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Summary

Rapid and accurate detection of a virus in a population is a critical factor in the eventual treatment and/or control of the virus. In this study, we examined use of the polymerase chain reaction (pcr) to detect swine influenza virus in nasal swab specimens from infected pigs. This approach was first standardized, using viral rna purified by guanidinium/phenol-chloroform extraction and placed in the same transport medium as the swabs. By using highly conserved primers for the swine H1 hemagglutinin, we amplified a 591-base pair fragment that was analyzed by use of agarose gel electrophoresis, Southern blot, and dna sequencing.

To evaluate pcr as a potential diagnostic tool for detection of swine influenza virus infection, we obtained nasal swab specimens from experimentally infected pigs. Amplification by pcr and reamplification of extracted samples with internal primers yielded detectable bands for an amount of virus less than that required to infect embryonating chicken eggs. We also tested swab specimens from pigs involved in 3 separate, natural episodes of swine influenza. These swab specimens were extracted, amplified and reamplified, producing visible bands on the gel and in Southern blots. We performed Southern blot analyses on all pcr products, to confirm that they were from viral H1 rna. We also cloned and sequenced a 591-base pair product from 1 specimen and found that it was 100% identical to the hemagglutinin gene sequence of A/Sw/Ind/1726/88. Results indicate that pcr can be used to detect swine influenza virus, even in nasal swab specimens, the specimen typically collected for diagnosis of virus infection.

Free access
in American Journal of Veterinary Research

Objective

To monitor the prevailing viral respiratory tract infections in cattle after transportation to feedlots.

Animals

100 cattle with signs of respiratory tract disease on arrival at 2 feedlots.

Procedures

Nasal swab samples were obtained from each animal and were used for inoculation of defined cell culture systems that detected bovine viruses known to cause respiratory tract infections, as well as viruses previously not recognized as respiratory pathogens for cattle.

Results

Bovine respiratory coronaviruses were isolated from 38 of the 100 cattle, including 6 of 50 cattle from California, 22 of 31 cattle from Oklahoma, 6 of 11 cattle from Texas, and 4 of 8 cattle of unknown origin. Parainfluenza 3 viruses also were isolated from 4 California cattle, but other bovine viruses were not detected.

Clinical Implications

The high rate of coronavirus isolations from feedlot cattle with signs of respiratory tract disease implied wide distribution and high susceptibility among cattle to this infection, which had not been detected by use of viral isolation systems in previous etiologic evaluations of feedlot cattle affected with bovine respiratory disease complex. (J Am Vet Med Assoc 1996; 208:1452-1455)

Free access
in Journal of the American Veterinary Medical Association

clinical signs of infection with either pathogen. Pigs were transported to the isolation facility and acclimatized for 3 days prior to initiation of the study. Blood and swab specimens of nasal secretions were collected for analysis via RT-PCR assay to

Full access
in American Journal of Veterinary Research

miscellaneous illnesses were treated on an individual basis according to clinical signs. Collection of samples —For each group of calves, paired nasal swab specimens and fecal samples were obtained prior to shipping, at arrival at the feedlot research station

Full access
in American Journal of Veterinary Research

calves with BRD may help veterinarians when designing antimicrobial treatment protocols for dairy operations. Multiple sampling methods are used to identify the various bacterial respiratory pathogens associated with BRD, with the nasal swab (NS), deep

Open access
in American Journal of Veterinary Research

influenza virus by rRT-PCR assay of nasal swab specimens through the University of Wisconsin Shelter Medicine Program and the WVDL. These 300 dogs represented a sampling of dogs with respiratory disease from each shelter. The combined annual intake for dogs

Full access
in Journal of the American Veterinary Medical Association

abnormalities were observed. Deep nasal swab samples were collected for aerobic and anaerobic culture; the results indicated a mixed growth of Staphylococcus spp, Micrococcus spp, and Bordetella spp, with the latter susceptible to chloramphenicol

Full access
in Journal of the American Veterinary Medical Association

horses with neurologic signs. Blood, nasal swab specimen, and CSF sampling and processing —Blood samples and nasal swab specimens were obtained on day −1 and 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, and 21 days after infection. Blood was drawn into 10-mL

Full access
in American Journal of Veterinary Research

backgrounding and stocker cattle operations and compare bacteriologic culture of nasal swab specimens with PCR assay for identification of cattle shedding M bovis. The prevalence of mycoplasmas not specifically identified as M bovis (ie, Mollicutes) was also

Full access
in Journal of the American Veterinary Medical Association

to maximize collection of nasopharyngeal secretions. Owing to the relatively smaller size of the ventral nasal meatus, a sterile culture swab d was used to collect nasopharyngeal samples in the foals. Swab tips were placed in conical centrifuge tubes

Full access
in Journal of the American Veterinary Medical Association