Hepatitis B virus infection in two Gambian villages

The prevalence of hepatitis B virus infection was markedly different in two neighbouring Gambian villages. 62% of children in Manduar aged 2-4 years were infected whereas in Keneba, the other village, only 27% of this age-group were infected. However, in both villages few infants were infected--none under 6 months of age and only 2 of 58 between the ages of 6 and 12 months. Carriage of hepatitis B surface antigen (HBsAg) was high, reaching a peak of 36% in the 5-9 age-group in Manduar and 17.6% in the 2-4 age-group in Keneba. 86% of all the children under the age of five who were HBsAg-positive also carried hepatitis B e antigen (HBeAg). This proportion fell to 17.6% for children aged 10-14 years and to 12.9% for mothers. Infection clustered in families, transmission from sib to sib being of major importance. The chances of a child being an HBsAg carrier were approximately 42% if an elder sib carried the antigen, 27% if either mother or father was a carrier, and 15% if neither mother or father was a carrier. There were 4 HBeAg-positive mothers who were highly infectious, since 10 of 11 of their children became HBsAg carriers. Carriage of surface antigen lasted many years; 63% of those carrying the antigen in 1972 were still positive in late 1980. 4 cases of primary hepatocellular carcinoma out of 672 adults have been diagnosed in the past five years. All 4 were in HBsAg carriers.

[A study on the possible transmission of hepatitis B virus from HBsAg carrier women to their husbands (author's transl)]

In order to assess the possible sexual transmission of hepatitis B virus (HBV), the occurrence of post-marital acute hepatitis and the prevalence of hepatitis B surface antigen (HBsAg) and antibody (HBsAb) were investigated among the husbands of HBsAg carrier women. The possible infectious routes and influencing factors in the HBV infection of the husbands by their HBsAg carrier wives were also discussed. This study demonstrates: 1. In the husbands examined, the exposure marker of HBV was found to be 32.8 per cent and the occurrence rate of post-marital hepatitis came up to 7.2 per cent. 2. The transmission of HBV from HBsAg carrier women to their husbands was supposed to take place shortly after marriage. E-Ag and e-Ab in ther sera of HBsAg carrier women could serve respectively as indicators of positive and negative HBV transmission. In the husbands with wives whose serum HBsAg-titers by R-PHA were higher than 39, a high exposure marker of HBV (87.5%) was observed. 3. The results of HBsAg detection rates and titers in various kinds of body fluids obtained from HBsAg carrier women suggested that cervical mucus and vaginal discharge might play an important role in the sexual HBV transmission.

Transmission of hepatitis B antigens from symptom free carrier mothers to the fetus and the infant

Materno-fetal transmission of hepatitis B was studied in 97 healthy carriers of hepatitis B surface antigen (HBsAg). Antepartum transmission occurred in at least 10 per cent. Intrapartum transmission may have occurred in about 40 per cent as a result of swallowing of the infective fluid by the baby during delivery, and materno-fetal transfusion during labour. Person to person transmission after delivery played a minor role. The presence of hepatitis B associated e antigen (HBeAg) in 48 per cent of maternal serum correlated strongly with the subsequent presence of antigen in the infants. There was a linear association between the incidence of antigens in cord blood and the duration of the first stage of labour, with a significant association when labour exceeded nine hours. Caesarean section is recommended if mothers have HbeAg; likewise amniocentesis and breast feeding should be discouraged if mothers have HbeAg.

Hepatitis B carrier state produced by a blood transfusion

A renal transplant patient was infected by a transfusion of blood from a chronic carrier of hepatitis B and he also became a symptomless carrier. Stored sera enabled detailed retrospective measurement of the rate of decline of passively transferred HBsAg, anti-HBc, and anti-HBe. Active HBsAg production was detected after two months and anti-HBc after six months; neither HBe nor anti-HBe was actively produced although there were many 42 nm HBV particles in the patient's serum.

Diphtheria carriers in Manchester: simultaneous infection with toxigenic and non-toxigenic mitis strains

A toxigenic strain of Corynebacterium diphtheriae mitis was isolated from a 10-week-old baby with membranous tonsillitis, and over the next 6 months thirty-nine symptom-free carriers of nitrate-positive mitis strains were found. All carriers were cleared by 14 days' treatment with erythromycin, though several relapsed after a 5-day course. Four contacts carried both toxigenic and non-toxigenic mitis strains; epidemiological evidence and phage studies suggest that these had a common origin. These findings have implications for the epidemiology of diphtheria and for the routine testing of isolates for toxigenicity.

Experimental vaginal colonization and mother-infant transmission of group B streptococci in rats

An animal model for group B streptococcal vaginal colonization and neonatal acquisition was developed with albino rats. Intravaginal inoculation of genital isolates of group B streptococci of serotypes Ia, II, and III either once or on 3 successive days resulted in carriage of the organisms for 7 days or longer in 26% of the virgin animals and 43% of the pregnant animals. Throat and perianal cultures of the offspring of pregnant rats revealed that 51% of the rat pups acquired the organisms at some time. Litter exchange studies were done to explore the contributions of environmental and intralitter spread. Significantly more infants born to mothers with positive vaginal cultures acquired the organisms than infants of culture-negative mothers who were suckled by positive adoptive mothers. However, 13% of the offsprinital cultures acquired group B streptococci. This model may be valuable in understanding the dynamics of vaginal carriage and mother-infant transmission of group B streptococci.

[Evaluation of the role of specific antimeningococcal antibodies in the spread of meningococcal carrier states in collectives]

The results of serological, bacteriological and epidemiological studies carried out in populations with different epidemic pattern of meningococcal infection are presented. A-group specific antibody was found to have the leading role in the intensity of the spread of meningococcal infection in the populations. The presence of antibody to this antigen in 16.7% of serum samples inhibited dissemination of meningococci in the populations. Simultaneously with an increase in the herd immunity level to 34.8% the attenuation of the active meningococcal dissemination cycle was observed. Meningococci isolated in the populations with different epidemic patterns of meningococcal infection were shown to have different ecological properties.

Transmission of hepatitis B virus infection by asymptomatic chronic HBsAg carrier mothers

The courses of 18 children born to 13 chronic hepatitis B surface antigen (HBsAg) carrier mothers were followed prospectively for serological and biochemical evidence of type B hepatitis. Three children developed transient HBsAg positivity accompanied by the appearance of antibody to the hepatitis B core antigen. Two others had no detectable HBsAg but developed antibody to HBsAg. These serological manifestations of hepatitis B virus infection occurred late--6 to 24 months after birth. None of the children had clinical evidence of hepatitis and none became chronic HBsAg carriers. The infrequency of transmission of infection, the mild course of disease, and the lack of persistence of HBsAg in these children probably reflected the low level of infectivity of the chronic carrier mothers and perhaps the healthy immunologic status of the children.