Polio which was once included among the world’s most dreaded diseases, has been virtually wiped out through successful vaccination programmes from most parts of the world, but the fight against it still goes on in countries like Pakistan, Afghanistan and Nigeria. Only last year, the highest number of polio cases in the world were reported from Pakistan and in the first two and a half months of this year, fourteen cases have been reported from KPK and FATA.
For the last several years, after almost every two or three months, in collaboration with WHO, the government launches a countrywide door to door polio vaccination campaign, with the hope of permanently eradicating this disease. But despite these repeated campaigns and the spending of huge sums of money, Pakistan is included among the few remaining countries of the world, where polio cases are still being reported regularly. Only last year, the highest number of polio cases in the world were reported from Pakistan and in the first two and a half months of this year, fourteen cases have been reported from KPK and FATA. Prime Minister’s Polio Monitoring Cell and WHO officials have issued a stark warning that if the situation is not tackled immediately and decisively, it may get out of control in the coming months of summer and autumn, when polio virus is most active. While some media reports are suggesting that there may be something wrong with the vaccines, WHO officials insist that the problem is being aggravated by the dangerously contaminated drinking water containing polio viruses, being used in many parts of the country. As the fight against polio continues, let us have a closer look at the nature and causes of this deadly disease and the ways of preventing and controlling its spread. wrong with the vaccines, WHO officials insist that the problem is being aggravated by the dangerously contaminated drinking water containing polio viruses, being used in many parts of the country. As the fight against polio continues, let us have a closer look at the nature and causes of this deadly disease and the ways of preventing and controlling its spread.
Poliomyelitis (commonly known as polio) is an infectious viral disease that sometimes causes temporary or permanent paralysis among children and young adults. In more than 95 per cent cases, it produces no alarming symptoms, whereas in the rest of the cases, its virus enters the nervous system through the mouth or the nose and infects the nerve cells controlling the muscles, often leading to the paralysis of legs. When it attacks the brain with severe complications, it may even cause death. Polio which was once included among the world’s most dreaded diseases, has been virtually wiped out through successful vaccination programmes from most parts of the world, but the fight against it still goes on in countries like Pakistan, Afghanistan and Nigeria.
WHO officials insist that the problem is being aggravated by the dangerously contaminated drinking water containing polio viruses, being used in many parts of the country.
in areas having poor sanitation and ineffective sewage disposal system, polio virus spreads in human feces and people become infected with it through contaminated food and water. Having entered the body, the virus proceeds through the digestive tract to the intestines. After rapidly multiplying in the body, it is shed into the feces, from where it can spread and cause infection, especially, when infected people with their unwashed hands touch food or other people. Adults can also catch it when they change the diapers of infected infants and then touch their mouth with their hands. Polio virus multiplies in the tonsils and in intestinal tissue known as Peyer’s patches, where cells of the body’s lymphatic system are concentrated. When the virus enters this system, it stimulates the production of antibodies, which are the body’s natural defenders that work to destroy the viral intruders. From the lymphatic system, the virus invades the bloodstream and can then cause three forms of polio, depending on the severity level. Abortive Poliomyelitis, which is a mild form of the disease, lasting from a few hours to a few days, produces simple symptoms, such as fever, headache, fatigue, nausea and vomiting. Nonparalytic poliomyelitis, in which the nerve cells are infected, is the common form of the disease, in which, besides experiencing the symptoms of the abortive poliomyelitis, the patients feel pain and stiffness in the neck and back. They may also develop aseptic meningitis, which is the inflammation of the membranes surrounding the brain and spinal cord. These Symptoms usually subside within a week without causing lasting damage. Paralytic Poliomyelitis, that occurs in one or two per cent cases, is a disabling form of the disease, in which the virus infects, damages or destroys the nerve cells that send signals to the muscles in the spinal cord. When muscles are weakened, they become immovable and paralysis begins. About 2 to 5 percent of infants who develop paralytic polio die. It is even deadlier among adults, causing death in 15 to 30 percent of cases. The older the person is when polio strikes, the more likely extensive paralysis becomes. At times, paralysis of muscles that control breathing occurs, requiring artificial respiration. In the most serious cases, the virus attacks the brainstem, causing the polio that can affect nerves that send signals to the ears, eyes, and the muscles controlling chewing and swallowing. Sometimes the virus affects the part of the brain that controls the rate of breathing and the heartbeat, causing death.
Polio has afflicted man since ancient times. A carved stone tablet found in Egypt, dating from roughly 1500 B.C., depicts a man whose withered, deformed leg and foot are characteristic of paralytic polio. In the late 18th century, a British physician Michael Underwood made one of the first accurate descriptions of polio. In around 1850 German physician Jacob von Heine named the condition infantile paralysis because the disease seemed to affect mainly young children. Until the 19th century, polio was a common infection that rarely caused paralysis in children. Serious polio epidemics hit Scandinavia in 1887 and the United States in 1894. In 1916, in the United States, over 37,000 polio cases were reported in 26 states, resulting in 6,000 deaths. For many years thereafter, polio struck about 38,000 Americans annually, and about 21,000 of them experienced paralysis. To intensify the fight against the disease, in 1938 U.S. President Franklin Delano Roosevelt (who had himself lost the use of both legs due to polio) founded the National Foundation for Infantile Paralysis. The organization raised millions of dollars for polio research and for the support of polio patients. In the early 1920s American physician Philip Drinker invented an artificial respirator to treat patients who could not breathe by themselves. Consisting of a large, airtight cylinder, it soon acquired the nickname iron lung. Patients lay on their backs inside the iron lung, with only their heads outside the machine. Motors attached to the cylinder rhythmically changed the air pressure inside, forcing air in and out of the patients’ lungs. In 1908 Austrian pathologist Karl Landsteiner first isolated and identified polio virus from the spinal fluid of a boy who had died from polio. At the same time, American pathologist Simon Flexner developed useful means of growing the polio virus for experimental purposes in laboratory. No vaccine became available for polio until 1955, when American physician Jonas E. Salk’s vaccine was approved for marketing.
In 1991, Western Hemisphere was declared Polio-free. But health officials insist that vaccination programmes must continue in areas considered polio-free, because the polio virus can easily become dangerous again among children who have not acquired immunity.
Immunization with polio vaccine is the best way to prevent polio. Two methods are successfully employed for producing polio vaccine. In one of these methods, quantities of inactivated or killed virus are administered by injection. In the other method, live virus grown in laboratories and systematically weakened so as not to produce any serious infection is used. This form of polio vaccine, known as oral polio vaccine, is administered by mouth, either in a drink or in a sugar cube or other food. This vaccine is easier to administer than the injected vaccine, particularly in remote areas that lack trained medical staff or proper hospital facilities. This method is also used in Pakistan. However, it also involves some slight risks. There is a chance that a dose may contain improperly weakened virus that is still capable of producing illness. In the 1990s the risk of contracting paralytic polio from oral polio vaccine was 1 in approximately 2.4 million doses of vaccine. In 1991, Western Hemisphere was declared Polio-free. But health officials insist that vaccination programs must continue in areas considered polio-free, because the polio virus can easily become dangerous again among children who have not acquired immunity. This danger was demonstrated in 1979, when there was a sudden outbreak of paralytic polio among unvaccinated members of Amish communities in Pennsylvania and Maryland.
The fight against polio has been one of the greatest medical successes of our time. While the war against polio has been convincingly won in most parts of the world, we still seem nowhere near victory. There is the urgent need for making the polio vaccination campaign more effective, especially in the far flung areas of KPK and FATA, where many people are still hesitant to allow their children to have polio vaccine doses. Since polio is an incurable disease, prevention is better than cure, and the growth of polio virus can also be checked by means of improved sanitary and hygienic conditions, better drainage system and increased level of public awareness.