Multi-organ donor transmission of hepatitis C virus to five solid organ transplant recipients and lack of transmission to corneal transplant recipients.

BACKGROUND: A multi-organ donor seronegative for hepatitis C virus (HCV) by 1st generation enzyme immunoassay (EIA) supplied 5 solid organs and 2 corneas to 7 recipients. This donor was retrospectively shown to be 2nd generation HCV EIA-positive and polymerase chain reaction (PCR)-positive. All 5 solid organ recipients but none of the corneal recipients developed HCV infection. OBJECTIVES: To demonstrate the discordance between serological and PCR-based HCV detection in solid organ transplant recipients and the lack of transmission of HCV to the two corneal transplant recipients. STUDY DESIGN: All 5 solid organ recipients were retrospectively shown to be HCV PCR-negative and -seronegative pre-transplant and HCV PCR-positive post-transplant. Serial serum samples on 3 recipients were evaluated by 2nd generation EIA, a prototypic structural and non-structural dual bead assay (EIA-SA, Abbott), the Chiron Recombinant Immunoblot Assay, 2nd generation (RIBA-2), and the Chiron RIBA HCV Test System Strip Immunoblot Assay 3.0 (RIBA-3, Chiron). RESULTS: The dual bead EIA-SA and RIBA-3 were able to detect HCV seroconversion approximately 6 months earlier than the 2nd generation EIA in 2 recipients, and in 1 recipient only PCR detected infection within the first 10 months. There was no evidence of HCV transmission to the corneal recipients. CONCLUSIONS: Although third generation assays such as the RIBA-3 and EIA-SA narrowed the window of HCV seronegativity in transplant recipients compared with the 2nd generation EIA, PCR was the most sensitive method of detecting acute HCV infection. Despite transmission of HCV to all of the solid organ recipients HCV was not transmitted to the corneal transplant recipients.

Norwalk-like Viruses Associated With A Gastroenteritis Outbreak Following Oyster Consumption.

In late October 1991, an outbreak of gastroenteritis, following the consumption of raw oysters involving more than 200 people, was reported in five locations in Quebec, Canada. Bacteriological analysis of the oysters involved indicated low levels of fecal coliforms, but direct electron microscopy of stool samples obtained from two people involved in the outbreak revealed that both contained 27-34 nm, small, round Norwalk-like viruses. Immunoelectron microscopy, using acute sera obtained from these individuals and convalescent serum from another person related to the outbreak, revealed antibody coatings on these Norwalk-like viruses with all three sera. Solid-phase immunoelectron microscopy demonstrated that these viruses were also antigenically similar or related to a Norwalk-like virus isolated as the cause of a gastroenteritis outbreak in a home for the aged between December 1988 and January 1989 in Thunder Bay, Ontario. From these findings and the symptoms of the illness, the Norwalk-like virus was considered as the causal agent of the outbreak due to the consumption of contaminated oysters. How the oysters became contaminated was not determined. Oysters harvested from the areas initially thought to have been the origin of the implicated shellfish were tested for the presence of viral fecal indicators using tissue culture and electron microscopy with negative results. It is most likely that the implicated lot also contained oysters harvested from another area, also open, but which was downstream from an identified source of human fecal contamination.

Prevalence of hepatitis B surface antigen, hepatitis C antibody, and HIV-1 antibody among residents of a long-term-care facility.

OBJECTIVE: To determine the prevalence of hepatitis B antigen (HBsAg), antibody to hepatitis C virus (anti-HCV), and antibody to human immunodeficiency virus (anti-HIV) among residents of a long-term care facility. DESIGN: Anonymous unlinked serosurvey. SETTING: Accredited university-affiliated long-term-care facility in Toronto with 300 chronic-care hospital patients, 350 nursing home residents, and 200 residents of a senior citizens' apartment complex. INTERVENTIONS: Sera from left-over blood samples obtained from residents in November 1990 were tested for HBsAg, anti-HCV, and anti-HIV using standard methods. RESULTS: A total of 508 sera were tested. The number (%) positive for HBsAg, anti-HCV, and anti-HIV, respectively were: 3(0.6%), 7(1.4%), and 0(0%). CONCLUSIONS: This is the first report defining rates of infection with bloodborne infective agents among residents of a long-term care facility. These results support the use of hepatitis B vaccine for medical and nursing staff and the implementation of universal precautions in long-term care facilities.

Detection of Norwalk-like virus and specific antibody by immune-electron microscopy with colloidal gold immune complexes.

Direct electron-microscopy (DEM), immune electron microscopy (IEM) and four different procedures of immune electron microscopy with colloidal gold immune complexes were evaluated for the detection of Norwalk-like virus and specific antibody. A solid-phase immune electron microscopy with colloidal gold immune complexes-triple layer method (SPIEMGIC-TLM) is developed for screening patients' specimens for the detection of Norwalk-like virus and its specific antibody. The method demonstrates low non-specific background labelling and is simple, sensitive and easy to perform. A quadruple layer method (SPIEMGIC-QLM), which is a modification of the triple layer method, has been established by adding a cross-linking anti-IgG layer to amplify the reaction and to provide a more sensitive test which is suitable for screening monoclonal antibodies prepared against 32-34-nm Norwalk-like virus isolated in our laboratory.

Amplified ELISA for the detection of western equine encephalitis virus from mosquitoes in Manitoba, Canada.

Current monitoring systems to detect western equine encephalitis (WEE) virus in mosquitoes involve isolation in suckling mice or cell culture followed by serological identification of the isolates obtained. Studies were undertaken to develop an amplified ELISA for the rapid detection of WEE virus from mosquitoes. Virus was inoculated onto primary chick embryo cells in 96 well plates, incubated at 37 degrees C for various time periods, monolayers were fixed, and an ELISA performed. By this procedure, 10 plaque-forming units or greater of WEE virus were detected by 24 h postinfection. This amplified ELISA procedure was successfully applied in parallel with standard isolation methods to monitor mosquitoes collected in Manitoba, Canada, in 1985 for WEE virus.

Diagnostic significance of anti-HBcIgM prevalence related to symptoms in Canadian patients acutely or chronically infected with hepatitis B virus.

A total of 362 sera from 295 Canadian patients were examined for HBsAg, anti-HBs, anti-HBc, anti-HBcIgM, HBeAg, and anti-HBe using commercial immunoassays. Serial samples from 70 acutely infected patients demonstrated that anti-HBcIgM may detect 10% more positives than HBsAg within 4 months after the onset of clinical symptoms, and all except two were negative for anti-HBcIgM after the fourth month. None of 66 asymptomatic (HBeAg rate 18.2%) and two of 14 (14.3%) symptomatic (HBeAg rate 64.3%) carriers of HBsAg were positive for anti-HBcIgM (P = 0.029). Elevated marker responses were measured in two symptomatic carriers for a 20-month period. Anti-HBcIgM was not detected in either 100 asymptomatic patients positive for total anti-HBc, negative for HBsAg and negative for or possessing low levels of anti-HBs, 25 patients with liver disorders not caused by HBV, or 20 healthy milk donors. In diagnostic laboratory practice this anti-HBcIgM test may be useful in the following situations: to supplement HBsAg testing, providing a theoretical 10% increase in positives within 4 months following onset of acute viral hepatitis; to replace testing for anti-HBc and anti-HBs in symptomatic HBsAg-negative patients; to confirm whether a patient is experiencing acute or chronic HBV infection or symptoms superimposed upon asymptomatic HBsAg carriage by another cause, such as nonA-nonB viral hepatitis.

Studies on fastidious adenoviruses in Ontario: a distinct strain associated with gastroenteritis.

From 100 cases of gastroenteritis among children caused by adenovirus infection in Ontario, 33 virus isolates were divided into three categories according to their biological behavior in tissue cultures. So far, the results of neutralization tests, structural protein analysis, and DNA restriction patterns showed that the virus of category 1 was similar to adenovirus type 40. However, the adenovirus of category 2 was a distinct adenovirus which shared some similarities with adenovirus type 5. Viruses of category 3 are still under investigation.

Use of antisera against bovine (NCDV) and simian (SA11) rotaviruses in ELISA to detect different types of human rotavirus.

Two ELISA systems for the detection of human rotaviruses were developed. In the first system antibodies to Nebraska calf diarrhea virus (NCDV) were used for coating the solid matrix and for the preparation of the enzyme conjugate. In the second system antibodies to human rotavirus and antibodies to simian rotavirus (SA11) were used for coating the solid matrix and for the preparation of the enzyme conjugate respectively. The second ELISA system proved to have a broader spectrum for the detection of human rotaviruses. By using the two ELISA systems, the different types of human rotavirus could be distinguished. The ELISA tests developed were 8 to 64 times as sensitive as electron microscopy (EM) and (or) counterimmunoelectrophoresis (CIEP). The antigen detected by ELISA was shown to be different from that detected by the hemagglutination test.

Enzyme-linked immunosorbent assay for detection of antibodies to influenza A and B and parainfluenza type 1 in sera of patients.

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of antibodies to influenza A/Hong Kong/1/68, influenza A/Victoria/3/75, influenza B/Hong Kong/5/72, and parainfluenza type 1 viruses. Development and standardization of the method indicated that an acetone-ethyl alcohol mixture was a suitable fixative for the preparation of the solid-phase coupled antigen. The addition of sodium azide to the enzyme-conjugated solution and the concentrations of the enzyme-conjugate antiglobulin and test sera employed were all critical factors in the success of the ELISA procedure. The ELISA test was specific; there was no cross-reaction between influenza A and B or parainfluenza type 1 viruses. The concordance between ELISA and hemagglutination inhibition results suggested that both tests probably detected the same type of antibodies. The ELISA procedure was 8 to 64 times more sensitive than complement fixation and/or hemagglutination inhibition tests. Low levels of antibody in patients' sera were detected only by the ELISA test. During the course of the testing period false positive reactions were not encountered. The results of ELISA could be obtained within 3 h. The ELISA test required a very small amount of serum and, therefore, offered an opportunity to detect the presence of maternal antibodies to influenza viruses in blood collected from infants by heel prick.

Physicochemical properties of Nebraska calf diarrhea virus hemagglutinin.

Highly purified Nebraska calf diarrhea virus (NCDV) was prepared by cesium chloride density gradient centrifugation. The effect of temperature, pH, different concentrations of formaldehyde, chloroform, ether, ethyl alcohol, and methyl alcohol on NCDV hemagglutinin and virus morphology was studied. NCDV hemagglutinin was inactivated by temperature, pH 2.0, chloroform, ethyl alcohol, and methyl alcohol.