Absence of poliovirus in apparently healthy school children in Bauchi state, Nigeria.

Introduction: Poliovirus infections have been established to be in circulation in the remaining three polio-endemic nations. These pathogens have been associated with several chronic diseases, particularly acute flaccid paralysis of children. This study sought to ascertain whether polioviruses are silently shed by apparently healthy schoolchildren in Bauchi, Katagum, and Misau local government areas of Bauchi state, Nigeria.

Methodology: This was a cross-sectional prospective study that involved 200 stool samples collected from apparently healthy schoolchildren. All samples were processed and inoculated onto rhabdomyosarcoma (RD) and L20B cell-lines. Inoculated cell lines were monitored for cytopathic effects (CPEs) for 10 days with one subculture after first 5 days.

Results: None of the samples came down with CPEs on L20B, and thus all samples were negative for poliovirus; however, three were positive for non-polio enteroviruses (NPEVs) on RD and not on the L20B cell line: one coxsackie B virus from a seven-year-old male, and two others were untypeable isolates, one each from a male and a female child. The coxsackie B virus was identified by microneutralization test using polyclonal sera as described by the World Health Organization.

Conclusions: Findings from this investigation indicate the absence of polioviruses in the children studied. This is an indication of good polio immunization coverage in these communities. However, more intensive and periodic surveillance is required to confirm the presence or exclude the absence of polioviruses in these communities and other parts of Nigeria.