Poliovirus-Serotype 2

"Where’s polio?"

Description: A member of the picornaviridae family of viruses, polio-2 is a small, positive sense, single-stranded RNA virus. Its virions are naked icosahedrons, which appear small and round under electron microscopy.

Power: Poliovirus-2 is the least common of three serotypes of poliovirus. However, this serotype is the one most commonly associated with paralytic poliomyelitis.

Attacks: Poliovirus-2 is known to only infect humans. It enters the body through the mouth, through fecal-oral transmission, and it multiplies in the lymphoid tissue of the intestinal wall. The multiplying virus then escapes into the bloodstream and travels to the oropharnyx and other body tissues. Occasionally, in about 1/1000 cases, the central nervous system is involved. This happens when the virus infects the anterior horn cells of the spinal cord.

Outcome: Usually, infection with poliovirus is inapparent. However, poliovirus-2 is associated more frequently with the more severe end of a spectrum of clinical manifestations, the most serious of which is paralysis. Paralytic poliomyelitis usually follows the initial mild form of febrile illness, which includes general malaise, sore throats, headaches, and vomiting. Viral damage to lower motor neurons results in an

asymmetric paralysis, which commonly involves the lower extremities.

Speed: The incubation period is between 1 and 2 weeks, but may range from 3 days to 4 or 5 weeks. The virus is present in feces before the onset of illness and usually persists for varying periods, up to about 6 weeks.

Vaccines: There are two types of vaccines for polio: 1) live attenuated virus (Sabin’s vaccine) and 2) inactivated virus (Salk’s vaccine). The one more widely used is Sabin’s vaccine, administered orally. This a trivalent vaccine that consists of all three serotypes. The vaccine is given on 3 occasions plus boosters.

Prevention: Because poliovirus is transmitted by fecal-oral contamination, improvements in hygiene and sanitation, especially in underdeveloped sectors are an effective preventive measure. Vaccination, however, has proven to be extremely effective in epidemiological control. In fact, the CDC has recently issued a statement that polio-2 is on the verge of eradication.

Treatment: Given the nature of the virus, there is no cure for polio-2. That is why vaccination has proven our strongest defense against this virus.

Game Action

Because the world may soon be free of polio-2, reward yourself by redeeming this card at the viral depository; a small monetary prize will be issued.

 

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