Introduction
1.1 Background of the Study
Poliomyelitis, is an infectious disease caused by poliovirus, a member of the genus Enterovirus. There are three serotypes of poliovirus: that is, 1, 2 and 3, these three serotypes are mainly different in their virulence. The serotype 1 is the most virulent of the three types, while serotype 2 and 3 are more sporadic (National Primary Health Care Development Agency, 2015).
Human cells contain specific protein receptors to which poliovirus may attach and thereby enter susceptible cells. The virus infects cells of the oropharynx, the tonsils, the lymph nodes of the neck, and the small intestines. Infection progresses through cycles of virus replication, resulting in destruction of the infected cells. Once infection is established, poliovirus can enter the bloodstream and invade the central nervous system through the blood/brain barrier, by spreading along nerve fibers, or by both routes (WHO, 1999). When non-immune persons are exposed to wild poliovirus (Wild Polio Virus is caused naturally and not caused by vaccine containing live virus) the results may include inapparent infection without symptoms, mild illness, aseptic meningitis, or paralytic poliomyelitis
The Poliovirus can be spread to others by droplets from the upper respiratory tract during the early days of infection. More commonly, infected persons pass large numbers of virus particles through their faeces, from where they may be spread indirectly, or directly to infect others.
Poliomyelitis is a serious public health problem. It has persisted in a few countries from where it has spread to a large number of countries and posed threat to health as it did earlier between the 1950's and 1980's. In the developing world, the disease presents a constant threat to underfives, resulting paralysis with devastating.
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