Report of the Australian National Polio Reference Laboratory. 1 January 1999 to 30 June 1999. Towards WHO certification as wild poliovirus-free: laboratory surveillance in Australia.

Since 1994 the Australian National Polio Reference Laboratory at the Victorian Infectious Diseases Reference Laboratory has been responsible for virological confirmation of the eradication of poliomyelitis in Australia. The laboratory is also a World Health Organization Western Pacific regional polio reference laboratory and the national polio laboratory for the Pacific Island countries and for Brunei Darussalam. It is now over two years since the last case of poliomyelitis was detected in the Western Pacific region of the World Health Organization. The co-operation of staff in all laboratories where polioviruses are handled and where samples from acute flaccid paralysis (AFP) patients are submitted is required until Australia and the region can be declared wild poliovirus-free. The characterisation of all polioviruses isolated in Australia in this reporting period led to the apparent detection of a non Sabin vaccine-like poliovirus in an environmental sample. The virus was found to be identical to a laboratory control isolate by sequencing. The environmental virus is therefore characterised as a contaminant, not a wild isolate. The investigation is outlined in this article, as well as the results of investigation and characterisation of all referred polioviruses.