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Biomedical subjects

A E Castro

Publications and source records attributed to A E Castro.

At least 37 records · Page 2Linked to original sources
PubMed1990

Comparison of polyacrylamide gel electrophoresis, an enzyme-linked-immunosorbent assay, and an agglutination test for the direct identification of bovine rotavirus from feces and coelectrophoresis of viral RNAs.

The dsRNA concentrated polyacrylamide gel electrophoresis (CPAGE) detected rotavirus directly from 19% of 77 stool specimens from diarrheic calves. A commercial enzyme-linked immunosorbent assay (ELISA) detected 25%, latex agglutination test, 23%, and polyacrylamide gel electrophoresis (PAGE), 19%. Establishing CPAGE as the "standard," the commercial ELISA and the latex agglutination test both had higher sensitivity (84%) than PAGE (79%). However, PAGE produced the highest specificity (100%), followed by agglutination (88%) and ELISA (84%). The commercial ELISA had a slightly higher sensitivity than agglutination, PAGE, and CPAGE, but the ELISA specificity was generally lower. The latex agglutination test had a lower sensitivity than ELISA, but specificity was higher. Agglutination had similar negative predictive values (94%), compared with agglutination and PAGe, but had the lowest positive predictive value (a measure of accuracy) (70%). Agreement with CPAGE was highest for PAGE (94.8%), followed by agglutination (87%) and ELISA (84.4%). The calculated percentages of total disagreement with all other tests indicated that ELISA differed from the other rotavirus detection assays in 10.4% of the cases, agglutination in 7.8%, PAGE in 2.6%, and CPAGE in 1.3%. The 2 PAGE assays allowed the detection of atypical rotaviruses from feces based on the characteristic "super-short" migration pattern of the 11 genomic segments of rotaviruses and of other members of the Reoviridae.

Animals↗
PubMed1989

Comparison of genomes of malignant catarrhal fever-associated herpesviruses by restriction endonuclease analysis.

The restriction endonuclease DNA cleavage patterns of eight isolates of malignant catarrhal fever-associated herpesviruses were examined using the restriction endonucleases HindIII and EcoRI. The eight viruses could be assigned to two distinct groups. Virus isolates from a blue wildebeest, a sika deer and an ibex had restriction endonuclease DNA cleavage patterns that were in general similar to each other. The restriction pattern of these three viruses was distinct from the other five. Of these five, four were isolated from a greater kudu, a white tailed wildebeest, a white bearded wildebeest, and a cape hartebeest. The fifth isolate C500, was isolated from a domestic cow with malignant catarrhal fever. These five viruses had similar DNA cleavage patterns.

Animals↗
PubMed1989

A rapid monoclonal immunofluorescence assay for Chlamydia psittaci in fecal smears from psittacine birds.

One hundred two fecal specimens from psittacine birds submitted to Veterinary Laboratory Services of the California Department of Food and Agriculture at Petaluma were screened for Chlamydia psittaci by a direct immunofluorescence assay using a fluorescein-labeled monoclonal antibody conjugate specific for Chlamydia sp. Results were compared with those obtained by isolation of chlamydia in cultures of McCoy mouse cells. The relative specificity of the direct fluorescent antibody test on fecal smears was 98.9% and the relative sensitivity was 62.5%. The results of this study suggested that the direct fluorescent antibody test was highly specific, and it proved to be a useful same-day antemortem diagnostic test for birds with symptomatic chlamydial infection. The use of centrifugation in the cell culture assay was found to significantly enhance the level of chlamydial infection in cell culture.

Animals↗
PubMed1989

Susceptibility of a fetal tongue cell line derived from bighorn sheep to five serotypes of bluetongue virus and its potential for the isolation of viruses.

A cell line (BHFTE) was derived from a tongue explant of a bighorn sheep fetus (Ovis canadensis nelsoni). The cells have been maintained through 23 serial passages, and the modal number of chromosomes was calculated to be 55. Monolayer cultures were shown to be susceptible to various viruses, including bluetongue virus (BTV). Of 5 BTV serotypes (2, 10, 11, 13, and 17) tested, each produced a cytopathic effect (CPE) on initial passage at 33 C. A field isolate (serotype 10) of BTV from a black-tailed deer (Odocoileus hemionus columbianus) in its second passage in Vero-M cells also produced CPE when inoculated into BHFTE cells. Antigens of BTV were demonstrated by direct immunofluorescence in the cytoplasm of BHFTE cells inoculated with homogenates of chicken embryos injected with clinical specimens from a domestic sheep and an Arabian oryx (Oryx gazella leucoryx). A suspension of BTV-infected gnats (Culicoides spp.) produced CPE and BTV-specific fluorescence on the first passage in cells inoculated with a suspension of blood from sheep experimentally infected with BTV. Additionally, selected bovine viruses induced CPE in the cells. The cell line, which is free of mycoplasma and bovine viral diarrhea virus contamination, may be useful in diagnostic medicine and research involving the ruminant species.

Animals↗
PubMed1989

Association of Reoviridae particles in an enteric syndrome of poults observed in turkey flocks during 1988.

An enteric syndrome of turkey poults, characterized by enteritis, crop mycosis, intestinal changes (pale, thin-walled ballooning with watery contents), and rickets, occurred during 1988 in 74 turkey flocks from different farms belonging to 9 California turkey growers. The flocks ranged in size from 9,000 to 120,000 birds. Pools of intestine sections from 618 birds, representing 78 field cases, were examined. Histopathological examination of the intestines showed a mild to severe atrophy with a reduced depth of crypts, which was more prominent in the distal part of the small intestine. Viral isolation attempts with primary cell cultures of chicken embryo kidney cells were negative. Examination by electron microscopy of negatively stained intestinal specimens revealed the presence of Reoviridae particles of 58.8 to 80 nm in diameter. Enzyme-linked immunosorbent assay results on the intestinal pools for mammalian and group A avian rotaviruses were negative. A statistically significant relationship was found for the presence of Reoviridae particles in the intestines of 10-21-day-old birds. Of the 7 most common pathological conditions analyzed, 2, rickets and intestinal changes (thin-walled ballooning intestine with watery contents), showed a statistically significant association with the presence of Reoviridae particles.

Age Factors↗
PubMed1988

Effect of interferons on the replication of alcelaphine herpesvirus-1 of malignant catarrhal fever.

Four isolates of alcelaphine herpesvirus-1 of malignant catarrhal fever (MCF) were tested for their inducibility of and sensitivity to various interferons. Viral isolates from an Indian gaur (Bos gaurus), a greater kudu (Tragelaphus strepsiceros) and two wildebeest (Connochaetes gnou) calves did not induce measurable interferon (IFN) in bovine fetal kidney cells. However, these low passages of each virus were all highly cell-associated and viral replication was inhibited at these passages by IFN at 14 IFN units/0.05 ml recovered from NDV-infected MDBK cells and at 7.6 IFN units/0.05 ml of IFN from NDV-infected bovine macrophages. The herpesvirus from the Indian gaur and greater kudu and high passages (greater than 50) of the cell-free WC-11 strain of alcelaphine herpesvirus-1 also were inhibited in their replication by recombinant IFN of bovine and human origins as determined by a fluorescent focus unit (FFU) reduction assay. The concentrations of IFN required to produce a 50% reduction in herpesvirus-produced FFU ranged between 6.4 and 480 IFN units. These findings promote the use of IFN as part of the regimens of treatment of captive endangered ruminant species with clinical MCF.

Animals↗
PubMed1988

Enzyme-linked immunosorbent assay for the detection of antibodies to the alcelaphine herpesvirus of malignant catarrhal fever in exotic ruminants.

An ELISA for antibodies to the alcelaphine herpesvirus-1 of malignant catarrhal fever was developed. Of sera that represented 42 exotic ruminant species, 216 were evaluated by the ELISA and a virus-neutralization test. A significant correlation (r = 0.564, P less than 0.001, n = 216) between the ELISA and virus-neutralization test results was found. Of the sera having positive test results by virus neutralization, 86.1% also had positive results by the ELISA, and of the sera having negative test results by virus neutralization, 83.9% also had negative results by the ELISA. The presence of antibody, as measured by the ELISA, correlated with clinical signs of malignant catarrhal fever and the isolation of herpesvirus.

Animals↗
PubMed1987

Bluetongue and epizootic hemorrhagic disease in white-tailed deer from Oklahoma: serologic evaluation and virus isolation.

Blood samples were collected from 194 white-tailed deer from 27 locations in Oklahoma from 1977 through 1984. Sixty-eight (35%) of the deer had antibody against bluetongue virus (BTV) and 78 (40%) had antibody against epizootic hemorrhagic disease virus. Seropositive deer were detected in each of the 4 geographic quadrants of the state. Virus isolation was attempted in 40 deer from the northeast quadrant of Oklahoma (1983 through 1984); BTV was isolated from 11 deer, but epizootic hemorrhagic disease virus was not isolated. The isolation of BTV serotype 11 from these deer from 1983 through 1984 coincided with reported isolations of this serotype in other ruminants in Oklahoma during this time.

Animals↗
PubMed1986

Canary pox causing high mortality in an aviary.

In an aviary housing 200 six-month-old canaries, 165 became ill and 145 died over a 6-week period from a disease initially characterized by lethargy, ruffled feathers, open-mouth breathing, and death in 2 to 3 days. Proliferative "pox-like" lesions around the eyes and mouth were not seen until the 4th week. At necropsy, initially affected birds had cloudy air sacs and patchy pneumonia. Histologically, the lungs had proliferative necrotizing bronchitis. Birds necropsied later had proliferative skin lesions and intracytoplasmic inclusions typical of poxvirus in the epidermis and airway epithelium. A virus was isolated from an organ pool of lung, air sac, liver, and skin of affected birds and was identified by electron microscopy as poxvirus.

Animals↗
PubMed1986

Unusual characteristics of a parvovirus isolated from a clinically ill steer.

A parvovirus was isolated from the feces of an 8- and 9-month-old steer that died acutely with hemorrhagic diarrhea and microscopic evidence of a coccidial infection. The concurrent intestinal parasitism in this steer appeared to play a role in the development of clinical disease. The viral isolate was identified as a bovine parvovirus (BPV) on the basis of its size (22 nm) and icosahedral morphology, the neutralization of viral cytopathology by antiserum to BPV, a strong immunofluorescent reaction with fluorescein-labeled antiserum to BPV, and the inhibition of viral hemagglutination of guinea-pig erythrocytes by antiserum to BPV. Cell cultures infected with this isolate showed a slight nuclear fluorescent reaction with fluorescein-labeled antiserum to canine parvovirus, suggesting an antigenic relationship to canine parvovirus. Patterns of hemagglutination for this isolate with human erythrocytes from 20 donors of various blood types differed from those obtained with the reference Abinanti strain of BPV. These results indicate that blood from multiple donors of a species may be necessary to confirm the presence or absence of viral hemagglutinating activity with clinical isolates of BPV.

Animals↗
PubMed1985

Serologic evaluation of vaccinated American river otters.

The Oklahoma Department of Wildlife Conservation acquired 20 American river otters (Lutra canadensis) between 1984 and 1985 for reintroduction into Oklahoma waterways. In 1985, 10 otters were evaluated for serum antibody titers after vaccination with canine distemper virus, canine adenovirus type 2, canine parvovirus (CPV), feline panleukopenia virus (FPV), feline rhinotracheitis virus (FRV), and feline calicivirus. Prevaccination serum-virus neutralization (SVN) antibody to feline rhinotracheitis virus was found in 2 otters and to feline calicivirus in 1 otter. Using an indirect fluorescent antibody (IFA) assay, prevaccination antibody to CPV and FPV was found in 2 otters. A significant increase in SVN antibody titers was found after vaccination of otters with canine adenovirus type 2 (6 of 8 animals) and feline calicivirus (1 of 8 animals). One of 8 otters developed significant antibody titers to CPV and FPV, as measured by IFA assay. Otters did not develop SVN antibody titers to canine distemper virus after vaccination. Antigens of feline leukemia virus, using ELISA, or antibodies to feline infectious peritonitis, using IFA assay, were not found in the 20 otters.

Adenoviridae↗
PubMed1985

Dexamethasone-induced recrudescence of malignant catarrhal fever and associated lymphosarcoma and granulomatous disease in a Formosan sika deer (Cervus nippon taiouanus).

Malignant catarrhal fever (MCF) was diagnosed in a 2-week-old Formosan sika deer. The fawn had been previously exposed to a clinically normal neonatal wildebeest calf from which alcelaphine herpesvirus-1 was isolated. Alcelaphine herpesvirus-1 was isolated from buffy coat leukocytes and nasal and ocular secretions of the fawn during the acute illness. The fawn clinically recovered after 3 weeks. Virus was not recovered from blood at this time. Dexamethasone, given 4 months after clinical recovery, resulted in reisolation of MCF virus from blood and recrudescence of clinical MCF. The deer was euthanatized. At necropsy, pathognomonic lesions of MCF, granulomatous disease, and malignant lymphoma were observed. Antibodies to bovine leukosis viral antigens were not detected in the serum. The epidemiologic and pathogenetic importance of the findings are discussed.

Animals↗
PubMed1985

Ultrastructure of cellular changes in the replication of the alcelaphine herpesvirus-1 of malignant catarrhal fever.

Cell cultures inoculated with 5 different viral isolates from 4 species of ruminants with clinical signs of malignant catarrhal fever (from the San Diego Wild Animal Park) were examined by electron microscopy. Each had the morphology of a herpesvirus (118 to 220 nm) and was icosahedral, and the nucleocapsid matured in the nucleus of the infected cell. Envelopment of budding occurred with each viral isolate at the nuclear and the plasma membranes. The virions egressed from the cell by budding from the plasma membrane or through channels of the Golgi apparatus or the endoplasmic reticulum. A proposed scheme for the morphogenesis of the herpesvirus of malignant catarrhal fever is presented.

Animals↗
PubMed1984

Characteristics of the herpesvirus of malignant catarrhal fever isolated from captive wildebeest calves.

A herpesvirus was isolated from buffy coat cells from a newborn wildebeest (Connochaetes gnou) and from tissues of a 12-day-old wildebeest during the 1982 calving season of a captive, inbred herd maintained in a zoologic collection. Both wildebeests were clinically healthy, and there was no herd record that malignant catarrhal fever (MCF) existed. Each viral isolate produced cytopathologic changes in bovine kidney cell cultures (intranuclear inclusions and massive syncytia). The viral-infected cell cultures contained antigens of MCF virus detected by immunofluorescence. The morphology of each viral isolate as determined by electron microscopy was that of a herpesvirus. Suspensions of 4 to 5 ml of disrupted cell culture material which contained virus from each wildebeest were inoculated (IV) into white-tailed deer (Odocoileus virginianus). Each deer became clinically ill within 28 days. Both deer had mucoid catarrh and a febrile response (40.5 to 41 C). Each also seroconverted to MCF virus. The histopathologic change in the tissues from the 2 inoculated deer was vasculitis. At 16 to 17 days after the deer were inoculated, a syncytial-forming virus was isolated from each deer from buffy coat cells fused with polyethylene glycol (1000) to bovine fetal kidney cells. The virus was identified as MCF virus by immunofluorescence and production of antibody to MCF virus. The presence of virus in the inbred wildebeest herd established this species as a reservoir or latent carrier of African MCF virus at the zoologic park.

Animals↗