In many western countries, polio was actually considered to have been eradicated long ago. Their triggers are polioviruses. The latest samples in London show that the disease could be closer to us than we think.
Alan Alda, Hildegard Knef, and even former US President Franklin D. Rooselvelt have one thing in common: they all had polio, also known as polio. Thanks to concentrated measures, the disease, triggered by polio viruses, was actually eradicated – with the exception of Afghanistan and Pakistan, the World Health Organization (WHO) has meanwhile classified all countries as “polio-free”. Exactly 20 years ago, Europe was declared polio-free by the WHO.
As the “New York Times” reports, traces of the virus have now been found in London’s wastewater – although England also ended the fight against poliomyelitis viruses 20 years ago. Now the authorities are worried – and have declared a nationwide incident.
The virus was discovered during a sewage inspection at a sewage treatment plant in north London. These checks are carried out regularly throughout the country. In contrast to the traces of the virus that sometimes appear, the concentration of the virus in London is worrying: the researchers detected the virus in several samples taken at different times. In addition, according to the current state of knowledge, they are related to each other.
The exact origin is currently unclear. The virus residue is believed to have come from a person who has traveled to London in recent months. The main argument for this is that the finds are limited to the catchment area of the sewage treatment plant. However, since this includes around four million people, precise identification is difficult.
The British authorities state that no polio cases have yet been registered and therefore there is no cause for concern. However, non-immunized people should be vaccinated.
Polio is caused by the so-called poliomyelitis virus or polio virus. These are relatively simple viruses that occur almost exclusively in humans. Of the three common virus types, two have already been eradicated. Only in Pakistan and Afghanistan do outbreaks of the remaining wild type 1 poliovirus occur again and again. The fact that these viruses are then also detected in other countries has to do with the mobility of the population. Flight or migration to other countries means that the pathogens are taken with them.
The vaccination campaign has also been progressing slowly in recent years. The “Bayerischer Rundfunk” reports that young parents are no longer aware of the extent of an infection with polio. In addition, the vaccination rate in other countries has declined due to the pandemic – poliomyelitis viruses have an easy time here. This could increase the risk of the virus spreading further.
According to the Robert Koch Institute (RKI), infection occurs through contact with excretions, for example in contaminated water. Because the viruses multiply in the intestine within a very short time. Propagation in the throat area can also lead to further infections if there is close physical contact via the air.
After infection, the disease is usually asymptomatic. If there are symptoms, they are expressed by fever, headache, nausea or muscle spasms. Motor weaknesses or even paralysis can occur in children – hence the commonly used name “polio”. Although the paralysis should recede, the affected persons often remain damaged. In particularly severe cases, the paralysis can become chronic.
The polio vaccine is the best protection against infection. Today’s vaccine consists of three doses and uses a weakened form of the poliomyelitis virus. It is now recommended for babies and toddlers from the age of two months, with a refresher course between the ages of nine and 16. For adults, it may be advisable to update the immunization when traveling to a country affected by poliomyelitis viruses – currently mainly Pakistan and Afghanistan.
The campaign against polio is considered one of the largest vaccination campaigns of all: in the former GDR and FRG, the so-called oral vaccination was widely advertised to combat the very high number of cases in the 1960s. It was a live vaccine containing a weakened form of the polio virus. The last case of polio in Germany was in 1992.