What are The Symptoms of Polio?
It is a viral disease characterized by inflammation of the spinal cord and brain stem.
There are three types. Nonparalytic polio, which has the same symptoms as influenza and yields no residual paralysis or muscle damage Paralysis can occur, but it lasts for less than 24 hours.
This type presents itself in people that have already been infected with non-polio enterovirus (or related viruses). Paralytic polio, which causes permanent paralysis: The virus enters the body through contaminated water and multiplies rapidly in the intestine.
The person then develops flu-like symptoms including headache, fever, and vomiting; this is followed by extreme fatigue, pain behind the eyes, and sensitivity to light. After several days severe spasms begin in the legs which spread to the arms.
The virus multiplies in the muscles and destroys nerve cells. Paralysis occurs within one to three weeks after symptoms first appear, but about 20% of infections are asymptomatic Non-paralytic polio can progress to paralytic polio.
What is poliomyelitis?
Poliomyelitis (polio for short) is a highly infectious disease caused by an enterovirus called poliovirus. It mainly affects children under five years old causing paralysis or death. The chance of contracting polio decreases rapidly with age due to previous exposure to the virus through vaccination or infection, resulting in lifelong immunity.
Polio was known throughout history until it became rare in developed countries thanks to the widespread use of vaccines, however, it still causes paralysis and death throughout the rest of the world. A global effort to eradicate polio is ongoing, but major progress has been made since it was targeted by the World Health Organization for elimination by 2005.
How does polio spread:
1. Person with the poliovirus in his throat coughs or sneezes, spreading infected droplets containing the poliovirus in the air
2. Person breathes the air containing these droplets into his nose and mouth (orbits), thereby infecting himself
3. Virus multiplies in cells lining throat and lungs causing inflammation of nerves leading to paralysis
4. Person starts excreting virus through saliva, urine, nasal secretions which causes infection if it comes in contact with child’s mouth (it is most infectious when a person is excreting it)
5. Child swallows this contaminated material by putting fingers/objects covered with it in mouth, hence becoming infected
6. Virus spreads to brain & spinal cord where nerve endings are destroyed leading to paralysis
7. Paralysis of one or more parts of the body causes disability for life
8. Viruses can also spread through semen in semen up to 6 weeks after a paralytic attack, resulting in birth deformities, abortions, and death among children if they come in contact with it.
9. Poliovirus is most stable at extremes of temperature between -5 C & 50 C but dies within minutes at 68 C (because of protein coating)
10. It can survive 2 hours outside the human body [on dust particles, soiled surfaces] [Good toilet hygiene, handwashing reduces risk] [polio vaccine protects even if given after exposure] [immunization should be done before monsoon]
11. Poliovirus enters through the nose & throat so it can be prevented by vaccination
12. This vaccine has no added preservatives, thiomersal, etc. making it safe for use of even very young children [immune system of a child responds to this vaccine with 10 times more vigor than an adult’s]
13. In our country due to lack of proper sanitation and hygiene, the vaccination did not reach people in places like Delhi Mumbai where there were outbreaks of polio affecting mainly 3-15-year-olds which is why we have been declared endemically malnourished, the worst at any time in world history.
The real cause of polio:
1. In most cases, poliomyelitis is a mild disease and many people infected with the virus have no symptoms at all
2. The person is not infectious until he/she has developed fever & muscle stiffness (paresis), which may be preceded by loss of appetite, nausea, vomiting, and sore throat
3. Fever comes on first in some cases, second or third day in others; paralysis can affect any voluntary muscle particularly those of legs (mainly) and arms; stiffness gradually subsides over 12 days to an average of 8 days; convalescence is slow and gradual with fatigue lasting for months following recovery from paralysis: this period varies from one month to 2 years.
4. Other modes of transmission were not documented
5. In endemic areas, 80-90% of infections were not paralytic & 90% of these were not detected; in fact, only about 20 cases of non-paralytic infection come to light for every 100 cases that cause paralysis.
polio is caused by which virus:
1. There are 3 types of poliovirus
2. Type 1 is highly contagious through both fecal-oral & parenteral routes; it is the most virulent & accounts for most paralytic cases (95%)
3. Type 2 was detected only in 1955, type 3 after 1961; paralysis caused by types 1 & 3 is permanent but that by type 2 temporary (after months or years)
4. All vaccines given to children contain all three types of the virus but with different strains of each type so they do not give polio to each other or to their contacts
5. Immunity conferred by the vaccine lasts long enough to prevent infection with wild viruses
Polio symptoms in kids:
Some people with polio (3%) may not show any symptoms; in others, the virus can cause paralysis of one or more muscles
The most common signs and symptoms are
headache, fever, nausea, vomiting change in sensation felt in arms & legs followed by weakness of leg muscles when the infection is highest – most children have a fever, headache, sore throat & pain in the limbs followed by stiffness of muscles within a day or two – neck is most stiff, back most painful weakness becomes progressively worse over 2-3 days
Symptoms can vary from mild to severe even within one family
weakened muscles are more prone to attacks of paralysis
A small number of people (3%) who get polio have serious complications, such as:
inflammation and infection of the brain and spinal cord (polio encephalitis damage to muscles and nerves that control breathing permanent loss of limbs
Another rare complication is called “bulbar polio” which causes weakness of muscles in the throat.
Most people recover completely within 2 months, but muscle pain & weakness can persist for years
Even if a person recovers from paralytic polio, he may still be infected with the virus & remain a source of infection to others; up to 75% of those exposed will develop the infection
Complete recovery from paralytic polio may take months, & sometimes years; muscle function may never return to normal
Vaccination is the best way to protect against paralytic polio
Sporadic cases of paralytic polio can still occur in highly vaccinated populations due to vaccine-derived poliovirus (VDPV) which appears in unvaccinated communities and is very rare
Wild Poliovirus (WPV)
The risk of VAPP depends on many factors, such as intensity of vaccination coverage levels, the size of the population to be vaccinated, and whether immunization is targeted at infants or includes older unvaccinated children & adults.