Poliovirus Type 1 (P1)

Polio is a contagious disease caused by a virus that survives in the throat and intestinal tract. It has three strains, wild poliovirus type 1, wild poliovirus type 2 and wild poliovirus type 3. But of the three, the wild poliovirus type 1 is considered the most contagious. It spreads very fast and one out of every 200 children is infected with this type, say experts. In affected areas like Uttar Pradesh, multiple factors come into play in the spread of polio. “In the case of western Uttar Pradesh, its peculiar demography like high density of population and high birth rate causes the rapid growth of this type of virus,” said Dr Naveen Thacker, consultant paediatrician, Deep Hospital, Gandhidham, Bhuj, and former president of the Indian Academy of Paediatrics.

Signs and symptoms

Up to 95 per cent of kids infected with polio may show no symptoms. About 4 to 8 per cent get minor symptoms like fever, fatigue, nausea, headache, flu, stiffness in the neck and back, and pain in limbs — all symptoms which subside completely at times. Less than one per cent of polio cases result in permanent paralysis of the limbs. Of those paralysed, 5 to 10 per cent die when the paralysis strikes respiratory muscles. Incidentally, it is difficult to gauge the strain of virus without a laboratory examination of stools.

Treatment

Two vaccines are used throughout the world to combat polio. The first was developed by Jonas Salk, first tested in 1952, and announced to the world on April 12, 1955. The Salk vaccine, or Injectable Polio Vaccine (IPV), consists of a dose of dead poliovirus.

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