Laboratory Surveillance for Poliomyelitis in Thailand during 1982-1993

The incidence of poliomyelitis has fallen dramatically since the nationwide oral polio vaccine immunization in 1979. The laboratory confirmed poliomyelitis in Thailand during 1982 to 1993 revealed that poliovirus type 1 still being the most common type of infection. Poliomyelitis was the most frequency detected in the central part of Thailand and mostly occurred in the age group of 1-4 years. The peak of confirmed poliomyelitis cases was in the rainy season (July-August). It is noted that the laboratory confirmed polio cases were scattered mostly in bordering provinces and the provinces that hosted refugee camps. The trends of poliomyelitis occurrence have been shifted from younger age groups (1-4 years) to older age groups (5-14 years) during the last three years. The fact that the strategies to eradicate poliomyelitis are not only the high coverage of immunization reduce poliovirus transmission but also the effective surveillance and laboratory support to confirm wild or vaccine type polioviruses from all clinical and environmental samples. Key words: Poliomyelitis, Laboratory diagnosis, Thailand