D. F. Twomey

Assessment of antemortem tests used in the control of an outbreak of tuberculosis in llamas (Lama glama)

An outbreak of tuberculosis (TB) caused by Mycobacterium bovis in a llama herd is described. Over a 25-month period, a total of 70 llamas were selected for postmortem examination using four distinct criteria: clinical suspicion of disease (15 animals), positive tuberculin skin test result (three animals), antibody positive using a novel serological test (Rapid Test, 54 animals) and elective cull (five animals). Some animals qualified on more than one criterion. Gross lesions of TB were detected in 15 animals, with lung and lymph node lesions consistently observed. Samples were collected from 14 of 15 animals with visible lesions as well as those with no visible lesions, for histopathology and mycobacterial culture. All 14 llamas with visible lesions had caseonecrotic granulomatous lesions associated with acid-fast bacteria and variable mineralisation, and M bovis was isolated from 13. There were no histopathological lesions of TB in llamas with no grossly visible lesions, and M bovis was not isolated from any of these. The predictive value of suspicious gross lesions at postmortem examination was therefore high in the herd. Molecular typing results indicated that the outbreak was caused by a single strain likely to have originated from a local reservoir, probably cattle or wildlife. Antemortem indicators of infection assisted control of the outbreak, but no single test accurately identified all TB cases. Visible lesions were detected in nine of 15 llamas with clinical suspicion of disease, in two of three that had positive tuberculin skin test results and in 10 of 54 that were antibody positive; there was none (zero out of five) in llamas that were electively culled.

Cutaneous TB caused by Mycobacterium bovis in a veterinary surgeon following exposure to a tuberculous alpaca (Vicugna pacos)

TUBERCULOSIS (TB) is an infectious disease caused by members of the Mycobacterium tuberculosis complex, which includes Mycobacterium tuberculosis and Mycobacterium bovis , as well as other Mycobacterium species ([de la Rua-Domenech 2006][1]). M tuberculosis is the primary cause of TB in human beings

Phenotypic characterisation and 16S rRNA sequence analysis of veterinary isolates of Streptococcus pluranimalium

Forty-two isolates of Streptococcus pluranimalium were identified from cattle (n=38), sheep (n=2), an alpaca (n=1) and a pheasant (n=1) in the United Kingdom. The isolates were confirmed as S. pluranimalium by 16S rRNA sequence analysis but could not be differentiated reliably from Streptococcus acidominimus by phenotypic characterisation using commercial kits routinely used in veterinary laboratories. The alanyl-phenylalanyl-proline arylamidase reaction could be used to differentiate S. pluranimalium (positive) from Aerococcus urinae (negative).

Streptococcus bovis biotype I meningoencephalitis in an alpaca ( Lama pacos ) cria

STREPTOCOCCAL infections, in particular the Lancefield Group C Streptococcus equi subspecies zooepidemicus, have been reported in alpacas (Lama pacos) and other South American camelids (Fowler 1998). Group D streptococci such as Streptococcus bovis are less commonly recorded, possibly because they are considered to be opportunistic pathogens (Quinn and others 1994). S bovis bacteraemia has been described in human beings and is associated with gastrointestinal disease, particularly colonic neoplasia, as well as extracolonic malignancy (Gold and others 2004); S bovis meningitis has also been described (Grant and others 2000). Diseases associated with S bovis reported in other species include lactic acidosis or ‘grain engorgement’ of ruminants (Russell and Hino 1985, Gill and others 2000), septicaemia and meningitis in calves (Seimiya and others 1992), endocarditis in mink (Pedersen and others 2003) and septicaemia in pigeons (De Herdt and others 1992). This short communication describes a fatal case of infection with S bovis biotype I in an alpaca cria in the UK. A 10-day-old, 8·5 kg, male, homebred alpaca was found dead without premonitory clinical signs. This cria had been born in an uneventful outdoor parturition and its colostrum intake was considered to have been adequate. It had shared a paddock with 25 other alpacas, including five crias, which had unrestricted access to a shed where they were fed once daily. Two of the other crias had previously had diarrhoea, but no aetiologic diagnosis was made at the time. A total of 150 alpacas of various ages, from different sources, were present on the farm. Postmortem examination was performed the day after death and the carcase was found to be autolysed. The stomach compartments contained a mixture of fibrous material and semiclotted milk. The large intestinal contents were liquid but the rectum was empty. Other organ systems were grossly normal. Samples of brain, heart, lung, liver, kidney and small intestine were fixed in 10 per cent neutral-buffered formalin and processed to paraffin wax, and sections of 4 μm thickness were stained with haematoxylin and eosin. Sections of the brain were also stained using Gram’s technique. Aerobic culture on sheep blood agar of a meningeal swab yielded a pure growth of a Group D streptococcus. Biochemical testing using the API 20 Strep system (bioMerieux) identified the isolate as S bovis biotype I (Table 1). Aerobic culture of the large intestinal contents yielded a mixed bacterial growth, including streptococci, but exact identification was not undertaken. Clostridium perfringens exotoxins were not identified by ELISA testing of small intestinal filtrate. Rotavirus antigen was detected by polyacrylamide gel electrophoresis (PAGE) testing of large intestinal contents. Neither cryptosporidia nor coccidia were identified on parasitological examination. On histopathological examination of the brain (cerebrum, cerebellum, pons and medulla), diffuse meningeal infiltration with predominantly neutrophils and macrophages, interFIG 1: Diffuse purulent meningitis in a sulcus, with extension into the superficial cortex and focal perivascular cuffing, in the cerebrum of an alpaca. Haematoxylin and eosin. x 100

Salmonella serovars and antimicrobial resistance patterns on a sample of high seroprevalence pig farms in England and Wales (2003-2008).

Following the introduction of a national abattoir‐based monitoring programme for Salmonella in pigs, advisory visits were made to pig farms in England and Wales with high Salmonella seroprevalence assessed by muscle tissue fluid (meat juice) ELISA. Samples (n = 15 790), including pooled pen floor faeces (n = 12 136), were collected for Salmonella culture from 296 farms, between October 2003 and February 2008. Salmonella was isolated from 4489 (28%) of all samples collected, including 3301 (27%) of pooled pen floor faecal samples, from 270 (91%) of farms visited. Salmonella Typhimurium and S. Derby were the most prevalent serovars, representing 64% and 16% of isolates serotyped, respectively. The main phage types of S. Typhimurium identified were U288 and DT193. Antimicrobial resistance (AMR) was seen in 92% of isolates tested, with the highest frequencies of resistance occurring to tetracyclines (T), sulphonamide compounds (SU), ampicillin (AM), sulphamethoxazole/trimethoprim (SXT), streptomycin (S) and chloramphenicol (C). Fifty‐nine AMR patterns were observed, the most frequent of these being T, AM, SXT, C, S, SU, seen in 35% of isolates tested. Multi‐drug resistance was commonly found, with 67% of isolates submitted for AMR testing showing resistance to between four and nine antimicrobials.

Association between biosecurity and Salmonella species prevalence on English pig farms.

BIOSECURITY is the implementation of preventive measures to avoid the introduction and contain the spread of infections and diseases on farms ([Casal and others 2007][1]). Although a wide variety of biosecurity measures are applied on pig farms, there is a paucity of research documenting the impact

Multisystemic necrotising vasculitis in a pygmy goat (Capra hircus).

tion. A sample of small intestinal contents was collected to test for Clostridium perfringens exotoxins by ELISA (Naylor and others 1987, 1997, Martin and others 1988). A sample of kidney was collected for lead analysis by flame atomic absorption spectroscopy. Samples of kidney, liver, lung, cerebral cortex, pons, medulla and cerebellum were fixed in 10 per cent neutral buffered formalin, dehydrated using increasing concentrations of alcohol, cleared with xylene and embedded in paraffin wax. Sections of 4 μm thickness were cut and stained with haematoxylin and eosin for histopathological examination. No bacteria were isolated from the brain or lung. Examination of the small intestinal contents for C perfringens exotoxins gave a positive ELISA result for alpha toxin and negative ELISA results for beta and epsilon toxins. Lead was not detected in the kidney sample. At histopathological examination, lesions of subacute necrotising vasculitis were identified in all the tissues examined, but were most severe in the kidney. Vasculitis was characterised by infiltration of the blood vessel walls, mainly by mononuclear cells (Figs 1, 2), with fibrinoid necrosis of some affected vessels. Moderate interstitial mononuclear nephritis, with hyaline material in the tubule lumina and Bowman’s capsules, were found in kidney samples. All levels of the brain examined revealed perivascular cuffing with mononuclear cells, focal gliosis and mild non-suppurative meningitis. In the liver, increased mononuclear cellularity within portal areas was evident, and in the lung extensive Multisystemic necrotising vasculitis in a pygmy goat (Capra hircus)

Confirmation of the chewing louse, Bovicola breviceps, in a British llama (Lama glama) herd.

LOUSE species identified on South American camelids include the chewing or biting louse, Bovicola ( Damalinia ) breviceps , and the sucking lice, Microthoracius species ([Fowler 1998][1]). Although B breviceps has anecdotally been identified in Great Britain ([Duff and others 1999][2]), specimens

Review of laboratory submissions from New World camelids in England and Wales (2000-2011).

Sample submissions to the Animal Health and Veterinary Laboratories Agencys (AHVLAs) diagnostic laboratory network in England and Wales were reviewed for diseases affecting New World camelids (NWCs). In the years 2000-2011, 6757 submissions were analysed, including 5154/6757 (76.3%) for diagnosing a disease problem and 1603/6757 (23.7%) for monitoring (no clinical disease). Wasting (weight loss, ill-thrift) was the most commonly reported clinical sign across all age groups. A diagnosis was reached for 1765/5154 (34.2%) diagnostic submissions. The proportion of submissions with diagnoses was higher for carcasses than non-carcass samples and multiple diagnoses were more likely to be reached from carcasses. Parasitic diseases were collectively the most common problem, including parasitic gastroenteritis (319/1765, 18.2%), coccidiosis (187/1765, 10.6%), fascioliasis (151/1765, 8.6%), ectoparasitic infestations (86/1765, 4.9%) and cryptosporidiosis (24/1765, 1.4%). The most frequently diagnosed non-parasitic problems included nutritional diseases (182/1765, 10.3%), septicaemia (104/1765, 5.9%, including 45 cases of colisepticaemia), gastric ulceration (79/1765, 4.5%), tumours/neoplastic diseases (65/1765, 3.7%), tuberculosis (57/1765, 3.2%), clostridial diseases (44/1765, 2.5%), congenital anomalies (41/1765, 2.3%), peritonitis (39/1765, 2.2%) and Johnes disease (20/1765, 1.1%).

Concurrent coccidiosis and listeriosis in a Bennett's wallaby (Macropus rufogriseus).

COCCIDIOSIS is a recognised cause of protozoal enteritis in macropods, which has been mostly reported in young kangaroos ([Winter 1959][1], [Barker and others 1963][2], [Barker and others 1972][3], [Mykytowycz 1964][4], [Budiarso and others 1971][5], [Finnie 1974][6], [Thiruthalinathan and others