How Does Polio Spread?

The detection of poliovirus in wastewater samples from New York and London has sparked fears on a possible public health crisis even if the world has yet to heal from the COVID-19 pandemic. 

However, health experts in the U.S. believe that the virus is unlikely to secure widespread transmission in the country, especially in highly vaccinated areas. 

Considering that the Americas declared the eradication of poliovirus in September 1994, not many people are aware of the disease it causes and its symptoms at present. There is also limited awareness on how it spreads. 

Polio Transmission

According to the Centers for Disease Control and Prevention (CDC), poliovirus spreads through person-to-person contact and other ways, such as the oral-fecal route and droplets. 

Poliovirus is very contagious that it can contaminate food and water in unsanitary conditions. Transmission is inevitable when a person makes contact with the feces from an infected person. Infection via droplets from a sneeze or cough is less common. 

The CDC noted that an infected person could spread the virus almost immediately before and up to two weeks after the symptoms of the disease appear. Once the virus enters the mouth, it can stay in the intestines for many weeks. Asymptomatic people can still pass the virus to other people and make them sick. 

Earlier this month, the New York health officials detected poliovirus in wastewater samples from Rockland County and its neighboring Orange County. The detection came about two weeks after the U.S. reported its first case of polio in almost a decade.

This week, Britain rolled out urgent polio vaccinations for all London-based children below 10 after the discovery of polio traces in sewage samples across several London boroughs. The move was made after the detection of polio in wastewater samples from New York, London and even Israel sparked fears of a wider outbreak. 

Polio Symptoms 

Most people who contract the virus will not develop visible symptoms, according to the CDC. For those who do, the symptoms tend to vary. About 1 out of 4 develop flu-like symptoms, such as sore throat, fever, nausea, headache, fatigue and stomach pain. The symptoms typically last 2 to 5 days before going away on their own. 

New York State Department of Health indicated that mild and flu-like symptoms of poliovirus take up to 30 days to appear. However, even before they show up, the infected individual can already shed the virus and infect others. 

A smaller portion of infected people will develop more serious symptoms affecting the brain and spinal cord. These include meningitis and paralysis. The former affects about 1-5 out of 100 people, while the latter impacts 1 out of 200 people or 1 in 2,000 people, per the CDC. 

Among the symptoms of polio, paralysis is the one most commonly associated with the disease since it can lead to permanent disability or even death. Scientific data showed between 2 and 10 out of 200 infected people develop paralysis and die because the virus can significantly impact the muscles used for breathing. 

Disease Prevention 

Since there is no cure or specific treatment for paralytic polio, patients rely on long-term physical or occupational therapy to help them with arm or leg weakness. 

Amid the resurgence of the virus, experts urge the public, especially in places where polio was recently detected, to take precaution and get vaccinated. There is an oral vaccine available in countries outside the U.S. Meanwhile, only the inactivated poliovirus vaccine administered through an injection is available in the U.S.

Aside from the vaccines, the public can also prevent the transmission of the virus by practicing good hand hygiene and washing hands often with soap and water. It is important to note that alcohol-based hand sanitizers are incapable of killing poliovirus.

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