What is subclinical polio?
It’s estimated that 95 to 99 percent of people who contract poliovirus are asymptomatic. This is known as subclinical polio. Even without symptoms, people infected with poliovirus can still spread the virus and cause infection in others.
What is poliomyelitis disease ppt?
Poliomyelitis, literally meaning “grey spinal cord inflammation It is a viral infection. INTRODUCTION Virus localized in the anterior horn cells of the spinal cord and certain brain steam motor nuclei. It is contagious: usually spread from person to person.
What are the 3 different types of polio?
There are three wild types of poliovirus (WPV) – type 1, type 2, and type 3. People need to be protected against all three types of the virus in order to prevent polio disease and the polio vaccination is the best protection.
How many polio cases are asymptomatic?
The majority of poliovirus infections are asymptomatic; up to 70% of infected individuals experience no symptoms and about 25% experience mild symptoms. Paralytic poliomyelitis occurs in less than 1% of all infections.
What type of virus is poliovirus?
Poliovirus, a nonenveloped, positive-sense, single-stranded RNA virus, is a member of the Enterovirus genus within the family Picornaviridae.
What is the structure of poliovirus?
Poliovirus is composed of an RNA genome and a protein capsid. The genome is a single-stranded positive-sense RNA (+ssRNA) genome that is about 7500 nucleotides long. The viral particle is about 30 nm in diameter with icosahedral symmetry.
What is the pathophysiology of polio?
Pathophysiology of Poliomyelitis A primary (minor) viremia follows with spread of virus to the reticuloendothelial system. Infection may be contained at this point, or the virus may further multiply and cause several days of secondary viremia, culminating in the development of symptoms and antibodies.
What is the difference between polio type 1 2 and 3?
Type 1 causes paralysis in about 1 in 200 infections; Type 2 was last recorded in 1999; Type 3 is less virulent than type 1, causing paralysis in about 1 in 1000 cases.
What is a feature of poliomyelitis?
Initial signs and symptoms of paralytic polio, such as fever and headache, often mimic those of nonparalytic polio. Within a week, however, other signs and symptoms appear, including: Loss of reflexes. Severe muscle aches or weakness. Loose and floppy limbs (flaccid paralysis)
What is the incubation period of polio?
The incubation period for nonparalytic poliomyelitis is 3 to 6 days. For the onset of paralysis in paralytic poliomyelitis, the incubation period is usually 7 to 21 days.
What type of virus is polio?
Polio is caused by a human enterovirus called the poliovirus. Polio can interact in its host in two ways: Infection not including the central nervous system, which causes a minor illness with mild symptoms. Infection including the central nervous system, which may cause paralysis.