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Characterization of a wild poliovirus type 3 isolated Japan in 1993
T Yoneyama1, T Fujiwara, Y Yokota
1Department of Virology II, National Institute of Health, Tokyo.
Abstract:
A wild poliovirus type 3 was isolated from a throat swab of a patient with upper respiratory symptoms without paralysis in Shiga Prefecture, in 1993. Wild poliovirus has never been isolated in these nine years in Japan. The most recent isolation of wild poliovirus was of type 1 in 1984 from a case of encephalomyelitis in Aichi Prefecture. Antigenic and PCR-restriction fragment length polymorphism analyses revealed that the Shiga strain was non-Sabin origin. Sequence analysis of the VP1 region confirmed that the isolate was a wild poliovirus type 3. Furthermore, this isolate had higher homology to the isolates from North Vietnam than those from Pakistan or Finland, suggesting that the Shiga strain was imported from Asian area. This strain was also shown to be neurovilurent in transgenic mice carrying human poliovirus receptor gene.
Insights
A wild poliovirus type 3 was detected in Japan in 1993, marking the first isolation in nine years. This non-Sabin strain, likely imported from Asia, was neurovirulent in mice.
Area of Science:
- Virology
- Epidemiology
- Public Health
Background:
- Wild poliovirus eradication efforts are ongoing globally.
- Japan has maintained a polio-free status for many years.
- Surveillance for wild poliovirus is crucial even in polio-free regions.
Observation:
- A wild poliovirus type 3 was isolated from a patient with respiratory symptoms in Shiga Prefecture, Japan, in 1993.
- This was the first isolation of wild poliovirus in Japan since 1984.
- The patient presented with upper respiratory symptoms but no paralysis.
Findings:
- Genetic analyses confirmed the isolate as wild poliovirus type 3 of non-Sabin origin.
- Sequence analysis indicated a higher homology to strains from North Vietnam, suggesting an Asian origin.
- The Shiga strain demonstrated neurovirulence in transgenic mice expressing the human poliovirus receptor.
Implications:
- Highlights the continued risk of wild poliovirus importation into polio-free countries.
- Underscores the importance of robust surveillance systems for early detection.
- Provides insights into the potential transmission routes and pathogenicity of wild poliovirus strains.