Prevalence of Hepatitis A, B, and C markers in school children of a rural area of Crete, Greece

Objective: To determine the prevalence of hepatitis A, B, and C markers in children who were attending junior and senior high schools in a high risk area in rural Crete, Greece. Methods: Three-hundred and thirty-four children who attended the three junior schools and one senior high school in the Agios Vassilios province of Southern Crete were invited to participate in the study. Three hundred and four of them were tested for hepatitis A, B, and C markers. Hepatitis B (HBV) markers (HBsAg and anti-HBc) as well as hepatitis A (anti-HAV) and hepatitis (anti-HCV) antibodies were tested with commercial enzyme-linked immunosorbent assay kits. Results: Six of the 304 children (1.97%) were found to be positive for anti-HAV, 1 (0.33%) to HBsAg, 7 (2.30%) to anti-HBc and none were found positive for anti-HCV. No significant differences were seen between the prevalence of anti-HAV antibodies in males (2%) and females (1.95%), and of anti-HBc antibodies in males (3.33%) and females (1.30%). Conclusions: The very low prevalence of anti-HAV is obviously due to the improved conditions of hygiene and it raises the question of the possible emergence of this disease at an older age and therefore appropriate preventative strategies should be considered. The low endemicity of hepatitis B in Crete in contrast to other areas of Greece also calls for a vaccination policy probably during adolescence. The absence of hepatitis C markers in the children in contrast to the observed higher prevalence of HCV-infected people in the adult population in the same rural area raises questions regarding possible sources of transmission of hepatitis C during the preceding years.     

Hepatitis A antibodies: prevalence and persistence in a group of Mexican children

The prevalence of antibodies against hepatitis A virus (anti-HAV) was evaluated in sera from 275 asymptomatic infants and children under the age of five years and in 46 maternal-cord serum pairs, followed by sera obtained thereafter each month from the first to the fifth month of life in 29, 17, 9, 9 and 7 infants (a total of 163 serum samples). Anti-HAV was found in all cord blood sera, but its prevalence declined progressively to 0% among 19 infants aged eight months. Four (25%) of 16 children aged one year had positive anti-HAV and the antibody prevalence was 89% in children five years old. Recent hepatitis A infection shown by circulating anti-HAV immunoglobulin M was detected in five infants under the age of two months and with frequencies ranging from 19-67% in one- and five-year-old children. It was concluded that in children living in Mexico City, hepatitis A infections occur at an earlier age and at higher rates than in children in other cities, especially those in developed countries.     

Prevalence of hepatitis A virus antibody among Navajo school children.

Previous studies of the prevalence of immunity to hepatitis A (anti-HAV) in the United States have used urban settings or institutions for the mentally handicapped. In a rural setting among normal children, a serologic investigation of prevalence of anti-HAV was conducted in a boarding school adjacent to the Navajo reservation. The results show rates of anti-HAV that are the highest reported at the ages tested in any subpopulation in the United States, comparable only with those in developing countries.     

抗—HAV水平动态变化与甲型肝炎流行的关系

Hepatitis A was prevalent in 43 villages of the suburbs of Jinan, Shandong Province in 1986. The annual morbidity rate was 1,104.46/100,000. The authors studied the development of anti-HAV among children of under 14 years of age during the early epidemic and post-epidemic periods, compared the prevalence of anti-HAV between epidemic and non-epidemic villages, and analysed the types of HAV infection. The positive rate of anti-HAV was 35.42% during the early epidemic period and was 82.1% during the post-epidemic period, while it was 79.75% in non-epidemic villages. The result indicates that, in rural area, hepatitis A is chiefly influenced by the prevalence of anti-HAV in the population. If it remains at about 80%, the occurrence of an epidemic can be prevented. The ratio of clinical, subclinical and apparent infection during the epidemic was 1:0.75:0.81.     

The changing epidemiologic pattern of hepatitis A infection in urban Greece

The point prevalence of antibody to hepatitis A virus (anti-HAV) in a sample of 1,113 healthy Greek children and adolescents 0-19 years old was estimated by radioimmunoassay. The overall anti-HAV prevalence was 8.7%; it increased from almost zero among children less than four years of age to 16.3% in adolescents 15-19 years. Anti-HAV prevalence was independent of sex; it was lower among children born in Athens than among those born in other parts of the country, and it was higher in children of lower socioeconomic class. Compared with the results of previous surveys, the findings of the present study indicate that the exposure of Greek children to hepatitis A virus is decreasing, probably because of the improvement of socioeconomic conditions of the Greek population.     

Prevalence of anti-HAV and anti-HEV antibodies in Konya, Turkey

OBJECTIVE: To determine the prevalence of antibodies to hepatitis A (HAV) and E (HEV) viruses in the different areas of Konya. METHODS: Anti-HAV and anti-HEV antibodies were investigated in 210 healthy children randomly selected (100 from rural areas and 110 from urban areas of Konya). None gave a history of previous icterus nor other signs of hepatitis, had received blood transfusion and HAV vaccine, or had been on hemodialysis. RESULTS: Evidence of HAV infection occurred in children under the age of 6 years. The seroprevalence rate was 67.8% in rural areas and 25.8% in urban areas. This increased rapidly with age and became universal after 11 years of age in both areas. In contrast, HEV infections were not detected until children were 6-11 year olds, and the 5.2% seroprevalence rate in urban areas and 8.5% seroprevalence rate in rural areas in this age group did not significantly increase in older age group. The prevalence of anti-HAV as well as anti-HEV was significantly higher in children with poor socio-economic conditions in both areas. CONCLUSIONS: These results suggest that HAV infection in rural areas of Konya is widespread and that environmental and socio-economic factors play a major role in its transmission. In contrast, hepatitis E is not a public health problem in Konya.     

The seroepidemiology of hepatitis A and B in a Japanese town.

Sera collected from 1,118 healthy children and adults aged between four years and 90 years during the period 1989 to 1990, were tested for serological markers of hepatitis A virus (HAV) [antibody to HAV (anti-HAV)] and hepatitis B virus (HBV) [hepatitis B surface antigen (HBsAg) and antibody to hepatitis B surface antigen (anti-HBsAb)]. The overall prevalence rates of anti-HAV, HBsAg, and anti-HBV were 20.2%, 0.36%, and 5.1%, respectively. No body was found to be positive for anti-HAV below 30 years of age but more than 70% of the adults aged 50 years or over were positive for anti-HAV. The level of exposure of HAV infection is declining in Japan and paradoxically at the same time a vast majority of people are becoming susceptible to more severe illness. The fall in prevalence of HBsAg possibly represents the positive impact of ongoing vaccination programs and other preventive measures against HBV.     

Prevalence of antibody to hepatitis A virus in Okinawa and Kyushu, Japan

Between 1968 and 1981, a total of 1955 serum samples from healthy subjects chosen at random in seven districts of Okinawa and two districts of Kyushu were surveyed for antibody to hepatitis A virus (anti-HAV) by radioimmunoassay. Overall prevalence of anti-HAV was 55.1% in Okinawa and 35.9% in Kyushu. Prevalence of less than 10% was observed in subjects less than or equal to 14 years of age in Okinawa and less than or equal to 24 years of age in Kyushu. In three of the districts of Okinawa, second serum samples were collected after intervals of eight, 10, and 12 years, respectively. Overall prevalence of anti-HAV decreased significantly over these time periods. When the age-specific prevalence of anti-HAV on the first occasion is compared with that on the second occasion, it can be seen that there have been few new cases of hepatitis A infection. These data suggest that hepatitis A infection among children has declined dramatically in recent years, and that young people may be highly susceptible to hepatitis A virus.     

Epidemiology of hepatitis A and B in the Shanghai area: prevalence of serum markers

Different population groups from the Shanghai area were surveyed by radioimmunoassay for serologic markers of previous infections with hepatitis A virus and hepatitis B virus. There were no significant differences in the prevalence of antibodies to hepatitis A virus (anti-HAV) in males and females, or in persons living in rural or urban areas. The prevalence of anti-HAV showed a biphasic increase with age, approaching 100% above age 50 years whereas the geometric mean titers declined. The rate of infection (attack rate) with hepatitis A among susceptibles in Shanghai declined appreciably between 1950 and 1960. The prevalence of hepatitis B markers also did not differ in the sexes, or in rural and urban populations. The patterns of prevalence of hepatitis B markers at different ages were compared to various theoretical mathematical models, and the data fitted best a model constructed from the assumption that two subpopulations of approximately equal size, one at low and the other at high risk, existed in the population groups studied. It was estimated that in Shanghai up to 12% of all individuals infected with hepatitis B became chronic hepatitis B surface antigen (HBsAg) carriers, although the overall prevalence of HBsAg carriers was only 6.9%. All HBsAg-positive individuals subtyped had been infected with hepatitis B virus of the subtype ad; 41.7% of HBsAg carriers also had hepatitis B e antigen (HBeAg), whereas in 32% of HBsAg carriers antibodies to HBe were present. Antibodies to HBsAg appeared to be lower in titer than in Western populations and to decline with age, and age-specific prevalence data indicated a relatively longer persistence of antibodies to hepatitis B core antigen.     

Hepatitis A control in a refugee camp by active immunization

An outbreak of hepatitis A occurred among children of a refugee camp in Croatia. In order to disrupt the outbreak, we decided to vaccinate children from 1 to 15 years of age in the camp, in addition to intensified general preventive measures. Assuming high prevalence of hepatitis A virus antibodies within this population, we conducted anti-HAV testing of the children eligible for vaccination. Of 108 children tested, 74 (68.5%) were anti-HAV positive. We vaccinated 34 children. One month after vaccination 31 previously negative children were tested for anti-HAV and 30 of them were found positive, suggesting a seroconversion rate of 96.8%. One child fell ill 5 days after vaccination, after whom no new cases of hepatitis A occurred. Thus we conclude that active immunization is a successful means of stopping an outbreak of hepatitis A.     

Decline in the exposure to hepatitis A and B infections in children in Naples, Italy

In May 1988, the hepatitis A antibody (anti-HAV) and hepatitis B virus (HBV) markers were studied by radioimmunoassay in 484 apparently healthy children between the ages of 7 and 12, attending a primary school in Naples, Italy. The overall anti-HAV prevalence was 11.2%, increasing from 5.2 in 7-year-old children to 28.2% in children between the ages of 11 and 12 years old. The overall prevalence of the hepatitis B surface antigen (HBsAg) and of other HBV markers were 0.8 and 6.8 respectively. Compared with a similar previous study conducted in Naples in 1980, the results show a significant reduction in the prevalence of anti-HAV in each of the two age-groups (P less than 0.01), in the prevalence of any HBV marker in the 11 to 12-year-old group, as well as in the total population (P less than 0.05). The findings of the present study indicate that today, children in Naples are less exposed to the hepatitis A virus than in the past, most likely because of improvements in both the socioeconomic conditions and in health education during recent years. These same reasons, as well as decreased family size and a lower prevalence of HBeAg among HBsAg carriers could explain the decline, although to a lesser degree, of exposure to HBV infection.     

Inapparent infection of hepatitis A virus

To detect inapparent infection with hepatitis A virus, serial sera were collected from patients with hepatitis A and their contacts in two waterborne epidemics in China. Epidemic 1 occurred in a rural village near Hangzhou during August 1978-January 1979, and epidemic 2 took place in a rural primary school in Pinghu County in Zhejiang in April-May 1985. These sera were tested for antibodies against hepatitis A virus (anti-HAV), serum glutamic pyruvic transaminase (SGPT) activity, and icteric index. Feces also were collected in epidemic 1 to test for hepatitis A virus antigen. Both anti-HAV immunoglobulin M (IgM) and total anti-HAV were assayed in sera from "healthy persons" (symptomless persons without icterus and with normal SGPT level) who were in close contact with hepatitis A patients. In epidemic 1, among 18 "healthy persons", 12 were anti-HAV IgM positive, two were immune, and four susceptibles escaped infection. In epidemic 2, among 32 "healthy children", three were anti-HAV IgM positive, five had been infected by hepatitis A virus in the past, and 24 were not infected. These results demonstrate that inapparent infections occur along with overt and subclinical infections during epidemics of hepatitis A. The proportions of inapparent, subclinical, and overt infections were, respectively, 34.3%, 45.7%, and 20% in epidemic 1, and 25%, 50%, and 25% in epidemic 2. In addition, hepatitis A virus particles were demonstrated in the feces of all infected subjects who were examined and who included all levels of clinical response. These particles were identified with immuno-electron microscopy and enzyme-linked immunoassay.     

甲型肝炎病毒感染的血清流行病学研究

对543例城、乡正常人群甲肝IgG抗体的IAHA检测指出阳性率为64.8%。男女差异无显著性（P>0.05）。约半数感染人群发生在10岁以前，到成年时已超过80%。农村较城市更高（P<0.001），多数感染（73.2%）发生在10岁以下的小年龄人群，城市感染则多发生在较大年龄人群，与农村不同。表明甲肝感染普遍而严重。包括幼儿在内的青少年应是防止甲肝感染的主要对象，控制这些易感人群集中单位的爆发流行，是降低甲肝发病的有力措施。成人的群体免疫力较强，主要是及时发现，处理好散在发生的甲肝患者及其密切接触的易感人群，防止造成流行是有积极意义的。     

Changing patterns of hepatitis A virus infection in children in Palermo,Italy

In 1988 in Palermo, Italy the prevalence of antibodies to hepatitis A virus (anti-HAV) in a sample of 490 children 6–13 years old was 10.6%; it increased from 6.3% among children 6–10 years old to 14.7% in children 11–13 years old (P < 0.01).Compared with findings from a survey conducted in 1978 in the same area, the results of the present study show a significant (P < 0.01) reduction in the anti-HAV prevalence in both age groups.Anti-HAV prevalence was inversely related to the father's years of education and positively related to the family size. Children of fathers with less than 6 years of schooling had a 3.2-fold risk (C.I. 95% = 1.3–8.1), and children with five or more members in their households had a 2.7-fold risk (C.I. 95% = 1.1–6.4) of previous exposure to hepatitis A virus (HAV) infection.Our findings indicate that exposure of children in Palermo to HAV is decreasing significantly, probably because of improvements in socio-economic conditions during recent years; however socio-demographic factors appear to be important determinants of infection.     

Hepatitis A in Peru. The role of children

A serologic survey in 1983-1984 evaluated the presence of hepatitis A antibody (anti-HAV) and hepatitis A immunoglobulin M antibody (anti-HAV IgM) in 3,251 adults and 811 children in the jungle and coastal areas of Peru. All subjects were asymptomatic. Adults had a 98% positive anti-HAV rate except for naval cadets, who had a 76% rate. Children had an 82% positive anti-HAV rate, increasing from 30% at one year of age to 100% at eight years of age. Anti-HAV IgM was present in 27% of children one to four years of age who had antibody and was not present in those older than 12. The vast majority of Peruvian adults are immune to hepatitis A, and children with asymptomatic infection play a significant role in the transmission of this disease.     

1988～1999年龙岩市出生人群甲型肝炎免疫水平调查

[目的]了解龙岩市1988～1999年出生人群甲肝免疫水平,为制订甲肝防治策略提供科学依据。[方法]采用分层随机抽样方法,各县（市、区）抽取3个乡镇,每个乡镇随机抽查1988～1999年出生的儿童90名,采用统一的调查表进行问卷调查,每人采集静脉血5 ml采用ELLSA法测定甲肝抗体（抗-HAVIgG）。[结果]调查1925名1988～1999年出生儿童,检测1925份血清,抗-HAVIgG阳性的621份,阳性率为32.3%。男童阳性率为30.1%（303/1006）,女童为34.6%（318/919）,差异有统计学意义（P〈0.05）。不同年龄组间抗-HAV IgG阳性率的差异有统计学意义（P〈0.01）。不同地区间抗-HAVIgG阳性率的差异有统计学意义（P〈0.01）。[结论]龙岩市该人群抗-HAVIgG阳性率显著低于1992～1995年全国和全省HAV流行率水平,今后应继续加强预防甲肝知识的宣传,并提高该人群甲肝疫苗接种率。     

Sex-related differences in immunoglobulin M and in total antibody response to hepatitis A virus observed in two epidemics of hepatitis A

Sixty symptomatic and 42 asymptomatic cases of hepatitis A detected during two epidemics on the Greek island of Crete in autumn-winter, 1978-1979 were tested for serum total and immunoglobulin M (IgM) specific antibody to hepatitis A virus (anti-HAV and IgM anti-HAV) by commercially available solid phase radioimmunoassays. All cases of symptomatic hepatitis A tested during the first eight weeks from onset were IgM anti-HAV positive with a geometric mean titer of 1:3,575 at 0-28 days from onset. The probability of positivity declined progressively thereafter: a 50% level was reached on the 128th day from onset and the geometric mean titer dropped to 1:317 in samples obtained after the 85th day from onset. Asymptomatic patients had a significantly shorter duration of IgM response than symptomatic ones and three months from onset the prevalence of IgM anti-HAV was only 33% in the former compared to 95% in the latter (p less than 0.0001). A significantly higher prevalence of IgM anti-HAV and higher titers of total and IgM specific anti-HAV was observed in females than in males. IgM anti-HAV was positive in 12 (57%) of 21 samples from females compared to three (12.5%) of 24 samples from males, collected after the 85th day from onset (p less than 0.01). Five months from onset, the cumulative probability of IgM anti-HAV positivity in females was 38% compared to 0% in males (p less than 0.05).     

Changing epidemiology of hepatitis A infection in Izmir, Turkey

The seroprevalence study was conducted in order to determine the current seroepidemiology hepatitis A in Izmir, Turkey and to evaluate the epidemiological shift in HAV serostatus. Blood samples collected from 595 subjects aged 1-60 years were analyzed for anti-HAV IgG antibodies. The current study results were compared with those of a previous study conducted in 1998 involving the same location. There was a marked decrease in the prevalence of anti-HAV between 1998 and 2008. While anti-HAV seroprevalence rates in the current study were 4.6% in children aged 1-4 years, 23% in children aged 10-14 years, and 85% in young adults aged 20-29 years, the prevalence rates were 36% in the 1-4 years age group, 65% in the 10-14 years age group, and 95% in young adults in the previous study, indicating a shift in HAV seroprevalence from the younger to the higher age groups. As HAV infection in childhood is decreasing, the pool of susceptible adolescents and young adults is increasing in Izmir, Turkey. The majority of adolescent population is susceptible to HAV infection. The potential risk of HAV epidemics still exists. The situation of Turkey, suggested to need for mass immunization. Also, introduction of hepatitis A vaccination into the national immunization schedule of Turkey should be considered.     

高流行区甲型肝炎疫苗免疫方案研究

目的探讨甲型肝炎高流行区疫苗免疫方案。方法观察新生儿母传抗ＨＡＶ抗体的衰减及处于甲型肝炎流行不同阶段儿童甲型肝炎病毒感染率随年龄上升的规律。结果新生儿母传抗体的阳性率按ｌｏｇｉｓｔｉｃ曲线下降,１３个月内从９７．４％下降为５．０％;非流行期儿童甲型肝炎病毒感染率从１．５岁起随年龄上升,２岁前保持在１０％以内;流行期儿童甲型肝炎病毒感染率随年龄增加而起点提前,速度加快。鉴于甲型肝炎发病随年龄上升的起点滞后于感染,认为甲型肝炎高流行区新生儿甲型肝炎母传抗体向自然感染抗体转换的“窗口期”是在出生后１２～２４个月。结论根据流行情况与经济条件,儿童适宜的甲型肝炎疫苗免疫时机一般选择在１２～２４月龄     

Seroepidemiology of hepatitis A in voluntary blood donors from Pune, western India (2002 and 2004-2005)

Recently, a changing pattern of hepatitis A epidemiology has been reported in the Indian population indicating a rise in the rate of hepatitis A infection among adults. The study's objective was to assess anti-HAV prevalence in voluntary blood donors from middle and high socioeconomic strata. Serum samples collected from voluntary blood donors from Pune city and its suburbs in the years 2002 and 2004-2005 were tested for anti-HAV IgG antibodies. Serum samples collected during 2004-2005 were examined for anti-HAV IgM antibodies. Positive samples were tested for HAV-RNA. Agewise anti-HAV positivity was significantly low in adults aged 18-25 years (90.4%) compared to those aged >25 years (97.4%) (P<0.01). A decline in anti-HAV prevalence was significant in 2004-2005 compared to that in 2002 (96.5% vs. 92.1%) (P<0.01). Overall, in both adult age groups, the proportion of anti-HAV positivity was remarkably low in the high socioeconomic group (HSG) (88.96%) compared to that of the middle socioeconomic group (MSG) (95.86%) (P<0.01). Anti-HAV IgM positivity was not significant (~1%), however, presence of HAV-RNA in one of the samples indicated the possibility of horizontal transmission of HAV. Increase in seronegativity to HAV in HSG implicates a rise in the susceptible pool and indicates the need for vaccination against hepatitis A.