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Biomedical subjects

K H West

Publications and source records attributed to K H West.

At least 19 recordsLinked to original sources
PubMed2001

Effect of vaccination on experimental infection with Bordetella bronchiseptica in dogs.

OBJECTIVE: To determine comparative efficacy of vaccines administered IM and intranasally, used alone or sequentially, to protect puppies from infection with Bordetella bronchiseptica and determine whether systemic or mucosal antibody response correlated with protection. DESIGN: Randomized controlled trial. ANIMALS: 50 specific-pathogen-free Beagle puppies. PROCEDURE: In 2 replicates of 25 dogs each, 14-week-old puppies that were vaccinated against canine distemper virus and parvovirus were vaccinated against B bronchiseptica via intranasal, IM, intranasal-IM, or IM-intranasal administration or were unvaccinated controls. Puppies were challenge exposed via aerosol administration of B bronchiseptica 2 weeks after final vaccination. Clinical variables and systemic and mucosal antibody responses were monitored for 10 days after challenge exposure. Puppies in replicate 1 were necropsied for histologic and immunohistochemical studies. RESULTS: Control puppies that were seronegative before challenge exposure developed paroxysmal coughing, signs of depression, anorexia, and fever. Vaccinated puppies (either vaccine) that were seronegative before challenge exposure had fewer clinical signs. Puppies that received both vaccines had the least severe clinical signs and fewest lesions in the respiratory tract. Vaccinated dogs had significantly higher concentrations of B bronchiseptica-reactive antibodies in serum saliva before and after challenge. Antibody concentrations were negatively correlated with bacterial growth in nasal cavity and pharyngeal samples after challenge exposure. CONCLUSIONS AND CLINICAL RELEVANCE: Parenterally and intranasally administered vaccines containing B bronchiseptica may provide substantial protection from clinical signs of respiratory tract disease associated with infection by this bacterium. Administration of both types of vaccines in sequence afforded the greatest degree of protection against disease.

Administration, Intranasal↗
PubMed2000

Coronavirus-associated epizootic catarrhal enteritis in ferrets.

OBJECTIVE: To characterize clinical signs and lesions and identify the etiologic agent associated with epizootic catarrhal enteritis in domestic ferrets. DESIGN: Cross-sectional study. ANIMALS: 119 ferrets with epizootic diarrhea of presumed viral cause and 5 control ferrets. PROCEDURE: Clinical records and biopsy or necropsy specimens of ferrets with presumed epizootic catarrhal enteritis were reviewed. Immunohistochemical staining for coronavirus antigen was performed on paraffin-embedded tissues from approximately 10% of affected ferrets to identify viral antigen and determine its distribution. Transmission electron microscopy was performed on fecal samples and sections of jejunum. Virus isolation studies as well as immunofluorescent tests for other similar viruses were performed. RESULTS: Characteristic microscopic lesions consistent with intestinal coronavirus infection (vacuolar degeneration and necrosis of villus enterocytes; villus atrophy, fusion, and blunting; and lymphocytic enteritis) were consistently detected in affected ferrets. Coronavirus particles were identified in feces and jejunal enterocytes by use of transmission electron microscopy. Immunohistochemical staining of jejunal sections revealed coronavirus antigens. Antigen staining was not detected in healthy ferrets or ferrets with other gastrointestinal tract diseases. Virus isolation was unsuccessful, and other similar viruses were not detected. CONCLUSIONS AND CLINICAL RELEVANCE: Results strongly implicate a coronavirus as the causative agent of epizootic catarrhal enteritis in ferrets. Diagnosis may be made on the basis of a combination of historical, clinical, and microscopic findings.

Animals↗
PubMed2000

Coinfection by porcine circoviruses and porcine parvovirus in pigs with naturally acquired postweaning multisystemic wasting syndrome.

Postweaning multisystemic wasting syndrome (PMWS) is an emerging disease in swine. Recently, the disease has been reproduced with inocula containing a newly described porcine circovirus (PCV), designated PCV 2, and porcine parvovirus (PPV). In order to determine if these viruses interact in naturally acquired PMWS, affected tissues from field cases were examined by immunohistochemistry (IHC) and polymerase chain reaction (PCR) for PCV 2 and PPV, as well as by PCR for the other recognized porcine circovirus, PCV 1. Porcine circovirus 2 was detected by PCR or IHC in affected fixed or frozen tissues from 69 of 69 cases of PMWS collected over 3 years from 25 farms. Porcine parvovirus was detected in 12 of the same cases, and PCV 1 was detected in 9 of 69; however, an apparent decrease was found in the sensitivity of the PCRs used to detect the latter 2 viruses when fixed tissue from the same cases were compared with the use of frozen tissues. Porcine circovirus 2 was not detected by PCR in affected tissues from 16 age-matched pigs that had Streptococcus suis-associated disease. Electron microscopic examination of plasma pooled from 15 pigs with PMWS revealed the presence of PCV and PPV, whereas these viruses were not observed in pooled plasma from 5 age-matched clinically normal pigs. These results confirm and extend previous findings documenting a consistent association of PCV 2 with PMWS. As well, infection by PPV or PCV 1 or both may be an important cofactor in the pathogenesis of some, but apparently not all, cases of PMWS.

Animals↗
PubMed1999

Synergistic effects of concurrent challenge with bovine respiratory syncytial virus and 3-methylindole in calves.

OBJECTIVE: To evaluate the potential synergy between bovine respiratory syncytial virus (BRSV) and 3-methylindole (3MI) in inducing respiratory disease in cattle. ANIMALS: 20 mixed-breed beef calves. PROCEDURE: A 2 X 2 factorial design was used, with random assignment to the following 4 treatment groups: unchallenged control, BRSV challenge exposure (5 X 10(4) TCID50 by aerosolization and 5.5 X 10(5) TCID50 by intratracheal inoculation), 3MI challenge exposure (0.1 g/kg of body weight, PO), and combined BRSV-3MI challenge exposure. Clinical examinations were performed daily. Serum 3MI concentrations, WBC counts, PCV, total plasma protein, and fibrinogen concentrations were determined throughout the experiment. Surviving cattle were euthanatized 7 days after challenge exposure. Pulmonary lesions were evaluated at postmortem examination. RESULTS: Clinical respiratory disease was more acute and severe in cattle in the BRSV-3MI challenge-exposure group than in cattle in the other groups. All 5 cattle in this group and 3 of 5 cattle treated with 3MI alone died or were euthanatized prior to termination of the experiment. Mean lung displacement volume was greatest in the BRSV-3MI challenge-exposure group. Gross and histologic examination revealed that pulmonary lesions were also most severe for cattle in this group. CONCLUSIONS AND CLINICAL RELEVANCE: Feedlot cattle are commonly infected with BRSV, and 3MI is produced by microflora in the rumen of all cattle. Our results suggest that there is a synergy between BRSV and 3MI. Thus, controlling combined exposure may be important in preventing respiratory disease in feedlot cattle.

Animals↗
PubMed1998

Clinical and immunologic responses of vaccinated and unvaccinated calves to infection with a virulent type-II isolate of bovine viral diarrhea virus.

OBJECTIVE: To determine efficacy of a modified-live type-I isolate of bovine viral diarrhea virus (BVDV) vaccine in protecting calves from infection with a virulent type-II isolate, and to determine which type of immune response (i.e., humoral or cellular) correlates with protection. DESIGN: Prospective study. ANIMALS: 28 neonatal Holstein and Holstein-cross calves. PROCEDURE: Within 18 hours of birth, calves received maternal colostrum or were fed pooled colostrum. On days 7 to 10 after birth, calves were determined to be seropositive (n = 16) or seronegative (12) for antibodies to BVDV on the basis of ELISA and virus neutralization test results. Seropositive and seronegative 10- to 14-day-old calves were then given a combined vaccine that contained a modified-live type-I isolate of BVDV or a similar vaccine that lacked protection against bovine viral diarrhea. All calves were inoculated intranasally approximately 21 days after vaccination with a virulent type-II isolate of BVDV. Clinical and immunologic variables, including clinical scores, rectal temperatures, results of CBC with lymphocyte subset analysis, antibody responses, and cell-mediated immune responses, were monitored for 14 days after inoculation. RESULTS: Seronegative-unvaccinated calves developed severe disease and required euthanasia. Vaccination of seronegative calves with a modified-live type-I isolate had a disease-sparing effect as did passive transfer of colostral antibodies to BVDV. Clinical scores were not significantly different between seropositive-vaccinated and seropositive-unvaccinated calves after viral inoculation. CLINICAL IMPLICATIONS: A single dose of a modified-live type-I isolate of BVDV vaccine protects young calves from clinical signs of disease associated with type-II isolates.

Animals↗
PubMed1998

Lesions and distribution of viral antigen following an experimental infection of young seronegative calves with virulent bovine virus diarrhea virus-type II.

During the past several years, acute infections with bovine viral diarrhea virus (BVDV) have been causally linked to hemorrhagic and acute mucosal disease-like syndromes with high mortality. The majority of BVDVs isolated in such cases have been classified as type II on the basis of genetic and antigenic characteristics. It was our objective to examine clinical disease, lesions and potential sites of viral replication, following experimental BVDV type II infection in young calves. On approximately day 35 after birth, calves that had received BVDV-antibody-negative colostrum were infected by intranasal inoculation of 5 x 10(5) TCID50 of BVDV type II isolate 24,515 in 5 mL of tissue culture fluid (2.5 mL/nostril). Calves were monitored twice daily for signs of clinical disease. Approximately 48-72 h after infection, all calves developed transient pyrexia (39.4-40.5 degrees C) and leukopenia. Beginning on approximately day 7 after infection, all calves developed watery diarrhea, pyrexia (40.5-41.6 degrees C), marked leukopenia (> or = 75% drop from preinoculation values), variable thrombocytopenia, and moderate to severe depression. Calves were euthanized on days 10, 11, or 12 after infection due to severe disease. Gross and histological lesions consisted of multifocal bronchointerstitial pneumonia (involving 10%-25% of affected lungs), bone marrow hypoplasia and necrosis, and minimal erosive lesions in the alimentary tract. Immunohistochemical staining for BVDV revealed widespread viral antigen usually within epithelial cells, smooth muscle cells and mononuclear phagocytes in multiple organs, including lung, Peyer's patches, gastric mucosa, thymus, adrenal gland, spleen, lymph nodes, bone marrow, and skin. This BVDV type II isolate caused rapidly progressive, severe multisystemic disease in seronegative calves that was associated with widespread distribution of viral antigen and few gross or histological inflammatory lesions.

Animals↗
PubMed1990

Viral hepatitis.

Viral hepatitis is the most common serious contagious disease caused by viruses that attack the liver. Approximately 70,000 cases are reported to the Centers for Disease Control each year, representing only a fraction of U.S. cases. There are five types of viral hepatitis currently known: Hepatitis A--formerly called infectious hepatitis; Hepatitis B--formerly called serum hepatitis, and the most serious form; Hepatitis C--formerly called non-A, non-B hepatitis; Hepatitis D--formerly called delta hepatitis; Hepatitis E--formerly called enteric or epidemic non-A, non-B hepatitis. The following Open Forum, prepared by leading EMS experts, explores the differences among the types of hepatitis, signs and symptoms, and EMS implications.

Allied Health Personnel↗
PubMed1990

Screening costs in a hepatitis B vaccine program.

Current statistics from the Centers for Disease Control (CDC) reveal that approximately 39 percent of all fire/rescue personnel have been vaccinated against hepatitis B. Iti well-documented that hepatitis B viral infection presents the greatest occupational health risk to emergency personnel, yet program development and care-provider participation have been slow to evolve.

Allied Health Personnel↗