Results Of Virus Isolation Research Articles

Comparison of four test kits for feline leukemia virus antigen

Summary The sensitivity and specificity of 4 commercial FeLV elisa kits, using blood, were compared with results of virus isolation from blood and immunofluorescent antibody (ifa) testing on blood. Significant differences were not found among the 4 elisa kits. Marked decrease in sensitivity of the elisa kits was detected when virus isolation was used as the standard of positivity rather than the ifa test. Virus isolation was a more sensitive indicator of early infection, with marked discrepancy among results obtained by virus isolation, elisa, and the ifa test. Results became progressively more concordant as infection became fully established. Cats FeLV-positive by virus isolation alone were more likely to eliminate viremia. All cats FeLV-positive by ifa testing remained persistently viremic. Virus isolation, elisa, and ifa testing appear to differ in their prognostic value. The use of blood rather than serum for the elisa resulted in several discordant results. Six cats were FeLV-positive by elisa when blood was tested but were FeLV-negative when serum was tested. Positive elisa results were obtained for 4 of these cats when serum was tested, using extended incubation to increase sensitivity. It is possible that blood may actually be more sensitive than serum for use of the elisa method.

Comparison of the efficacy of three commercial feline leukemia virus vaccines in a natural challenge exposure

Summary Forty-seven kittens were exposed for 31 weeks to 12 FeLV-positive carrier cats. The carrier cats were infected with 2 laboratory strains of FeLV and at least 2 strains of street virus. Eleven nonvaccinated control kittens and 12 vaccinated kittens were allotted to 3 groups. After 31 weeks of exposure, the following kittens were persistently blood FeLV positive by elisa and immunofluorescence antibody (ifa) testing: 7 of the 11 control kittens, 0 of 12 kittens inoculated with vaccine A, 5 of 12 kittens inoculated with vaccine B, and 6 of 12 kittens inoculated with vaccine C. Only the kittens inoculated with vaccine A were significantly (P < 0.05) different from the control group. After 23 weeks of exposure, culture was done to identify FeLV in the bone marrow of the kittens. Feline leukemia virus was isolated from the bone marrow of 9 of 11 control kittens. Virus was isolated from the bone marrow of 5 of 12 kittens inoculated with vaccine A, 11 of 12 kittens inoculated with vaccine B, and 10 of 12 kittens inoculated with vaccine C. Of the 17 cats that had FeLV isolated only from culture of bone marrow (negative results of blood virus isolation, elisa, and ifa testing), 13 eliminated the virus from the bone marrow by week 31 of exposure. After 31 weeks of exposure, FeLV was isolated from the bone marrow of 8 of 11 control kittens, O of 12 kittens inoculated with vaccine A, 7 of 12 kittens inoculated with vaccine B, and 7 of 12 kittens inoculated with vaccine C.

1986年の北九州市におけるエコーウイルス7型の流行について

In 1986, under the Infectious Disease Surveillance system in Fukuoka Prefecture, no isolation of echovirus type 7 from aseptic meningitis patients were reported. It was unclear that epidemics of this virus occurred in Fukuoka Prefecture, including Kitakyushu City. We tried to isolate enteric viruses from the sewage (activated sludges) in Kitakyushu City in 1986. Outbreaks of isolations of echovirus type 7 started in September and continued until in December. This result suggested that echovirus type 7 caused epidemic during this period in Kitakyushu City. Sera were collected from children in 1989, and were examined neutralizing antibody titer against echovirus type 7. Antibody titers were positive in the sera of about half of children above 1 year of age in 1986. From results of virus isolations from the sewage and serological study, it was confirmed that echovirus type 7, reported no isolation in Fukuoka Prefectural surveillance system, caused epidemics in Kitakyushu City in 1986.

Detection of cattle infected with bovine viral diarrhea virus using nucleic acid hybridization.

A ribonucleic acid (RNA) hybridization assay to identify cattle infected by bovine viral diarrhea virus (BVDV) is described. The RNA probe was derived from the coding region at the 3' end of the genome of the NADL strain of BVDV. Total RNA from infected cell cultures or peripheral blood leukocytes from suspect animals was extracted and applied to nylon membranes with a slot blot apparatus. Peripheral blood leukocytes were tested concurrently for BVDV by virus isolation. The results of hybridization and virus isolation were in agreement for 92% of the cases. When compared with virus isolation, hybridization had a sensitivity of detection of 59.5% and a specificity of 95%. Cross-reactivity to RNA extracts of border disease virus-infected cells was noted. No cross-reactivity was detected to other common bovine viruses (bovine herpesvirus-1, bovine respiratory syncytial virus, parainfluenza-3 virus, and bluetongue virus), to viruses classified in related families (equine arteritis virus and Venezuelan equine encephalitis virus), or to viruses having similar genomic organization (dengue virus type 2 and Japanese encephalitis virus).

Equine herpesvirus type 1: Detection of viral DNA sequences in aborted fetuses with the polymerase chain reaction

Primers and probes were selected from the gene encoding glycoprotein 13 (gp13) of equine herpesvirus 1 (EHV-1). The polymerase chain reaction (PCR) was run on infected and noninfected cultured cells and on 63 specimens from 29 aborted equine fetuses. The results were evaluated by electrophoresis and dot-blot hybridization using an oligonucleotide probe labeled with biotin. In the infected samples electrophoresis showed a PCR product of about 280 base pairs. The dot-blot hybridization confirmed that this product contained EHV-1 DNA sequences. PCR took 4 h and hybridization another 14 h; the results were thus achieved within 24 h and were highly specific for EHV-1. Close concordance was found between the results of PCR and virus isolation.

Comparison of polyethylene glycol precipitation and ultracentrifugation for recovery of cytomegalovirus from urine prior to detection of DNA by dot-blot hybridisation

Polyethylene glycol (PEG) precipitation provided a useful alternative to ultracentrifugation for recovering cytomegalovirus (CMV) from clinical specimens prior to DNA hybridisation studies. The conditions for use of PEG are described. In a study of 61 urine samples from patients suspected of CMV infection 18 yielded a positive DNA hybridisation result. Fifteen were positive after both concentration procedures, two after PEG precipitation only and one after ultracentrifugation only. The DNA hybridisation results are discussed in the light of the results of virus isolation by cell culture.

Laryngotracheitis in Chickens: The Length of the Preinfectious and Infectious Periods

Transmission studies to measure the length of the infectious period and the interval between virus inoculation and infectiousness were conducted using the standard National Veterinary Services Laboratory laryngotracheitis (LT) challenge virus (Log 10(6.7) EID50 per ml). Previously unexposed sentinel chickens were placed in contact with chickens inoculated intratracheally with LT virus. Transmission of virus to the sentinel birds was assessed by studying clinical signs and results of virus isolation and challenge. Chickens began to shed infective quantities of virus 2-4 days postinoculation and continued until day 6.

Surveillance of arbovirus activity in Iowa, USA, 1978-1980.

Considerable information pertaining to the epidemiology of mosquito-borne viruses in Iowa, USA, has been acquired during a continuing arbovirus surveillance program. Virus isolation results indicate that Culex tarsalis is the primary vector of St. Louis encephalitis (SLE) and western equine encephalomyelitis (WEE) viruses in Iowa, but that Culex spp. ( Cx. pipiens, Cx. restuans, or Cx. salinarius ) may contribute to the amplification of SLE virus. Also, Aedes trivittatus may be important in the natural maintenance of WEE virus in Iowa. From 1978 through 1980, a total of 243 isolations of viruses such as Flanders and trivittatus were made from various species of mosquitoes in Iowa. Many of the wild-bird bloods tested had hemagglutination-inhibition (HI) antibodies (titer ≥ 20) to WEE virus, and a few had antibodies to SLE in Council Bluffs, where a human case occurred in 1980. Eighteen human cases of La Crosse encephalitis occurred in Iowa in 1978, and a 3-year-old girl who lived near the Iowa state line died from the effects of this virus. La Crosse virus was isolated from a pool of Aedes triseriatus collected in Dubuque, where a human case occurred in 1979 and a 2nd case occurred in 1980.

Rapid diagnosis of respiratory syncytial virus and influenza A virus infections by immunofluorescence: experience with a simplified procedure for the preparation of cell smears from nasopharyngeal secretions.

A simplified procedure for preparing direct smears of exfoliated cells from nasopharyngeal secretions is presented. The specimens were examined by the indirect immunofluorescence (IF) technique for the presence of respiratory syncytial (RS) virus and influenza A virus antigens. Specimens from 457 children hospitalised at twelve different hospital departments in Norway were examined during the winter season 1980-81. RS virus was identified in samples from 139 children and influenza A virus from 28. Results of IF examinations for RS virus were copositive with serology in 19 of 23 cases (83%) and with probably no false positive results. Samples from 29 children were also prepared by the conventional washing technique. RS virus was identified in 18 of these specimens. Seventeen of these were also found positive by the simplified method. This comparison was done blind. Compared to results of virus isolation and serology the IF examinations for influenza A virus were somewhat less sensitive with copositivity in 12 of 17 cases (71%) and in one instance the IF finding was probably false positive. However, also for influenza A virus our IF findings were fully comparable with figures obtained by others who performed the conventional washing technique for preparation of exfoliated cells from nasopharyngeal secretions. General practitioners submitted samples from 65 patients, and RS virus and influenza A virus were identified in eleven and four cases respectively. The simplicity of preparation of cell smears from nasopharyngeal secretions with our simplified method opens up the possibility of the application of rapid respiratory virus diagnostic service to an increasing number of hospital departments and also for general practitioners. We feel that this method is a suitable tool for surveillance of certain respiratory virus infections.

Rapid diagnostic tests for cutaneous eruptions of herpes simplex

Comparison was made of the results of virus isolation, indirect immunofluorescent staining (IF-test) and Tzanck smears from 32 patients with cutaneous eruptions clinically diagnosed as herpes simplex. Herpesvirus hominis was isolated from 21 patients; IF-test was positive in 22 patients; Tzanch smears were positive in 20 patients. 23 to 25 of the 25 patients in whom one of the diagnostic tests was positive could be identified by a combination of any two of the diagnostic methods employed. No false-positive reactions were observed for IF-test or Tzanck smear.

Radioimmunoassay of Herpes Simplex Virus Antibody: Correlation with Ganglionic Infection

SUMMARY Results of herpes simplex virus (HSV) isolation from a series of human postmortem trigeminal, thoracic and sacral ganglia were correlated with the HSV antibody type(s) detected in the sera by radioimmunoassay (RIA). HSV type 1 was isolated from trigeminal ganglia of 44 out of 90 individuals, from thoracic ganglia of 1 out of 25, and from sacral ganglia of 1 out of 68 cases. HSV type 2 was recovered from sacral ganglia of 8 out of 68 individuals. In all cases in which an HSV was isolated from ganglia and serum was available for testing, homologous, type-specific antibody was demonstrable, and in a few instances antibody to the heterologous HSV was also detected. In those individuals in which HSV type 1 was isolated from trigeminal ganglia and HSV type 2 from sacral ganglia, antibody to both virus types was present in the sera, indicating that simultaneous latent infections with each of the two viruses can occur, and that antibody is produced to each virus independently. Antibody to HSV type 1, 2 or both types was demonstrated in 8 out of 10 cases in which virus isolation attempts were negative, suggesting either a higher sensitivity of RIA for detecting HSV infection, or the presence of latent HSV at some other site in the body which was not sampled.

Observations on the epidemiology of Rift Valley fever in Kenya.

The epizootic range of Rift Valley fever in Kenya is defined from the results of virus isolations during epizootics, and form an extensive serological survey of cattle which were exposed during an epizootic. A study of the sera from a wide range of wild bovidae sampled immediately after the epizootic, showed that they did not act as reservoir or amplifying hosts for RVF. Virus isolation attempts from a variety of rodents proved negative. Rift Valley fever did not persist between epizootics by producing symptomless abortions in cattle in areas within its epizootic range. A sentinel herd sampled annually after an epizootic in 1968 revealed not one single seroconversion from 1969 to 1974. Certain forest and forest edge situations were postulated as enzootic for Rift Valley fever, and a small percentage of seroconversions were detected in cattle in these areas, born four years after the last epizootic. This has been the only evidence for the persistence of the virus in Kenya since 1968, and may be a part of the interepizootic maintenance cycle for Rift Valley fever in Kenya, which otherwise remains unknown.

The Immune Response to Infectious Bronchitis Virus Determined by Respiratory Signs, Virus Infection, and Histopathological Lesions

SUMMARY Protection of the respiratory tract of chickens as stimulated by infectious bronchitis (IB) vaccine virus was assessed by the criteria of respiratory signs (rales), tracheal virus infection, and histopathological lesions. Used as vaccines and for challenge were Massachusetts and Connecticut types of infectious bronchitis virus (IBV). Results of virus isolations (VI) from tracheal swabs and histological observations at 96 hours postchallenge (PC) were in close agreement in determining the protection from virus infection and incitement of lesions in vaccinated groups of chicken. When the PC examination period was extended to 144 hours, however, lesions were still present histologically in a high proportion of the individuals in a vaccinated group but the challenge virus was not detected on tracheal swabs. Subtype variations were found in two Massachusetts-type vaccine viruses in their relative ability to stimulate protection of the respiratory tract.

Infection of cattle with parainfluenza 3 virus with special reference to udder infection. II. Pathogenicity of the virus for cattle, with particular reference to the mammary gland.

ABSTRACTIn the previous study, parainfluenza 3 virus was isolated not only from nasal secretions but also from the milk of naturally infected cows. In the present study it was confirmed that the virus isolated by us is similar in its pathogenicity for cattle as the bovine strains of this virus previously reported. In view of the fact that the virus was isolated from milk, the virus was inoculated directly into the udders of lactating cows. The infected cows showed the same respiratory symptoms as well as the symptoms of fever, malaise, anorexia, diarrhea and leukopenia as observed in cattle infected by other routes of inoculation. The affected udders developed swelling and induration, and milk from these glands showed coagulation, color change, and increased pH and cell count. The milk contained increased numbers of glandular epithelial cells, mature and young neutrophils and monocytes. Virus was excreted in large amounts in milk from the quarters inoculated with virus. However, many of the uninoculated quarters also excreted virus in milk, but in smaller amounts. Virus was recovered from blood and nasal discharges of infected cows. Antibodies were produced in the infected cows and were excreted in milk. These findings, together with the clinical observations and the results of virus isolation from milk in natural cases, indicate that, in natural infection of cows with this virus, udder infection occurs frequently, but seldom results in overt clinical mastitis. However, the role and significance of the virus in the pathogenesis of mastitis should be further investigated.

Infection of Cattle with Parainfluenza 3 Virus with Special Reference to Udder Infection

ABSTRACTThirty‐seven strains of parainfluenza 3 virus were isolated on bovine kidney cell cultures from Japanese cattle in herds suffering from acute respiratory illness. This finding, together with the clinical and epidemiologic observations and the results of a serologic survey, indicates that in Japan, as in the United States and other countries, this virus is one of the important causes of acute respiratory disease in cattle. A significant finding in the present study is that virus was recovered from milk as well as from nasal secretions. This finding suggests an important role for milk, along with nasal discharges, in disseminating the virus among cattle. In addition, the recovery of virus from milk presents a new problem concerning this infection in cattle, in particular, the potential role of this virus in the pathogenesis of mastitis.

Spread of polioviruses in the families of patients.

1. In the families of patients with poliomyelitis the polioviruses spread easily, especially among the youngest children. Of the adults few can be shown to excrete the virus. 2. From the results of virus isolations and the antibody patterns of familial contacts it is obvious that few children escape the infection with the circulating virus. Of the older people males are much less readily infected than females. 3. There was no seasonal influence demonstrable on the spread of the polioviruses in the families.

Studies of an epidemic of aseptic meningitis associated with coxsackie and Echo viruses

An epidemic of aseptic meningitis was studied. Results of virus isolations and typing in two different types of tissue cultures, human embryonic lung cultures and cultures of trypsinized monkey kidney, and in baby mice indicated that the epidemic was mainly caused by ECHO virus type 6. This virus was prevalent in 57% of the cases. Coxsackie viruses were found in 13% and poliomyelitis virus type 3 in one %. In total, virus was recovered in 73%.

STAPHYLOCOCCIC PNEUMONIA OCCURRING DURING AN EPIDEMIC OF INFLUENZA

During the late fall and early winter of 1940-1941 an epidemic of influenza involved most sections of the United States, as well as the Hawaiian Islands, Puerto Rico and probably many other areas. 1 Virus isolations during the acute phase and immunologic studies of acute and convalescent phase serums on patients from widely scattered localities indicated that the virus of influenza A was by far the predominant, if not the only, one of the known viruses implicated in the epidemic. 2 If one judges from the available reports, the disease generally was mild and pulmonary complications were neither frequent nor severe. The epidemic reached Boston late in December and persisted throughout January; most cases of the disease occurred during the first two weeks of the latter month. The clinical features of some of the uncomplicated cases, along with the results of virus isolations and immunologic studies, have been reported