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Biomedical subjects

C J Issel

Publications and source records attributed to C J Issel.

At least 91 records · Page 5Linked to original sources
PubMed1982

Transmission of equine infectious anemia virus from horses without clinical signs of disease.

Twenty seven adult horses positive to the agar gel immunodiffusion (AGID) test for equine infectious anemia (EIA), but with no history of clinical EIA, were used in transfusion studies to determine whether infectious EIA virus was present in 1 to 5 ml of their blood. Of 27 recipients, 21 (78%) became AGID test-positive at an average of 24 days after inoculation. Two horses that were initially negative when screened were retested and found to carry infectious virus in 5-300 ml of whole blood; the other 4 horses were not retested. Horse flies (Tabanus fuscicostatus Hine) were unable to transmit EIA virus from 10 AGID test-positive donors with no history of clinical EIA, but virus was transmitted from a pony with artificially induced acute EIA and from a horse that had recovered from a clinical attack of EIA 9 months earlier. Histopathologic changes indicative of EIA were noted in all test-positive recipients. The most consistent lesion was paracortical lymphoid hyperplasia in the splenic lymph node.

Animals↗
PubMed1982

Detection of equine infectious anemia virus in a horse with an equivocal agar gel immunodiffusion test reaction.

A horse whose serum reacted equivocally in the agar gel immunodiffusion (AGID) test for equine infectious anemia was studied over a 3-year period. The horse remained afebrile and virus was detected in only 1 of 6 horse inoculation tests. The intensity of AGID test reactions increased temporarily following this evidence for virus. Although the AGID test reaction was equivocal and 5 of the 6 transmission attempts failed, the 1 successful transmission proved the horse was infected.

Animals↗
PubMed1982

Ataxia in four horses with equine infectious anemia.

In 4 horses with equine infectious anemia (EIA), the predominant clinical sign was ataxia. Other clinical and laboratory findings often associated with EIA included weight loss, anemia, pyrexia, thrombocytopenia, hemorrhages, hypergammaglobulinemia, and high activity of biliary epithelial enzymes. Neuropathologic findings were nonsuppurative granulomatous ependymitis, meningitis, and encephalomyelitis and plasmacytic-lymphocytic infiltration of the brain and spinal cord. The onset of neurologic signs corresponded to the acute stage of infection in at least 2 horses, and the signs developed at least 18 months after infection in 1 case. Cerebrospinal fluid from 3 of the horses contained high concentration of protein and white cells, although changes in 1 horse may have been associated with a prior traumatic attempt to collect CSF. By comparison, CSF from 3 ponies inapparently infected with EIA was normal. Active production of anti-EIA antibody in the CSF was suspected on the basis of serologic findings.

Animals↗
PubMed1982

Isolation and comparative biochemical properties of the major internal polypeptides of equine infectious anemia virus.

We describe procedures for the large-scale production of equine infectious anemia virus (EIAV) and for the isolation of the four major non-glycosylated virion proteins, designated p26, p15, p11, and p9. Comparisons of the purified proteins by peptide mapping procedures and by enzyme-linked immunosorbent assays demonstrated the unrelatedness of the four proteins. The characteristic properties of each purified protein were examined by determining isoelectric points and amino acid compositions. We found that EIAV p26 and p9 focus at pI values of 6.2 and 5.0, respectively, and that these proteins contain no unusual amino acids. In contrast, EIAV p15 reproducibly displayed a heterogeneous isoelectric focusing pattern, with major pI values ranging from 5.7 to 8.3. This charge variation evidently correlated with different levels of phosphorylated serine or threonine or both, which could be detected by an amino acid analysis of purified p15. EIAV p11 apparently focused at a pI of greater than 10, reflecting its high content of basic amino acids. Moreover, localization experiments indicated that all four nonglycosylated proteins constitute the internal components of the virus, with all of the virion p11 closely associated with the viral RNA genome. Thus, our results demonstrated that EIAV, a lentivirus, contains structural polypeptides which are analogous to the structural polypeptides described previously in prototype C oncoviruses.

Amino Acids↗
PubMed1982

Virulence and in vitro growth of a cell-adapted strain of equine infectious anemia virus after serial passage in ponies.

Five serial passages of a cell-adapted strain of equine infectious anemia (EIA) virus were conducted in Shetland ponies. The 13 recipient ponies became agar-gel immunodiffusion test-positive by 25 days after they were inoculated. The virulence of the cell-adapted strain of EIA virus markedly increased through 3 serial passages, although individual variation within passages was high. The 1st serial-passage recipient remained afebrile through 200 days, whereas a febrile episode occurred about every 185, 44, 35, and 33 days in the 2nd, 3rd, 4th, and 5th serial-passage recipients, respectively. Severe clinical signs of EIA were noted in the ponies at each serial passage, but the mean virulence rating of each passage, graded on frequency of febrile episodes and number of clinical signs evident within 200 days after ponies were inoculated, increased from 0 through 4, 21, 24, and 29 for the 1st through 5th serial passages, respectively. Isolates of EIA virus, made in fetal equine kidney cells, were obtained from plasma of 75% of the samples of blood collected during febrile episodes and from 45% of the samples collected during afebrile periods, indicating that the cell culture growth capacity of this strain of EIA virus may be relatively stable through 5 serial passages in Shetland ponies.

Animals↗
PubMed1981

Studies with equine infectious anemia virus: transmission attempts by mosquitoes and survival of virus on vector mouthparts and hypodermic needles, and in mosquito tissue culture.

Biological and mechanical transmission trials with Psorophora columbiae (Dyar and Knab) and Aedes sollicitans (Walker) and ponies acutely infected with equine infectious anemia virus (EIAV) were negative. The EIAV antigen was detected by radioimmunoassay in Ae sollicitans immediately after the mosquitoes had fed on an acutely ill pony, but not 14 days after feeding. Psorophora columbiae mosquitoes had detectable EIAV antigen as determined by radioimmunoassay 24 hours after they fed on an acutely ill pony; this antigen was not detected again until 6 days after feeding and was still detected 14 days after feeding. The EIAV was detected on hypodermic needles held at 25 C for 96 hours, but was not detected 120 hours after the needles were dipped in solutions of EIAV. The virus was detected on the mouthparts of mosquitoes for 1 hour after they had fed on an EIAV-rich medium, but was not detected 4 hours after feeding. Culex pipiens quinquefasciatus Say ovarian cells maintained the infectivity of EIAV for 10 weekly passages, but no evidence for virus multiplication was obtained.

Aedes↗
PubMed1979

Serologic survey for equine infectious anemia virus in Louisiana.

In 1975, a survey was conducted in East Baton Rouge Parish, Louisiana, to determine the prevalence of equine infectious anemia. Using the agar gel immunodiffusion test, 94 of 1,398 horses (6.7%) were found to be infected. Infection rates were especially high in areas where clinical cases of equine infectious anemia had been diagnosed. Clinical signs compatible with the disease were noted in 1 of the 94 seropositive horses. The sample set of 1,398 horses represented 22% of the census population obtained during the 1971 Venezuelan equine encephalomyelitis vaccination campaign.

Animals↗
PubMed1979

Equine infectious anemia virus: development of a simple reproducible method for titrating infectivity of the cell-adapted strain.

An equine dermal cell line between the 14th and 30th subpassages was used to develop a reproducible method of titrating the infectivity of the cell-adapted strain of equine infectious anemia virus (EIAV). Cells inoculated with EIAV were subcultured or fed once each week and were monitored for the production of P26 antigen of EIAV in supernatant fluids. Ultrathin sections were prepared once each week and were examined for the detection of budding virus-like particles (VLP). The VLP could not be detected in the infected cells subcultured once each week. When the medium was changed once week and when the cells not transferred, budding VLP were detected routinely after 3 to 4 weeks, Feeding of the infected cells once each week was used to establish the infectivity assay. The reproducibility of the assay on a frozen viral stock preparation was within an endpoint of one tenfold dilution.

Animals↗
PubMed1978

Simple method for preparation of specific antisera against viral proteins: rabbit antisera against equine infectious anemia virus proteins p26 and p16.

A simple method for preparation of highly specific antisera against equine infectious anemia virus proteins p26 and p16 is described. Viral proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The motility of the viral proteins in the gel was compared with standards. Unstained portions of the slab gel were sliced into 5-mm bands, emulsified with Freund's complete adjuvant, and injected into rabbits to produce specific antisera.

Animals↗
PubMed1976

Transmission of equine infectious anemia virus by Tabanus fuscicostatus.

The mechanical transmission of equine infectious anemia (EIA) virus by Tabanus fuscicostatus was investigated. In 1 of 7 transmission trials, a single horsefly transmitted EIA virus from an acutely infected pony to a susceptible pony. Groups of horseflies isolated for 3, 10, or 30 minutes before refeeding transmitted EIA virus, whereas those isolated for 4 or 24 hours did not. Data from field studies indicate that the home range or flight distance of horseflies may exceed 4 miles. That information together with our observations suggest that segregation of infected horses (usually defined as at least 200 yards from susceptible horses) as a control measure for EIA may not be an adequate safeguard against transmission in areas where horseflies are numerous.

Animals↗
PubMed1975

Selection for plaque variants of two California group arboviruses (Jamestown canyon and La Crosse) by passage in natural vertebrate hosts.

The plaque size and distribution of prototype La Crosse (LAC) and Jamestown Canyon (JC) viruses were investigated in Vero cell cultures. The effect of serial passage of the viruses in their natural vertebrate hosts - the chipmunk and grey squirrel for LAC and the white-tailed deer for JC virus - was studied. Prototype JC virus was predominately a pinpoint plaque type (about 0.3 mm in diameter). A large plaque variant (about 1.0 mm in diameter), which was only 1 percent of prototype JC virus, increased to over 80 percent of the resultant virus after one passage in white-tailed deer. The large plaque type (about 1.0 mm in diameter) also predominated in JC isolates from mosquitoes, biting flies, and a white-tailed deer in Wisconsin. Prototype LAC virus consisted of a variety of plaque sizes, ranging in diameter from 0.3 mm to 3.0 mm. Passage through chipmunks increased the mean plaque diameter almost twofold, whereas passage in the grey squirrel resulted in a more uniform small plaque population practically eliminating the largest plaques. Preliminary results suggest that the resultant viruses are antigenically different. If these selective processes occur in nature, they man explain how four serologically related California group arboviruses with distinct vector-host cycles in nature could have evolved and have sympatric distribution.

Animals↗