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Biomedical subjects

J R Gorham

Publications and source records attributed to J R Gorham.

At least 73 records · Page 4Linked to original sources

Experimental salmon poisoning disease in juvenile coyotes (Canis latrans).

Salmon poisoning disease (SPD) was experimentally induced in juvenile coyotes (Canis latrans). The disease was lethal in 11 of 12 coyotes within 15 days after inoculation with 1,000 or 4,000 metacercariae of Nanophyetus salmincola. Clinical manifestations of the disease included lymph node enlargement, anorexia, pyrexia, diarrhea and death. Coccoid bodies indistinguishable from rickettsiae were observed in macrophages of spleen, liver, lymph nodes, and duodenum. Percentage recovery of adult trematodes from metacercariae administered was 23% from 12 inoculated coyotes, compared to 13% in one inoculated dog. Juvenile coyotes appear to be highly susceptible to experimental SPD.

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Antigen requirements and specificity of enzyme-linked immunosorbent assay for detection of canine IgG against canine distemper viral antigens.

An enzyme-linked immunosorbent assay (ELISA) was developed for detection of specific immunoglobulin G (IgG) against canine distemper virus (CDV) antigens. Sucrose gradient separation of viral and cellular proteins was required to produce coating antigens for the ELISA. The specificity of the ELISA was demonstrated by blocking CDV-positive canine sera with CDV-specific antisera produced in goats and rabbits and adsorption of positive sera with CDV antigens. A comparison of the ELISA with the serum-neutralization technique for the detection of CDV antibodies was conducted. Anti-CDV IgG was detected in conventional dogs as early as 6 days after inoculation with a commercial vaccine to CDV. Paired sera from the immunized dogs were evaluated by both techniques and a statistically (P less than 0.01) significant agreement between the ELISA and the serum-neutralization technique was shown (r = 0.6121, n = 75).

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Relationship of neonatal mortality in lambs to serologic status of the ewe for Toxoplasma gondii.

The indirect hemagglutination method was used to determine the seroprevalence of Toxoplasma gondii in a random sample (250) of lambing ewes from a large (4,226 ewes) western range flock. Agglutination (greater than or equal to 2+) at the 1:64 serum dilution was considered a positive reaction; the seroprevalence was 20.8%. The neonatal mortality for lambs born to seropositive ewes was 30.7%, which was significantly greater than that for seronegative ewes (13.6%). The average age at death for lambs born to seropositive ewes was 24.8 hours, which was significantly less than that for lambs born to seronegative ewes (31.2 hours).

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Serologic prevalence of ovine progressive pneumonia in a western range flock of sheep.

Of 254 sheep examined for antibodies to the virus of ovine progressive pneumonia, 162 (63.8%) were seropositive. The mean age of the seropositive ewes was 4.9 +/- 1.8 years, which was significantly greater than that for the seronegative ewes (4.1 +/- 2.3 years). The age-specific prevalence increased with ewe age, from 25% among yearling ewes to 85% among 7-year-old ewes. Seropositive ewes produced more pounds of live lamb at birth than did seronegative ewes.

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Evaluation of chemical disinfectants for aleutian disease virus of mink.

Nine chemicals and commercial disinfectants were tested for inactivation of Aleutian disease virus of mink. In the presence of distilled water, a commercial disinfectant (O-Syl), halogen derivatives (iodophor and sodium hypochlorite), and glutaraldehyde (2.0%) inactivated 4 log10 (based on 0.25 ml) of the virus within 10 minutes at 23 C. Formalin (2.0%) and O-Syl were slower to inactivate the virus, but achieved a 4 log10 reduction in titer by 30 minutes' contact time. In the presence of 10% bovine serum, formalin (1.0%), O-Syl, and sodium hydroxide (0.5%) achieved a 4 log10 reduction within 10 minutes. All agents tested had some virucidal effect.

Aleutian Mink Disease Virus↗

Ovine progressive pneumonia: pathologic and virologic studies on the naturally occurring disease.

Pathologic and virologic studies were conducted on 13 mature ewes with serum precipitin antibodies to progressive pneumonia virus (PPV). Pulmonary lesions of ovine progressive pneumonia were found in 4 sheep, a meningoencephalitis resembling visna in 1 sheep, chronic proliferative carpal arthritis in 2, and massive lymphoid proliferation in the mammary gland in 3. Virus producing cytopathic effect typical of PPV was isolated from the lungs, mediastinal lymph node, spleen, and choroid plexus of 4 sheep and from the carpal synovium of 2 sheep with chronic carpal arthritis. Three viral isolates selected for further study were antigenically related to visna virus by immunofluorescence and immunodiffusion, but these 3 isolates were not neutralized by antisera to reference strains of visna virus. Seemingly, infection of sheep by ovine retroviruses is common in the United States, and these viruses are capable of causing disease in more than 1 organ system.

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Field studies: pseudomonas pneumonia of mink.

Epizootics of pneumonia in mink caused by Pseudomonas aeruginosa were investigated to characterize the serotype of organisms and to identify possible predisposing factors. Most epizootics were associated with P aeruginosa Fisher serotype 1, and a few were associated with 3 other serotypes. There were no predisposing factors identified that could be used to differentiate farms affected and those not affected with pseudomonas pneumonia. Cultural studies indicated that P aeruginosa was present in mink from affected and nonaffected herds. Organisms isolated included serotypes associated with naturally occurring disease. Serostudy results were similar among herds. A prospective field vaccination trial did not yield definitive results, since only slight losses occurred in both vaccinated and nonvaccinated mink. Significant levels of antibody were detected in mink 15 to 17 weeks after they were given a single dose of P aeruginosa lipopolysaccharide vaccine.

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Ovine progressive pneumonia: experimental intrathoracic, intracerebral, and intra-articular infections.

Three groups of 4 lambs each were experimentally infected with an isolate of progressive pneumonia virus (PPV) by intracerebral, intra-articular, or intrathoracic routes of inoculation. An additional control group was sham-inoculated by all 3 routes with identically prepared, noninfected inoculum. Sheep were killed 12 to 42 days after inoculation. A mild generalized leptomeningitis was found in 2 of the 4 lambs inoculated intracerebrally. A severe, proliferative synovitis with massive infiltration of lymphocytes and plasma cells was found in the 4 lambs inoculated intraarticularly. Germinal center formation was found in the synovial membrane 42 days after inoculation. Appreciable differences in lung morphologic features were not observed among the 4 groups. The PPV was isolated from virus-inoculated sheep from the choroid plexus, synovium, and lungs from inoculated and noninoculated sites. Nine of the 12 virus-inoculated lambs developed serum antibody to PPV, and specific antibodies were found in the synovial fluid of virus-inoculated joints. Virus was not isolated, lesions were not found, and serum antibody was not demonstrated in sham-inoculated sheep.

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Naturally occurring picornavirus infection of domestic mink.

The isolation and preliminary characterization of a virus from domestic mink- are reported. The virus was tentatively classified as a member of the family Picornaviridae on the basis of its physicochemical properties. The mink virus was not neutralized by antiserum to some known members of the calicivirus genus, which included the nine serotypes of vesicular exanthema of swine virus, ten serotypes of San Miguel sea lion virus and feline calicivirus. Seroepidemiological studies indicated that the incidence of mink virus infection was widespread in domestic mink populations. Although the virus was isolated from mink on ranches with a history of hemorrhagic pneumonia (pseudomonas pneumonia), no specific disease process could be attributed to the virus infection.

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Pseudomonas pneumonia of mink: pathogenesis, vaccination, and serologic studies.

Fulminating pneumonia was produced in mink by the intratracheal administration of Pseudomonas aeruginosa. The sequence of pulmonary lesions was focal inflammation, focal necrosis, and widespread inflammation and necrosis. Secondary lesions of peracute hemorrhage and necrosis were the result of bacterial spread via the airways. Invasion of vessel walls by P aeruginosa was a terminal event and was secondary to bacillary invasion and necrosis of adjacent tissues. Regional (lymphatic) and systemic spread of bacteria followed the development of pulmonary lesions, but there was little morphologic evidence of tissue damage in other organs. Immunofluorescence studies showed that P aeruginosa antigen was dispersed within pulmonary cells and was free in the lung parenchyma. Mink surviving beyond postinfection hour 60 had a macrophage infiltration into limited pulmonary lesions. A vaccine trial was conducted with P aeruginosa lipopolysaccharides (LPS) used as antigen, and an enzyme-linked immunosorbent assay was used to detect antibody. Antibody was detected in mink after vaccination with LPS or natural exposure. Mink with antibody to LPS, from vaccination or naturally acquired, were resistant to experimental infection.

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The connective tissue component of the caprine arthritis-encephalitis syndrome.

The gross and microscopic connective tissue lesions in 12 goats with caprine arthritis-encephalitis (CAE) are described, including those from which a virus (CAEV) was isolated. Lesions were most often associated with synovial-lined structures including joints, tendon sheaths, and bursae, and were typified by synovial cell proliferations, subsynovial mononuclear cell infiltration, the presence of fibrin, fibrinous concretions, necrosis, and mineralization. Extrasynovial lesions were located in kidneys, vessels, and brain. The inflammatory infiltrates in these organs were predominantly mononuclear. Amyloid was also found in liver, spleen, and kidney. Microbiologic techniques failed to demonstrate any bacteria, mycoplasma, or chlamydia in the lesions.

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Prolonged bleeding time in Aleutian mink associated with a cyclo-oxygenase-independent aggregation defect and nucleotide deficit in blood platelets.

A prolonged mean template bleeding time of 13 minutes was present in nine Aleutian mink affected with Chediak-Higashi syndrome (CHS) compared with 4 minutes in dark control mink. The concentrations of blood platelets in normal and affected animals did not differ significantly. However, in mink with CHS, a marked disturbance of platelet response to collagen was present. Administration of aspirin and indomethacin completely blocked CH platelet response to collagen. Blood platelet adenosine triphosphate and adenosine diphosphate values from mink with CHS were significantly less than those of normal mink, and the platelet adenosine triphosphate/adenosine diphosphate ratios were 10.31 in affected mink and 2.74 in normal mink. These findings are consistent with our previous investigations in affectd cattle and persons and indicate that a "storage pool disease" of platelets exist in the mink with CHS.

Adenine Nucleotides↗

Serologic survey of prevalence of ovine progressive pneumonia in Idaho range sheep.

Blood samples from 2,310 mature sheep in 3 Idaho range flocks were examined by agar gel immunodiffusion to determine the prevalence of ovine progressive pneumonia. The prevalence ranged from 58% for all ages combined in one flock to 90% of cull ewes in another flock. Age-specific prevalence rates increased from 16% in yearlings to 83% in ewes greater than or equal to 7 years old. Rambouillet sheep had a significantly (P less than 0.01) lower prevalence than sheep of 5 other breeds, whereas one-half Finnsheep crosses had a significantly (P less than 0.01) higher prevalence than sheep of other breeds. Within breed and age, there was no significant difference in reproductive performance between seropositive and seronegative ewes.

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