Poliomyelitis Virus and Other Enteroviruses
Enteroviruses are named because of their ability to infect the gastrointestinal tract and to shed into the feces. Enteroviruses can cause varying temporary or permanent damage, including:
There are more than 70 types of enteroviruses. The most common enteroviruses that infect humans include:
- Poliomyelitis virus.
There are three subtypes of poliomyelitis virus (known as serotypes), which include: P1, P2, and P3.
Poliomyelitis virus is a highly contagious virus that can spread easily from person to person. In fact, when a person is infected with poliomyelitis virus, it is expected that poliomyelitis transmission among susceptible household contacts will occur in nearly 100 percent of children and more than 90 percent of adults.
When a person is infected with poliomyelitis virus, the virus resides in the intestinal tract and mucus in the nose and throat. Poliomyelitis virus transmission most often occurs through contact with stool of this infected person (known as fecal-oral transmission). Less frequently, the virus can be spread through contact with infected respiratory secretions or saliva (oral-oral transmission).
Following infection with poliomyelitis virus, a person does not become immediately sick. Once the virus enters the body, it travels to the back of the throat, nose, and intestines, where it begins to multiply. It can also travel to other parts of the body. Symptoms usually appear after 7-14 days. This period between transmission of the virus and the beginning of symptoms is called the polio incubation period. The polio incubation period can be as short as 4 days or as long as 35 days.
Up to 95 percent of people who are infected with poliomyelitis virus will have no symptoms of polio. However, infected people who do not have poliomyelitis symptoms can still spread the virus and cause others to develop polio.
(Click Polio Transmission for more information on how polio is transmitted or Poliomyelitis Symptoms for more information on polio symptoms and signs.)