Sex-related differences in transmission of hepatitis B infection in a Melanesian population.

Factors involved in the spread of hepatitis B virus (HBV) in the largely Melanesian population (N = 909) of Graciosa Bay, Ndeni, are examined. Based upon cultural information from Ndeni and ways in which HBV is spread in other populations, certain practices and interactions, predicted as effective routes of HBV infection, are analyzed. Most significant are father-to-son transmission and older-brother-to-younger-sibling transmission, indicating that males are instrumental in the transmission of HBV on Ndeni. Other possible routes of HBV transmission that are not shown to be significant on Ndeni are significant modes of disease spread in other cultures. Cross-cultural differences are discussed with regard to behavior, age of infection, and persistence of HBeAg (an antigen linked to HBV infection). Particularly with regard to maternal transmission, it is clear that the average age of infection combined with the degree of HBeAg persistence limits the number of infective mothers in this population. Cultural practices, however, may explain the disproportion of male carriers over 30 implicating a largely extinct set of culturally sanctioned practices involving very early exposure to HBV in boys and their age-related inability to make antibody to the virus.

Hepatitis B virus (HBV) infection among children and adults in the Solomon Islands.

A total of 593 inhabitants of Graciosa Bay, Santa Cruz, the Solomon Islands were tested for HBsAg and anti-HBs in 1974 and again in 1977. An additional 102 children born during this study period were tested for HBsAg and anti-HBs in 1977. Loss of HBsAg was observed in 20% of the 66 HBsAg-positive individuals identified in 1974 and retested in 1977. Conversely, acquisition of HBV infection, as documented by seroconversion on HBsAg or anti-HBs, was observed in 38% of the individuals identified as negative for all HBV markers in 1974. Acquisition of HBsAg was noted in 22 individuals, eight of whom were born after 1974. Acquisition of HBsAg was noted in 66 individuals, two of whom were born after 1974. Males and females acquired HBV infection at somewhat similar rates (42% vs. 34%), except between ages 15 and 29 years, when males were infected at a much higher rate (53%) than females (11%) (p = 0.008). Contact with a carrier appears to be the predominant mode of transmission of the virus. Acquisition of HBV by children and females was strongly correlated with the presence of an HBsAg-positive individual among the household contacts. Adult males, on the other hand, tended to acquire HBV infections from sources outside their family or household setting. The relationship between the patterns of acquisition of HBV infection and the cultural practices in this Melanesian population is discussed.

Red cell enzyme and serum protein types in a population from Ndeni (Santa Cruz Islands).

Data for 14 red cell enzyme systems, haemoglobin and four serum proteins are presented for 351 people from the island of Ndeni in the Santa Cruz group of the British Solomon Islands Protectorate. The results support the view based on linguistic studies that the Ndeni population is derived from a mixing of older Papuan and later Austronesian-speaking peoples.

Prevalencia de los anticuerpos contra el virus A de la hepatitis (VAH) en donantes de sangre de 13 países y territorios del hemisferio occidental / Prevalence of antibodies to hepatitis A virus (HAV) in blood donors of 13 Western Hemisphere countries and territories

Los resultados de una encuesta con 7.342 muestras de sangre de 13 países y territorios de las Américas indican una elevada prevalencia de los anticuerpos contra el virus A de la hepatitis en esa Región. Los resultados señalan también una correlación significativa entre la ausencia de dichos anticuerpos y la ausencia de marcadores indicativos de infección por el virus B de la hepatitis (AU)

Prevalencia de los anticuerpos contra el virus A de la hepatitis (VAH) en donantes de sangre de 13 paises y territorios del Hemisferio Occidental. / Prevalence of antibodies to hepatitis A virus (HAV) in blood donors of 13 countries and territories of the Western-Hemisphere

Los resultados de una encuesta con 7,342 muestras de sangur de 13 paises y territorios de las Americas indican una elevada prevalencia de los anticuerpos contra el virus A de la hepatitis en esa Region. Los resultados senalan tambien una correlacion significativa entre la ausencia de dichos anticuerpos y la ausencia de marcadores indicativos de infeccion por el virus B de la hepatitis

Prevalencia de los anticuerpos contra el virus A de la hepatitis (VAH) en donantes de sangre de 13 países y territorios del hemisferio occidental / Prevalence of antibodies to hepatitis A virus (HAV) in blood donors of 13 Western Hemisphere countries and territories

Los resultados de una encuesta con 7.342 muestras de sangre de 13 países y territorios de las Américas indican una elevada prevalencia de los anticuerpos contra el virus A de la hepatitis en esa Región. Los resultados señalan también una correlación significativa entre la ausencia de dichos anticuerpos y la ausencia de marcadores indicativos de infección por el virus B de la hepatitis (AU)

Distribution of hepatitis B virus (HBV) markers in blood donors of 13 western hemisphere countries: proceedings of the red cross Latin American hepatitis B workshop

Report presenting the results of a study made of Hepatitis B viral markers. A total of 7.487 donor blood samples from 13 Western Hemisphere countries (Argentina, Barbados, Brazil, Chile, Colombia, Costa Rica, the Dominican Republic, Ecuador, Mexico, Peru, Puerto Rico, Suriname, and Venezuela) were tested for various markers of hepatitis B virus (HBV) infection with several different techniques. HBsAg was detected in 1.6 per cent of the samples, anti-HBs in 20.2 per cent, and anti-HBs in 21.3 per cent. The incidence of HBsAg varied from 0.2 per cent (in Puerto Rican samples) to 4.1 per cent (in the samples from the Dominican Republic). Overall, 5.8 per cent of the samples found to contain HBsAg also contained HBeAg, while 24.8 per cent had detectable anti-HBe. Sixty-six (54.5 per cent) of the 121 HBsAg-positive samples were found to contain subtype HBsAg/ad, and 5(4.1 per cent) were found to contain subtype HBsAg/ay. Subtypes of the remaining samples could not be determined because of insufficient antigen. In a comparitive study, reverse passive hemagglutination (RPHA), counterelectrophoresis (CEP), and immunodiffusion (ID) detected by HBsAg in 90.9. 67.2, and 62.0 per cent of the samples previously found positive by radioimmunoassay (RIA) screening. Considerable variation was observed in the prevalence of HBV markers in samples from different countries, the highest prevalence being 82.8 per cent in samples from the Dominican Republic. Over-all, the findings suggest that exposure to HBV is quite extensive in some Latin American populations......(AU)

A new antigenic determinant on HBsAg. Geographic and subtype distribution and association with HBeAg and anti-HBe.

A new antigenic specificity for HBsAg is described, and its usefulness as an epidemiological marker is discussed. This specificity, l, was found in specimens from all geographic areas studied (United States, Latin America, South Africa, the Solomon Islands, and New Guinea). In these areas, l was strongly associated with HBsAg/ay; y-positive, l-negative samples were observed only among specimens from United States volunteer blood donors. This determinant allowed a distinction of HBsAg/ad classes. Thus, the l determinant was detected in 51.4% of HBsAg/adw4, 44.1% of HBsAg/adw(non-w4), and 50% of HBsAg/adr. The association of l and other HBsAg determinants with HBeAg or anti-HBe was also investigated. HBeAg was found to be associated with the presence of the l determinant and with the r determinant. Anti-HBe was associated with the presence of the d and w determinants and with the absence of the l specificity.

Relationship of subtypes of hepatitis B surface antigen with e antigen and its corresponding antibody.

A total of 3,212 samples of blood from asymptomatic volunteer donors positive for hepatitis B surface antigen (HBsAg) by radioimmunoassay and 860 samples negative for HBsAg were tested for the presence of hepatitis e antigen (HBeAg) and its corresponding antibody (anti-HBe) using a rheophoresis technique. Neither HBeAg nor anti-HBe was detected in any sample negative for HBsAg. Of the HBsAg-positive samples, 237 (7.4%) contained HBeAg and 749 (23.3%) had anti-HBe. HBeAg was significantly (P less than or equal to 0.0005) more likely to be in samples with high titers of HBsAg. Anti-HBe had an equal chance of occurring in samples with low or high titers of HBsAg. Both HBeAg and anti-HBe were found in samples with HBsAg subtypes ad or ay. However, a significant association (P less than or equal to 0.0005) between HBsAg/ay and HBeAg as well as an association between anti-HBe and HBsAg/ad was found.

Distribution and persistence of hepatitis B surface antigen and antibody in a Melanesian population.

The population of Graciosa Bay, Santa Cruz, British Solomon Islands Protectorate, was tested for HBsAg and anti-HBs in 1973 and 1974. Both the antigen and antibody occurred more often in males, presumably due to a higher exposure rate. None of 28 infants under one year of age had antigen and only one of 50 individuals under two years (2%) did. The prevalence of antigenemia was higher in older children and did not decline with increasing age. This pattern is contrasted to that found in other populations which is characterized by onset during the first year and a decrease in prevalence in older age groups. The ratio of antigenemia prevalence to that of antibody is significantly higher in the population under six years of age (p less than 0.01), indicating that younger infected people tend to be asymptomatic carriers while older individuals tend to have produced antibody. Three of 28 individuals with antigen detectable by immunodiffusion in 1973 had lower levels, detectable only by reversed passive hemagglutination after one year. The age specific prevalence of anti-HBs increases to a peak of 34% in the 15-19 year age group and declines thereafter.

Limited family clustering of hepatitis B surface antigen in a Melanesian population.

The entire population of Graciosa Bay, Santa Cruz, Solomon Islands, was tested for hepatitis B surface antigen (HBsAg) by reverse passive hemagglutination and antibody to HBsAg (anti-HBs) by passive hemagglutination. Analysis of the distribution of HBsAg in relatives of HBsAg carriers and non-carriers showed clustering only in children of carrier mothers. Similarly, there was no clustering of total exposure as measured by serologic tests except in children of carrier parents primarily due to the antibody and antigen of children of carrier mothers. This distribution pattern is probably due to cultural and environmental factors which increase exposure between HBsAg carriers and people who are not related to them and also reduce the amount of contact between siblings.