Imported wild poliovirus causing poliomyelitis–Bulgaria, 2001

In March 2001, a 13-month-old unvaccinated Roma (i.e., gypsy) girl from Bourgas, Bulgaria, had onset of bilateral leg weakness. The National Enterovirus Laboratory in the capital city of Sofia subsequently isolated a wild type 1 poliovirus in the patient’s stool. In April, a second case, with wild type 1 poliovirus isolate was found in lambol located approximately 50 mileswest of Bourgas in an unvaccinated 26-month-old Roma girl who had onset of paralysis of both legs. Subsequent analyses indicated that these viruses were related closely to a strain isolated from Uttar Pradesh, India, in July 2000. A third confirmed case with clinical and serologic evidence of poliomyelitis was diagnosed in a 3-month-old Roma boy in Bourgas who had onset of paralysis on May 7. Following the identification of the poliovirus, the Bulgarian Ministry of Health implemented contact investigations, screening of children at high risk, retrospective record review, intensified acute flaccid paralysis (AFP) surveillance, and mass vaccinations. This report summarizes the outbreak investigation and supplemental vaccination activities in response to these polio cases. High routine vaccination coverage and certification standard AFP surveillance are necessary to detect rapidly and prevent the spread of poliovirus importations in areas and countries where polio is not endemic.