Hepatitis A shifting epidemiology in the Middle East and Africa

Data on the endemicity of hepatitis A virus (HAV) infection in Africa and the Middle East are scant, but most of Africa appears to remain a high endemicity region, with the exception of subpopulations in some areas, e.g. White people in South Africa. Saudi Arabia is a model for the Middle East, and is a country in which shifting HAV epidemiology has been documented in recent years, concurrent with the social and economic development that has occurred over the last two decades. Earlier studies generally showed very high prevalence rates, with most people becoming infected in early childhood. Between 1989 and 1995, however, there was a significant fall in the seroprevalence of antibodies to HAV in children up to 12 years old throughout the country except in one region bordering the Yemen. The highest seroprevalence is found in children from rural backgrounds, while the seroprevalences in Bedouin and urban children are similar. Seroprevalence is related to socioeconomic status, being highest in the lowest groups. Similar findings have been reported from other countries in the Middle East. The existence of pockets of high endemicity for HAV infection with surrounding areas shifting towards intermediate endemicity may lead to outbreaks, and widespread vaccination should be considered.     

Hepatitis A shifting epidemiology in South-East Asia and China

A review of the epidemiology of hepatitis A virus (HAV) infection over the last 20 years shows shifting patterns in the prevalence of antibodies to HAV (anti-HAV) throughout South-East Asia and China. A number of countries have shifted from high to moderate and from moderate to low endemicity, with a corresponding increase in the age of exposure from childhood to early adulthood. The changes have resulted from improvements in hygiene, sanitation and the quality of drinking water, reflecting improvements in living standards and socioeconomic progress. In general in the late 1970s and early 1980s, 85-95% of the population of developing countries like the Philippines, Korea, China and Thailand were anti-HAV-positive by age 10-15 years, compared with only about 50% in the more affluent countries like Malaysia and Singapore. In the early 1990s, 85-95% of the population were immune by age 30-40 years in the Philippines, Korea, China and Thailand, and by 50 years of age and above in Malaysia and Singapore. Similar trends were noted in Hong Kong, Taiwan and Japan. Exposure to HAV at a later age may be associated with an increase in hepatitis A morbidity and a greater propensity for outbreaks.     

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.     

用马尔科夫链对四川省城乡居民甲肝流行模式的研究

目的：探讨我省城乡居民甲肝流行模式,为我省甲肝流行趋势的预测和甲肝预防提供科学依据。方法：多阶段整群系统随机抽样法共计调查我省城乡居民3041人。用ELISA法检测HAV感染标志物（抗－HAV）。资料分析采用随机过程方法－两状态非齐次马尔科夫链。结果：抗－HAV阳性率城市和农村分别为72．99％和80．83％。城市人群总体MRR高达211．71,农村人群为153．17。MRRt以每5岁划分年龄组,城市人群除5－岁年龄组外,35岁以前各组MRRt均大于10,且接近20年年龄组主要集中在1－、15－和20－岁年龄组。农村人群只有11岁以前两组MRRt高于10,且随年龄增大呈下降趋势。结论：城市居民因感染HAV所承受的疾病负荷大于农村居民,其高危年龄为1－25岁。故应在该年龄组人群中实施有计划的免疫预防措施,以减少发病和控制流行。农村居民HAV感染的高危年龄发生在儿童期早期,故在农村应密切监测甲肝流行趋势,及时发现和控制可能发生的流行。     

Hepatitis A seroprevalence in adolescents and young adults in Mexico: A 2012 National Health and Nutrition Survey analysis

To describe hepatitis A virus (HAV) seroprevalence and associated factors in adolescents (10–19 years) and young adults (20–25 years) in different Mexican regions, using 2012 National Health and Nutrition Survey data. A random selection of 1581 serum samples was analyzed. Weighted HAV seroprevalence with 95% confidence intervals (95%CI) and its association with sociodemographic factors were estimated. Mean weighted HAV seroprevalence was 69.3% (95%CI: 64.8–73.4) overall, with 58.8% (95%CI: 53.4–64.1) in adolescents and 83.0% (95%CI: 75.3–88.7) in young adults. By age of 10, 46.7% (95%CI: 33.9–60.0) were seropositive and by age of 15, 52.8% (95%CI: 36.5–68.5), corresponding to intermediate endemicity nationally. Factors associated with HAV seropositivity (adjusted odds ratio, aOR) included: lower socioeconomic status (SES) (aOR = 4.09 for low and aOR = 2.31 for medium versus high SES), older age (aOR = 0.29 for adolescents versus young adults), living in the South (aOR = 2.12 versus Central Mexico) or in rural areas (aOR = 2.25 versus urban areas). Regional differences and increased seroprevalence of HAV in marginalized populations present an important public health issue, as a relatively large proportion of young adults are susceptible to infection. The burden of symptomatic disease must be addressed further to support specific programs of continued sanitation and education improvement, and the possibility of vaccination in more susceptible regions.     

1992年河北城乡居民甲肝流行的随机过程模式研究

目的 :探讨城乡居民甲肝流行模式 ,为制定免疫预防策略提供依据。方法 :研究对象选择采用多阶段整群系统随机抽样法 ,甲肝抗体检测采用ELISA法 ,资料分析采用随机过程方法—两状态非齐次马尔可夫链 ,首次使用了“年龄组细分法”。结果 :城市人群总体MRR高达 10 9.5 6 ,而农村人群则只有 41.16。MRRts以每 10岁划分年龄组 ,城市人群MRR1 9、MRR1 0 1 9及乡村人群MRR1 9均高于2 0 ;以每 5岁划分年龄组 ,城市人群中 2 0岁以下的 4个年龄组的MRRts均超过 10 ,而农村人群只有 10岁以下的 2个年龄组超过 10 ;以每 2岁划分年龄组 ,城市人群年龄组MRRts绝对值较大 ,正负值交替出现 ,但正值大于 10的年龄组集中在 7～ 16岁之间 ,而农村人群的MRRts值随年龄增大呈下降趋势 ,至 7～ 8岁组已降至 10以下。结论 :城市居民因HAV所承受的的疾病负荷远大于农村居民 ,故应在其高危年龄组 (7～ 16岁 )人群进行有计划的免疫预防 ;农村居民HAV感染的高危年龄为儿童期早期 ,应密切监测甲肝流行趋势 ,以及时发现发病年龄后移和控制可能发生的流行。     

Prevalence of anti-HAV antibodies in selected groups of children

Hepatitis A is a significant endemic and epidemic disease of global importance. There are few studies on the epidemiology of hepatitis A in Poland. The aim of this study was to investigate the prevalence of the antibodies to HAV (anti-HAV IgG) in children and adolescents living in urban and rural areas. Sera from 377 children were collected: 195 lived in Warsaw and 182 in rural area (voyevodship opolskie). The prevalence of anti-HAV was very low--9.3% and 3.8% respectively. This finding suggest that epidemiological shift from intermediate to low endemicity is possible in Poland and a new policy of prophylaxis hepatitis A may be necessary.     

Seroprevalence of viral hepatitis A in the Czech Republic

Over recent decades, the epidemiology of hepatitis A has changed in most European countries: the age of infection has been shifting towards older age groups. In view of this evolution and the central location of the Czech Republic in Europe, we wanted to assess current anti-hepatitis A seroprevalence. We determined the anti-hepatitis A seroprevalence among three different groups: military personnel between 1991–1995, prior to their deployment as UN troops, civilians participating in a national serological survey in 1996 and volunteers for vaccine clinical trials in 1996. The anti-HAV prevalence <20 years of age was about 4%; in the age cohort 40–49 it ranged between 47 and 51%. Only over the age of 60 years was the seroprevalence rate >85%. The risk of acquiring HAV is low for younger age groups. We could demonstrate some regional differences with higher rates in some age strata for the North Bohemian region and the lowest rates in East Bohemia and Prague. Compared to archived sera from a previous serological survey in 1984 we demonstrate a shift towards low endemicity. For the first time it is shown that an Eastern European country, i.e. the Czech Republic, is a country with a low endemicity for HAV. Substantial parts of the population are or will be at an increased risk of HAV infection and active immunisation against HAV should be considered.     

Hepatitis A in Poland in 2001

A total of 738 cases of hepatitis A were reported in 2000, which was 3 times higher as compared to 1999. The incidence rate was estimated to be 1.91 per 100,000. The incidence rate in urban areas was 2 times higher than in rural population. The highest incidence rates were reported among persons 10-14 and 20-24 years old. Patients in these age groups constituted 29.4% of the total number of cases. The above data show that, from 1997 epidemiological situation of hepatitis has been approaching low endemicity pattern.     

Are homosexual males a risk group for hepatitis A infection in intermediate endemicity areas?

The purpose of this study was to examine the prevalence of antibody against hepatitis A (anti-HAV) in a population of homosexual men compared with that of heterosexual men in an area of intermediate HAV endemicity (Madrid, Spain). A total of 148 patients were recruited in a Sexually Transmitted Diseases Clinic: 74 homosexuals (mean age of 28 +/- 5 years) and 74 heterosexuals (29 +/- 5 years). The prevalence of anti-HAV antibody was 47% and 43% for homo- and heterosexuals, respectively. Among the factors evaluated (age, sexual orientation and practices, travel to high HAV endemicity areas) oral-anal contact was significantly associated with a higher prevalence of anti-HAV antibody (odds ratio, 2.8; 95% confidence interval, 1.1-7.4; P = 0.03). These results indicated that in an area of intermediate endemicity young homosexual men are not at increased risk of having acquired hepatitis A infection than heterosexuals. Oral-anal contact is an independent risk factor that influences the presence of anti-HAV antibody, regardless of sexual orientation.     

A new method for imputing country-level estimates of hepatitis A virus endemicity levels in the Eastern Mediterranean region

Background

Few country-level estimates for hepatitis A virus (HAV) seroprevlance are available for the 23 countries in the Eastern Mediterranean region (EMRO) of the World Health Organization.

Methods

We used a three-stage approach to assign an HAV endemicity level to each country in North Africa and the Middle East based on the age at midpoint of population immunity. First, we conducted a systematic review to identify all age–seroprevalence studies conducted within the past 10 years. Second, for countries without first-stage evidence we searched for incidence data and older seroprevalence data. Third, for countries with no hepatitis A data, we estimated HAV endemicity based on socioeconomic and water indicators.

Results

This three-stage method allowed us to estimate country-specific endemicity levels for every country in EMRO even though first-stage evidence was only available for nine countries and for three countries only third-stage evidence was available. The region has a heterogeneous hepatitis A risk profile, with 13 countries having very high endemicity (an age at midpoint of population immunity in early childhood), three having high endemicity (late childhood), and seven having intermediate endemicity (early adulthood).

Conclusions

The three-stage estimation approach enables the creation of a complete country-level map of HAV risk in EMRO. Given the heterogeneity of HAV endemicity levels in the region and the likelihood of transitions to lower incidence rates and greater adult susceptibility in the near future, enhanced surveillance for hepatitis A would strengthen decisions about vaccination policy in the region.     

1997-2011年中国丙型肝炎流行特征分析

目的描述中国丙型肝炎流行特征及其变化趋势.方法收集1997-2011年中国丙型肝炎报告病例资料,资料整理和数据分析采用SPSS 19.0软件.结果自1997年中国丙型肝炎报告病例数及发病率逐年增加,特别是在2004年网络直报以来,每年报告病例数快速上升,报告发病率从2004年的3.03/10万上升至2011年的12.97/10万.15～49岁年龄组每年报告例数所占比例均>50%,≥50岁年龄组报告例数和所占比例同样逐年上升,随年龄增加发病率呈上升趋势.2005-2011年全国报告城乡病例数均逐年增加,病例数比从2005年的1.47下降至2011年的0.99.1997-2011年全国31省(自治区、直辖市)报告发病率均呈增长趋势,发病率较高的地区多分布在北方省份.74.8%的HCV/HIV双重感染者报告有注射毒品史或献血浆史或输血史或手术史.结论中国丙型肝炎病例报告发病数及发病率均逐年上升,应加强重点人群和地区疫情监测.     

The epidemiology of hepatitis A infection in Palestine: a universal vaccination programme is not yet needed.

In Palestine, there has been an increase in the reported incidence of acute hepatitis A virus (HAV) infection since 1995. Since overt clinical disease occurs only among adults, questions were raised whether or not a shift in the epidemiology of HAV has occurred. This is generally characterized by a decrease in the overall incidence rate and a shifting in the mean age of infection towards adolescence and early adulthood. The need for a vaccination programme is being discussed. To resolve this issue, we examined the prevalence of anti-HAV in a representative sample of 396 school children in the Gaza Strip. The prevalence of anti-HAV was 93.7% (95% CI: 91.3, 96.1%). Stratifying the prevalence by age showed that 87.8% (95% CI: 78.6, 97%) were HAV antibody positive by the age of 6. By the age of 14, almost 98% (95% CI: 92.7, 100%) were HAV antibody positive. This means that the majority of HAV infection is still taking place in early childhood, when it is usually asymptomatic and of little clinical significance. The results refuted the shifting epidemiology theory and we recommend that a vaccination programme against HAV infection is not yet needed. Alternative explanations for the increase in reported cases are discussed.     

Human exposure to allergenic pollens: a comparison between urban and rural areas

Background

Pollinosis is found more frequently in urban areas than in rural environments. This could be partly related to the different types of pollen exposure in these dissimilar areas. The objective of this study was to compare the distribution of pollen in these environments across an urbanization gradient.

Methods

Daily pollen abundances were obtained in France using Hirst-type sensors. Sampling was conducted from January to June in 2003 and 2006 in a rural area, a semi-rural area and in two urban areas, which were characterized by several urbanization criteria.

Results

Total allergenic pollen abundance was higher in rural and semi-rural areas than in urban areas irrespective of the sampling year. Multivariate analyses showed that pollen exposures differed according to the type of area and were strongly explained by the urbanization gradient. Grass, ash, birch, alder, hornbeam, hazel and plantain pollen quantities exceeded the allergy threshold more often in rural settings than in urban areas. In urban areas, only plane pollen quantities exceeded the allergy threshold more often than in rural areas.

Conclusions

Allergenic pollen exposure is higher in rural areas than in urban areas, and the most abundant pollen in each area did not originated from the same taxa. This result should be taken into account in epidemiological studies comparing allergies in rural and urban areas to adapt the panel of pollen extracts for human environmental exposure. In addition, this study highlights that some ornamental trees produce a large number of allergenic pollens and provide new sources of aeroallergens.     

Immunity to Hepatitis-A virus: A nationwide population-based seroprevalence study from Iran

BackgroundThe mortality rate of acute Hepatitis A increases from 0.1% in the children to 1.2%, in the adults. Hepatitis A is efficiently prevented by HAV-vaccine, but the strategy for distributing this vaccine among countries is dependent on their level of immunity to HAV. This study aimed to detect the level of immunity to HAV in Iran.MethodsIn this population-based seroprevalence study, 5419 participants from 12 of provinces of Iran, including 57 urban and 120 rural areas were chosen through a multi-stage cluster random sampling. Participants were interviewed by filling checklists and 3 cc of blood sample was obtained from each of them. IBM SPSS statistics V.21 software was used for univariable and multivariable analysis of data.ResultsMean of age of Interviewees was 26.4 ± 16 years, ranging from 1 to 94 years with a male to female ratio 1.02. Overall, 3603 (66.5%) of subjects were seropositive for HAV-IgG. Among the age groups, 41.1% of children by the age 15 years and 82.6% of adults around 30 years old were immune to HAV. The Mid-point age of population immunity was 21 years. Residents of the borders of the country, people who had less access to the safe water or sanitary toilet, individuals with low socioeconomic status and persons who were a member of dense families had the most probability of seropositivity.ConclusionsThis study showed that Iran is among HAV low endemic countries and vaccination against HAV is recommended only in the high-risk population, including patients with chronic liver diseases, patients with coagulopathy, travelers to the high endemic areas, and homosexuals. Establishment of national HAV surveillance system, concerning of health system about the occurrence of the HAV outbreaks, implementation of harm reduction strategies, improving economic indices and sanitation and access to the safe water in the deprived regions is recommended.     

Age-specific prevalence of hepatitis A virus antibody in Thailand

Serum specimens drawn at random from three geographically defined populations of healthy Thais were tested for antibody to the hepatitis A virus (anti-HAV) by radioimmunoassay. A total of 746 specimens were tested. The age by which 50 per cent were antibody positive was 4-5 years for residents of an urban Bangkok housing project, 8-9 years for rural villagers, and 10-11 years for urban Bangkok government school pupils. Overall, specimens from 97 per cent of Thai adults 16 years of age or older were anti-HAV positive. These data suggest widespread distribution of HAV in Thailand.     

Marked decrease in the incidence and prevalence of hepatitis A in the Basque Country, Spain, 1986-2004

The aim of this study was to determine changes in the epidemiology of hepatitis A virus (HAV) infection in the Basque Country, Spain, and to evaluate their implications for vaccination strategies. A total of 1356 persons were enrolled in a study of the prevalence of anti-HAV in 2004 and compared with two previous studies (1986-1987 and 1992). The selection method and the characteristics of the population were similar in the three studies. A marked decline in the seroprevalence in all age groups (P<0.001) and in the incidence of cases/100,000 inhabitants (from 38.0 in 1986-1988 to 2.9 in 2002-2004) were observed. The mean age of patients with hepatitis A increased from 17.7 years in 1986-1992 to 21.2 years in 1993-1998 and 25.3 years in 1999-2004 (P<0.001). Between 1997 and 2004, 20% of patients were hospitalized. The changes observed have occurred rapidly causing a change in the epidemiological pattern from middle-high endemicity (1986) to low endemicity (2004).     

利用网络爬虫技术分析我国活禽贸易与H7N9禽流感病毒传播的关系

采用网络爬虫技术分析2013年中国各省份通过活禽贸易携带H7N9禽流感病毒活禽的可能传播方向和范围,并预测疫情发展趋势。数据分析显示,有18个省份存在高感染风险,其中13个省份截止2014年2月已有报告病例。预测5个元感染风险的省份迄今未报告病例。     

Hepatitis A in Poland in 2000

A total of 262 cases of hepatitis A were reported in 1999. The incidence was estimated to be 0.7 per 100,000 and represented 74% decrease compared to the preceding year. The incidence rates within rural and urban populations were similar. The highest incidence was reported among persons 20-24 years old. Patients in this age group constituted 20.2% of the total number of cases. The above data shows that since 1997 epidemiological situation of hepatitis A is making for low endemicity pattern.     

Seroprevalence of hepatitis A among Thai population residing near Myanmar border

hen compared with Thailand, the seroprevalence of hepatitis A virus (HAV) is extremely high among its neighbouring countries. To investigate the seroprevalence of HAV among the Thai people residing in the border area between Thailand and Myanmar, 308 residents in Umphang, Maesod district, Tak, were recruited. Sera were tested for HAV IgG antibodies by enzyme-linked immunosorbent assay. The overall seroprevalence among the Thai people residing in the border area of Thailand was significantly higher than that among the general Thai population (71% vs 27% respectively, p < 0.05). As asymptomatic or mild HAV infection typically occurs in children, the Thai people residing in the border area may receive little benefit from universal HAV vaccination. Lower protective antibodies against HAV, along with the exclusion of HAV vaccine from the Expanded Programme on Immunization, potentially increase the susceptibility to HAV among the general Thai population and may lead to more future outbreaks if HAV is introduced from the border areas. The findings suggest that HAV vaccines should be recommended to travellers before their journey to the border between Thailand and Myanmar where HAV is endemic.