Viral Aetiology of Acute Flaccid Paralysis Surveillance Cases, before and after Vaccine Policy Change from Oral Polio Vaccine to Inactivated Polio Vaccine.

T S Saraswathy Subramaniam,Zainah Saat,Mohd Apandi Apandi,Rohani Jahis,Mohd Samsul Samsudin

doi:10.1155/2014/814908

T S Saraswathy Subramaniam, Zainah Saat + Show 3 more

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https://doi.org/10.1155/2014/814908

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Abstract

Since 1992, surveillance for acute flaccid paralysis (AFP) cases was introduced in Malaysia along with the establishment of the National Poliovirus Laboratory at the Institute for Medical Research. In 2008, the Ministry of Health, Malaysia, approved a vaccine policy change from oral polio vaccine to inactivated polio vaccine (IPV). Eight states started using IPV in the Expanded Immunization Programme, followed by the remaining states in January 2010. The objective of this study was to determine the viral aetiology of AFP cases below 15 years of age, before and after vaccine policy change from oral polio vaccine to inactivated polio vaccine. One hundred and seventy-nine enteroviruses were isolated from the 3394 stool specimens investigated between 1992 and December 2012. Fifty-six out of 107 virus isolates were polioviruses and the remaining were non-polio enteroviruses. Since 2009 after the sequential introduction of IPV in the childhood immunization programme, no Sabin polioviruses were isolated from AFP cases. In 2012, the laboratory AFP surveillance was supplemented with environmental surveillance with sewage sampling. Thirteen Sabin polioviruses were also isolated from sewage in the same year, but no vaccine-derived poliovirus was detected during this period.

Highlights

Poliomyelitis is an acute communicable viral disease affecting humans, mainly young children
Till 2008, the methods used for virus isolation and microneutralization for identification of positive isolates were as described in World Health Organization (WHO) Polio Laboratory Manual 2004 and, from 2008 onwards, the supplemental manual of 2006 for the New Algorithm Technique was used for poliovirus isolation
Poliovirus isolates were sent to the Victorian Infectious Disease Reference Laboratory (VIDRL) in Melbourne, Australia, for further identification and intratypic differentiation (ITD), till August 2010

Summary

Introduction

Poliomyelitis is an acute communicable viral disease affecting humans, mainly young children. The disease is caused by 3 serotypes of Poliovirus (Poliovirus types 1, 2, and 3), belonging to the genera Enterovirus and Picornaviridae family. The virus is transmitted through contaminated food and water and multiplies in the intestine, from where it can invade the nervous system. Many infected individuals may be asymptomatic but do excrete the virus in their faeces, transmitting infection to others. In about 1% of affected individuals, the virus enters the central nervous system and replicates in anterior horn cells, that is, motor neurons of the spinal cord. The typical neurological manifestation of paralytic poliomyelitis is acute flaccid paralysis (AFP) of limbs, predominantly lower limbs, usually asymmetric and with intact sensation. Viral destruction of bulbar cells results in respiratory paralysis and even arrest

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