Mark Wessels

Cryptosporidiosis in eight-month-old weaned alpacas

CRYPTOSPORIDIOSIS is a recognised cause of diarrhoea in preweaned alpacas, especially in crias less than three weeks of age (Waitt and others 2008). Published studies on the pathogens of crias with clinical diarrhoea describe the detection of Cryptosporidium species from 10 to 45 days of age (Cebra and others 2003), seven to 100 days (Whitehead and Anderson 2006) and six to 180 days (Waitt and others 2008). Here we report the detection of Cryptosporidium parvum as the cause of diarrhoea and death in eight-month-old weaned alpacas. In December 2012, the carcase of an eight-month-old female alpaca, belonging to a group of …

Histophilus somni myocarditis in a beef rearing calf in the United Kingdom

A severe, subacute to chronic, necrotising myocarditis was noted, characterised by multifocal to coalescing large areas of myocyte necrosis and degeneration surrounded and dissected by large numbers of neutrophils and leucocytoclastic debris, plus a moderate interstitial fibrinous exudate. Bordering these areas were moderate to large numbers of macrophages, lesser fibroblasts, neutrophils and degenerating/mineralised myocytes (Fig 1). Where lesions were subjacent to the endocardium there was full-thickness endocardial necrosis overlain by large, focally adherent thrombi. Moderate-sized bacterial colonies of Gram-negative coccobacilli with the morphology of Histophilus species were noted within areas of myocardial necrosis/inflammation. The sample of affected kidney showed multifocal, moderate to large areas of cortical lytic necrosis with large numbers of neutrophils and degenerate leucocytes, fibrin and haemorrhage within the interstitium. Tubules frequently contained cellular (neutrophilic) and necrotic cell casts plus fibrin, red blood cells and bacterial colonies. Occasional thrombosis of both medium and small blood vessels was noted. A severe, subacute, haemorrhagic and necrotising bronchointerstitial pneumonia consistent with that caused by H somni, Mannheimia haemolytica or Pasteurella multocida was present histologically. The clinical history and gross and microscopic findings in the bull are consistent with those previously described for H somni myocarditis (Jubb and Huxtable 1993, Moisan and Fitzgerald 1996, Radostits and others 2000). H somni can be isolated as a normal commensal from the mucous membranes of the bovine respiratory and reproductive tracts. The method of transmission and site of entry are unknown, but contact with infected secretions or by aerosol leading to mucosal colonisation and penetration is the likeliest route. Survival in the blood is facilitated by the ability of H somni to resist being killed by neutrophils, and to persist and multiply in blood monocytes (Harris and Janzen 1989). Once localised, it causes endothelial apoptosis, precipitating the clotting cascade and resulting in thrombosis and ischaemic necrosis, leading to the development of clinical signs (Sylte and others 2001). As such, the myocarditis and nephritis seen in the present case are likely to represent septicaemic dissemination. Myocardial localisation results in infarction, inflammation and abscess formation (commonly in the left ventricular free wall) leading to ventricular arrhythmias, cardiac failure and death (Jubb and Huxtable 1993). The production system and disease presentation in this case has some similarities to that seen in the feedlot situation in North America. Thrombotic meningoencephalitis was originally the most common manifestation of disease caused by H somni in North America, but recently myocarditis Histophilus somni myocarditis in a beef rearing calf in the United Kingdom

Sarcoptic mange in badgers in the UK.

WE would like to report the identification of sarcoptic mange in badgers ( Meles meles ) from south-west England. An adolescent female badger was received for postmortem examination, following the deaths of four other badgers in the same locality over a two-week period. All the affected badgers

Rickets in sheep flocks in northern England

SIR, — Rickets is a disease of the developing skeleton characterised by abnormal endochondral ossification and defective bone formation, most commonly caused by a deficiency of vitamin D or phosphorus. Although cases of rickets have been documented in weaned lambs with evidence of vitamin D

Systemic necrotizing polyarteritis in three weaned lambs from one flock

Systemic necrotizing polyarteritis was diagnosed in three 7–11-mo-old lambs from the same flock. Aneurysmal dilation and rupture of the gastroduodenal artery in 1 lamb resulted in fatal hemorrhage. All lambs had severe necrotizing vasculitis involving the small intestine, abomasum, mesentery, kidney, and heart with concurrent lymphocytic enteritis. Immunohistochemistry for T- and B-lymphocytes and macrophages found a T-cell– and macrophage-dominant transmural vascular infiltrate and T-cell–associated enteritis. PCR analysis for pestivirus failed to identify infection in 1 lamb, and more extensive viral microarray techniques applied to the second and third lamb failed to detect viral nucleic acid. The identification of 3 cases within 1 flock raises the possibility of a common etiology; however, no cause was established. A genetic etiology was not considered likely as not all of the lambs were related. The presence of concurrent T-lymphocyte–associated enteritis raises the possibility of an immune-mediated disease process linking the vasculitis and enteric lesions.

Intercurrent tickborne fever infection and Bibersteinia trehalosi septicaemia in a five-week-old lamb.

WE wish to report the findings of a postmortem examination carried out by the Wales Veterinary Science Centre (WVSC) at Aberystwyth. Lamb deaths began to occur, at a rate of one per day over a two-week period, in a 300-ewe flock grazing mountain pasture. A postmortem examination carried out at the local veterinary practice revealed a focal 3 cm diameter swelling on the spleen, and a lymphadenopathy affecting particularly the mesenteric lymph nodes. A test for clostridial toxins in small intestinal contents gave a negative result. A second lamb was then submitted to the WVSC. This was a well grown, five-week-old Welsh mountain lamb, which was found dead with no prior clinical signs. Postmortem findings included a spleen that was approximately three times the normal size, with fibrin tags attached to the splenic capsule. All lymph nodes were grossly enlarged, oedematous, and dark purple in colour, particularly the mediastinal and bronchial lymph nodes. The lungs were uniformly dark pink in colour and had a firm rubbery texture. Bacteriological examination of mediastinal lymph node and spleen produced a profuse pure growth of Bibersteinia trehalosi.....

GM2 Gangliosidosis in British Jacob Sheep

GM2 gangliosidosis (Tay-Sachs disease) was diagnosed in 6- to 8-month-old pedigree Jacob lambs from two unrelated flocks presenting clinically with progressive neurological dysfunction of 10 days to 8 weeks duration. Clinical signs included hindlimb ataxia and weakness, recumbency and proprioceptive defects. Histopathological examination of the nervous system identified extensive neuronal cytoplasmic accumulation of material that stained with periodic acid--Schiff and Luxol fast blue. Electron microscopy identified membranous cytoplasmic bodies within the nervous system. Serum biochemistry detected a marked decrease in hexosaminidase A activity in the one lamb tested, when compared with the concentration in age matched controls and genetic analysis identified a mutation in the sheep hexa allele G444R consistent with Tay-Sachs disease in Jacob sheep in North America. The identification of Tay-Sachs disease in British Jacob sheep supports previous evidence that the mutation in North American Jacob sheep originated from imported UK stock.

Idiopathic arterial aneurysm/rupture causing sudden death in dairy cattle

OVER the past decade we have seen cases of adult Holstein-Friesian cattle presented for postmortem examination with an acute fatal haemorrhage from a major artery. Since 2003, the Animal Health and Veterinary Laboratories Agency (AHVLA) has recorded 52 cases, with the greatest annual incidence in 2010 (16 cases), although increased awareness may be biasing recording. An increasing trend has been reported in North America, where there was an increase in the number of cases submitted for necropsy between 1980 and 2005 (Lamm and others 2007). Seventy-four cases of rupture of the cranial mesenteric or coeliac artery were recorded in the Netherlands from 2002 up to 2010 (K. Peperkamp, personal communication), three cases have been recorded in Scotland, one in Northern Ireland and two in the Irish Republic. There appears to be no marked seasonality in the cases, but more have …

Hepatic coccidiosis in red lechwe (Kobus leche leche).

HEPATIC coccidiosis is relatively common in rabbits but only rarely reported in other mammals, including goats, a calf, a dog, and mink (Mahmoud and others 1994, Schafer and others 1995, Oruc 2007). We would like to report two cases of hepatic coccidiosis in 12- to 18-month-old red lechwe (Kobus leche leche) in a mixed-aged herd of 74 animals from a zoological collection. The animals were submitted to Animal Health and Veterinary Laboratories Agency (AHVLA) – Preston for postmortem examination with a brief history of diarrhoea before death. Case 1 had multifocal 1 to 2 mm diameter white spots within the liver, which contained soft white purulent material, and the bile ducts showed multifocal/segmental moderate ectasia containing yellow purulent material and bile. Moderate catarrhal enteritis with a coccidial oocyst count of 62,200 opg was also …

Yersinia pseudotuberculosis as a cause of ocular disease in goats

YERSINIOSIS is a significant cause of disease in goats, causing enterocolitis, mesenteric lymphadenitis, septicaemia, placentitis/abortion and mastitis. It is also a zoonotic infection. In 1983 in New Zealand, McSporran reported ulcerative conjunctivitis with swelling of the ipsilateral parotid