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Molecular and serological characterization of adenovirus genome type 7h isolated in Japan
M Hashido1, A Mukouyama, K Sakae
1Infectious Diseases Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
Abstract:
In 1996, three adenovirus type 7 (Ad7) strains were isolated from children with fever and upper respiratory diseases in Japan. Restriction endonucleases (REs) analysis and PCR amplification of the E3 7.7 kDa ORF revealed that these strains were genotype Ad7h and closely related to an Argentine Ad7h strain, which has been reported to be highly virulent and so far predominant only in South America. These strains showed weak cross-neutralizing activity and specific haemagglutination-inhibition activity to Ad3 antiserum. The present findings suggest that Ad7h in South America has spread to other parts of the world. Since the seroprevalence to Ad7 in the current Japanese population is very low due to the absence of Ad7 circulation in Japan for decades, Ad7 outbreak as a typical case of re-emerging infectious diseases is a cause for serious concern.
Insights
Adenovirus type 7h (Ad7h) strains, previously confined to South America, have emerged in Japan. This re-emerging infectious disease poses a significant concern due to low population immunity to Ad7.
Area of Science:
- Virology
- Infectious Diseases
- Public Health
Background:
- Adenovirus type 7 (Ad7) circulation has been absent in Japan for decades.
- Low seroprevalence in the Japanese population increases vulnerability to Ad7.
- Previous Ad7h strains from South America were noted for high virulence.
Purpose of the Study:
- To characterize newly isolated adenovirus strains from Japanese children.
- To investigate the genetic relationship and potential origin of these strains.
- To assess the public health implications of Ad7 re-emergence in Japan.
Main Methods:
- Isolation of adenovirus strains from pediatric patients with respiratory illness.
- Restriction endonucleases (REs) analysis for genetic fingerprinting.
- PCR amplification of the E3 7.7 kDa ORF for genotyping.
- Cross-neutralization and haemagglutination-inhibition assays.
Main Results:
- Three Ad7 strains, identified as genotype Ad7h, were isolated in Japan in 1996.
- These Japanese Ad7h strains are genetically similar to a highly virulent Argentine Ad7h strain.
- The isolated strains exhibited weak cross-neutralizing and specific haemagglutination-inhibition activities against Ad3 antiserum.
Conclusions:
- The findings suggest the global spread of South American Ad7h strains.
- The re-emergence of Ad7 in Japan presents a potential outbreak risk.
- Ad7 represents a re-emerging infectious disease threat requiring public health attention.