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Australia's last reported case of wild poliovirus infection
M L Kennett1, K A Brussen, D J Wood
1Australian National Polio Reference Laboratory (ANPRL), North Melbourne, Victoria.
Abstract:
In 1986 tests on faeces collected from a 22 year old Australian born man who had symptoms consistent with poliomyelitis yielded poliovirus type 3. In a neutralisation test using a panel of monoclonal antibodies the isolate was identified as wild poliovirus type 3 at that time. After further classification using microneutralisation, nucleic acid probe hybridisation, immunoassay and sequencing carried out in three laboratories between 1994 and 1997, the isolate has been reclassified as 'Sabin-like' with 'wild type' characteristics. This case has been quoted in the literature as Australia's last case of locally acquired wild poliovirus. Efforts are now being made to identify the true last case in Australia. This article describes the isolation, identification and further characterisation of this virus.
Insights
A 1986 poliovirus type 3 isolate initially identified as wild poliovirus was reclassified as Sabin-like with wild characteristics. This finding prompts a re-evaluation of Australia's last wild poliovirus case.
Area of Science:
- Virology
- Epidemiology
- Public Health
Background:
- Poliomyelitis remains a significant public health concern globally.
- Accurate identification of poliovirus strains is crucial for disease surveillance and eradication efforts.
- Australia has a history of poliomyelitis cases, necessitating ongoing monitoring.
Purpose of the Study:
- To re-evaluate a poliovirus type 3 isolate from 1986 initially classified as wild poliovirus.
- To clarify the classification of a potential last case of indigenous wild poliovirus in Australia.
- To contribute to the accurate epidemiological understanding of poliovirus circulation.
Main Methods:
- Isolation and initial identification of poliovirus type 3 from fecal samples.
- Neutralization tests using monoclonal antibodies.
- Advanced molecular techniques including microneutralization, nucleic acid probe hybridization, immunoassay, and sequencing.
- Multi-laboratory collaborative analysis between 1994 and 1997.
Main Results:
- The 1986 poliovirus type 3 isolate was initially identified as wild poliovirus.
- Subsequent comprehensive testing reclassified the isolate as 'Sabin-like' but with 'wild type' characteristics.
- This reclassification challenges the established record of Australia's last indigenous wild poliovirus case.
Conclusions:
- The reclassification of the 1986 isolate necessitates a review of historical poliomyelitis case data in Australia.
- Accurate strain characterization is vital for maintaining confidence in polio eradication programs.
- Further investigation is required to identify the definitive last case of indigenous wild poliovirus in Australia.