Polio eradication: intratypic characterization of poliovirus strains isolated in Kuwait

ABSTRACT

It is expected that the circulation of wild-type poliovirus strains will stop world-wide due to the WHO-recommended expanded programme of immunization. In Kuwait the situation is rather unique because thousands of the workforce come from countries where a number of polio cases are reported every year. The question is whether imported wild polio strains can survive in a well-vaccinated population. To answer this question we investigated the vaccine-relatedness of 60 poliovirus strains isolated in Kuwait. Reverse-transcription polymerase chain reaction [RT-PCR] coupled with restriction fragment length polymorphism assay were used for the identification of poliovirus isolates. Fragments obtained after digesting the RT-PCR-amplified product with three restriction enzymes [HaeIII, DdeI, HpaII] were compared with that of standard wild and vaccine type poliovirus strains. Isolates from healthy, vaccinated infants [n = 15], children [n = 15] and from patients with the diagnosis of aseptic meningitis [n = 30] were analysed. Molecular characterization revealed a strict vaccine-relatedness of all the 60 poliovirus isolates. The results suggest that rigorous vaccination policy implemented in Kuwait provides a high level of immunity which prevents the circulation of wild poliovirus strains in Kuwait