Diseases and causes of death among alpacas in Sweden: a retrospective study.

BACKGROUND: Due to increasing popularity in Sweden during the last decade, alpacas are frequently encountered by practising veterinarians and pathologists. Knowledge regarding their health and diseases under Swedish conditions is, however, limited. OBJECTIVES: To improve knowledge about the health of alpacas in Sweden by collecting information on diseases and health status. DESIGN: A retrospective study was made of 93 necropsies conducted on alpacas in Sweden during the period 2001-2013. SETTING: Data were obtained from the two major veterinary pathology centres in Sweden. The alpacas were hobby or farm animals and they were submitted by veterinarians in local practices or at a national animal healthcare organisation. RESULTS: The digestive system was most frequently affected (29 per cent), with parasitic gastroenteritis (17 per cent) and hepatic disease being especially prevalent (15 per cent fascioliasis and 7 per cent hepatitis). Cardiovascular conditions (9 per cent), systemic diseases (7 per cent) and perinatal deaths were also common, including abortions (10 per cent) and fatal septicaemia (4 per cent). Wasting/emaciation was a frequent finding (26 per cent). Other diagnoses included dermatitis (8 per cent), diseases of the central nervous system (8 per cent), traumatic injuries (7 per cent), neoplasia (5 per cent), pneumonia (5 per cent) and nephritis (3 per cent). CONCLUSIONS: This study identified areas of concern regarding diagnostic and pathological procedures, for which specific measures have been recommended. One particular cause for concern was the number of deaths from emaciation in weanling alpacas during late winter or early spring. For adult alpacas, infectious and non-infectious causes of death were approximately equally frequent. Many of the diseases were considered clinically acute but pathology often showed them to be chronic conditions that had eventually deteriorated and presented as acute cases in the late stages. This study revealed similarities in the health/disease status reported in other European countries and in North America. The results can be used by alpaca keepers and veterinary practitioners to improve management, diagnosis and treatment of alpacas.

Occurrence of Treponema spp. in porcine skin ulcers and gingiva.

Porcine shoulder ulcers and ear necrosis are a significant animal welfare concern and impair efficient livestock production. Although spirochetes have been detected in both types of lesions the potential role of these bacteria in lesion propagation has received little attention. The objective of this study was to investigate the occurrence of spirochetes of the genus Treponema in shoulder ulcers or ear necrosis in pigs and compare these with treponemes from porcine gingiva. Samples were collected from gingiva and necrotic ulcers in 169 pigs. Presence of spirochetes was observed in silver stained histological sections and by phase contrast microscopy in scrapings from the necrotic lesions. Additionally, PCR of the 16SrRNA-tRNA(Ile) intergenic spacer region (ISR2) was used to detect Treponema spp. in all samples. Combined analysis showed that 73% of the shoulder ulcers and 53% of the ear necroses were positive for spirochetes. Treponema spp. were detected in 9.7% of the gingival samples. Comparative DNA sequence analysis of the ISR2 sequences revealed the presence of three distinct genetic phylotypes of Treponema spp. corresponding to Treponema pedis, and as yet two unnamed phylotypes represented by GenBank sequences C1UD1 (Acc. No. AY342041) and C1BT2-8 (Acc. No. AY342046). Detection of identical ISR2 sequences from gingiva and ulcer samples indicates that oral Treponema spp. are spread from mouth to ulcer. We conclude that Treponema spp. frequently occur in shoulder ulcers and ear necrosis in pigs, and suggest a possible infection route through biting and licking.

Classical swine fever: comparison of oronasal immunisation with CP7E2alf marker and C-strain vaccines in domestic pigs.

Effective oronasal vaccination against classical swine fever (CSF) is essential to achieve protection in wild boar. However the currently available live CSF vaccines, e.g. C-strain, do not allow serological differentiation between infected and vaccinated animals (DIVA). A modified live marker vaccine candidate (CP7E2alf) has been recently developed (Reimann et al., 2004). This communication reports the comparison of CP7E2alf and C-strain virus vaccines during 98 days following oronasal immunisation in domestic pigs. C-strain vaccine virus was consistently detected in tonsils of all (n=30) animals from 3 to 77 days post vaccination (dpv) and in blood (n=36) between 3 and 13dpv by CSFV-specific rRT-PCR. CP7E2alf virus RNA was detected in 6 animals slaughtered between 4 and 63dpv by a BVDV-specific rRT-PCR. The chimeric virus was not detected in blood samples. As detected by CSFV E2-specific antibody ELISA and virus neutralisation tests, seroconversion first occurred at 11dpv in the C-strain vaccinated group and between 11 and 15dpv in the CP7E2alf vaccinated group. The serological response was still present at 98dpv. The CP7E2alf serological response remained negative using the CSFV E(rns) ELISA whereas seroconversion occurred in the C-strain vaccinated group. In conclusion, the primary replication site of CP7E2alf vaccine virus was found to be the tonsils as in the C-strain and virulent field strains. Persistence of CP7E2alf in the tonsils was also demonstrated up to 63dpv. Both vaccines showed immunogenicity after oronasal administration in domestic pigs. In contrast to the C-strain, CP7E2alf vaccine allowed the use of DIVA approaches in serological tests. This study confirms CP7E2alf as a promising marker vaccine candidate for oronasal vaccination programmes to control CSF in domestic pigs and wild boar.

Comparative studies on the pathogenicity and tissue distribution of three virulence variants of classical swine fever virus, two field isolates and one vaccine strain, with special regard to immunohistochemical investigations.

BACKGROUND: The aim of this study was to compare the tissue distribution and pathogenicity of three virulence variants of classical swine fever virus (CSFV) and to investigate the applicability of various conventional diagnostic procedures. METHODS: 64 pigs were divided into three groups and infected with the highly virulent isolate ISS/60, the moderately virulent isolate Wingene'93 and the live attenuated vaccine strain Riems, respectively. Clinical signs, gross and histopathological changes were compared in relation to time elapsed post infection. Virus spread in various organs was followed by virus isolation, by immunohistochemistry, applying monoclonal antibodies in a two-step method and by in situ hybridisation using a digoxigenin-labelled riboprobe. RESULTS: The tissue distribution data are discussed in details, analyzing the results of the various diagnostic approaches. The comparative studies revealed remarkable differences in the onset of clinical signs as well as in the development of the macro- and microscopical changes, and in the tissue distribution of CSFV in the three experimental groups. CONCLUSION: The present study demonstrates that in the case of highly and moderately virulent virus variants the virulence does not affect the pattern of the viral spread, however, it influences the outcome, the duration and the intensity of the disease. Immunohistochemistry has the advantage to allow the rapid detection and localisation of the virus, especially in cases of early infection, when clinical signs are still absent. Compared to virus isolation, the advantage of this method is that no cell culture facilities are required. Thus, immunohistochemistry provides simple and sensitive tools for the prompt detection of newly emerging variants of CSFV, including the viruses of very mild virulence.

Post mortem findings in sows and gilts euthanised or found dead in a large Swedish herd.

BACKGROUND: The aim of this study was to get information on post mortem diagnoses of sows found dead or euthanised and to understand the diagnoses aetiology (causative background). Moreover, the study was to evaluate the association between the clinical symptoms observed on farm and post mortem findings. METHODS: A large Swedish herd was studied from January to September 2006. During the 32-week period 3.9% of the removed sows and gilts (old enough to be mated) were found dead, 12.0% were euthanised and the rest were sent to slaughter. Of 32 sows/gilts found dead 17 (53%) were post mortem examined, and of 98 sows euthanised 79 (81%) were examined. The 96 examined carcasses were after 70 sows and 26 gilts. The findings at examination were together with data from the herd monitoring program PigWin Sugg the base for the descriptive statistics presented. RESULTS: The average parity number at removal was 2.8 for those found dead and 2.1 for those euthanised. The highest number euthanised and found dead was in parity 0 (gilts). The main proportion of post mortem examinations was made on sows being in the period = 28 d of gestation at death (37.5%), followed by weaning to next service period (24.0%). Arthritis, with an incidence of 36.4% was the most common main finding of pathological-anatomical diagnosis (PAD). Of sows/gilts found dead were circulatory/cardiac failure (23.5%) and trauma related injuries (23.5%) most common PAD. The most commonly observed clinical symptom and reason for euthanasia of the sows/gilts was lameness. Notably, in 43% of the cases with PAD arthritis, the clinical symptoms suggested it being a fracture. Further one or more abscesses (38.5%) and teeth injuries (31.0%) were common findings when also incidental findings were included. CONCLUSION: This post mortem study based on carcasses from sows/gilts found dead or euthanised showed that arthritis was a significant problem in the studied herd and that post mortem examination was important to get proper diagnosis.

Phylogenetic analysis of porcine circovirus type 2 (PCV2) pre- and post-epizootic postweaning multisystemic wasting syndrome (PMWS).

The porcine circovirus type 2 (PCV2) genome encodes three major open reading frames (ORFs) encoding the replicase proteins (ORF1), the viral capsid protein (ORF2), and a protein with suggested apoptotic activity (ORF3). Previous phylogenetic analyses of complete genome sequences of PCV2 from GenBank have demonstrated 95-100% intra-group nucleotide sequence identity. However, although these isolates were readily grouped into clusters and clades, there was no correlation between the occurrence of specific PCV2 genotypes and the geographic origin or health status of the pig. In the present study, a unique dataset from a field study spanning the years pre and post the recognition of postweaning multisystemic wasting syndrome (PMWS) in Sweden was utilized. Using this dataset it was possible to discriminate three Swedish genogroups (SG1-3) of PCV2, of which SG1 was recovered from a pig on a healthy farm ten years before the first diagnosis of PMWS in Sweden. The SG1 PCV2/ORF2 gene sequence has been demonstrated to exhibit a high genetic stability over time and has subsequently only been demonstrated in samples from pigs on nondiseased farms. In contrast, SG2 was almost exclusively found on farms that had only recently broken down with PMWS whereas the SG3 genogroup predominated in pigs from PMWS-affected farms. These results further support the results obtained from earlier in vitro and in vivo experimental models and suggest the association of specific PCV2 genogroups with diseased and nondiseased pigs in the field.