S. F. E. Scholes

Lack of evidence for circovirus involvement in bovine neonatal pancytopenia

THE newly described syndrome of bovine neonatal pancytopenia (BNP) (previously known as idiopathic haemorrhagic diathesis or bleeding calf syndrome), reported in the UK by [Penny and others (2009)][1], has caused considerable animal health and welfare interest across Europe. The detection in calves

Coccidiosis in British alpacas (Vicugna pacos)

SEVERE intestinal disease associated with Eimeria punoensis, Eimeria lamae, Eimeria alpacae, Eimeria macusaniensis and Eimeria ivitaensis has been observed in South American camelids in the Americas and Australia (Guerrero and others 1971, Rosadio and Ameghino 1994, Cebra and others 2003, Lenghaus and others 2004, Palacios and others 2006). However, there is conflicting information about the pathogenicity of the various camelid Eimeria species. Experimental infection of one-month-old llama crias with E macusaniensis did not result in disease (Rohbeck and others 2003), whereas experimental infection of a six-month-old naive alpaca cria with E lamae resulted in haemorrhagic ileitis with diarrhoea, and death (Guerrero and others 1970). This short communication describes a case of coccidiosis in a 16-month-old, UK-born alpaca. The animal had been purchased at an auction four weeks previously, and was reported to have been found dead after a short period of restlessness. At postmortem examination, severe necrotising enteritis was observed (Fig 1). Histological examination of the small intestine detected multiple clumps of eosinophilic material on the mucosal surface, loss of enterocytes associated with large numbers of coccidial structures in the crypt epithelium, lamina propria and, less frequently, submucosa, including immature schizonts, macrogametes with up to 10 round, variably sized, eosinophilic inclusions, and pearshaped oocysts approximately 60 to 75 μm in length (Fig 2). Gram-positive, rod-shaped bacteria were present on the luminal surface. Faecal coccidial counts revealed 3450 oocysts per gram of faeces, subsequently speciated as 91 per cent E macusaniensis, 3 per cent E alpacae and 3 per cent E lamae. Clostridium perfringens α toxin was identified by ELISA in the small intestinal filtrate. The loss of architecture associated with the large numbers of coccidial structures in superficial as well as deep layers of the mucosa strongly suggested that the Eimeria species had caused disruption of the intestinal lining, predisposing to clostridial enterotoxaemia. Prompted by this confirmed case of coccidiosis in an adult alpaca, a review of Veterinary Investigation Diagnosis Analysis data and material received at Veterinary Laboratories Agency – Lasswade between 1999 and 2004 identified 54 recorded cases of coccidial infection in alpacas. Of the 35 animals where the age was recorded, six were crias less than two months of age, 14 were juveniles (two to 11 months) and 15 were adults (one year and older) (Table 1). In 19 cases where clinical signs had been recorded, they included diarrhoea in six cases, weight loss in six, death in five, nervous signs in one and sudden-onset weakness in one. Congestion of the small intestine was commonly observed, with some cases showing marked thickening of the enteric mucosa. Variable numbers of coccidial structures were seen in small intestinal tissue sections. Concomitant findings in 19 cases where details were recorded included bacterial enteritis in nine cases, hepatic lipidosis in five and paracentral necrotisVeterinary Record (2007) 160, 805-806

A novel astrovirus associated with encephalitis and ganglionitis in domestic sheep

In June 2013, a 4-year-old Welsh Mountain ewe and in March 2014 a 10-day-old lamb of the same breed and the same flock presented progressive neurological signs including depressed sensorium, tremor, and unusual behaviour. Neuropathological examination of the brain and spinal cord detected non-suppurative polioencephalomyelitis and dorsal root ganglionitis, characteristic of a neurotropic viral agent in both sheep. Metagenomic analysis of different tissue samples from both animals identified a novel Ovine Astrovirus (OvAstV). The presence of viral genome in the central nervous system was confirmed by RT-qPCR. Although the cases presented nine months apart, the identified OvAstV shared nearly identical sequences, differing in only three nucleotide positions across the complete genome. Phylogenetic analysis revealed a close relation of OvAstV to neurotropic bovine astroviruses and an enteric OvAstV. In conclusion, these are the first reported cases of astrovirus infection in domestic sheep that were associated with encephalitis and ganglionitis.

Factors Associated with Bovine Neonatal Pancytopenia (BNP) in Calves: A Case-Control Study

Bovine neonatal pancytopenia (BNP; previously known as idiopathic haemorrhagic diathesis and commonly known as bleeding calf syndrome) is a novel haemorrhagic disease of young calves which has emerged in a number of European countries during recent years. Data were retrospectively collected during June to November 2010 for 56 case calves diagnosed with BNP between 17 March and 7 June of the same year. These were compared with 58 control calves randomly recruited from herds with no history of BNP. Multivariable logistic regression analysis showed that increased odds of a calf being a BNP case were associated with its dam having received PregSure® BVD (Pfizer Animal Health) vaccination prior to the birth of the calf (odds ratio (OR) 40.78, p<0.001) and its herd of origin being located in Scotland (OR 9.71, p = 0.006). Decreased odds of a calf being a BNP case were associated with the calf having been kept outside (OR 0.11, p = 0.006). The longer that a cattle herd had been established on the farm was also associated with decreased odds of a calf in that herd being a BNP case (OR 0.97, p = 0.011).

Congenital tremor and hypomyelination associated with bovine viral diarrhoea virus in 23 British cattle herds

This paper presents data from 23 British herds investigated between 1991 and 2007 where neurological disease in calves was caused by bovine viral diarrhoea virus (BVDV) infection. A variety of clinical signs, most commonly tremor or trembling, were apparent in the calves from birth, and most were recumbent or unable to stand unsupported. Severe diffuse neuraxial hypomyelination was present in all of the calves, and immunohistochemistry revealed cerebral neuronal labelling consistent with congenital persistent pestivirus infection in each brain. BVDV was detected in peripheral blood samples from eight of 15 calves tested using an antigen ELISA, and was isolated in culture from samples of viscera, brain or blood collected from 17 of 24 affected calves. TaqMan RT-PCR for pestivirus RNA was positive for BVDV-1 in all six calves tested. Six of the virus isolates on which molecular classification was carried out, obtained from calves in four of the herds, were identified as BVDV-1a, while three isolates from one affected and two unaffected calves on a fifth farm were confirmed as BVDV-1b.

Mycoplasma bovis isolated from brain tissue of calves

SIR, — We wish to report two separate cases of Mycoplasma bovis isolation from brain tissue of calves at veterinary diagnostic laboratories in England and Ireland. To our knowledge this is the first report of the isolation of M bovis from brain tissue of cattle in Britain or Ireland. The English

Reproduction of bovine neonatal pancytopenia (BNP) by feeding pooled colostrum reveals variable alloantibody damage to different haematopoietic lineages

Bovine neonatal pancytopenia (BNP) is a recently described haemorrhagic disease of calves characterised by thrombocytopenia, leucopenia and bone marrow depletion. Feeding colostrum from cows that have previously produced a BNP affected calf has been shown to induce the disease in some calves, leading to the hypothesis that alloantibodies in colostrum from dams of affected calves mediate destruction of blood and bone marrow cells in the recipient calves. The aims of the current experimental study were first to confirm the role of colostrum-derived antibody in mediating the disease and second to investigate the haematopoietic cell lineages and maturation stages depleted by the causative antibodies. Clinical, haematological and pathological changes were examined in 5 calves given a standardised pool of colostrum from known BNP dams, and 5 control calves given an equivalent pool of colostrum from non-BNP dams. All calves fed challenge colostrum showed progressive depletion of bone marrow haematopoietic cells and haematological changes consistent with the development of BNP. Administration of a standardised dose of the same colostrum pool to each calf resulted in a consistent response within the groups, allowing detailed interpretation of the cellular changes not previously described. Analyses of blood and serial bone marrow changes revealed evidence of differential effects on different blood cell lineages. Peripheral blood cell depletion was confined to leucocytes and platelets, while bone marrow damage occurred to the primitive precursors and lineage committed cells of the thrombocyte, lymphocyte and monocyte lineages, but only to the more primitive precursors in the neutrophil, erythrocyte and eosinophil lineages. Such differences between lineages may reflect cell type-dependent differences in levels of expression or conformational nature of the target antigens.

Clostridium perfringens type D epsilon intoxication in one-day-old calves

Clostridium perfringens type D enterotoxaemia, or ‘pulpy kidney disease’, is a very common cause of sudden death in sheep worldwide. There are numerous scientific publications on the epidemiology and pathology of enterotoxaemia in sheep; in contrast, there have been few studies of type D

Clostridium perfringens type D enterotoxaemia in neonatal lambs.

SIR, — Ovine enterotoxaemia caused by Clostridium perfringens type D occurs most commonly in lambs at four to 10 weeks of age and in finishing lambs of six months and older, often associated with increased amounts of dietary carbohydrate ([Lewis 2000][1]). Here we report the results of examination

Bluetongue virus serotype 8-associated hydranencephaly in two calves in south-eastern England

DEVELOPMENTAL lesions of the central nervous system (CNS) have been described associated with transplacental infection with bluetongue virus (BTV) in cattle ([MacLachlan and others 1985][1]) and sheep ([Osburn 1972][2]). In the past, the development of these deformations was mostly associated with