Hepatitis B follow-up among Indochinese refugees

During 1979 and 1980 the Department of National Health and Welfare carried out a survey and later routine testing to determine the prevalence of serologic markers of hepatitis B in Indochinese refugees entering Canada. Between March and July 1981 the hepatitis-B-marker status of 220 selected refugees in the Ottawa-Hull area was reassessed. Overall, 173 (79%) of the participants had the same serologic markers when retested, but in 47 (21%) the markers had changed. The most significant changes were the loss of antigenemia in 22% of those who had been HBsAg-positive and the appearance of evidence of infection in 18% of those who had been seronegative. Most of these changes occurred among persons under 30 years of age, especially females aged 10 to 19 years.

Detection of hepatitis A virus by a modified commercial radioimmunoassay

A commercial radioimmunoassay test has been modified for the detection of hepatitis A virus in tissue culture lysate, marmoset liver homogenate, and simulated stool samples.

Perinatal transmission of hepatitis B virus

Transmission of hepatitis B virus from carrier mothers to their infants seems most likely to occur during birth. Both cord blood and breast milk have been found to be positive (in 35% and 72% of cases respectively) for hepatitis B surface antigen (HBsAg), but they do not appear to play an important role in transmission. To control this problem high-risk women should be tested during pregnancy for HBsAg. The infants of infected women should be given several doses of hepatitis B immunoglobulin starting at birth. In less developed regions, where hepatitis B is endemic, administration of the immunoglobulin in combination with vaccine, or even the vaccine alone, may be preferable in order to provide infants with lasting protection.

Prevalence of hepatitis B markers in Indochinese refugees

The prevalence of hepatitis B surface antigen (HBsAg) in 14 347 Indochinese refugees was 11.6%; the rate was significantly higher (P less than 0.01) in males (14.0%) than in females (8.8%). Most of the HBsAg-positive refugees were in the age group 20 to 29 years. Antibody to HBsAg was detected in 50.9% of the males and 46.6% of the females, a significant difference (P less than 0.01). Antibody to core antigen alone was found in 2.4% of the males and 2.2% of the females. The cumulative prevalence of one or more hepatitis B markers was significantly higher (P less than 0.001) in the males (67.3%) than in the females (57.5%). The hepatitis B e antigen and its antibody were detected in 54.8% and 39.2% respectively of 1050 HBsAg-positive blood samples. The adw, adr and ayw determinants of HBsAg were found in 23%, 35% and 42% respectively of 74 samples.

Measurement of antibodies to rabies virus by immunoelectron microscopy

Immunoelectron microscopy (IEM) was used to measure rabies antibodies in 47 serum samples from vaccinees with results similar to those obtained by mouse neutralization test (MNT). The use of inactivated rabies virus for IEM eliminated the hazard associated with live virus used in the MNT.

Prevalence of hepatitis B infection among residents of an institution for the mentally retarded

Data on prevalence of antibody to hepatitis B surface antigen (anti-HBs) and of hepatitis B surface antigen (HBsAg) among 95 matched pairs of Down's syndrome (DS) and other mentally retarded (OMR) patients in an institution were analyzed by age on admission and by length of residence. Passive hemagglutination test were used to determine anti-HBs. Anti-HBs prevalence increased with admission age among DS patients (26%, 42% and 56% for age groups less than or equal to 5, 6-15 and greater than 15 years, respectively) but decreased among OMR patients (85%, 71% and 78%), giving overall rates of 38% for DS and 77% for OMR which are significantly different (p less than .001). Anti-HBs prevalence increased with length of residence for OMR patients but was unchanged for DS patients. For both groups, the prevalence of hepatitis B (HB) infection (both anti-HBs and HBsAg) increased with length of residence and, overall, was nearly the same for DS and OMR patients. These observations are consistent with the hypothesis that, with respect to response to HB virus, younger DS patients are immunologically immature.

Hepatitis B surface antigen and its subtypes in an institution for the mentally retarded

The prevalence of hepatitis B surface antigen (HBsAg) in 155 patients with Down's syndrome (DS) and 209 with other types of mental retardation (OMR) at Huronia Regional Centre, Orillia, Ontario was 34.8 and 5.3%, respectively. There was no significant difference in prevalence between males and females in either group of patients. In 75 matched pairs (DS-OMR) the HBsAg prevalence was 45% in DS and 8.3% in OMR males; in females 40% of those with DS were HBsAg-positive, whereas all the OMR residents were negative. The prevalence of HBsAg in both DS and OMR groups was higher in those admitted in early childhood and in those who had resided in the institution for more than 10 years. In all 54 HBsAg-positive DS patients the antigen subtype was ad. Among the 11 HBsAg-positive OMR patients the subtype was ad in 10 cases and ay in 1.

Hepatitis B antigen: distribution of ad and ay subtypes in blood donors and hepatitis patients

Hepatitis B antigen (HBAg) from blood donors and patients with hepatitis was tested for ad and ay subspecificity by immunodiffusion in agarose. A total of 59 sera from blood donors and 81 sera from hepatitis patients were subtyped.Subtyping of HBAg from blood donors showed ad and ay subspecificity in 64.4 and 35.6% of cases respectively. Patients' sera on the other hand showed HBAg with ad and ay subspecificity in 6 and 94% of cases respectively. Therefore, ad subtype was more frequently associated with blood donors whereas ay subtype was predominant among hepatitis patients. The relationship between clinical findings and HBAg subtype is also discussed.

Use of polyelectrolytes and electron microscopy for detection of viruses from stool

Insoluble polyelectrolytes (PE60) were used for the concentration of viruses from stool specimens, confirming the results of Wallis et al. (1969). Ten percent suspensions inoculated with poliovirus type 3 were used in these experiments. A small number of stool specimens from patients naturally infected with enteroviruses were also tested. Preferential adsorption of viruses to PE60 was maximum at a pH range of 4.5 to 6.0. The elution of the adsorbed viruses was optimal at pH 8.5. Other parameters were also investigated. Electron microscopy was used successfully to detect the eluted viruses.

Serological cross-reactivity within the picornaviruses as studied by electron microscopy

A sensitive electron microscopic method has been developed to determine the antigenic relationship within the picornavirus group. Negatively stained mixtures of antigens (poliovirus type 1 and 3, echovirus type 9, and coxsackievirus type A9) and antibodies (poliovirus type 3 and echovirus type 9 antisera) were examined under the electron microscope. The results showed clumping of homologous and heterologous viruses with both antisera, which was considered as evidence of cross-reaction. The controls showed no clumping or attachment of antibody molecules. The significance of clumping was tested by treating adenovirus type 7 with the two test antisera.

Detection of cross-reactions by immunofluorescence within the picornavirus group

A rapid and sensitive method has been developed to determine the degree of cross-reactions within the picornavirus group by the indirect method of fluorescent antibody staining in green monkey kidney cells. The viruses included in the study were poliovirus type 1, 2, and 3; echovirus type 3, 9, and 11; and coxsackievirus type A9 and B5. It has been found that the cross-reactions are in fact extensive amongst the viruses tested. The heterologous reactions were almost as strong as homologous reactions. The degree of group reactivity was unexpected and its implication and advantages are discussed.

Plaque assay of poliovirus in plastic chambers

A method for the plaque assay of Poliovirus type I using plastic chambers on glass microscope slides with an agar overlay has been developed. This microtechnique offers a reliable system for plaque assays which is directly comparable with other systems. The maximum efficiency of adsorption was 80–85% and clear and countable plaques appeared within 30–34 hours. The advantages of this system include simplicity, economy of materials, and flexibility. Other applications of the technique include plaque inhibition, plaque size reduction, immunofluorescent plaque assays, and cytological studies.