Cholera is an infectious disease that causes severe diarrhoea. It is usually acquired by consuming contaminated food or water during travel to areas where cholera is common. The greatest danger is the dehydration diarrhoea causes. Following some advice can help prevent this condition.…
What is polio?
In the past, polio was found worldwide. In the early 20th century, it became a major public health concern after repeated outbreaks affected millions of people worldwide.
After polio vaccines were developed and approved for use in 1955 (Salk vaccine) and 1962 (Sabin vaccine), the incidence of polio went down drastically in vaccinating countries. The last infectious polio case in the United States was in 1979. A global polio eradication program brought down the global incidence of polio from 350,000 cases per year in 1988 to only 416 in 2013. 
Today, polio is found only in a few countries and is mostly considered a 'disease of the past'. However, the number of cases in these countries has been slowly growing. Public health organizations aim to eradicate the disease completely in the near future and are currently concentrating on the countries where the polio virus is still found, namely Pakistan, Afghanistan, Nigeria, Syria and Somalia.
People who have had polio in the past can experience 'post-polio syndrome' later on in life.
The cause of polio is the polio virus, which can reside in the human digestive system. It spreads from person to person via accidental contact with human stools (feces). In a minority of cases, the virus enters the body's nervous system, causing nervous system symptoms.
Anyone can contract polio, but it mainly affects children. You are at increased danger of being infected with the virus if you are:
- A child under five years of age (80%-90% of cases); 
- Living or travelling to a country where the virus is found;
- Pregnant, or;
- Suffering from a condition that weakens your immune system.
Types and prognosis
Infection with the polio virus can have several outcomes:
- Most people infected with the polio virus do not get ill and suffer no symptoms;
- A minority of people experience mild symptoms ('abortive polio');
- In a small minority of people, the virus enters the central nervous system and causes more pronounced nervous system symptoms ('non-paralytic polio'), and;
- One to two in 1000 people infected with the virus will develop paralysis, which may be life-threatening ('paralytic polio'). 
- Stiff muscles;
- Sore throat;
- Nausea, vomiting, and;
These symptoms go away naturally after a few days.
In 1-3% of infected people, the virus causes the mild symptoms as for abortive polio, but then enters the central nervous system and causes inflammation there.  At this stage, the muscles, neck and back can become stiff and painful.
The symptoms of non-paralytic polio go away naturally after a week or two.
A serious complication of non-paralytic polio that can appear in 0.1-0.2% of people infected with the virus.  The polio virus enters the central nervous system as above, but then begins infecting and destroying nerve cells. This can cause paralysis of the muscles, leading to:
- Severe muscle weakness;
- Weak, strained breathing;
- Severe constipation;
- Drooling, and;
- Loss of function in the limbs (most often the legs).
The more serious subtypes of paralytic polio can cause severe difficulties in breathing, speaking and swallowing. Those affected may need artificial ventilation in order to breathe.
Methods for diagnosis
If your doctor suspects polio, they will look at your medical history, vaccination status and travel history. A throat swab and/or a sample of your feces may be examined for the presence of the virus. A sample of fluid from around the spinal cord and brain may be taken by lumbar puncture, to detect the presence of virus in the nervous system.
Types of treatment
Polio cannot be cured; treatment focuses on easing the symptoms. Treatment can include:
- Pain-relief medications, such as acetaminophen or ibuprofen;
- Heating pads to relieve muscle pain;
- Physical therapy, massage, gentle exercise, and;
- Mechanical breathing aids (usually portable ventilators) for those who have breathing problems.
People who have had polio in the past can, decades later, experience post-polio syndrome (PPS). It is not yet clear why this happens, but may be connected with deterioration of damaged neurons in the spinal cord.
It has been shown that the polio virus is not present in PPS cases and people with PPS are not infectious.
Symptoms of post-polio syndrome can include:
- Muscle weakness and fatigue;
- Muscle and joint pain, and;
- Breathing, sleeping and swallowing problems.
PPS usually develops gradually. It is not life-threatening, but can have a significant effect on your quality of life. As a general rule, people who have had a more serious polio illness are more likely to experience PPS.
PPS cannot be cured, but can be managed by:
- Avoiding physical exertion and breaking up physical activities into smaller, more manageable steps ('pacing');
- Avoiding exposure to cold temperatures;
- Watching your diet;
- Mobility aids (braces, scooters, walking sticks), and;
- Pain-relief medication.
A polio vaccine is available and is routinely given as part of the regular childhood vaccination schedule. Adults can also receive the vaccine, if they have not previously received it.
In very rare cases, the weakened polio virus within the vaccine has been known to cause illness, including paralysis, in the person it is given to. The virus may also infect unvaccinated people who come into contact with that person. However, it is important to remember that the benefits of the vaccine out-weigh the very rare potential risk of the vaccine.
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FAQ Frequently asked questions
What are the symptoms of polio?
Polio initially shows up as mild flu-like symptoms. In a minority of cases, more serious symptoms may appear including muscle pain, muscle weakness and, in extreme cases, paralysis.
Who gets polio?
Anyone can be infected with the polio virus. 80%-90% of cases appear in children under five years of age.
How is polio diagnosed?
Polio is diagnosed by testing samples taken from the feces or the throat, and, if necessary, from the fluid around the spinal cord and brain.
How is polio treated?
Severe polio is treated by supportive treatment, including pain relief and physical therapy.