Definitely, viruses have tough skin. Polio is making an unexpected comeback in the United States and the United Kingdom. While the world was still cherishing the prospect of eradicating this disease, endemic only in Afghanistan and Pakistan, the question now arises of avoiding a return to grace in our latitudes. We asked Dr Alessandro Diana (HUG, Grangettes), pediatric infectious disease specialist and specialist in vaccinology, to give us his analysis.
Heidi.news – Let’s take a look at the fundamentals. What do you need to know about poliomyelitis to understand the situation?
Alessandro Diana – Even if the situation is worrying, do not panic. We are not facing the emergence of a new disease, like the coronavirus. Polio is very old, from ancient Egypt we see representations of people with atrophied lower limbs. It is an RNA viral infection – which means that it mutates easily – which is transmitted by the orofecal route, that is to say by contact with the hands, but also for example if you eat a salad with water contaminated by someone who has not washed their hands. This virus has a tropism for the digestive system, this is where it lodges, multiplies and spreads, to end up in the stool.
There is a phase of the disease where it passes from the digestive tract to the blood, and this is where possible non-specific symptoms appear, with fatigue, fever, like a cold. But for one in 200 people, it has the bad idea of going into the central nervous system – it’s not clear why – and attacking the motor part of the nervous system. It leads to paralysis, usually of the lower limbs. It’s very debilitating, you can’t walk anymore, and you can also have deformities, unscrewing knees, it gives those horrible images that we all know.
The existence of viral circulation is inferred indirectly by monitoring wastewater. Why is polio so hard to detect?
A diagnosis of polio is very difficult to see because the symptoms are very unspecific. If someone in consultation comes to see me in consultation with a headache or a stomach ache, I will usually diagnose gastroenteritis and tell them to come back in ten days. It is when people develop paralysis of the lower limbs a few weeks later that we see that it was polio. And alas, by then it is too late. But it should be noted that this only happens in someone who has never had the disease or received the vaccine.