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Biomedical subjects

S M Goyal

Publications and source records attributed to S M Goyal.

At least 55 records · Page 3Linked to original sources
PubMed1993

Persistence of bovid herpesvirus-4 in experimentally inoculated pregnant rabbits.

To study the persistence and reactivation of bovid herpesvirus-4 (BHV-4), pregnant rabbits were inoculated with BHV-4 via the intrauterine route. Disease production and virus shedding were monitored for up to 67 days post infection (DPI). Virus isolation was attempted from nasal, vaginal and buffy coat samples of all rabbits. Virus shedding was observed between 5 and 12 DPI but not thereafter. Some of the animals were given intramuscular injections of dexamethasone (DEX) for 4 consecutive days starting at 7 weeks post infection. One group of rabbits was euthanized at 5 days post-DEX treatment (58 DPI) and the other was euthanized 2 weeks post-DEX treatment (67 DPI). Virus shedding was not detected in either group but BHV-4 was recovered on multiple occasions from spleen, kidney, uterus, and ovary explants of both DEX-treated and non-treated rabbits indicating that BHV-4 can persist in these organs but cannot be reactivated by DEX. To further study the in vitro reactivation of persistent BHV-4, a methylating agent, hexamethylenebisacetamide (HMBA), was used in organ cultures of neural and extraneural tissues. Limited data on enhanced recovery of BHV-4 from spleen indicated that it may be the site of latency in BHV-4 infection.

Acetamides↗
PubMed1992

Use of an enzyme-linked immunosorbent assay for detection of infection with pseudorabies virus on a herd basis.

The use of an ELISA that can differentiate between swine infected with pseudorabies virus (PRV) and swine vaccinated with a specific PRV vaccine was evaluated on an individual and herd basis, and a system for interpreting ELISA results on a herd basis was developed. In 17 herds, recently introduced replacement gilts, seronegative for PRV, were vaccinated with a thymidine kinase- and glycoprotein X (gpX)-deleted vaccine. After vaccination, blood samples were collected from these gilts approximately every 1 to 2 months for up to 19 months. Serum samples were analyzed for antibodies to gpX antigen, using a commercially available ELISA kit according to the manufacturer's protocol. Herd status was determined as positive, suspect, or negative, according to the serum sample:negative control (S:N) values of the samples collected from the herd. From the 17 herds, 130 evaluations were performed. On 49 (38%) of the 130 herd evaluations, 1 or more gilts had suspect test results. Additional testing was required in 19 (39%) of these 49 herd evaluations to determine the PRV infection status of the herd. Status of herds having gilts with suspect results and no positive results was usually negative after retesting. Herds having gilts with positive results were unlikely to have negative status after retesting.

Animals↗
PubMed1992

Isolation of swine infertility and respiratory syndrome virus (isolate ATCC VR-2332) in North America and experimental reproduction of the disease in gnotobiotic pigs.

A recent epizootic of swine infertility and respiratory syndrome (SIRS) in a Minnesota swine herd was investigated. Examination of a sow, neonatal piglets, and stillborn fetuses obtained during the epizootic from the affected herd revealed interstitial pneumonitis, lymphomononuclear encephalitis, and lymphomononuclear myocarditis in the piglets and focal vasculitis in the brain of the sow. Fetuses did not have microscopic lesions. No cause for the infertility and respiratory syndrome was determined. Therefore, attempts were made to experimentally reproduce the disease. Eleven 3-day-old gnotobiotic piglets exposed intranasally to tissue homogenates of piglets from the epizootic became inappetent and febrile by 2-4 days postexposure and had interstitial pneumonitis and encephalitis similar to that seen in the field outbreak. After 2 blind passages in gnotobiotic piglets, tissue homogenates were cultured on continuous cell line CL2621, and a cytopathic virus (ATCC VR-2332), provisionally named SIRS virus, was isolated. Gnotobiotic piglets exposed intranasally to the SIRS virus developed clinical signs and microscopic lesions that were the same as those in piglets exposed to the tissue homogenates, and the virus was reisolated from their lungs. This is the first isolate of SIRS virus in the United States that fulfills Koch's postulates in producing the respiratory form of the disease in gnotobiotic piglets and the first report of isolation and propagation of the virus on a continuous cell line (CL2621). The virus is designated as American Type Culture Collection VR-2332.

Animals↗
PubMed1992

Characterization of swine infertility and respiratory syndrome (SIRS) virus (isolate ATCC VR-2332).

The characterization of an isolate of swine infertility and respiratory syndrome (SIRS) virus (ATCC VR-2332) is reported. A commercial cell line (CL2621) was used for the propagation of the virus for all assays. Laboratory studies indicate that this isolate is a fastidious, nonhemagglutinating, enveloped RNA virus. Cesium chloride-purified virions visualized by electron microscopy were spherical particles with an average diameter of 62 nm (range: 48-83 nm) and a 25-30 nm core surrounded by an envelope. Virus replication was restricted to the cytoplasm, as demonstrated by immunofluorescence. The virus did not react serologically with antisera to several common porcine viruses or with antisera to known viruses in the alphavirus, rubivirus, pestivirus, and ungrouped lactic dehydrogenase virus genera of the Togaviridae. However, convalescent sow sera and rabbit hyperimmune sera neutralized the SIRS virus at titers of 1:256 and 1:512, respectively. The virus was stable at 4 and -70 C, but was labile at 37 and 56 C. The properties of this isolate of SIRS virus resemble those of the family Togaviridae but do not match the described genera.

Animals↗
PubMed1992

Seroprevalence of Lyme disease in gray wolves from Minnesota and Wisconsin.

To determine the seroprevalence of Lyme disease in gray wolves (Canis lupus) from various counties of Minnesota and Wisconsin (USA), 589 serum samples were collected from 528 wolves from 1972 to 1989. An indirect fluorescent antibody (IFA) test was used to detect the presence of antibodies against Borrelia burgdorferi. Titers of greater than or equal to 1:100 were considered positive. Results were confirmed by testing a few selected sera by Western blotting. Of the 589 sera tested, 15 (3%) had IFA titers of greater than or equal to 1:100. Three of the positive samples were collected from Douglas County in Wisconsin and twelve were from Minnesota counties. This study indicates that wolves are exposed to B. burgdorferi and are susceptible to Lyme disease.

Animals↗
PubMed1992

Prevalence of antibody titers to Leptospira spp. in Minnesota white-tailed deer.

Serum samples (n = 204) from 124 white-tailed deer (Odocoileus virginianus) in northeastern Minnesota (USA) were collected from 1984 through 1989 and tested for antibodies to six serovars of Leptospira interrogans (bratislava, canicola, grippotyphosa, hardjo, icterohemorrhagiae, and pomona) using a microtiter agglutination test. Eighty-eight (43%) sera were positive at greater than or equal to 1:100 for antibodies against serovars pomona and/or bratislava; none was positive for any of the other four serovars. None of the 31 sera collected in 1984-85 was positive, whereas all 54 sera collected from 1986 through 1988 had titers of greater than or equal to 1:100. During 1989, only 34 (29%) of 119 sera had titers of greater than or equal to 1:100. Based on these results, we believe there to be wide variability in exposure of Minnesota deer to Leptospira interrogans.

Agglutination Tests↗
PubMed1992

Evaluation of three methods for the concentration of poliovirus from oysters.

Three methods for the concentration of poliovirus from oyster homogenates were compared. The adsorption-elution-precipitation method gave the lowest average virus recovery (24.1%), while the beef extract elution-acid precipitation method and the non-fat dry milk elution-acid precipitation methods gave recoveries of 47.2% and 39.6%, respectively. Although the overall recovery rates with these methods were lower than those reported in previous studies, recoveries of 40-47% obtained with the elution-precipitation methods used in the present study are considered to be above average in terms of recovery efficiency.

Animals↗
PubMed1992

Comparison of three immunoassays for the rapid detection of bovine respiratory syncytial virus.

Three enzyme-linked immunosorbent assays (EIA) designed for the detection of human respiratory syncytial virus (RSV) were evaluated for the detection of bovine respiratory syncytial virus (BRSV) in bovine lungs and the results were compared with those obtained by a direct fluorescent antibody assay (DFA). The EIA tests used were Directigen EIA, Kallestad Pathfinder EIA, and Abbott RSV EIA. Homogenates of lung tissues obtained from 64 cattle that had died of respiratory disease were used; 32 were positive by DFA and 32 were negative. All EIA's varied in the amount of labor and time involved but their relative sensitivities were similar ranging between 59 and 66% when compared with DFA. The specificity of Pathfinder EIA was lower than those of the Directigen and Abbott tests. The overall agreement between the three EIA's and the DFA was 66-77% indicating that DFA is still the test of choice for detecting BRSV infection in lung tissues of cattle.

Animals↗
PubMed1991

Clinical evaluation of cats with lower urinary tract disease.

In a prospective study, 141 cats with hematuria, dysuria, urethral obstruction, or combinations of these signs were evaluated by contemporary diagnostic methods and compared with 26 clinically normal cats (controls). Specific diagnosis was established in 45% (64/141) of cats affected with lower urinary tract disease (LUTD). Crystalline matrix plug-induced urethral obstruction was diagnosed in 21% (30/141) of affected cats, uroliths were identified in 21% (30/141) of affected cats, uroliths with concomitant bacterial urinary tract infection (UTI) were identified in less than 2% (2/141) of affected cats, and bacterial UTI alone was identified in less than 2% (2/141) of cats with LUTD. Viruses, mycoplasmas, and ureaplasmas were not isolated from urine samples collected from affected or control cats. Bovine herpesvirus 4 (BHV-4)-neutralizing antibodies were not detected in any serum sample obtained from cats with LUTD or from control cats. In contrast, BHV-4 antibodies were detected by an indirect immunofluorescent antibody (IFA) test in sera obtained from 31% (44/141) of cats with LUTD and 23% (6/26) of control cats. The prevalence of positive BHV-4 IFA test results in affected cats was not significantly different from that observed in control cats. Significant association was not apparent between positive BHV-4 IFA test results and clinical diagnosis, abnormal laboratory findings, or cat age. However, the number of male cats with BHV-4 IFA titer was significantly (P less than 0.02, chi 2 test) greater than that of female cats. Detection of BHV-4 antibodies in approximately 30% of affected and control cats indicates prior virus exposure. Further investigations are warranted to clarify the specific role of BHV-4 in cats with naturally acquired LUTD.

Animals↗
PubMed1991

Pig herds having a single reactor to serum antibody tests to Aujeszky's disease virus.

The introduction of Aujeszky's disease virus into a herd of pigs usually results in a rapid spread of the virus and a high percentage of pigs become seropositive. However, herd monitoring for the virus occasionally reveals a single seropositive breeding pig, referred to as a single reactor. The seropositive status of single reactors may be due to previous vaccination against Aujeszky's disease, or to exposure to a field strain of the virus, or to a false positive reaction in the serological assay. During a monitoring programme in Minnesota, 30 pig herds with single serological reactors were detected. Twenty-seven of these single reactors from 19 herds were segregated from their herds immunosuppressed with dexamethasone. Aujeszky's disease virus was isolated from four of the 27 pigs. Three of the four herds subsequently had outbreaks of Aujeszky's disease, suggesting that some single reactors were infected with Aujeszky's disease virus and had the potential to spread the virus within and between herds.

Animals↗
PubMed1991

Tissue distribution of bovid herpesvirus-4 in inoculated rabbits and its detection by DNA hybridization and polymerase chain reaction.

A DNA hybridization technique, using the polyrepetitive EcoRI L-fragment of bovid herpesvirus (BHV-4) as a probe, was developed to determine virus distribution in the tissues of BHV-4-infected pregnant rabbits. The cloned fragment did not react with the DNA of rabbits or of other herpesviruses, e.g., infectious bovine rhinotracheitis, bovine herpes virus mammillitis, and pseudorabies viruses. The detection limit was 10(-13) g of DNA or approximately 600 genome equivalents of viral DNA, which indicates a level of sensitivity of one viral genome per 500 cells in our assay. Using conventional cell culture techniques, the virus was isolated from only one of fifteen infected rabbits and a few aborted fetuses. However, when organ culture or dot blot hybridization was used, BHV-4 was detected in all rabbits and their fetuses. Viral DNA was detected by DNA hybridization in spleen, ovary, uterus, lung, liver, salivary gland, lymph node, and placentome of adult rabbits and in a composite of fetal tissues. When polymerase chain reaction (PCR) was used, the virus was detected in several organs (including the nervous tissues) that were found negative by other techniques. These results indicate that blot hybridization and PCR are more sensitive than conventional techniques for studying the pathogenesis of BHV-4 in animals. The data obtained by these methods suggest that BHV-4 may be maintained in infected rabbits in a latent state in a variety of tissues including the nervous system.

Animals↗
PubMed1991

Variation in the pathogenic potential and molecular characteristics of bovid herpesvirus-4 isolates.

Seven bovid herpesvirus-4 (BHV-4) isolates recovered from various clinical conditions of cattle were studied for their pathogenic potential in pregnant rabbits. These viruses were originally recovered from respiratory and reproductive tract infections of cattle. A virus dose of 4 x 10(6.8)TCID50 per fetus was inoculated via the intrauterine route in 10- and 17-day pregnant rabbits. Clinical, virologic, and pathologic data were collected to compare the effect of each isolate on does and fetuses/kits. Three isolates (LVR-140, QVR-3140 and 86-068) caused abortion, fetal reabsorption and/or mummification in inoculated rabbits. Virus was recovered from tissues of inoculated rabbits (especially the spleen, ovaries and uterus) by organ explanation and/or co-cultivation. Intravenous inoculation of isolate 86-068 did not produce any clinical signs in either 10- or 17-day pregnant rabbits. All seven isolates of BHV-4 showed a predilection for the reproductive tract of pregnant rabbits but varied in the severity of disease signs produced. Variation was also observed in the genome of various isolates on the basis of restriction endonuclease (RE) analysis. Relationship of RE patterns to the variation in the pathogenic potential of seven BHV-4 isolates is discussed.

Animals↗
PubMed1991

Multilaboratory evaluation of methods for detecting enteric viruses in soils.

Two candidate methods for the recovery and detection of viruses in soil were subjected to round robin comparative testing by members of the American Society for Testing and Materials D19:24:04:04 Subcommittee Task Group. Selection of the methods, designated "Berg" and "Goyal," was based on results of an initial screening which indicated that both met basic criteria considered essential by the task group. Both methods utilized beef extract solutions to achieve desorption and recovery of viruses from representative soils: a fine sand soil, an organic muck soil, a sandy loam soil, and a clay loam soil. One of the two methods, Goyal, also used a secondary concentration of resulting soil eluants via low-pH organic flocculation to achieve a smaller final assay volume. Evaluation of the two methods was simultaneously performed in replicate by nine different laboratories. Each of the produced samples was divided into portions, and these were respectively subjected to quantitative viral plaque assay by both the individual, termed independent, laboratory which had done the soil processing and a single common reference laboratory, using a single cell line and passage level. The Berg method seemed to produce slightly higher virus recovery values; however, the differences in virus assay titers for samples produced by the two methods were not statistically significant (P less than or equal to 0.05) for any one of the four soils. Despite this lack of a method effect, there was a statistically significant laboratory effect exhibited by assay titers from the independent versus reference laboratories for two of the soils, sandy loam and clay loam.

Enterovirus↗
PubMed1991

Seroepidemiology of leptospirosis in Minnesota wolves.

Serum samples (n = 457) from wolves (Canis lupus) in northern Minnesota were collected from 1972 through 1986 and were tested for antibodies against Leptospira interrogans using a microtiter agglutination test. Twelve serovars included in the study were: australis, autumnalis, ballum, bataviae, bratislava, canicola, copenhageni, grippotyphosa, hardjo, pomona, pyrogenes, and tarassovi. Fifty-two (11%) sera had antibody titers of greater than or equal to 1:50 against one or more serovars of L. interrogans. The seroprevalence of different serovars in decreasing order was: grippotyphosa, bratislava, autumnalis, canicola, pomona, ballum, pyrogenes, hardjo, and copenhageni. No antibodies were found against australis, bataviae, and tarassovi. These results indicate that L. interrogans infection may occur in wolves of Minnesota.

Agglutination Tests↗
PubMed1990

Excretion and persistence of bovine coronavirus in neonatal calves.

Following oral inoculation, the excretion of a virulent or an attenuated strain of bovine coronavirus in calf feces and their persistence in spiral colon, ileum, and jejunum were studied using hemagglutination and direct fluorescent antibody tests, respectively. The virus was excreted in feces for only 3 days at high titers and then intermittently at low titers. However, viral antigen was detected in crypt or Peyer's patches for at least 3 weeks after infection in 1 of 3 calves given virulent virus and 1 of 2 calves given attenuated virus.

Animals↗
PubMed1990

A dot immunobinding assay on nitrocellulose for the detection of bovid herpesvirus-4 antibodies.

A dot immunobinding assay (DIA) was developed for the detection of antibody against bovid herpesvirus-4 (BHV-4) in bovine sera. A semipurified virus preparation was used as the antigen and an antispecies horseradish peroxidase-labeled IgG and diaminobenzidine were employed as the detection system. The sensitivity and specificity of the DIA were similar to those of indirect fluorescent antibody test, indicating the suitability of DIA as a rapid field test for the detection of anti-BHV-4 antibodies in cattle.

Animals↗