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Biomedical subjects

R A Crandell

Publications and source records attributed to R A Crandell.

At least 19 recordsLinked to original sources
PubMed1990

Effects of human alpha interferon on experimentally induced equine herpesvirus-1 infection in horses.

The immunotherapeutic effect of low-dose human alpha interferon on viral shedding and clinical disease was evaluated in horses inoculated with equine herpesvirus-1 (EHV-1). Eighteen clinically healthy weanling horses, 5 to 7 months old, were allotted to 3 equal groups. Two groups were treated orally with human alpha-2a interferon (0.22 or 2.2 U/kg of body weight), on days 2 and 1 before inoculation with EHV-1, the day of inoculation, and again on postinoculation day 1. The horses of the remaining group were given a placebo orally on the same days. The horses were monitored daily for changes in body temperature and for clinical signs of respiratory tract disease. Blood and nasal swab specimens were collected daily for virus isolation. Blood was also collected at intervals throughout the monitoring period for evaluation of CBC, serum IgG and IgM concentrations, and antibody titers to EHV-1. Febrile responses, nasal discharge, viral shedding, changes in CBC, and an increase in antibody titers to EHV-1 were noticed in all horses after inoculation. There was no significant difference (P greater than 0.05) in mean values of the factors measured between treatment and control groups.

Animals↗
PubMed1989

Laboratory investigation of a naturally occurring outbreak of arthrogryposis-hydranencephaly in Texas sheep.

An epizootic of abortions, weak lambs, stillbirths, and congenital arthrogryposis-hydranencephaly occurred in a sheep flock in West Texas. The outbreak began during the first week of January 1987 and continued through the third week of February 1987. Lambs born after February 1987 were not affected. A high incidence of antibodies to Cache Valley virus (Texas 7856 isolate) was demonstrated in the ewes' serum and in precolostral serum from affected lambs. No virus was isolated from tissues and body fluids of the affected lambs. The clinical, pathological, and immunological features of the epizootic were similar to those reported in Akabane virus infection in sheep. Although serological findings strongly suggest Cache Valley virus as the etiological agent of this outbreak, transmission studies are needed.

Animals↗
PubMed1989

Molecular confirmation of an abortigenic strain of equine herpesvirus 1 (subtype 1) in a pregnant mare study.

Four pregnant mares were inoculated intranasally and/or intravenously with equine herpesvirus 1 (EHV-1), subtype 1 during the third trimester of gestation. One mare aborted on postinfection day 15, one mare delivered a sick, weak full term foal, and two mares delivered healthy, full term foals. EHV-1, subtype 1 was isolated from several tissues of the aborted fetus and from the thymus of the sick foal. DNA restriction endonuclease patterns of the recovered EHV-1 viruses were identical to those of the EHV-1 challenge strain, documenting the origin of the abortigenic viruses.

Abortion, Veterinary↗
PubMed1988

Isolation and characterization of caliciviruses from dogs with vesicular genital disease.

Two virus isolates, one from lesions of the vagina of a Bearded Collie and the other from the penis and prepuce of a Black Labrador, were partially characterized. The two viruses possessed the physicochemical properties, size and morphology of viruses belonging to the family Caliciviridae. The two isolates were shown by cross neutralization tests to be distinct from previously reported canine and feline caliciviruses. The viruses, isolated four years apart, are antigenically related. Additional studies are necessary to determine whether they are two distinct viruses or strains of another serotype belonging to the caliciviruses of the canine species.

Animals↗
PubMed1988

Isolation and comparative restriction endonuclease DNA fingerprinting of equine herpesvirus-1 from cattle.

Deoxyribonucleic acid fingerprinting analyses with 4 restriction endonucleases (EcoRI, BamHI, BglII, and HindIII) and serotest results have definitively indicated that 5 herpesviruses isolated from 1974 to 1986 from aborted bovine fetuses and from bovine tissues and nasal secretions were abortigenic subtypes of equine herpesvirus type 1 (EHV-1). The herpesviruses, designated BH1247, 3M20-3, G118, H1753, and 9BSV4, were neutralized by EHV-1-specific antiserum and could be propagated in cultures of either bovine or equine cells. Only minor differences in restriction endonuclease patterns were detected from the pattern of an Army 183 isolate of EHV-1 subtype 1 that had been passaged only in equine cells and from that of an attenuated EHV-1 subtype 1 (RQ) strain that had been passaged several hundred times in non-equine cells. The individual differences in the restriction endonuclease fragments of the 5 bovine isolates and the Army 183 and RQ strains mainly were attributable to alterations in the terminally repeated and the unique short nucleotide sequences of the EHV-1 genomes, which are known to be hot spots for deletions and tandem repeats. The BamHI restriction endonuclease pattern of the 1977 bovine isolate H1753 was identical to that of EHV-1 subtype-1 strains responsible for most of the virus abortions in vaccinated horses since 1981. Abortigenic EHV-1 strains have the ability to infect cattle and cause disease under natural conditions.

Abortion, Veterinary↗
PubMed1987

Isolations of Cache Valley virus in Texas, 1981.

Two strains of the same virus (isolates AR 168 and 7856), were isolated in 1981 from an apparently healthy cow and a sick sheep in TX, U.S.A. These isolates were shown to be members of the Bunyamwera serogroup (family Bunyaviridae, genus Bunyavirus) by complement-fixation tests. Serum dilution-plaque reduction neutralization test results indicated that the isolates are closely related to Cache Valley virus. The virus isolates were characterized by sensitivity to lipid solvent, size (50-100 nm by filtration and 70 nm by electron microscopy), heat (56 degrees C) and pH 3 lability, cytopathic effects or plaques in cultures of Vero, LLC-MK2, embryonic bovine testicle and PS cells, and pathogenicity for suckling and weaned mice by the intracranial but not the intraperitoneal route. Gnotobiotic and conventional sheep and goats were experimentally infected by inoculation with one of the isolates given either intravenously or intraperitoneally. Elevation of body temperature, depression, tremors, muscle spasms, disorientation, feeding anomalies, convulsions, or other signs of central nervous system disturbances were observed.

Animals↗
PubMed1985

Isolation of equine coital exanthema virus (equine herpesvirus 3) from the nostril of a foal.

The virus causing equine coital exanthema (equine herpesvirus 3) was isolated from a lesion on the nostril of a 2-month-old foal. One week after the mare had returned from a stallion station, vesicular lesions developed on her vulva. They were diagnosed clinically as coital exanthema, and 5 days later a lesion developed on the nostril of her foal. This case is an example of horse-to-horse transmission of coital exanthema virus without coitus. A laboratory diagnosis is necessary to differentiate viruses that cause vesicular lesions about the oral and nasal cavities of horses.

Animals↗
PubMed1982

Comparative study of vaccines in preventing respiratory disease in beef calves after weaning.

Vaccines against infectious bovine rhinotracheitis (IBR), bovine viral diarrhea (BVD), bovine parainfluenza-3 (PI-3), and bacterin against Pasteurella hemolytica and P. multocida were studied to determine their effectiveness when given 30 days before weaning in preventing respiratory disease in beef calves after weaning. A total of 310 calves, 6 to 8 months old, were divided into 3 groups. Group I consisted of 51 calves vaccinated with a temperature sensitive mutant vaccine intranasally (IBR-PI-3 TSV2). The 56 calves in Group 2 received another intranasal vaccine containing a modified live virus (IBR-PI-3 IP). Calves in both groups received a modified live bovine virus diarrhea (BVD) virus vaccine 30 days before weaning, and a bacteria containing Clostridium chauvei-septicum, Pasteurella hemolytica, and P. multocida. The bacterin was given twice, 2 weeks apart before weaning. The remaining 207 calves were used as unvaccinated controls. All calves were treated at lest once after weaning for clinical respiratory illness. The only virus isolated was PI-3. The serologic response to the viral vaccines was good. There was some doubt as to the effectiveness of the PI-3 component because vaccinated calves were affected by this virus after weaning. Further studies are needed on PI-3 virus vaccine and the most effective vaccination schedule. Vaccination at the time of weaning may have been helpful in the present experiment in preventing clinical disease.

Animals↗
PubMed1982

Horizontal transmission of pseudorabies virus in cattle.

Pseudorabies virus (PRV) was not transmitted horizontally from 3 PRV-infected calves to 2 contact control calves during 4 days of comingling in experiment 1. Although these contact control calves developed clinical signs of pseudorabies when infected intranasally with PRV in experiment 2, they did not transmit PRV to a second pair of contact control calves. However, 1 of 2 pigs comingled with these 4 calves seroconverted. During both experiments, moderate amounts (10(2) to 10(5) TCID50) of PRV were present in the nasal secretions of the infected calves during the contact periods. All infected calves traumatized their nares or periorbital tissue. Infected calves developed a nonsuppurative meningoencephalitis mainly involving the brain stem. Four of the 5 infected calves had nonsuppurative ganglioneuritis and acute lymphoid necrosis of germinal centers. Virus could not be recovered from nasal and tonsillar swab samples from contact-control calves and pigs.

Animals↗
PubMed1981

Pseudorabies in a dog.

Pseudorabies was diagnosed in a 5-year-old female crossbred dog by histologic examination and virus isolation. The clinical signs were depression, salivation, head pressing, and emesis. There were no gross pathologic findings. The microscopic findings in the brain stem consisted of mononuclear cell infiltrates in the leptomeninges, subarachnoid space, and neuropil. In addition, there were mononuclear cell perivascular cuffs, focal areas of gliosis, neuronal degeneration, and acidophilic intranuclear inclusions in neurons and astrocytes. Other microscopic findings were edema of lungs and fatty change in the liver. The virus was isolated from the brain and tonsils and identified by fluorescent antibody technique. Pseudorabies virus was isolated from pigs on the farm.

Animals↗
PubMed1981

Induced latency in pseudorabies vaccinated pigs.

A latent pseudorabies virus infection was established in pigs despite vaccination with a modified-live pseudorabies virus vaccine. Although the vaccinated pigs developed high concentrations of antibody, virus was recovered from the tonsils and lungs of pigs treated with dexamethasone three months after inoculation with virulent virus. These results may explain why vaccination programs have failed to eliminate the persistence and spread of virulent pseudorabies virus in infected herds.

Animals↗