This article describes the nucleotide sequence of a porcine circovirus (PCV) which possesses a high degree of association with postweaning multisystemic wasting syndrome (PMWS), a newly described disease of young pigs. The DNA sequence of this PMWS-associated PCV (pmws PCV) has 68% homology with that of a previously published nonpathogenic strain of PCV. The strains appear to be closely related yet distinct from one another.

Cesarean-derived, colostrum-deprived pigs (n = 23) were inoculated intranasally and subcutaneously with a low cell culture passage of type 2 porcine circovirus. In 11 pigs, a persistent fever that lasted 7-17 days began 12-15 days after inoculation with virus. Additional signs of disease in those 11 pigs included depression (11 of 11 pigs), palpable enlargement of inguinal, prefemoral, and popliteal lymph nodes (11 of 11), icterus (6 of 11), and hyperpnea (2 of 11). The remaining 12 pigs had fever that occurred intermittently for 2-4 days between days 12 and 20 postinoculation. Overt signs of disease in those pigs were limited to palpable enlargement of inguinal and popliteal lymph nodes (9 of 12 pigs). When compared with control pigs of similar age, the average daily rate of weight gain for all pigs inoculated with virus was less over a 2-week period that began 2 weeks post inoculation. At postmortem examination, lymph node enlargement was seen in 14 of 14 pigs euthanized between days 20 and 28 postinoculation. Lymph node enlargement was especially prominent in pigs that developed a persistent fever. Microscopic lesions noted in pigs that developed a persistent fever included cellular depletion in lymphoid tissues; hepatic cell necrosis; and lymphogranulomatous inflammation of lymph nodes, Peyer's patches of the intestine, liver, kidney, and heart. Virus was isolated with varying frequency from nasal, rectal, or tonsil swab specimens, buffy coat, serum, urine, and lung lavage fluid obtained antemortem or postmortem. Virus was isolated from or viral DNA was detected in a variety of tissues obtained postmortem up to 125 days postinoculation. Antibody against type 2 porcine circovirus usually was detected in serum between 15 and 20 days postinoculation; however, antibody against virus was not detected in serum from 4 pigs euthanized 20-24 days postinoculation. Direct contact with pigs inoculated with virus 42 days previously resulted in transmission of virus to 3 of 3 control pigs.

The utility of the VecTest antigen-capture assay to detect West Nile virus (WNV) in field-collected dead corvids was evaluated in Manitoba and Ontario, Canada, in 2001 and 2002. Swabs were taken from the oropharynx, cloaca, or both of 109 American Crows, 31 Blue Jays, 6 Common Ravens, and 4 Black-billed Magpies from Manitoba, and 255 American Crows and 28 Blue Jays from Ontario. The sensitivity and specificity of the antigen-capture assay were greatest for samples from American Crows; oropharyngeal swabs were more sensitive than cloacal swabs, and interlaboratory variation in the results was minimal. The sensitivity and specificity of the VecTest using oropharyngeal swabs from crows were 83.9% and 93.6%, respectively, for Manitoba samples and 83.3% and 95.8%, respectively, for Ontario birds. The VecTest antigen-capture assay on oropharyngeal secretions from crows is a reliable and rapid diagnostic test that appears suitable for incorporation into a WNV surveillance program.

Crohn's disease may be triggered by an infection, and it is plausible to consider that such an infection may be animal borne and ingested with our food. There has been considerable interest in the past in determining whether Mycobacterium avium subsp. paratuberculosis (M. avium) might be the etiologic agent in Crohn's disease since it causes a disease in cattle that is similar to Crohn's disease in humans. We aimed to determine if there was an association between Crohn's disease and infection with M. avium or other zoonotic agents and compared the findings with those for patients with ulcerative colitis, unaffected siblings of Crohn's disease patients, or population-based controls without inflammatory bowel disease. Patients under age 50 years with Crohn's disease or ulcerative colitis, unaffected siblings of patients, or healthy controls drawn from a population-based age-and gender-matched registry were enrolled in a study in which subjects submitted to a questionnaire survey and venipuncture. A nested cohort underwent colonoscopy plus biopsy. Samples were batched and submitted to PCR for the detection of M. avium and other zoonotic agents known to cause predominately intestinal disease in cattle, sheep, or swine. Only one patient with ulcerative colitis, no patients with Crohn's disease, and none of the sibling controls were positive for M. avium, whereas 6 of 19 healthy controls were positive for M. avium. Since the control subjects were significantly older than the case patients, we studied another 11 patients with inflammatory bowel disease who were older than age 50 years, and another single subject with ulcerative colitis was positive for M. avium. One other subject older than age 50 years with ulcerative colitis was positive for circovirus, a swine-borne agent of infection. In conclusion, by performing PCR with mucosal samples from patients with Crohn's disease and controls, no association between Crohn's disease and infection with M. avium or any of the other six zoonotic agents studied could be found.

This is the first published report of a PCR assay for detecting porcine cytomegalovirus (PCMV), the causative agent of inclusion body rhinitis in pigs. The DNA to be tested was extracted directly from lungs and nasal scrapings of pigs with various clinical syndromes. Fifty-nine percent (74 of 126) of tested pigs with various clinical syndromes were found to be PCR positive for PCMV. It is hoped that veterinary diagnostic laboratories will benefit by using this PCR assay for routine testing and surveillance of PCMV in pigs.

Abstract.A commercially available blocking ELISA was analyzed for its ability to identify antibodies to porcine coronaviruses (transmissible gastroenteritis virus [TGEV] or porcine respiratory coronavirus [PRCV]), to differentiate antibodies to TGEV and PRCV, and to identify TGEV-infected herds. Nine sera from uninfected pigs, 34 sera from 16 pigs experimentally infected with TGEV, and sera from 10 pigs experimentally infected with PRCV were evaluated using both the TGEV/PRCV blocking ELISA and a virus neutralization (VN) assay. The ELISA was not consistently effective in identifying pigs experimentally infected with TGEV until 21 days postinfection. Sera from 100 commercial swine herds (1,783 sera; median 15 per herd) were similarly evaluated using both tests. Thirty of these commercial herds had a clinical history of TGEV infection and a positive TGEV fluorescent antibody test recorded at necropsy within the last 35 months, while 70 herds had no history of clinical TGEV infection. The blocking ELISA and the VN showed good agreement (kappa 0.84) for the detection of porcine coronavirus antibody (TGEV or PRCV). The sensitivity (0.933) of the ELISA to identify TGEV-infected herds was good when considered on a herd basis. The ELISA was also highly specific (0.943) for the detection of TGEV-infected herds when the test results were evaluated on a herd basis. When sera from specific age groups were compared, the ELISA identified a greater proportion (0.83) of pigs in herds with TGEV antibody when suckling piglets were used. In repeatability experiments, the ELISA gave consistent results when the same sera were evaluated on different days (kappa 0.889) and when sera were evaluated before and after heating (kappa 0.888). The blocking ELISA was determined to be useful for herd monitoring programs and could be used alone without parallel use of the VN assay for the assessment of large swine populations for the detection of TGEV-infected herds.

We describe a simple method for the rapid detection of bovine viral diarrhea virus (BVDV) that uses a one-tube reverse transcription PCR (RT-PCR) and total RNA extracted directly from a variety of bovine specimens, including whole blood and tissues. Reagents for both RT and PCR were combined in a one-tube, single-buffer system, and amplification was performed with a single uninterrupted thermal cycling program. Using the novel cationic surfactant tetradecyltrimethylammonium oxalate (Catrimox-14), we consistently extracted RT-PCR-quality RNA from specimens containing blood. Amplification with primers derived from conserved sequences within the BVDV 5-untranslated region yielded a 244-bp product. Assay specificity was confirmed by ethidium bromide-stained gel electrophoresis and by chemiluminescence-assayed Southern blot hybridizations involving BVDV 5-untranslated region-specific digoxigenin-labelled cDNA probes. The assay detection level was 0.1 50% tissue culture infectious dose of BVDV when ethidium bromide-stained gel electrophoresis was used and 0.01 50% tissue culture infectious dose of BVDV when Southern blot hybridization was used. Our method is an alternative to the conventional cell culture assays used in a diagnostic laboratory and is an improvement over existing RT-PCR assays for BVDV.

The Salmonella status of 15 different farm flocks was assessed at the farm level and at processing plants. Bacteriological examination for Salmonella was made of litter, dust, feed, 5-day-old culled chicks, and chicken carcasses. Fresh straw litter was found contaminated with Salmonella and may be a source of flock infection. Culture of floor litter can be a practical method for detecting flock infection, and culture of 6-weeks litter in particular would be a good indicator of carcass contamination at processing plants. Properly pelleted feed did not contain Salmonella. Processing did not render carcasses free of Salmonella.