[Subtypes of HBsAg of the hepatitis B virus in Western Siberia]

HBs antigens were subtyped in blood samples of intravenous drug-addicts (IDA) and of donors from as many as 10 cities of Western Siberia by using the immune-enzyme assay with 6 high-specific monoclonal antibodies. Two HBsAg subtypes were found, in a ratio of 3% ayw2: 97% ayw3 (varA and varB), in IDA blood samples from Novosobirsk. Three HBsAg subtypes were found, in a ratio of 57% ayw2: 42% ayw3 (varA and varB): 1% adw2, in the donors' blood samples. The obtained data are sufficient for developing the first national sera panel containing different HBsAg subtypes of hepatitis B virus typical of Russia.

Determination of HBsAg subtypes in Western Siberian part of Russia

A set of monoclonal antibodies with specificity for hepatitis B surface antigen (HBsAg) was used for subtyping this antigen in sera from indigenous natives, blood donors, and drug users in Western Siberia with a modified commercial enzyme immunoassay kit for HBsAg detection. Three subtypes of HBsAg in a ratio of 36 (78%) ayw2:8 ayw3varB (18%):2 (4%) adw2 were found in 46 (100%) HBsAg-positive sera of different aboriginal populations of Western Siberia: the Tundra Nenets, Northern Khanty, Southern Altaians, and Kazakhs. Four subtypes of HBsAg in a ratio of 81 (57%) ayw2:58 (15 ayw3varA and 43 ayw3varB; 44%):2 (1%) adw2 were detected in 141 (100%) samples of blood donors from ten cities of Western Siberia. Three subtypes of HBsAg in a ratio of 34 ayw3:(both variants, 33 ayw3varA and 1 ayw3varB; 97.1%):1 (2.9%) ayw2 were found in blood of 35 injection drug users in Novosibirsk.

Hepatitis B virus genotypes and HBsAg subtypes in refugees and injection drug users in the United States determined by LiPA and monoclonal EIA

Hepatitis B virus (HBV) genotyping and hepatitis B surface antigen (HBsAg) subtyping were carried out on sera from 196 HBsAg-positive patients, including 151 refugees entering the United States and 45 injection drug users in Seattle. HBsAg subtyping was performed by enzyme immunoassay (EIA) using a panel of monoclonal antibodies and the HBV genotype was determined by polymerase chain reaction (PCR) followed by detection of amplified HBV DNA by a reverse-phase hybridization line probe assay (LiPA) using genotype-specific probes. HBV DNA was detected by PCR in 155 (79%) of the 196 sera and all 155 were genotyped by LiPA. Samples from Southeast Asia were predominantly genotype B/subtype ayw1 and genotype C/adr; samples from the former Soviet Union and eastern Europe were mostly genotype D/ayw2 and genotype D/ayw3; samples from east Africa were mainly genotype A/adw2 and genotype D/ayw2; and samples from injection drug users were mostly genotype D/ayw3 and genotype A/adw2. Some strains of ayw3 gave atypical monoclonal antibody reactivity patterns in the subtyping assay due to a Val/Ala instead of a Thr at amino acid residue 118 and a Thr instead of a Met at residue 125. A strain of ayw2 also gave an atypical monoclonal antibody reactivity pattern due to an Ala instead of a Thr at amino acid residue 123. LiPA genotyping and monoclonal EIA subtyping can provide useful information for epidemiological studies.

[Hepatitis B markers in southern Altaĭ inhabitants of the village of Mendur-Sokkon (the Republic of Altaĭ). HBsAg subtyping in hepatitis B virus isolates with monoclonal antibodies]

Blood samples taken from 231 native inhabitants of the village of Mendur-Sokkon located in the Republic of Altai (South-Western Siberia, Russia) were tested for the presence of virus hepatitis B (HBV) markers. 31 samples (13.4%) were found to contain HBsAg, 111 samples (48.05%) were found to contain total anti-HBc antibodies, 123 samples (53.24%) were found to contain anti-HBs antibodies and 15 blood samples (6.49%), anti-HBc antibodies without anti-HBs antibodies and HBsAg. The age-dependent distribution of the occurrence of HBV markers among the aboriginal population of the South Altal remained unchanged (69.9 +/- 7.9%) for the last 50 years. The vertical and horizontal routes of HBV transmissions were noted. The data obtained in this study are indicative of a highly endemic character of HBV of the territory of Mendur-Sokkon. HBsAg-positive blood samples were taken for HBsAg subtyping with the use of a panel of monoclonal antibodies. Two subtypes of HBsAg were detected: ayw1-2 and ayw3varB with the occurrence of 92.6% and 7.4%, i.e. distributed in the ratio 25/2.

Antigenic diversity of hepatitis B virus strains of genotype F in Amerindians and other population groups from Venezuela

The adw4 subtype of hepatitis B virus (HBV) belongs to a unique genomic group (genotype F) representing the original HBV strains from the New World. Data regarding the prevalence of this subtype among HBV carriers in South America are, however, scarce, and those concerning HBV genotype F are based on only a few samples from Latin America. In this study, serum samples were obtained from 141 hepatitis B surface antigen (HBsAg) carriers from Amerindians and urban populations from Venezuela. The HBsAg subtype was identified with monoclonal antibodies in 105 samples, and the HBV genotype was identified by reverse-phase hybridization with DNA fragments in 58 samples. The adw4 subtype was highly prevalent in the population studied (75%); among the Amerindians, the prevalence was 97%. The adw2 subtype was also present (10%), while other subtypes (ayw3 and ayw4) were only occasionally found. The HBV subtype was associated with the expected genotype in most cases (80%), and thus genotype F was highly prevalent. Sequencing of viral strains that gave genotypes unpredicted by the HBsAg subtyping confirmed seven of them as belonging to not previously described genotype-subtype associations: namely, adw2 and ayw4 within genotype F.

Evaluation of the use of mass chemoprophylaxis during a school outbreak of enzyme type 5 serogroup B meningococcal disease

BACKGROUND

A vaccine for prevention of serogroup B meningococcal disease is not available in the United States, and indications for the use of mass chemoprophylaxis for control of meningococcal outbreaks are not well-defined. In response to an outbreak of six cases of enzyme type 5 serogroup B meningococcal disease among students at a middle school, we implemented a program of mass rifampin prophylaxis and evaluated the effectiveness of this preventive measure.

METHODS

Oropharyngeal cultures were obtained from 351 of the 900 students before prophylaxis; 196 participants were recultured 3 weeks later. Meningococcal isolates were subtyped and tested for rifampin susceptibility, and risk factors for disease or carriage among students were evaluated.

RESULTS

No cases occurred after prophylaxis. Before prophylaxis 10% (34 of 351) of students were meningococcal carriers and 3.4% (12 of 351) carried the epidemic strain. After prophylaxis 2.5% (5 of 196) were carriers and 1.0% (2 of 196) carried the epidemic strain. Rifampin was 85% effective in eradicating carriage, and the rate of acquisition of carriage during the 3-week period was low (0.5%). Carriage persisted after prophylaxis in 4 students; 3 of these postprophylaxis isolates were rifampin-resistant. Rifampin resistance thus developed in 12% (3 of 26) of preprophylaxis isolates. Disease/epidemic strain carriage was associated with enrollment in the school band and certain other classes.

CONCLUSIONS

These findings suggests that mass chemoprophylaxis may be effective and should be considered for control of school serogroup B meningococcal outbreaks. This approach is less likely to be effective for control of outbreaks affecting larger, less well-defined populations and is associated with the rapid development of antibiotic resistance.

Sexual behaviors and risk factors for HIV infection among men who have sex with men in the Dominican Republic

OBJECTIVE

To describe self-reported types of sexual identity of men who have sex with men (MSM) in the Dominican Republic, assess sociodemographics and behavioral characteristics, and measure the prevalence of HIV-1 and syphilis.

DESIGN

Cross-sectional study of MSM recruited from a variety of community settings.

METHODS

A total of 354 men agreed to participate after giving verbal informed consent. Information was obtained using a standardized questionnaire assessing demographics and AIDS-relevant information. Blood was obtained for HIV and syphilis testing.

RESULTS

Five main sexual identity groups emerged: cross dressers, homosexuals, gigolos, bisexuals and heterosexuals. Receptive anal and oral intercourse were commonly reported by men self-identifying as cross dressers or homosexuals, whereas nearly all of the remaining three groups practiced only insertive intercourse. Sexual contact with women was also commonly reported; overall, consistent condom use was infrequent. HIV antibodies were detected in 11.0% and serologic evidence of syphilis was found in 7.3%. Factors independently associated with HIV infection included serologic evidence of syphilis, having visited at least one of four local brothels in 1975-1985, and having had receptive anal intercourse with four or more partners in the last 12 months.

CONCLUSIONS

Syphilis, sexual practices and social context of sex (commercial sex), rather than sexual identity per se, were associated with HIV infection. The complex social networks of MSM in this setting, the tendency to practice either insertive or receptive sex, but not both, infrequent condom use, high rates of syphilis and the frequency of sex with women need to be taken into account for targeted HIV prevention programs to be successful.

Adenovirus types 2, 8, and 37 associated with genital infections in patients attending a sexually transmitted disease clinic

Adenoviruses (Ads) are an important cause of respiratory illness, conjunctivitis, and gastroenteritis, but they are seldom recognized as a potential cause of sexually transmitted disease. We performed virus cultures on approximately 7,000 patients attending a sexually transmitted disease clinic or other health department clinics for the evaluation of genital ulcers, urethritis, or conjunctivitis. Ads were isolated from genital or conjunctival specimens obtained from 23 (0.33%) patients. Among the 20 Ad-positive men, 15 (75%) had urethritis, 12 (60%) had conjunctivitis, and 10 (50%) had both. All three Ad-positive women had vaginal discharge and genital ulcers or fissures. Ad isolates from 17 patients were available for serotyping. Ad type 37 was isolated from 14 patients, Ad type 8 was isolated from 2 patients, and Ad type 2 was isolated from 1 patient. In three of the Ad type 37 cases, Ad was recovered from both urethral and conjunctival specimens. One of the Ad type 8 cases had conjunctivitis, but the Ad type 2 case did not. Ads, particularly type 37, may be a sexually transmissible cause of genital ulcers, urethritis, and conjunctivitis.

Herpes simplex virus detection from genital lesions: a comparative study using antigen detection (HerpChek) and culture

The sensitivity of a rapid enzyme immunoassay test (HerpChek Direct Herpes Simplex Virus Antigen Test [DuPont Medical Products, Wilmington, Del.]) for the detection of herpes simplex virus (HSV) antigens in patient specimens was compared with HSV culture. HerpChek positivity for HSV occurred with 179 (65%) of 275 lesion specimens, whereas culture for HSV was positive for 145 (53%) lesions (P = 0.002). HerpChek was twice as sensitive as culture for the detection of HSV in late-stage lesions and was equivalent to culture for the detection of HSV in early lesions. We conclude that HerpChek provides greater sensitivity than culture for HSV detection in late-stage genital lesions.

Determination of HBsAg subtypes in different high risk populations using monoclonal antibodies

Monoclonal antibodies with restricted specificity were used in a modified commercial enzyme immunoassay for detection of HBsAg to subtype HBsAg in sera from 122 Southeast Asian refugees entering the United States, 62 inmates of a correctional facility, and 19 homosexual men. This method was able to classify HBsAg as aywl-2, ayw3, ayw4, ayr, adw2, adw4, or adr. The HBsAg subtype was identified in 183 (90.1%) of the serum samples, but the serum HBsAg concentration was too low to determine the subtype for the 20 (9.9%) remaining samples. Among the Southeast Asian refugees, aywl-2 was demonstrated in 35 (33.0%) of the subtyped serum samples, the adw2 subtype was identified in 33 (31.1%) sera, adr was detected in 37 (34.9%) sera, and the adw 4 subtype as found in 1 (0.9%). The most common subtypes in Vietnam, Laos, and Cambodia were aywl-2, adw2, and adr, respectively. In prison inmates, the ayw3 subtype accounted for 31 (52.5%) of the subtyped serum samples, an ayw2 variant and the adw2 subtype were each found in 13 (22.0%) sera, and the aywl-2 subtype was detected in 2 (3.4%) sera. Many of these inmates admitted intravenous drug use. Among homosexual men, the adw2 subtype was identified in 16 (88.9%) of the subtyped serum samples and the ayw3 subtype was detected in 2 (11.1%) sera. This subtyping method can distinguish between most of the nine major HBsAg subtypes and can be easily performed with these monoclonal antibodies and commercially available reagents.

The antigenic structure of HBsAg: study of the d/y subtype determinant by chemical modification and site directed mutagenesis

Lysine residue 122 of the major protein of HBsAg/adw has been shown previously to be involved in the d subtype determinant. We demonstrate here that the corresponding residue of the HBsAg/ayw, arginine 122, does not play such a critical role the y site of this antigen subtype. Thus, conversion by site directed mutagenesis of arginine 122 to lysine 122 in HBsAg/ayw does not result in the loss of y activity nor gain of d activity. Moreover, chemical modification studies of both the adw and ayw antigens with the reagents o-methylisourea and cyclohexanedione, demonstrate that arginine 122 plays at most only a minor role in this subtype antigenic site.

Prevalence of antibody to human immunodeficiency virus and hepatitis B surface antigen in blood samples submitted to a hospital laboratory. Implications for handling specimens

The prevalence of hepatitis B surface antigen (HBsAg) and antibody to human immunodeficiency virus (HIV) was determined in serum or plasma specimens of 506 patients submitted to the clinical chemistry laboratory of an urban teaching hospital, and the results were correlated with "biohazard" warning labels on the specimens. Hepatitis B surface antigen, HIV antibody, or either of these were present in 32 (6.3%), 15 (3.0%), and 44 specimens (8.7%), respectively. Ten (67%) of 15 specimens with HIV antibody and nine (28%) of 32 with HBsAg bore biohazard labels. Among 473 unlabeled specimens, HIV antibody was present in five (1.1%), HBsAg was present in 23 (4.9%), and 27 (5.7%) contained either or both of these markers. All clinical and laboratory personnel should be vaccinated against hepatitis B and should handle all blood specimens as if they were infected, regardless of biohazard labeling. By fostering complacency in handling unlabeled specimens, the use of biohazard labels may paradoxically increase the risk that health care workers will be exposed to HIV and hepatitis B virus.

Comparison of two rapid culture methods for detection of cytomegalovirus in clinical specimens

The conventional virus isolation technique was compared with a 24-h shell vial centrifugation culture technique and with a 48-h tube culture method for the detection of cytomegalovirus (CMV) in MRC-5 cells. Of 200 clinical specimens tested, 41 were positive for CMV by at least one procedure. Indirect immunoperoxidase staining was positive for 32 (78.0%) of 41 specimens in the tube culture method and for 30 (73.2%) of 41 specimens in the shell vial centrifugation method. CMV was detected in 23 (56.1%) of 41 specimens by the development of cytopathic effect within 14 days.

Rapid detection of influenza virus in cell culture by indirect immunoperoxidase staining with type-specific monoclonal antibodies

Seventy respiratory specimens culture-positive for influenza virus were stored at -70 degrees C and retested in duplicate by virus isolation and by indirect immunoperoxidase (IPA) staining of cell monolayers 24 hr postinoculation using influenza type-specific monoclonal antibodies. The IPA stain was positive for 24 of 28 specimens from which influenza virus was reisolated and for eight specimens from which influenza virus was not reisolated.

Comparison of detection of varicella-zoster virus by the Tzanck smear, direct immunofluorescence with a monoclonal antibody, and virus isolation

A study comparing direct immunofluorescence assay using a new monoclonal antibody specific for a varicella-zoster virus glycoprotein complex, the Tzanck smear, and virus isolation for detection of varicella-zoster virus in 56 patients with clinically apparent herpes zoster is presented. Of 47 patients with clinical herpes zoster and with cultures negative for herpes simplex virus, 30 (64%) had positive Tzanck smears, direct immunofluorescence assay results were positive in 26 (55%), and cultures were positive in only 12 (26%). Both direct immunofluorescence assay and the Tzanck smear were found to be superior to culture technics; however, direct immunofluorescence assay was found to have greater specificity.

Evaluation of clinical specimens for the presence of respiratory syncytial virus antigens using an enzyme immunoassay

An enzyme-linked immunoassay (EIA) was developed for the detection of respiratory syncytial virus (RSV) antigen in nasopharyngeal secretions. This assay, which employs goat and rabbit anti-RSV as the capture and detector antibodies respectively, was used in a retrospective evaluation of frozen clinical specimens from children. The EIA results were compared with those of virus isolation in cell culture and direct fluorescent antibody staining performed at the time of specimen collection. The sensitivity of the RSV EIA compared to cell culture was 91.3% (63/69) with a specificity of 96.8% (93/96). The predictive value of a positive EIA result was 95.4% and for a negative EIA result, 93.9%. The sensitivity of the RSV-EIA compared to direct FA was 91.5% (43/47) with a specificity of 96.5% (83/86). These data represent the preclinical evaluation of the Abbott RSV-EIA. This assay could prove to be a useful alternative to virus isolation or direct FA for the diagnosis of RSV infection.

Rapid detection of respiratory syncytial virus in nasopharyngeal aspirates by a commercial enzyme immunoassay

A commercial enzyme immunoassay (EIA) for the rapid detection of respiratory syncytial virus (RSV) in respiratory secretions was evaluated by comparison with both virus isolation in HEp-2 cells and indirect immunofluorescence (IFA) staining of exfoliated respiratory cells. Initial examination of 80 nasopharyngeal aspirates collected from infants with acute respiratory illness showed that the RSV EIA was positive for 21 of 24 specimens positive by virus isolation or IFA (87.5% sensitivity) and negative for 53 of 56 specimens negative by virus isolation and IFA (95% specificity). The EIA appears to be an acceptable and more rapid test than virus isolation for the detection of RSV, especially for laboratories in which prompt inoculation of specimens is not always possible. IFA staining with commercial bovine anti-RSV serum was found to be the most sensitive and rapid test for the detection of RSV. However, three of four specimens positive by IFA and negative by virus isolation were not cultured under optimal conditions. In addition, the IFA test requires a highly trained technologist to interpret the staining results.

Rapid detection of cytomegalovirus in cell culture by indirect immunoperoxidase staining with monoclonal antibody to an early nuclear antigen

A method for the rapid detection of cytomegalovirus (CMV) in MRC-5 cells 48 h after inoculation with clinical specimens was developed. A commercially available monoclonal antibody to a CMV early nuclear antigen was used in an indirect immunoperoxidase (IPA) staining procedure performed directly on acetone-fixed cell monolayers in standard tubes (16 by 125 mm). Of 190 clinical specimens tested, 30 specimens produced CMV cytopathic effect in tissue culture (TC-CPE) within 14 days after inoculation and, of these 30, 28 were positive for CMV after 48 h by the IPA staining procedure (sensitivity, 93%). Of the remaining 160 clinical specimens negative by TC-CPE within 14 days, 7 were positive by the IPA stain (specificity, 96%). However, three of these seven specimens were positive by TC-CPE upon subculture after the initial 14-day incubation period, and one specimen was overgrown by herpes simplex virus type 2 before CMV cytopathic effect could develop. The mean time to appearance of cytopathic effect for the 30 specimens positive by TC-CPE within 14 days was 6.7 days. These findings indicate that this IPA staining is a useful method for the rapid detection of CMV in cell monolayers inoculated with clinical specimens.

Failure of preexisting antibody against hepatitis B surface antigen to prevent subsequent hepatitis B infection

We studied a patient who developed acute hepatitis B virus (HBV) infection despite the presence of preexisting antibody to the surface antigen of HBV (anti-HBs). Anti-HBs has been reported to consist primarily of antibody against the common a determinant of HBV. Antibody directed against this major determinant appears to confer protection against HBV, regardless of the subtype. Our patient was shown to have had preexisting anti-HBs of anti-d but not anti-a specificity. She subsequently developed non-A, non-B viral hepatitis followed by an episode of acute hepatitis B after exposure to HBV of the ayw subtype.

Determination of immunoglobulin M antibodies against hepatitis B core antigen and hepatitis A virus by reorienting sucrose gradient high-speed centrifugation for diagnosis of acute viral-hepatitis

Immunoglobulin M (IgM) antibodies against hepatitis B core antigen (anti-HBc) and hepatitis A virus (anti-HAV) were determined in 41 cases of acute viral hepatitis. In sera positive for anti-HBc or anti-HAV, IgM was separated from IgG by reorienting sucrose gradient high-speed centrifugation, and the IgG- and IgM-containing serum fractions were tested for the presence of specific antibody by radioimmunoassay. At the onset of illness, 4 of the 41 cases were classified as hepatitis A, 31 were hepatitis B, and 6 were non-A, non-B hepatitis, based on the results of these tests and of assays for hepatitis B surface antigen and antibody and hepatitis B e antigen and antibody. Fourteen of these 41 patients (34%) required IgM anti-HBc or IgM anti-HAV testing or both for appropriate classification. IgM anti-HBc persisted for at least 7 weeks after onset but no longer than 17 weeks in all patients tested with transient hepatitis B surface antigen-positive acute hepatitis. IgM anti-HAV persisted up to but not longer than 62 days in the patients with hepatitis A. Therefore, IgM anti-HBc and IgM anti-HAV determinants are valuable tools for the differential diagnosis of acute A, B, and non-A, non-B hepatitis.