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Studies on the outbreak of hepatitis A in an institute for mentally retarded children
Insights
An outbreak of Hepatitis A virus (HAV) occurred in a Japanese institute. Researchers confirmed HAV transmission via contaminated food and water, and identified the virus, leading to effective protective measures.
Area of Science:
- Virology
- Epidemiology
- Public Health
Background:
- An acute hepatitis outbreak occurred in a public institute in Aomori Prefecture, Japan.
- The outbreak affected children and staff, with suspected transmission through contaminated water, meals, and close contact.
Purpose of the Study:
- To investigate the cause of the hepatitis outbreak.
- To confirm the etiological agent and transmission routes.
- To evaluate preventive measures.
Main Methods:
- Clinical and epidemiological investigations of 41 individuals.
- Immune electron microscopy to detect Hepatitis A virus (HAV) antigen in stool samples.
- Antigen extraction, purification, and serological testing using immune adherence hemagglutination (IAHA).
Main Results:
- Hepatitis A virus antigen particles were identified in stool specimens.
- The extracted HAV antigen was the first reported from a natural outbreak in Asia.
- IAHA tests confirmed a significant increase in antibody titers, serologically establishing the outbreak as Hepatitis A.
- Administration of human immune serum globulin was effective in preventing clinical hepatitis.
Conclusions:
- The epidemic was confirmed as an outbreak of Hepatitis A.
- Contaminated water, meals, and close contact were identified as probable transmission vehicles.
- Human immune serum globulin proved effective in preventing clinical manifestations of Hepatitis A.
Abstract:
The authors encountered an outbreak of acute hepatitis in a public institute for mentally retarded children in Aomori Prefecture, Japan. Studies revealed that the probable vehicles of transmission of infection were contaminated water, contaminated meals, and close contact. From the clinical manifestations and epidemiological investigations of 41 affected children and staff members, an outbreak of hepatitis A was strongly suspected. Immune electron microscopy disclosed hepatitis A virus antigen particles in the stool specimens collected during the few days before and after peak transaminase elevation. Hepatitis A antigen was further extracted and purified. The antigen was the first reported recovery of the virus from a natural outbreak of hapatitis A in Asia. Subsequently, with the immune adherence hemagglutination test, using this extracted antigen, an increase in titer of antibody to hepatitis A antigen was demonstrated. Thus, this epidemic was serologically established as an outbreak of hepatitis A. Human immune serum globulin for the protection against hepatitis A was administrated to the 80 individuals concerned, and it was effective in preventing the clinical manifestation of hepatitis.