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Biomedical subjects

J F Evermann

Publications and source records attributed to J F Evermann.

At least 19 recordsLinked to original sources
PubMed1998

Serologic and molecular characterization of an abortigenic strain of equine arteritis virus isolated from infective frozen semen and an aborted equine fetus.

A virus isolated from an aborted equine fetus was determined to be antigenically distinct from several other strains of equine arteritis virus (EAV) by use of a neutralization assay with a large panel of neutralizing monoclonal antibodies. The virus was readily neutralized by polyclonal equine anti-EAV serum. Comparative nucleotide and amino acid sequence analyses indicated that the virus (WA97) isolated from the aborted fetus was virtually identical to a virus (S1971) isolated from imported semen used to inseminate another mare on the farm. Phylogenetic analysis indicated that the WA97/S1971 virus was more related to European than to North American strains of EAV. These sensitive molecular procedures may be useful for epidemiologic investigations of EAV infections. Screening and certification of stallions and frozen equine semen would prevent dissemination of pathogenic strains of EAV.

Abortion, Veterinary↗
PubMed1997

Laboratory diagnostic tests for retroviral infections in dairy and beef cattle.

Detection of bovine retroviruses stretches our diagnostic creativity to its limits. The nucleic acid-based, PCR-amplified assays are finding increased clinical use as the veterinary and livestock industry seek earlier detection of infection for eventual corrective management decisions. We are evolving from a point of disease diagnosis by tumor identification through conventional histopathology, to molecular diagnostics for early identification of retroviral nucleic acid (provirus). The clinical use of antibody-based assays lies in the simplicity of testing large numbers of animals, the relative sensitivity of the assays, and the low cost of testing. Although the pathogenicity of bovine leukemia virus (BLV) for cattle has been well documented, the disease potential for bovine immunodeficiency-like virus (BIV) for cattle is still being determined. Nevertheless, pressure to test for retroviral infections of livestock and, when feasible, removal of these infected animals from the herd will be increased.

Animals↗
PubMed1997

Bluetongue virus detection: a safer reverse-transcriptase polymerase chain reaction for prediction of viremia in sheep.

A reversible target capture viral RNA extraction procedure was combined with a reverse-transcriptase nested polymerase chain reaction (PCR) to develop a capture PCR assay providing a rapid and safe prediction method for circulating bluetongue virus in infected ruminants. This new assay was compared with virus isolation and a recently developed antigen-capture enzyme-linked immunosorbent assay (ELISA) for the detection of bluetongue virus. Eight Warhill crossbred sheep were inoculated subcutaneously with bluetongue virus serotype 10, and blood samples were taken sequentially over a period of 28 days. The capture PCR detected the peak of viremia, as determined by virus isolation and antigen-capture ELISA, from day 5 to day 14 after challenge. The results indicate that the rapid-capture bluetongue virus PCR provides a rapid indicator of samples in which virus can be isolated. In addition, this capture bluetongue virus PCR procedure does not require a lengthy phenol extraction or the use of the highly toxic methyl mercury hydroxide denaturant.

Animals↗
PubMed1997

Occurrence of puma lentivirus infection in cougars from Washington.

Puma lentivirus (PLV) antibodies were detected in 13 (25%) of 52 serum samples obtained from cougars (Felis concolor) collected by hunters. The serum samples were collected from November 1993 through January 1994 from four specific regions throughout the state of Washington (USA), and included the Olympic Mountains, the Cascade Mountains, the Blue Mountains, and the Selkirk Mountains. More (38%) seropositive cougar samples originated from the Cascade Mountains than from any other site. The overall seroprevalence for PLV infection in Washington cougars was higher than previously reported for cougars sampled in Oregon and Idaho (USA), but lower than in cougars sampled in Arizona, Colorado, and California (USA).

Animals↗
PubMed1996

Serological evidence of morbillivirus infection in polar bears (Ursus maritimus) from Alaska and Russia.

One-hundred-and-ninety-one samples of blood serum collected from 186 polar bears (Ursus maritimus) between 1987 and 1992 were analysed for morbillivirus antibodies. The samples were collected in the Bering, Chukchi and East Siberian seas. Sixty-eight samples (35.6 per cent) had morbillivirus antibody titres > 5; the percentage of positive samples ranged from 26.2 to 46.2 per cent from year to year. The proportions of adults, sub-adults and cubs which were seropositive were 43.9, 35.7 and 37.9 per cent respectively. Some seropositive dams had seronegative young and some that were seronegative had seropositive young. One litter of two cubs, in which the dam was seronegative, had one seropositive and one seronegative cub. Seropositive bears occurred in all the areas from which the samples were collected but there was a significantly greater incidence in the bears sampled in Russia. The high prevalence of seropositive bears over the period suggests that the bear morbillivirus is endemic in these regions of the Arctic, but its source is unknown.

Alaska↗
PubMed1996

Evolution of canine parvovirus involved loss and gain of feline host range.

Canine parvovirus (CPV) type-2 emerged as a new virus infecting dogs in 1978, and it was probably derived as a variant of feline panleukopenia virus or of a closely related virus infecting another carnivore. CPV type-2 was subsequently replaced in nature by antigenically variant viruses (CPV type-2a and CPV type-2b) which now coexist in dog populations worldwide. We show that CPV type-2 isolates did not replicate in cats, but that both CPV type-2a and CPV type-2b isolates replicated efficiently. About 10% of the viruses isolated from cats with natural parvovirus disease were antigenically indistinguishable from CPV type-2a or type-2b. The capsid protein gene sequence of a 1990 feline parvovirus isolate ("FPV-24") was essentially identical to the sequence of CPV type-2b viruses from dogs. The loss and reacquisition of the feline host range in CPV was most likely due in each case to small numbers of changes in a region of the virus capsid where three protein monomers interact.

Animals↗
PubMed1995

Diagnosis of naturally occurring bovine viral diarrhea virus infections in ruminants using monoclonal antibody-based immunohistochemistry.

Formalin-fixed paraffin-embedded tissues from 50 spontaneous cases (39 bovine, nine ovine, two caprine) of bovine viral diarrhea virus (BVDV) infection diagnosed by virus isolation were retrospectively examined for BVDV antigen by immunohistochemistry using anti-BVDV gp-43 monoclonal antibody (Mab 15C5). The cases were separated into enteric disease syndrome, respiratory disease syndrome, and abortion/weak calf syndrome based upon clinical disease. The purposes of the study were to 1) compare routine virus isolation with immunohistochemistry in determining BVDV infection and 2) define tissue and cellular distribution of BVDV in various clinical manifestations of infection. In bovids, there was 100% concordance of virus isolation and immunohistochemistry using Mab 15C5 in cases of enteric disease (mucosal disease, acute and chronic diarrhea, neonatal diarrhea), respiratory disease, and abortion. When laboratory tests were restricted to gastrointestinal tissue and/or feces, virus isolation detected BVDV in only 65% of cattle, whereas immunohistochemistry detected BVDV antigen in 100% of cattle. Immunohistochemical detection of pestivirus was poor in cases of ovine abortion, ovine hairy shaker syndrome, and caprine abortion. The tissue distribution of BVDV antigen was widespread in individual cattle with all clinical forms of BVDV infection. Viral antigen accumulation was spatially correlated with tissue lesions (in the absence of other pathogens) only in the gastrointestinal tract, lymphoid tissue, lung, placenta, and eye. This study demonstrates the utility of immunohistochemistry using Mab 15C5 to diagnose BVDV infections in cattle with a broad spectrum of clinical disease.

Abortion, Veterinary↗
PubMed1994

In utero infections responsible for abortion, stillbirth, and birth of weak calves in beef cows.

A multitude of in utero infections may cause abortion, stillbirths, or the birth of weak calves (see Table 1). Because the diagnostic success for determining the cause of abortions may be low (25%-40%), it is important that more knowledge about the causes and differential diagnoses is gained, and proper samples are collected and submitted. Use of an abortion diagnosis kit enables multiple samples to be analyzed and increases the likelihood of making a diagnosis. The immune response is suppressed during pregnancy. In part, this can be controlled by proper nutrition and appropriately timed vaccination programs.

Abortion, Veterinary↗
PubMed1994

Evaluation of agar gel immunodiffusion serology using caprine and ovine lentiviral antigens for detection of antibody to caprine arthritis-encephalitis virus.

The sensitivity of the agar gel immunodiffusion (AGID) test for the detection of antibody to caprine arthritis-encephalitis virus (CAEV) was investigated with CAEV or ovine progressive pneumonia virus (OPPV) as the source of antigen. A total of 218 goat serum specimens were tested for anti-CAEV antibody by AGID and immunoprecipitation of [35S]methionine-labeled CAEV. In comparison with that of immunoprecipitation, the sensitivity of the CAEV AGID test was 0.91, and that of the OPPV AGID test was 0.56. The AGID test with either antigen was 100% specific. The lower sensitivity of the OPPV AGID test in detecting caprine antibody to CAEV indicates that OPPV antigen is of limited value for use in CAEV diagnosis and control programs.

Animals↗
PubMed1994

Evaluation of a kinetic enzyme-linked immunosorbent assay for detection of caprine arthritis-encephalitis virus-specific antibodies.

A kinetic indirect enzyme-linked immunosorbent assay (k-ELISA) was evaluated for detection of antibody to caprine arthritis-encephalitis virus (CAEV), using sodium dodecyl sulfate-treated CAEV-63 as antigen. Two hundred fifteen caprine sera submitted to the diagnostic laboratory were tested for CAEV antibody by the k-ELISA and by immunoprecipitation of [35S]-methionine-labeled CAEV. A k-ELISA positive cutoff point of 80 yielded a sensitivity of 94.4% and a specificity of 100%, as compared with immunoprecipitation. A k-ELISA cutoff point of 50 resulted in a sensitivity of 100%, with 95.6% specificity. When sera with k-ELISA scores between 50 and 80 were considered suspect, testing of 1,001 diagnostic sera resulted in < 1.5% suspect reactions. Using the 80 cutoff point, the CAEV k-ELISA had good sensitivity and specificity, with the added advantages of quick turn-around time, few suspect reactions, and adaptability to large numbers of samples

Animals↗