Though cases of polio worldwide have been reduced by 99 percent since 1988, it continues to be a major public health concern in Afghanistan, India, Nigeria, and Pakistan. Recent outbreaks have also been seen in the Congo Republic. Vaccination programs have been put in place in the hopes of eradicating the disease, but according to experts, infection in even one individual can put an entire population at risk. Though previous vaccination efforts helped to reduce the number of cases in many regions, in Nigeria and some other African nations the social stigma and fear associated with vaccinations must be overcome. By utilizing a newly developed, more effective polio vaccine and working to educate individuals about the importance of getting vaccinated, it may be possible to meet the Global Polio Eradication Initiative’s (GPEI) goal of eradication polio worldwide by 2013.
Polio (poliomyelitis) is a contagious viral illness that, in its most severe form, can cause paralysis, difficulty breathing, and death. Often contracted through contact with the feces of an infected person, polio can be spread through contaminated food or water, and the risk of contamination is particularly in areas with poor sanitation. Though individuals of all ages can contract polio, children under five years of age, pregnant women, and individuals with weakened immune systems are even more vulnerable. Ninety-five percent of individuals infected with polio have no symptoms, and between four and eight percent experience minor, flu-like symptoms including fever, fatigue, and stiffness or pain in the back, neck, or limbs. Individuals with polio who show no symptoms or only minor symptoms may still spread the virus to others.
Though infection rates of non-paralytic and paralytic polio were significant in the 1950s in the United States and other areas worldwide, in recent years fewer than one percent of individuals who contract polio develop paralytic polio, the most serious form of the disease, which can lead to loss of reflexes, severe muscle aches and spasms, and paralysis. Paralytic polio can manifest in a variety of ways, and is classified by the areas of the body that are most affected. Spinal polio, the most common form of paralytic polio, attacks the motor neurons in the spinal cord and may cause paralysis of the muscles that control breathing and movement of the arms and legs. Bulbar polio affects the motor neurons of the brainstem, impacting an individual’s ability to see, hear, smell, taste, and swallow, and may also affect intestine, heart, and lung function. A combination of both, bulbospinal polio can lead to paralysis of the limbs, as well as affecting breathing, swallowing, and heart function.
The lack of a cure for polio and limited treatment options available underscore the need for effective vaccination campaigns. Inactivated polio vaccine (IPV), an injection given in the arm or leg, has been used in the United States since 2000. Most children in the U.S. are given four doses of IPV, which has been found to be 90 percent effective after two shots, and 99 percent effective after three. The oral polio vaccine (OPV) is used throughout much of the world, but may soon be replaced by the newly developed bivalent oral polio vaccine (bOPV). The bOPV contains two key strains of the virus and thus may provide improved inoculation results. In addition to efforts to increase vaccination rates, improved sanitation and education related to personal hygiene can help to reduce the spread of polio, as well as cholera and other water-borne illnesses.
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