What is the Polio Virus?
The polio virus is a small virus that is part of a group called Enterovirus. Inside a protein coat, it contains a single piece of RNA which is its genetic material. The virus is strong and can survive outside the human body for many weeks, specially in feces or water. The disease is easily spread from one person to another through contact with infected feces, often by not washing hands properly or through contaminated food and water.
Polio, also known as poliomyelitis, is a dangerous illness caused by a virus called polio. It mostly affects the nervous system and can lead to extreme muscle weakness, paralysis, and sometimes death. The virus mostly affects children under five, but anyone who hasn’t had the vaccine also is in danger.
There have been big efforts to get rid of polio all around the world, and we’re making a lot of progress. Nevertheless, the virus is still present in some areas of the world and continues to be a danger, specially in places with poor cleanliness and low rates of vaccination. The best way to stop polio is by getting vaccinated. Proper hygiene, like washing hands with soap and water, can also stop it from spreading.
Understanding Polio: Causes, Symptoms, How It Spreads, and Ways to Prevent It
There are three serotypes of the poliovirus
Type 1 Poliovirus (PV1)
PV1 is the most common and dangerous type of polio virus out of the three. This is the main reason behind most polio cases globally.
PV1 spreads easily and has caused many outbreaks in the past. The virus can live outside the body for a long time, specially in places with bad sanitation, making it easy to spread between people.
PV1 has been a main focus in global efforts to get rid of it because it can cause serious paralyzing sickness and death.
Although there has been progress in reducing PV1 cases, the virus is still spreading in some areas, especially in Afghanistan and Pakistan.
This is because vaccination efforts are facing challenges like fighting, wrong information, and logistical problems. Continuing to stop the spread of polio is very important for getting rid of polio worldwide.
Type 2 (PV2): Declared Eradicated in 2015
In 2015, the World Health Organization declared that Type 2 polio virus (PV2) was officially eradicated.
This type of poliovirus was one of the three strains found in the wild, with the last known case reported in Uttar Pradesh, India in 1999.
PV2 was not as strong as Type 1 but still had the ability to cause serious paralysis.
The oral polio vaccine (OPV), which contains weakened strains of the virus, was widely used to successfully get rid of PV2.
Although the OPV has been eliminated, it has sometimes caused vaccine-derived poliovirus (VDPV) cases in areas with low immunization rates.
In order to minify this problem, health organizations are switching to inactivated polio vaccines (IPV) and making routine immunization programs stronger.
This is to make sure that PV2 is gone for good and to stop it from coming back.
Type 3 (PV3): The Least Common Strain, Declared Eradicated in 2019
The least common type of poliovirus, called PV3, was declared eradicated in 2019 after the last reported case in Nigeria in 2012.
Like the other types, PV3 caused polio, which can result in paralysis and very serious health problems.
The worldwide elimination of PV3 happened because different types of polio vaccines were used for coordinated vaccination efforts.
This included the oral polio vaccine (OPV) and inactivated polio vaccine (IPV). Another important milestone in the global effort to stop polio was reached when PV3 was eliminated.
This means there is now only one circulating strain of poliovirus left (PV1).
The elimination of PV3 shows that long-term vaccination efforts work, but we still need to be careful to stop the virus from coming back in places with few vaccinated people or problems with healthcare.
History of the Polio Virus
For thousands of years, polio has been impacting people. Ancient Egyptian carvings depict people with shrunken arms and legs, suggesting they may have had the disease. Even though polio has been around for a long time, it wasn’t until the late 1800s and early 1900s that it started causing big outbreaks in Europe and the United States. Surprisingly, this was connected to better public health, specially in keeping things clean.
Before these changes, many people got the poliovirus when they were very young, and still protected by their mothers’ antibodies. This early exposure often led to mild cases, which helped them develop immunity. Nevertheless, due to better sanitation, people had a lower chance of being exposed to the virus during their early years. Consequently, they got the virus when they were older and no longer had their mother’s antibodies to help them. This delay in being exposed to the virus caused bigger outbreaks. It affected older kids and adults who hadn’t built up their natural immunity yet.
These illnesses made a lot of people worried and unhappy, and some even lost the ability to move. This paved the way for the development of vaccines in the middle of the 20th century, which eventually helped to beat polio.
The development of Effective vaccines in the middle of the 20th century was a important moment in the battle against polio:
Jonas Salk’s Inactivated Polio Vaccine (IPV)
Jonas Salk created the first effective polio vaccine, called the Inactivated Polio Vaccine (IPV), in 1955. This vaccine was injected into the body and contained dead virus particles. The virus was completely destroyed, so it couldn’t make people sick.
The IPV stimulated the body’s immune system to make antibodies against polio, but without the risk of getting infected. Many people were happy about this important discovery in medical science. It became very useful in the fight against polio, specially in countries with good medical facilities.
The IPV was very successful in stopping polio, which caused a big reduction in cases around the world. The start of a worldwide effort to get rid of polio happened when this was introduced, and it also set the stage for other vaccines to be created in the future.
Albert Sabin’s Oral Polio Vaccine (OPV)
Albert Sabin created the Oral Polio Vaccine (OPV) in 1961. Instead of using a killed virus like Jonas Salk’s vaccine, Sabin’s OPV used weakened live virus strains. The vaccine was given by mouth, usually as a few drops on a sugar cube or as a liquid. This made it easier to give, especially when immunizing a lot of people at the same time.
The live virus in the OPV boosted immunity in the intestines and bloodstream, making it more effective in stopping the virus from spreading in communities. The OPV became the favorite vaccine in many countries because it was easy to distribute and did not require needles, especially in places with a limited medical system.
Sabin’s vaccine played an important role in the worldwide mission to eliminate polio, helping health workers to reach more people in faraway and remote areas. It is still an important tool in areas where polio virus has not been completely eliminated.
Since 1988, these vaccines have played a key role in reducing global polio cases by more than 99%. Many areas have completely gotten rid of the disease.
Causes of Polio Virus Infection
The poliovirus is what causes polio, and it enters the body through the mouth and then grows in the throat and intestines. The virus mainly spreads between people through:
Fecal-Oral Transmission
The virus mostly spreads through feces and is shared orally, specially in areas with poor sanitation. When a person has the virus, it comes out in their poop. If we don’t follow good hygiene, the virus can get into water, food, or things that other people touch.
For example, if a person doesn’t wash their hands well after using the bathroom, they can pass on the virus to others by touching things or making food. If someone drinks dirty water, eats contaminated food, or touches a dirty surface and then touches their mouth, they can get sick.
This way of passing the virus to others is very risky in places where it’s hard to get clean water and dispose of waste properly. It is very important to improve sanitation, promote handwashing, and make sure people can drink safe water in order to stop polio from spreading through fecal-oral transmission
Oral-Oral Transmission
The polio virus is normally spread through contact with feces, but it can also spread through saliva. This occurs when the virus is spread by coming into direct contact with an infected person’s respiratory secretions or saliva. If a person with the virus coughs or sneezes, small droplets carrying the virus can be spread into the air. Another person can inhale these droplets or touch surfaces where the droplets have landed, then touch their mouth, causing infection.
The virus can also be spread by sharing things that an infected person has put in their mouth, like food or drinks. Even though this way of spreading a disease is not as common as the fecal-oral way, it can still be risky, specially in busy or close-contact places. Practicing good hygiene, such as covering your mouth when you cough or sneeze and not sharing foods, can lower the chances of spreading illness through oral contact.
After entering the body, the virus grows in the intestines and can move into the bloodstream. In many cases, the immune system can fight off the virus. However, in a few cases, the virus can attack the nervous system and cause paralysis.
Symptoms of Polio Virus Infection
The symptoms of polio can be vary depending on how bad the infection is. There are three kinds of polio infections:
Asymptomatic Infection (Approximately 72% of Cases)
About 72% of people who get the poliovirus don’t have any symptoms. This is called an asymptomatic infection. Even if these people aren’t showing any signs of being sick, they can still pass the virus on to others. The virus can survive in their intestines and be passed through their poop, which can pollute water, food, or surfaces. The virus can spread in a community silently, without anyone knowing, and that’s dangerous. It’s important to keep vaccinating people to prevent polio outbreaks, since the infections may not show any symptoms. This helps to protect everyone from getting sick.
Non-Paralytic Polio (About 24% of Cases)
The majority of people who get the polio don’t experience serious symptoms. A lot of people may not even know they have been infected because they don’t show any symptoms. Many people with symptoms have mild ones that are like the flu. These symptoms may consist of fever, headache, sore throat, fatigue, nausea, and muscle pain. Usually these symptoms will go away on their own after a few days. This kind of polio is known as non-paralytic polio because it doesn’t cause paralysis. Even though these cases are not as serious, they still help the virus spread.
Some people infected with the polio virus develop mild, flu-like symptoms. These can include:
- Fever: An increase in body temperature that is not very strong and may happen on and off. When the body is fighting an infection, this symptom often occurs.
- Fatigue: Feeling very tired and weak, even without doing a lot of activity. This can make everyday activities seem more difficult than they usually are.
- Headache: Feeling pain or pressure in the head. It can vary from a slight pain to a stronger, pulsing sensation.
- Sore Throat: A sensation of discomfort, itchiness, or pain in the throat, like the symptoms of a cold. Swallowing might cause more pain.
- Nausea and Vomiting: Feeling sick in the stomach that might make you vomit. This can cause difficulty when eating or drinking.
- Stiffness in the Neck, Back, and Legs: Pain or stiffness in these places, sometimes caused by aseptic meningitis, which is swelling in the protective layers around the brain and spinal cord.
Paralytic Polio (Less than 1% of Cases)
Paralytic polio is the most serious type of polio, but it only happens in less than 1% of cases. This virus attacks the nerves that control muscles in this form, causing weakness or paralysis. Paralysis can impact the arms, legs, or both, and sometimes the muscles used for breathing. This can make it hard or even impossible for someone to move specific body parts. Paralysis can occur suddenly, usually within a few days after the first symptoms appear. In very serious situations, if the muscles used for breathing are impacted, it can be dangerous for life. Some people may get better, but others could have permanent paralysis or weakness for the rest of their lives.
The worst type of the illness, called paralytic polio, can lead to:
Loss of Reflexes: A person might no longer have their natural reflexes, like when their knee jerks. This means that the body doesn’t respond automatically to certain things anymore.
Severe Muscle Pain or Weakness: Intense pain or a big reduction in muscle strength that makes it hard to move or do easy things.
Flaccid Paralysis (Limp, Floppy Limbs): The muscles get weaker and lose their strength, causing the arms or legs to become floppy or limp. This makes it difficult to manage movement.
Respiratory Muscle Failure: Breathing problems can happen when the muscles used for breathing get weak or paralyzed.Without immediate treatment, this could be very dangerous and could even cause death.
Paralytic polio can also be divided into:
Spinal Polio
The most common type of polio is spinal polio, and it impacts the spinal cord. When the virus affects the nerves in the spinal cord, it can cause paralysis, often in the legs or arms. This type of polio leads to weak muscles or no movement in the arms or legs, which makes it hard to walk or use the arms. The seriousness of paralysis can differ. Some people have only some weakness, while others cannot move at all. Some people might get their movement back eventually, but others may be permanently paralyzed.
Bulbar Polio
Bulbar polio impacts the brainstem, which is in charge of important functions like breathing, swallowing, and speaking. Having the virus in this area can cause trouble swallowing, slurred speech, and breathing problems. In serious situations, bulbar polio can make it difficult to breathe without medical assistance because it weakens the muscles used for breathing. This type of polio is more risky because it affects important body functions and, if not treated properly, it can be deadly. Many people can recover from bulbar polio with treatment.
Bulbospinal Polio
Bulbospinal polio is a mix of spinal and bulbar polio. This means it impacts both the arms and the muscles used for breathing. Bulbospinal polio can cause paralysis or weakness in the arms or legs, as well as trouble breathing or swallowing because of how it affects the brainstem. This type of polio can be very dangerous because it affects both movement and important body functions, such as breathing. Individuals with bulbospinal polio frequently need a lot of medical attention, like help with breathing, to deal with the symptoms. The paralysis and breathing problems can be different in how serious they are.
Post-Polio Syndrome (PPS)
Post-Polio Syndrome (PPS) is a condition that can happen to people who have had polio, sometimes many years after they’ve gotten better. PPS is known for causing weakness, tiredness, and pain in muscles and joints. Some survivors may have trouble breathing or swallowing, and their ability to do daily tasks may get worse as time goes on. The exact reason for PPS is not completely known, but it is thought to be connected to using the nerves that were hurt by the first polio infection too much. Although PPS is not dangerous to life, it can be difficult and frustrating for people who have it, as they slowly lose their physical abilities.
A condition that affects people who had polio many years ago, characterized by:
Progressive Muscle Weakness: As time goes on, the muscles may get weaker, which can make it more difficult to lift things, walk, or do regular activities. This weakness tends to slowly get worse over time.
Joint Pain: Joint pain or discomfort, specially in the areas affected by polio, can make it hard to move.
Fatigue: Feeling very exhausted and having no energy, even after doing very little. This type of tiredness can make it difficult to keep going throughout the day.
Breathing or Swallowing Difficulties: Some individuals may have difficulty breathing or swallowing, which can impact their ability to eat and talk. This occurs when the muscles for these tasks become less strong.
Muscle Atrophy: Lack of use can cause muscles to get smaller and weaker over time, resulting in reduced movement.
Transmission of the Polio Virus
The poliovirus spreads easily and can be transmitted for many reasons:
Fecal-Oral Route
The polio virus mainly spreads through the fecal-oral route, specially in areas with poor sanitation and hygiene. When someone gets polio, the virus comes out in their poop. If people don’t wash their hands well and keep things clean, the virus can get into the water, food, or things that other people touch. In places where there’s no clean water or sewage systems, the virus can spread easily when people consume dirty water or eat food made with unwashed hands.
If a person drinks or eats contaminated water or food, they can get the virus. Even people who do not have symptoms of the virus can still have it and spread it to others without knowing. It’s important to promote clean water, proper sanitation, and good hygiene to stop polio from spreading through poop getting into the mouth.
Person-to-Person Contact
Polio can be passed to another person through touching someone who has it, specially in crowded or dirty places. The virus can spread through saliva or respiratory droplets when someone who has it coughs, sneezes, or talks. If a person is near that person, they can breathe in the virus or touch things that have the virus on them. Sharing food, drinks, or utensils with an infected person can also spread the virus.
The virus can easily spread from one person to another in places like schools or homes with bad cleanliness. Even if someone has the virus but doesn’t feel sick, they can still give it to other people, which makes it difficult to stop it from spreading. Following good hygiene practices, avoiding contact with sick people, and keeping living spaces clean are important in preventing the spread of polio, as shown by this type of transmission.
Environmental Stability
The polio virus can stay alive for a long time in water or damp environments because it is very tough. After the virus comes out of someone who is infected, it can stay alive for many weeks outside the body. This makes it simple for the virus to spread, specially through contaminated water sources. The virus can enter water systems in areas with bad sanitation if human waste is not handled correctly. People can get sick from drinking or touching the dirty water.
The virus can survive outside the body for a long time, so it can spread through a community even after someone first gets it. In places where there is a risk, it is very important to improve sanitation and make sure there is clean water. This helps to keep the environment stable. This can greatly decrease the risk of polio spreading through dirty water.
Immunodeficiency
Prevention of Polio Virus Infection
Vaccination
- Inactivated Polio Vaccine (IPV)
The IPV is given as a shot and works well to keep people safe from polio. This vaccine helps your body fight the virus if it gets into your blood by giving you immunity. Preventing the more serious types of polio, such as paralysis, is particularly important. In many countries, IPV is given to children as a regular part of their vaccinations.
Although IPV prevents the disease, it doesn’t stop the virus from multiplying in the intestines. This means that even people who have been vaccinated can have the virus in their gut and pass it to others through poop, specially in places with bad sanitation. As a result, IPV works well for protecting individuals but is not very good at stopping the spread of polio in areas where the virus is still present. This is the reason why it is important to use other vaccines, such as the oral polio vaccine, to prevent the virus.
- Oral Polio Vaccine (OPV)
The Oral Polio Vaccine (OPV) is taken by mouth and has a weaker version of the polio virus. This vaccine helps the body’s immune system to make protection in both the bloodstream and the intestines. Intestinal immunity is crucial because it prevents the virus from multiplying in the gut, which lowers the chance of spreading the virus to others through poop.
OPV has been important in the worldwide effort to get rid of polio, especially in places with not a lot of medical help. Because it is easy to give and does not need to be injected, OPV can be given in big vaccination efforts. The double protection from OPV is very effective in stopping the spread of polio from person to person, helping to prevent outbreaks and keep communities safe from the disease.
Hygiene and Sanitation
- Regular Handwashing with Soap and Water
One of the easiest and most effective ways to stop diseases like polio from spreading is to wash your hands with soap and water. It is very important to wash your hands after using the bathroom. This will help get rid of any germs from dirty surfaces or waste.
It is important to wash your hands before eating because it stops germs from getting into your body from the food. In areas where there is a risk of polio, regularly washing your hands can greatly lower the risk of getting infected. It is important to teach both kids and grown-ups the proper way to wash their hands to help prevent the spread of diseases like polio. This is a simple yet effective way to stay healthy.
- Proper Disposal of Human Waste and Clean Water Supplies
The proper disposal of human waste is very important in order to stop polio and other diseases from spreading. In places with bad sanitation, human waste can pollute water sources and make it easier for the virus to spread. Having good bathrooms and sewage systems are important because it keeps waste far from where people live and from where they get their water.
It is also important to have access to clean drinking water. If the water sources are clean, there is much less chance of spreading polio through contact with feces. People in communities should be taught why it’s important to use toilets, throw away garbage correctly, and keep water sources clean to keep everyone healthy.
- Educating Communities About Hygiene Practices
It is important to educate people about good hygiene to prevent diseases like polio from spreading. In rural areas or places with less resources, lots of people might not understand how diseases spread or why it’s important to have good hygiene. Community education programs can offer people helpful tips for staying healthy. Doing things like washing your hands a lot, boiling water before you drink it, and keeping your food areas clean can have a huge impact.
These programs also teach people how polio is spread and how families can keep themselves safe. People can avoid getting sick and stop polio from spreading in their communities by practicing these habits. Education helps people understand how to prevent diseases like polio from spreading, specially in places where it is still a threat.
Public Health Surveillance
- Monitoring and Reporting Polio Cases
It is important to find polio cases early in order to stop the virus from spreading. Health authorities can quickly stop possible polio outbreaks by watching communities closely and reporting any new cases. Health workers can figure out how the virus spread and find other people who might have gotten it when a new case is found. This stops the virus from spreading more.
Reporting polio cases helps to find out which areas are most at risk, so that resources can be sent to the places that need them most. Monitoring polio cases closely enables health officials to react swiftly, safeguarding communities and preventing the virus from causing bigger outbreaks.
- Ensuring High Vaccination Coverage
It is important to vaccinate as many people as possible in high-risk areas to keep communities safe from polio. Mass vaccination efforts are important in making this happen. These campaigns provide vaccines to many people in places where it’s hard to get healthcare. Vaccinating many people at the same time can help prevent the spread of the virus, even in places where polio is still a problem.
It is very important to make sure that high-risk groups, such as young children, receive all their vaccinations to help the whole community stay healthy. Maintaining high vaccination rates is important for stopping polio outbreaks and getting closer to the goal of wiping out the disease worldwide.
Travel Precautions
- Ensuring Full Vaccination Before Travel
If you are going to a place with polio outbreaks, it’s important to get fully vaccinated against the virus. Polio can easily spread in areas where it still exists, and not getting vaccinated increases your chances of getting infected. Even if you had vaccines as a child, getting a booster shot before you travel can give you more protection. Health experts frequently advise doing this to reduce the risk of getting or spreading the virus. Staying updated on your vaccines is an easy and effective way to stay safe when you travel.
- Proof of Vaccination for Entry
Some countries may ask for evidence that you have been vaccinated against polio before letting you in. This is to stop the virus from spreading to places where polio is no longer a problem. Travelers need to make sure they have the right vaccinations and documents for their destination. Having an International Certificate of Vaccination can help prevent problems at border crossings and make travel easier. It is important to follow these precautions for your own safety and to help stop polio from spreading globally.
Community Engagement and Awareness
- Educating Communities About Vaccination and Hygiene
It is very important to educate communities about the significance of vaccination and practicing good hygiene in the effort to stop polio. A lot of people might not know how polio spreads or why vaccines are important. Health workers can teach people in communities about how vaccines help not only individuals but also the whole community.
Doing basic things like washing your hands often and using clean water can help a lot in preventing polio from spreading. Teaching programs in schools, community centers, and on local media can help spread these messages. If people know how vaccines and good hygiene help, they will probably do what’s necessary to keep themselves and their families safe from polio.
- Addressing Vaccine Hesitancy
Many parts of the world are facing the challenge of vaccine hesitancy. Some people are scared of vaccines or don’t believe in them because they have heard false information or myths about them. In order to deal with this issue, public health campaigns can give accurate and clear information about vaccines and how safe they are.
Getting community leaders like religious figures or local influencers involved can also help reassure people and persuade them to get vaccinated. When these leaders support vaccination, the people in their communities are more likely to get vaccinated. It is important to hear people’s fears and questions and give them answers to help them trust and feel confident about vaccines. By talking openly and involving the community, we can help reduce people’s reluctance to get polio vaccines and encourage more people to get vaccinated.
Global attempts and difficulties in getting rid of polio virus.
The Global Polio Eradication Initiative (GPEI) started in 1988 has greatly reduced polio cases by more than 99%. Organizations like the World Health Organization (WHO) and UNICEF have led a global effort to vaccinate millions of children and prevent many cases of polio around the world. Because of GPEI, a lot of countries have been announced as polio-free.
But, there are still some problems that need to be addressed. The virus is still spreading in areas where there is fighting, not enough medical facilities, and people are unsure about getting vaccinated. Vaccinating every child is hard because some places are difficult to get to and there is political instability. Even though there are challenges, the GPEI keeps working towards the ultimate goal of getting rid of polio worldwide.
Vaccine-Derived Poliovirus (VDPV)
In some cases, the weakened virus in the Oral Polio Vaccine (OPV) can change and cause outbreaks. This occurs when the virus goes through the intestines, evolves and becomes stronger over time. This changed virus can spread easily in areas where not many people have gotten the full polio vaccine.
Even though VDPV cases are rare, they show how important it is to make sure that everyone gets vaccinated to keep people safe. The chance of VDPV outbreaks is much less than the risk of wild poliovirus, but it’s still important to keep vaccinating to completely get rid of polio worldwide.
Conflict and Insecurity
In places like Afghanistan and Pakistan, where there is fighting and unrest, it’s hard to give vaccines for polio. Continual violence makes it hard for health workers to reach kids who need vaccines. In certain places, it’s not safe to travel or establish vaccination centers, causing some people to miss out on getting vaccinated. These spaces allow the virus to spread, leading to new outbreaks.
Distrust and wrong information about vaccines can increase in places with fighting, making it harder to help. Even though there are difficulties, organizations still work in these places to make sure every child gets life-saving vaccines and to stop the spread of diseases.
Vaccine Hesitancy
When people are not sure about getting a vaccine or refuse to get one, it is called vaccine hesitancy. Incorrect information, cultural beliefs, or lack of trust in health authorities may be the cause of this. False rumors and myths about vaccines in some communities can cause fear and confusion, leading parents to be unsure about vaccinating their children. Some people may believe vaccines are not necessary or harmful because of their cultural or religious beliefs. Lack of trust in healthcare workers or government programs can make people more hesitant.
When people are unsure about vaccines, it can make it harder to stop diseases like polio, especially in places where the virus is still a threat. In order to solve this problem, public health campaigns should work on building trust, giving clear and accurate information, and openly addressing any concerns. This will help to convince more people to get vaccinated.
Here are Some Resources for More Information
- World Health Organization (WHO) – Polio ( https://www.who.int/health-topics/poliomyelitis )
- Centers for Disease Control and Prevention (CDC) – Polio ( https://www.cdc.gov/polio/index.html )
- Global Polio Eradication Initiative (GPEI) ( https://polioeradication.org )
In last
Polio is still a big health issue, mostly in places where not many people get vaccinated and the sanitation is not good. In order to prevent polio from spreading, we need to know how the virus spreads, what symptoms it causes, and how to stop it. Vaccination is still the best way to keep people safe from polio, especially in places where the risk is high. It’s important to keep it going. Improving hygiene and sanitation, such as making sure people have clean water and proper waste disposal, is extremely important along with vaccines.
Teaching people in the community about the importance of vaccines and good hygiene can have a significant impact. If we continue to work hard, we can make a world without polio a reality. We are near to getting rid of this illness, but we need to keep working hard to achieve that aim.
