POLIO:
Polio is caused by a virus called the poliovirus. The poliovirus causes most of its infections in the summer and fall and primarily affects young children, though it can also infect older children and adults. Poor hygiene and crowded living conditions encourage the spread of this virus.
Cause: Poliovirus is transmitted through saliva and feces. It is passed on when people do not wash their hands after eating or using the bathroom. The virus enters the body through the mouth and multiplies in the intestine. It invades the lymphatic system, which consists of organs and tissues that help protect a person against disease.
Symptoms: About 90 percent of those infected with poliovirus have mild or no symptoms. The mild symptoms include a low fever, fatigue, headache, sore throat, nausea and vomiting. These symptoms usually last two or three days. People with these symptoms are still infectious and can pass the disease on to other people. In severe cases, the disease can enter the bloodstream and central nervous system causing muscle weakness, paralysis, and death.
New cases: 1227 cases in 2004
Deaths: Due to widespread vaccination campaigns, deaths are relatively rare. However, an unusually serious outbreak in Namibia has killed over 20 people this year.
Sources
General FAQs on Polio
World Health Organization on Polio
Official website for Center for Disease Control and Prevention
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