Hepatitis A in day care centre

Spatiotemporal dynamics of viral hepatitis A in Italy

Viral hepatitis A is still common in Italy, especially in Southern regions. In this study, a metapopulation model for hepatitis A virus (HAV) transmission is proposed and analyzed. Analytical results on the asymptotic and transient behaviors of the system are carried out. Based on the available Italian movement data, a national spatial contact matrix at the regional level, which could be used for new studies on the transmission dynamics of other infectious diseases, is derived for modeling fluxes of individuals. Despite the small number of fitted parameters, model simulations are in good agreement with the observed average HAV incidence in all regions. Our results suggest that the mass vaccination program introduced in one Italian region only (Puglia, the one with the highest endemicity level) could have played a role in the decline of HAV incidence in the country as a whole. The only notable exception is represented by Campania, a Southern region showing a high endemicity level, which is not substantially affected by HAV dynamics in Puglia. Finally, our results highlight that the continuation of the vaccination campaign in Puglia would have a relevant impact in decreasing long-term HAV prevalence, especially in Southern Italy.

An individual-based model of hepatitis A transmission

Viral hepatitis A, as other endemic diseases, represents a public health priority worldwide. To study long-time scale human pathogens through individual-based simulations, the development of a dynamic network of contacts is required. In this work, we introduce an individual-based model accounting for the birth and death of the individuals, the generation of new households, and the educational career of the individuals, in order to investigate viral hepatitis A dynamics in the most affected Italian areas. Intervention options such as targeted vaccination, social distancing measures (e.g., closure of day care centers and kindergartens) and improvements in standards of living and hygiene are evaluated. Results show that a very low vaccination coverage is sufficient to control hepatitis A in Italy, while its elimination is not possible since new cases are continuously imported from high endemicity areas outside the country. Finally, the considered social distancing measures can be counterproductive since the fraction of recovered individuals does not decline while the age at infection increases, thus augmenting the probability of developing acute symptoms.

Outbreaks of hepatitis A among children in western India

Hepatitis A in most developing countries is a sporadic childhood disease, but lately focal outbreaks have been observed among children in India. During 2004, we investigated a large-scale outbreak of hepatitis among children living in a residential colony in Daund Taluka of District Pune in the western region of India. In total, 123 overt and 56 sub-clinical cases were detected. All the patients were reactive for IgM antibodies against hepatitis A virus (IgM anti-HAV) and were negative for IgM anti-hepatitis E virus, confirming HAV to be the etiological agent of the outbreak. Serum samples, feces and sewage samples were tested for HAV RNA and molecular characterization of the positives showed the presence of genotype IIIA. Further, IgM anti-HAV-positive sera from eight focal outbreaks were analyzed. The causative HAV in all these small-scale outbreaks also belonged to genotype IIIA, indicating the predominance of genotype IIIA in this region. This report of a large-scale, explosive outbreak of hepatitis A in Indian children once again emphasizes the need to evolve proper public health strategies, especially for vaccination, in countries in the transitional phase from hyperendemicity to intermediate endemicity.

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.

Comparative efficacy of hand hygiene agents in the reduction of bacteria and viruses

Background

Health care-associated infections most commonly result from person-to-person transmission via the hands of health care workers.

Methods

We studied the efficacy of hand hygiene agents (n = 14) following 10-second applications to reduce the level of challenge organisms (Serratia marcescens and MS2 bacteriophage) from the hands of healthy volunteers using the ASTM-E-1174-94 test method.

Results

The highest log₁₀ reductions of S marcescens were achieved with agents containing chlorhexidine gluconate (CHG), triclosan, benzethonium chloride, and the controls, tap water alone and nonantimicrobial soap and water (episode 1 of hand hygiene, 1.60-2.01; episode 10, 1.60-3.63). Handwipes but not alcohol-based handrubs were significantly inferior from these agents after a single episode of hand hygiene, but both groups were significantly inferior after 10 episodes. After a single episode of hand hygiene, alcohol/silver iodide, CHG, triclosan, and benzethonium chloride were similar to the controls in reduction of MS2, but, in general, handwipes and alcohol-based handrubs showed significantly lower efficacy. After 10 episodes, only benzethonium chloride (1.33) performed as well as the controls (1.59-1.89) in the reduction of MS2.

Conclusions

Antimicrobial handwashing agents were the most efficacious in bacterial removal, whereas waterless agents showed variable efficacy. Alcohol-based handrubs compared with other products demonstrated better efficacy after a single episode of hand hygiene than after 10 episodes. Effective hand hygiene for high levels of viral contamination with a nonenveloped virus was best achieved by physical removal with a nonantimicrobial soap or tap water alone.

Polymerase chain reaction-based prevalence of hepatitis A, hepatitis E and TT viruses in sewage from an endemic area

BACKGROUND/AIMS

Hepatitis A and E viruses (HAV, HEV) are transmitted enterically and are highly endemic in India. This study aims to evaluate prevalence of these and TT virus (TTV) in the sewage.

METHODS

Influent and effluent samples from a sewage treatment plant from Pune, India were collected twice a week for 1 year and subjected to nested polymerase chain reaction (PCR) for the detection of HAV RNA, HEV RNA and TTV DNA. HAV and HEV PCR products were sequenced. Effluent samples were not collected for 5 months as the plant was non-functional.

RESULTS

The overall prevalence was 24.42% (21/86, HAV), 10.98% (9/82, HEV) and 12.7% (8/63, TTV). Prevalence of HAV was significantly higher than HEV (P=0.023). During summer months, significantly higher HAV RNA positivity was noted (P<0.01). A substantial reduction in HAV RNA positivity (15/48 vs. 2/48, P=0.0008) was recorded for treated sewage samples. However, HEV RNA or TTV DNA positivity did not reduce significantly. Of the 17 HAV and HEV RNA negative sewage samples concentrated using ultracentrifugation, 13 and none were positive for HAV and HEV RNA, respectively. Phylogenetic analyses grouped these viruses in IB and Ia, respectively, the genotypes most prevalent in India.

CONCLUSIONS

Sewage may play an important role in maintaining hyper-endemicity of these infections. Sustained efforts are obligatory to render sewage less/non-infectious.

Changing scenario of hepatitis A virus and hepatitis E virus exposure among the primitive tribes of Andaman and Nicobar Islands, India over the 10-year period 1989-99

The Andaman and Nicobar Islands, Union Territory of India, are home to six primitive tribes. Studies carried out earlier among these tribes revealed very high rates of hepatitis B infection. We have now studied hepatitis A and E infection among them. A total of 951 serum samples were collected from four accessible tribes (Nicobarese, Shompens, Onges and Great Andamanese) and tested for antibodies against hepatitis A and E viruses. In addition, 240 serum samples collected a decade earlier from age-stratified Nicobarese were also screened. Hepatitis A virus (HAV) infection was found to be highly endemic among all the tribes, whereas hepatitis E virus (HEV) infection was common among the Nicobarese and Shompens. The age group-wise prevalence of these infections among the Nicobarese showed different patterns, HAV prevalence rising significantly from those aged 10 years and thereafter reaching a plateau, whereas HEV prevalence was found to be more evenly distributed over all age groups, but rising somewhat after 30 years of age. Over the last decade, the prevalence of HAV among the Nicobarese has declined slightly, particularly in those aged 10 years or less whereas HEV infection has more than doubled over all age ranges. Different HEV prevalence observed among the tribes could not be attributed to differences in sanitation or water supply. This fact and the different age-wise patterns of HAV and HEV prevalences is suggestive of different modes of transmission of HEV that are not shared. The highest rates for HEV were among those tribes which reared pigs suggesting that pigs might serve as reservoir of HEV. Further studies are needed, however, to validate these findings.

Changing epidemiology of hepatitis A and hepatitis E in urban and rural India (1982-98)

The epidemiology of hepatitis A virus (HAV) and hepatitis E virus (HEV) was assessed among age-stratified urban high socioeconomic, lower middle socioeconomic status and rural populations from western India in 1998. When compared with previous surveys, a clear shift from high to intermediate endemicity of HAV was evident only for higher socioeconomic population (1982-98), raising the possibility of outbreaks of hepatitis A in this category. A decrease in anti-HAV positivity was noted in rural children aged 6-10 years. Lower circulation of HEV was noted among < 25-year-old urban higher socioeconomic and rural individuals. For both viruses, the lower middle socioeconomic populations were comparable in 1982 and 1998. Socioeconomic status and family size (odds ratio = 23 and 1.6, respectively) were independently associated with anti-HAV positivity. Age, lower middle socioeconomic status and well water were significant independent variables for HEV infection (odds ratio = 5.7, 2.4 and 1.9, respectively). Hence, vaccination policy for hepatitis A needs to be reviewed.