TellZall's object for July is Polio.

A generation ago, parents feared the coming of summer. They were not worried about having the kids underfoot. Rather, they feared the annual "polio season" when thousands of youngsters were stricken with a disease that left many of them permanently paralyzed.

Polio, more properly poliomyelitis or infantile paralysis, is an inflammation of the nerve cells of the spinal cord that is caused by a virus. Much about the virus and the disease remain uncertain. What is known is that there are three strains of the virus and that most people who come into contact with it develop only mild symptoms that include fever, headache, and muscle stiffness. In some cases, however, the virus penetrates the central nervous system and damages nerve cells, which can result in paralysis of the lower limbs or of the lungs. Breathing can become so difficult that suffocation can result. Patients may require mechanical braces for weakened limbs, wheelchairs for complete leg paralysis, or mechanical devices, called iron lungs, to assist breathing.

Researchers remain uncertain as to how the virus is transmitted. The best evidence indicates that it resides in the digestive tract and is spread by contact with feces and by hand-to-hand contact. The introduction of modern sanitation systems may actually have contributed to the virus becoming more deadly because children living in more sanitary conditions did not develop the antibodies to reject the virus that earlier populations had acquired. Regardless of the mechanism, the disease reached epidemic proportions in the twentieth century. In 1952 alone, some 58,000 cases were reported in the United States. Most of them were contracted during the summer months, which led to such measures as closing swimming pools during late July and August.

A breakthrough in polio prevention came in 1952 when Dr. Jonas E. Salk (1914–95) conducted field trials of a vaccine that he had developed at the University of Pittsburgh School of Medicine. Despite some manufacturing problems, the vaccine was successful, and on April 12, 1955, it was released for use in this county. Dr. Salk's vaccine was an injection of dead polio virus.

A second type of vaccine, an oral preparation of live but weakened (attenuated) polio virus was developed by Dr. Albert B. Sabin (1906–93) of the University of Cincinnati College of Medicine. Dr. Sabin's vaccine was even more successful and offered fewer side-effects. It was approved for use in the United States in 1960 and largely supplanted the Salk vaccine worldwide.

Today, polio has been nearly eradicated throughout the world. This is truly one of medicine's success stories. And parents need no longer fear the coming of summer.