Poliomyelitis or infantile paralysis is an acute infectious viral disease of the human alimentary tract but may affect the central nervous system (brain, spinal cord and nerves) result in paralysis, the extent of which depends upon the damage done to the nerve cells by the virus. The legs are more affected than arms.
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If they are only slightly damaged complete recovery is possible but if nerve centre is completely destroyed then the recovery will not be possible leading to permanent disability because the nerve cells once dead cannot grow again.
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If the nerve cells controlling breathing are affected then the breathing stops and patient dies unless some mechanical device is provided for breathing. It affects all ages but childrein below five years of age are more susceptible. It is one of the main crippling diseases of childhood. It affects both male and female, rich and poor but males are affected more i.e. about three times more than females.
Poliomyelitis is worldwide distributed. The developed countries have almost eliminated this disease by widespread use of polio vaccine but polio is most common in developing countries where immunisation against polio is not in wide use. In India a large number of children are affected every year by this disease.
Causative Organism:
The causative organism of poliomyelitis is a filterable virus which has 3 serotypes designated as type 1, type 2 and type 3. Type 1 virus is responsible for most of the outbreaks of polio epidemics.
Mode of Spread:
The polio virus is found in the nasopharyngeal secretions, faeces and urine of patients and carriers. Faecal carriers are more dangerous than the nasopharyngeal carriers.
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Faecal-oral route is the most common route of transmitting the disease. Infection can spread directly through contaminated fingers or indirectly through contaminated water, milk, food and other articles of daily use. Flies also play a major role in spreading the disease.
Polio may also spread though droplet infection during acute stage of disease when virus is present in pharynx. Close personal contact helps in spreading the disease.
Incubation Period:
Incubation period of polio is 7-21 days but may vary from 3 to 35 days.
Signs and Symptoms:
In 90 percent cases there are no symptoms, about 8% cases suffer from mild illness and 1-2 percent suffers from major illness when polio virus attacks the CNS and produces varying degree of paralysis.
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Pre-paralytic symptoms include high fever, headache, chillness, diarrhoea, vomiting and pain all over the body. Children are drowsy but the adults are restless.
After the pre-paralytic stage there is recovery for 2-3 days and then paralytic stage begins. At this stage pain is produced when an attempt is made to bend the spine forward. The paralysis is of flaccid type and shows great variation in degree and range.
The limbs seem to be loose. There is foot drop, facial paralysis and squinting of eyes. If muscles of larynx and pharynx are involved, it may prove fatal sometimes resulting in death of the patient.
Prevention:
Polio can be prevented by active immunisation of all infants and children upto five years of age. Oral polio vaccine (OPV) Sabin type is widely used because it is cheap, easy to administer and confers immunity for a long period. It is a live attenuated liquid vaccine. The vaccine is stored at 4°C.
Oral polio vaccine is given in three doses (two drops are put into the mouth as a dose) at the age of I Vi month, 2Vi month and V/i month. One booster dose is given in the same dose at the age of 18 to 24 months. The second booster dose may be given at the age of five years.
Precautions:
(i) Polio vaccine should not be given to any child suffering from diarrhoea, dysentery, vomiting and fever.
(ii) Hot milk and hot fluids should not be given to the child at least for half an hour after the administration of the vaccine.
(iii) Vaccine should be stored at sub-zero temperature in a deep freezer to prevent inactivation of the vaccine. For short periods it may be stored in the freezer of the refrigerator. The vaccines prepared now a days are heat stabilized so the problem of storage does not arise.
Other Preventive Measures:
(i) The patient should be isolated.
(ii) The faeces, urine and other discharges of the patient should be properly disposed of. The faeces remain infective for 4 weeks.
(iii) Proper provision for safe and adequate water supply and sanitary disposal of solid wastes should be made.
(iv) Hygienic conditions should be maintained.
(v) Flies should be destroyed.
(vi) Avoid overcrowding in schools and other places of gatherings.
Treatment:
There is no specific treatment for polio. Give complete bed rest to the patient. Antibiotics may be given to prevent respiratory complications. Good nursing care, fomentation and massage help the patient from sufferings After acute illness, graded physiotherapy helps to a great extent. It helps the weakened muscles to regain strength and become useful again and may prevent crippling.