Wastewater analyzes were carried out in this American state after the confirmation of a case of polio. They revealed traces of the virus causing this disease, which would mean that it circulates in the population.
New York State health officials reported a case of poliomyelitis in Rockland County on July 21. The man has paralysis, one of the possible, but rare, consequences of this disease. Analyzes have since been carried out in the wastewater of the State where “the virus was detected in samples of wastewater from June and July”, in the counties of Rockland, but also of Orange, is it explained in a press release.
“New Yorkers should know that for every case of paralytic polio observed, there may be hundreds more infected,” said state health commissioner Mary T. Bassettwhich explains that this identified case would only be the tip of the iceberg.
“What we know is clear: the danger of poliomyelitis is present in New York today,” she says.
Tests were conducted in the sewage to estimate the presence of poliovirus, and as of August 5, the CDC (American Centers for Disease Control and Prevention), had confirmed the presence of 11 positive samples dating back to June and July, linked to the identified infected individual: six in Rockland County, five in Orange County.
These results show that the virus circulates in the population but apart from the case of paralysis mentioned above, no other infected individual has been identified for the moment.
“Hundreds, if not thousands of” potential cases
Poliomyelitis is caused by a virus called poliovirus, and “most people who are infected with it (about 72%) have no visible symptoms”, writes the CDC. More serious symptoms appear in more rare cases – less than 1% – such as paralysis, but also paresthesia (feeling tingling, tingling, etc.) or meningitis.
In that sense, “there’s not just one case of polio if you see a paralytic case,” said Patricia Schnabel Ruppert, Rockland County Health Commissioner at the BBC. “Most cases are asymptomatic or mildly symptomatic, and these symptoms are often missed,” she explains, “so there are hundreds, if not thousands, of cases that have occurred for us to see a paralytic case .”
Paralysis is the most severe manifestation of this disease and leads to death for 2 to 10% of people affected by this symptom, “because the virus affects the muscles allowing breathing”, explains the CDC.
The transmission of this disease “is exclusively human-to-human and takes place essentially by the faecal-oral route, in particular via contaminated water, aerosols or food contaminated by the stool”, explains the Pasteur Institute.
How was the paralyzed patient infected?
It is possible to transmit the virus without having symptoms and “infected people can transmit the infection as long as the virus persists in the throat (one week) and in the feces (3 to 6 weeks or even more)”, underlines the ‘Pastor Institute.
The identified patient was infected with a type 2 Sabin poliomyelitis virus, explain the health authorities of New York. The results indicate that the man was infected by an individual who received the oral polio vaccine (OPV) “which is no longer licensed or administered in the United States”, where only the injectable polio vaccine (IPV) is used. . The identified strain cannot indeed come from an inactivated vaccine, like the one used across the Atlantic, assures the New York State Department of Health.
The patient having traveled to Europe before feeling the first symptoms, as ABC writes, it is there that he could have caught polio.
With OPV – which contains live attenuated polioviruses – there is a rare “possibility of inducing disease in some vaccinated people and the introduction into the environment of live strains of poliovirus, admittedly attenuated but which can establish chains of transmission in contexts where vaccination coverage is low after their excretion by vaccinated people”, writes the Institut Pasteur.
“All unvaccinated children and adults should receive a first vaccination immediately”
However, if vaccination against polio approaches 80% in New York State, it only reaches 58.68% in Orange County, and 60.34% in Rockland. The authorities are therefore calling on the unvaccinated population to receive doses to be protected from possible contamination.
“It is concerning that poliomyelitis, a disease which has been largely eradicated through vaccination, is now circulating in our community, especially given the low vaccination rates against this disease” in some territories, says the health commissioner of the Orange County Irina Gelman. “I urge all unvaccinated residents of Orange County to get vaccinated as soon as possible,” she adds.
“All unvaccinated children and adults should immediately receive a first vaccination against poliomyelitis”, abounds Patricia Schnabel Ruppert.
According to the latest CDC data, 92.6% of the American population is vaccinated against polio, and therefore must be protected against transmission, which limits fears of a large epidemic, and does not worry excessively public health experts according to the Los Angeles Times, which however call for vaccination.
“Two doses of poliomyelitis vaccines are 90% effective against poliomyelitis, while three doses are more than 99% effective in preventing the disease,” writes the ECDC (European Center for Disease Prevention).
In France, this vaccination is one of the 11 compulsory vaccines, and “the last case of autochthonous poliomyelitis dates back to 1989” while “the last case imported in 1995, both concerning adults”, assures the High Authority of Health, but the vigilance remains constant on this subject. At the end of June, traces of a form of polio had indeed been found in the sewage of London.