever. A final diagnosis is based on histological results of biopsy specimens from affected organs.     

Heat stress as a manageable risk factor to mitigate pneumonia in lambs

Abstract

Extract

The paper by Goodwin et al (2004 Goodwin, KA, Jackson, R, Brown, C, Davies, PR, Morris, RS and Perkins, NR. 2004. Pneumonic lesions in lambs in New Zealand: patterns of prevalence and effects on production. New Zealand Veterinary Journal, 52: 175–9. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) which appeared in the August 2004 issue of the New Zealand Veterinary Journal highlighted the prevalence and costs to the sheep industry of pneumonia in lambs. The costs are considerable, and the article begs the question, “what can sheep farmers do to reduce the effects of pneumonia in lambs?”     

A herd fertility progamme for dairy cattle and computerized data processing

The data involved, and the steps taken, in establishing a fertility control programme are discussed. The incorporation of this fertility control programme into a computer programme is described. This involves the processing of data on reproduction (on calving, oestrus, insemination and pregnancy diagnosis) by computer system. This programme is designed to provide the dairy farmers with information to facilitate herd management. Thus, each month the farmer is sent an advisory list stating which cows should be inseminated, which should be dried off, and those expected to calve. In addition, he will receive a bi-annual report on the fertility status of his herd. Among others, the following terms are listed: the pregnancy rate after first insemination, the interval between parturition and first insemination, the interval between parturition and conception, the number of inseminations per conception and the number of cows culled through failure to conceive. The initial results and advantages of operating such a programme are given.     

Behaviour of early-weaned calves in indoor individual cubicles and group pens

Extract

Units have been designed to house calves for veal production, but only recently has a large intensive unit been designed to rear surplus dairy-bred calves for beef production in New Zealand. This was built by the Rangitaiki Plains Dairy Company, Edgecumbe, early in 1973 and consisted of two types of housing: a fully enclosed and insulated calf house with 500 individual cubicles in which to rear the animals till weaning at 5 weeks of age, and a “loafing barn” with slatted walls and sawdust floor to house calves for a further 5 weeks before sale as beef weaners.     

Deletion of the GI-2 integrase and the wbkA flanking transposase improves the stability of Brucella melitensis Rev 1 vaccine

Brucella melitensis Rev 1 is the best vaccine available for the prophylaxis of small ruminant brucellosis and, indirectly, for reducing human brucellosis. However, Rev 1 shows anomalously high rates of spontaneous dissociation from smooth (S) to rough (R) bacteria, the latter being inefficacious as vaccines. This S-R instability results from the loss of the O-polysaccharide. To overcome this problem, we investigated whether some recently described mechanisms promoting mutations in O-polysaccharide genes were involved in Rev 1 S-R dissociation. We found that a proportion of Rev 1 R mutants result from genome rearrangements affecting the wbo O-polysaccharide loci of genomic island GI-2 and the wbkA O-polysaccharide glycosyltransferase gene of the wbk region. Accordingly, we mutated the GI-2 int gene and the wbk IS transposase involved in those arrangements, and found that these Rev 1 mutants maintained the S phenotype and showed lower dissociation levels. Combining these two mutations resulted in a strain (Rev 2) displaying a 95% decrease in dissociation with respect to parental Rev 1 under conditions promoting dissociation. Rev 2 did not differ from Rev 1 in the characteristics used in Rev 1 typing (growth rate, colonial size, reactivity with O-polysaccharide antibodies, phage, dye and antibiotic susceptibility). Moreover, Rev 2 and Rev 1 showed similar attenuation and afforded similar protection in the mouse model of brucellosis vaccines. We conclude that mutations targeting genes and DNA sequences involved in spontaneous O-polysaccharide loss enhance the stability of a critical vaccine phenotype and complement the empirical stabilization precautions taken during S Brucella vaccine production.