Risk factor analysis of an epidemic of hepatitis A in a factory in Shanghai

Influence of socioeconomic events on cause-specific mortality in urban Shanghai, China, from 1974 to 2015: a population-based longitudinal study

BACKGROUND

Understanding how socioeconomic events influence cause-specific mortality is essential for optimizing disease-control strategies. We characterized long-term trends in cause-specific mortality in a stable population from a very large urban centre.

METHODS

We derived population data from 1974 to 2015 on vital status, demographics and causes of death from the death registration system in Yangpu District, Shanghai, China. We examined temporal trends in mortality and assessed the effects of age, period and birth cohort.

RESULTS

Over 41 879 864 person-years of follow-up, we analyzed 290 332 deaths: 3.80% from communicable conditions (group 1), 86.50% from noncommunicable diseases (group 2), and 5.56% from injuries (group 3). Age-standardized mortality decreased after 1988 for group 1 (average annual percentage change [AAPC] -6.7, 95% confidence interval [CI] -9.3 to -4.1), after 1995 for group 2 (AAPC -2.9, 95% CI -3.5 to -2.3), and after 1994 for group 3 (AAPC -5.4, 95% CI -6.3 to -4.5), after improvements in public health and clinical service infrastructure and the removal of polluting industries during the 1980s. We observed increased mortality from group 2 and group 3 causes in those born between 1955 and 1965, a period that included the Great Chinese Famine. Cause-specific mortality risks increased in those born after 1949 for cancer and diabetes only.

INTERPRETATION

Birth cohorts exposed to extreme starvation in early life had increased premature cause-specific mortality in later life. Decreased cause-specific mortality followed improvements in public health, medical infrastructure and pollution control, but not for cancer or diabetes, likely because of exposure to new risk factors.

Shellfish-Associated Enteric Virus Illness: Virus Localization, Disease Outbreaks and Prevention

Numerous outbreaks of shellfish-borne enteric virus illness have been reported worldwide. Most notable among the outbreaks are those caused by NoV and HAV. Lessons learned from outbreak investigations indicate that most outbreaks are preventable. Anthropogenic sources of contamination will continue to invade shellfish growing waters. Shellfish, by their very nature, will continue to bioconcentrate these contaminants, including enteric viruses. There is no quick fix for enteric virus contamination of shellfish; however, vigilance on behalf of the industry, regulatory agencies, and the consumer could substantially reduce the incidence of illness. Enhanced monitoring in all areas of shellfish production, harvesting, distribution, and processing would help to reduce viral illnesses. Pollution abatement and improved hygienic practices on behalf of the industry and consumers are needed. Improved analytical techniques for the detection of enteric viruses in shellfish will lead to enhanced shellfish safety and better protection for the consumer and the industry. Better reporting and epidemiological follow-up of outbreaks are keys to reducing the transmission of foodborne viral infections. It is anticipated that recent advances in analytical techniques, particularly for NoV, will lead to better monitoring capabilities for food and water and a reduction in the incidence of enteric virus illness among shellfish consumers.

Clusters of autochthonous hepatitis A cases in a low endemicity area

At the University Hospital of Besançon (département of Doubs, France), an unusually high number of patients were hospitalized for hepatitis A during the 1999-2000 period, some of whom had not travelled abroad. This prompted us to conduct an investigation on a population basis and search for clusters of cases possibly related to local sources of contamination. Accordingly, case definition was restricted to autochthonous cases. During the 1999-2002 period, 45 autochthonous cases were classified as possibly originating from local environmental sources. A space-time scan statistic detected one most likely cluster (standardized incidence ratio 20.63, 95% confidence interval 10.6-37.1), consisting of 11 persons (of whom five children had attended the same swimming pool). It remained significant in a sensitivity analysis, strongly supporting the hypothesis of an environmental source of contamination. This study reveals the necessity of regular surveillance for hepatitis A and raises the issue of virological surveys of pool waters.

Viruses and bivalve shellfish

The epidemiological data clearly demonstrates that filter feeding bivalve shellfish can, and do, act as efficient vehicles for the transmission of enteric viruses transmitted by the faecal-oral route. This identified hazard has been documented as a cause for concern by various international agencies and has a long history. Disease outbreaks can occur on an epidemic scale as graphically illustrated by an outbreak of Hepatitis A in Shanghai, China in 1988 involving about 300,000 cases. Improvement of harvesting area water quality offers the most sustainable route to improvement in the virological quality of bivalve shellfish sold live. However there is growing awareness, and concern, that current regulatory standards based on faecal coliform monitoring do not fully protect the shellfish consumer from viral infection. New viral test methods based on PCR, and the development of alternative more reliable faecal pollution indicators, offer new approaches for the further development of public health controls. However, further work is required to build a scientific consensus and to understand the implications of their introduction into legislation.

The changing epidemiological pattern of hepatitis A in an urban population of India: emergence of a trend similar to the European countries

The present study was undertaken to determine the seroprevalence of the antibody against hepatitis A virus (IgG anti-HAV) in an urban population sample from Delhi (India) and to assess any change in the epidemiological pattern of HAV infection in this part of the world. A total of 500 healthy subjects were enrolled and divided into groups on the basis of age, sex and per capita income and evaluated for the presence of IgG anti HAV antibodies using a commercially available kit. The mean age of all the subjects was 32.6 +/- 13.2 yr. and the male:female ratio was 1.5:1. The overall prevalence of IgG anti-HAV in all subjects was 71.2% (356/500). The prevalence in subjects >35 years (92.1% [186/202]) was significantly higher than that in subjects <35 years (92.1% [186/202]) was significantly higher than in subjects <35 years (57% [170/298]). No statistically significant difference was observed between male and female subjects (71.4% [217/304] vs. 70.9% [139/196]) or between subjects belonging to middle and low socioeconomic groups (68.9% [135/196] vs. 72.7% [221/304]). These findings when compared with the results that were obtained in 1982, showed a decreasing prevalence of IgG anti-HAV, most significantly in younger age groups (16-35 years). Thus, we may conclude that the seroepidemiology of hepatitis A virus infection in urban population of India seems to be changing with seroprevalence in the younger population approaching a figure similar to that of the more developed European countries.

Hepatitis A seroprevalence rate in Syria

Hepatitis A is a benign infection, which in the developing world affects mainly children; the majority of adults are immune by the age of 30. In the last decade or so, a shift in the prevalence pattern of hepatitis A virus (HAV) infection from a low- to a high-age group has appeared in the developed countries. This shift has been attributed to an improvement in the socio-economic and hygienic conditions. In the present study, 849 Syrians of all age groups and both sexes were tested by enzyme-linked immunosorbent assay technique for the seroprevalence of hepatitis A IgG antibody (anti-HAV IgG). It was observed that anti-HAV IgG was present in 89% Syrian population; with 50% in the 1-5 year age group and 95% in the 11-15 year age group. These results demonstrate that HAV infection in Syria is mostly acquired during childhood. As yet there is no serological evidence of a shift in HAV infection from a younger to a higher age group.

Effect of virus strain and antigen dose on immunogenicity and reactogenicity of an inactivated hepatitis A vaccine

A randomized double-blind comparison of five killed hepatitis A vaccine preparations was carried out with eligible medical student and staff volunteers. Vaccines were prepared in M RC-5 cells and formalin-inactivated. Three monthly injections of 1 ml in the deltoid muscle were given. Group A received the CLF strain at a dose of 360 ELISA units (El.U) in 0.5 mg aluminium hydroxide (n = 35). The other groups received the HM175 strain as follows: 180 El.U in 1 mg aluminium hydroxide (to group B, n = 42), 360 El.U in 0.5 mg aluminium hydroxide (to group C, n = 40), 360 El.U in 1 mg aluminium hydroxide (to group D, n = 39) and 720 El.U in 1 mg aluminium hydroxide (to group E, n = 43). The geometric mean anti-HAV concentration (GMC) measured in mIV/ml by an ELISA method one month after each injection were: group A, 223, 480, 1635; group B, 123, 221, 649; group C, 185, 365, 1085; group D, 144, 323, 1076; group E, 229, 646, 2521. At month 6, the GMC had fallen by approximately 20%. Seroconversion as measured by ELISA was 100% in groups A and E after one injection, and 100% in all groups after three injections; after two injections, only one subject in group C was still negative. The dose effect with HM175 vaccine was significant. There was a good correlation between ELISA and neutralization (radioimmunofocus inhibition test) titres. One month after the second dose, all subjects in groups A and E had both hepatitis A virus immunoglobulin M (HAV IgM) geometric mean titre, (GMT > 5000) and IgG (GMT > 25,000) as measured by a sensitive terminal dilution ELISA.(ABSTRACT TRUNCATED AT 250 WORDS)