Clinical and diagnostic virology最新文献

Background: The recently discovered hepatitis G virus (HGV) belongs, as hepatitis C virus (HCV), to the Flaviviridae family. HGV has been isolated from the serum of patients with non A-E hepatitis. However, the association of HGV with hepatitis is uncertain.

Objective: To determine the HGV prevalence in blood donors and in patients with liver disease and to evaluate a possible correlation between HGV infection and liver disease.

Study design: Sera from a total of 113 consecutive patients with chronic liver disease were submitted to a series of liver enzymes and function tests and analyzed for the presence of HBsAg, anti-HBs, anti-HBc, anti-HCV, HCV RNA and HGV RNA. Prevalence of HGV RNA was determined in a group of 87 blood donors.

Results: Nine (10%) sera from blood donors and 15 (13%) sera from patients with chronic liver disease were HGV RNA positive. Some 28 (25%) patients were HCV RNA positive, with genotypes 1a, 1b and 3 present in 10, 12 and 5 patients, respectively. A total of 20 (18%) patients were HBsAg carriers. Five (4%) patients were double infected (one with HBV+HCV, one with HBV+HGV and three with HCV+HGV).

Conclusion: The proportion (10%) of HGV-infected blood donors was very high when compared with other countries. The results did not allow to establish HGV as an etiologic agent for chronic liver disease. The parenteral route was the presumed means of HGV transmission for only one-third of the patients.

Background: Little is known about the prevalence of infections in different population groups in Africa, and about the influence of living conditions on the spread of infections. This study is the first of its kind in the state of Eritrea and is expected to serve as an evaluation of the situation in the country.

Objective: A serosurvey for human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) was carried out during the summer of 1995 in Massawa, a small sea port in Eritrea (East Africa) in four groups considered to be at risk for these infections.

Study design: The study subjects were former Guerrilla Fighters, Female Sex Workers, Truck Drivers, and Port Workers. Participants from a tribe called Rashaida were believed to be at low risk, and thus served as a control.

Results: The Female Sex Workers had the highest incidence of HIV-1 infection, 29%, compared to 10% for Port Workers, and 3% for Guerrilla Fighters. On the other hand presence of HBsAg, indicating a high prevalence of hepatitis B carrier status, was highest in the Guerrilla Fighters, followed by the Rashaidas, and lowest in the Female Sex Workers. The Female Sex Workers were further tested for antibodies against HBV and the results revealed that 53% of them, 5%, had antibodies against HBcoreAg. Excluding the possibility of an acute infection at sampling time, three of them became HBsAg carriers. Surprisingly, our group of Truck Drivers did not show HIV-1 infection, and no HIV-2 infections were seen in the whole cohort.

Conclusion: The study shows that the described groups have different prevalences of infection with HIV, hepatitis B and C which can partly be explained by their living conditions.

Background: The development of antiviral therapy increases the need for rapid, sensitive and reliable methods or combination of methods for diagnosis and monitoring herpes simplex encephalitis, HSE.

Objectives: Evaluation of diagnostic performance of three successively developed HSV PCR assays when combined with a new capture ELISA for HSV intrathecal antibody production (ITT).

Study design: During a 3.6 year period a total of 4.206 CSF and serum samples from about 4.140 hospitalized patients with a tentative diagnosis of HSE were analyzed by a new ELISA for ITT. 1.962 CSF samples were examined also by PCR. Clinical signs and symptoms and additional tests were obtained on all ITT and/or PCR positive patients. In 1993 the PCR was a double PCR. In 1994 the PCR was a single PCR with internal inhibition control. Positive samples were confirmed by a different confirmative PCR to increase the specificity. From 1995 the PCR was as in 1994 but samples were no longer divided in the serology routine laboratory.

Results: A total of 33 HSE cases was found (incidence 1.8 HSE per million people). All patients were treated with aciclovir. Three patients died, 9 patients had primary infection, 2 patients had HSE previously, and 2 patients relapsed. Only 11 patients recovered satisfactory. Of all 37 positive ITT 7 were unlikely positive. False positive PCR was seen in 1993 and 1994, due to sample-to-sample contamination during division of samples, but was not seen since 1995 when this procedure was changed. The test results depended on the state of the disease. Thus, the sensitivity, specificity, PPV and NPV for ITT were highest when performed more than 1 week after debut of symptoms whereas these values were highest using PCR within the first week.

Conclusion: Routine PCR diagnosis of HSE type 1 and 2 is a highly sensitive and specific method that should be performed together with serological ITT to cover the whole time span from debut of symptoms to several weeks after hospitalization.

Background: Different subtypes of HIV-1 are prevalent in various geographical regions. Knowledge of their distribution is of importance with respect to possible differences in biological properties (such as reported for subtype E) as well as to diagnostic problems that may arise when specific subtypes are not recognized by standard serological assays.

Objectives: The objectives of this study were to investigate the presence of the five major subtypes of HIV-1 (A–E) in the Austrian population and to estimate the prevalence of the individual subtypes in different risk groups.

Study design: Serum samples from 88 HIV-1 positive patients were tested for the presence of subtype-specific antibodies using a peptide ELISA.

Results: The majority of the patients were shown to be infected with HIV-1 subtype B, but infections with subtypes A, C, and E were also detected in the Austrian population, primarily in the heterosexual transmission group. While subtypes A and C were probably imported from different African countries, subtype E appears to have been introduced by sex tourists returning from Thailand.

Conclusion: Introduction of HIV subtypes other than B from Africa and Asia into Austria has already occurred and will certainly increase within the next few years.

Background: Diagnosis of acute and past infection with parvovirus B19 is based on detection of IgM and IgG antibodies.

Objectives: To evaluate two commercial recombinant antigen-based enzyme immunoassay (EIA) test kits for detection of IgM and IgG antibodies to parvovirus B19 and to compare the commercial EIAs to in-house EIA test procedures.

Study design: A panel of 121 sera was used to compare the three IgM EIAs. The panel included 84 sera submitted for parvovirus B19 testing and 37 sera that were IgM positive for other viral pathogens. The same serum panel plus an additional 14 sera submitted for B19 testing was used to compare the three IgG EIAs. The commercial EIAs were performed according to manufacturers' instructions. Using the in-house EIA test procedures as the reference, sensitivity and specificity for each of the commercial EIAs was determined.

Results: The commercial B19 IgM EIAs showed agreements of 95.0 and 93.4% to the in-house IgM EIA. Compared to the in-house B19 IgM EIA, the commercial B19 IgM EIAs, were 97.4 and 97.5% sensitive, respectively. Specificities were 93.5 and 91.4%, respectively. Sensitivities for the commercial IgG EIAs, compared to in-house IgG EIA, were 88.0 and 85.2%, respectively, and specificities were 94.1 and 98.0%.

Conclusion: We found that the commercial parvovirus B19 IgM and IgG EIAs are comparable to standard in-house EIAs and are suitable for testing for B19 antibodies in human sera.

Background: The duration and stage of hepatitis C might be associated with the source of infection and hepatitis C virus (HCV) types.

Objective: We studied the relationship among the different HCV types, source, duration, and stage of infection in 100 patients from the Apulia, southern Italy, selected from consecutive clinical records. They were 20 parenterally infected haemophiliacs with 10–20 years of disease history, but without cirrhosis; 20 patients (matched for sex, age and disease) and without known risk factor for parenteral infections; 60 patients with community acquired infection (ten with CAH and ten with cirrhosis with less than 20 years disease history; 20 with cirrhosis and hepatocellular carcinoma (HCC) and more than 20 years of liver disease and 20 matched cases with cirrhosis without HCC).

Results: Type 1 and 2 HCVs had comparable prevalence in patients with long lasting and recent HCV infection, 56 and 64%, 26 and 30% respectively. HCV type 3 was found in 6.5–12% of the patients with recent HCV infection, but it was not detected in those with infection longer than 20 years. Type 1 b HCV was more frequently found in HCC patients (68% of cases) than in the other forms of liver disease. The opposite was observed for HCV types (2 and 3).

Conclusions: The prevalence of the different HCV types appears associated with the source and duration of the infection. The interesting association between HCV type 1 b and HCC prompts further studies in larger series of patients.

Background: While many previous studies have focused on the impairment in the cellular immunity during measles virus infection, to date, a limited amount of data is available concerning the virus-specific IgG subclass response during measles virus infection.

Objective: The purpose of this study is to analyze the measles virus infection on the basis of virus-specific IgG subclass (G 1 and G 3).

Study design: Frozen-stored, serum and/or cerebospinal fluid samples from three groups of patients were tested retrospectively; Group 1 comprised 14 patients with measles primary infection, group 2, ten patients with reinfection/vaccine failure, and group 3, seven patients with subacute sclerosing panencephalitis. The method used was a modified ELISA method utilizing the Enzygnost IgG detection kit with mouse-monoclonal antibodies (clone HP6091 for IgG 1 and clone HP6050 for IgG 3). Avidity testing for each subclass IgG was also performed for selected samples by means of an 8 M urea-denaturation method.

Results: In group 1, the IgG 3 could be detected in serum within 7 days from the onset of rash more frequently than IgG 1. In the cases of group 2, both subclasses were detected in very acute phase serum samples. In these cases, the IgG 1-specific avidity was always higher than that of IgG 3. In group 3, the subclass IgGs detected in the cerebrospinal fluid had a lower avidity than those in the serum.

Conclusions: Our results suggested that in measles virus infection, like other viral infections, the IgG 3 response normally occurs before the IgG 1 response, and plays a major role in the acute phase immunity during the primary infection, while the IgG 1 plays a major role in the maintenance of immunity. Continuously produced IgG 1 and IgG 3 in the central nervous system in cases of subacute sclerosing panencephalitis may be derived from cell populations different from those in the blood.

Background: Epidemiological studies need easier tools to evaluate HIV prevalence, particularly in high-risk groups under difficult field conditions. Testing saliva antibody with accurate immunoassay could serve as an alternative to serum testing.

Objectives: To evaluate performances on saliva of a novel commercially available assay for anti-HIV antibody.

Study design: Samples of saliva from 530 patients were tested for the presence of HIV antibodies with a third generation commercially available serum-screening kit and the use of a sample diluent adapted to saliva.

Results: Compared with serum sampling the sensitivity and specificity of oral sampling were respectively, 100 and 99.8%.

Conclusion: The ICE HIV-1.0.2 assay used on saliva could be an efficient and non-invasive epidemiological tool for HIV testing.