National Polio Eradication Awareness Week, from April 6 to 12, is a reminder of the global effort to eradicate the polio virus from the world. Though continued efforts by global organisations have decreased the global infection rates, the threat of polio re-emerging remains.
Dr Raveen Parboosing, a consultant clinical virologist from the University of KwaZulu-Natal’s National Health Laboratory Service in Durban, says that “the issue with polio is the continuous possibility that the number of cases, which is currently small, could surge if vaccination and surveillance are stopped or interrupted.”
Part of the eradication effort includes the vaccination of children and the monitoring of suspected polio cases by health workers.
Polio is a virus that is transmitted through the faecal-oral route (through contaminated hands and food with faeces, through poor sanitation, hygiene and unsafe drinking water) and through the respiratory route.
There are three different kinds of the poliovirus: polio one, two and three. Parboosing says that most cases do not exhibit any signs of infection. But a small percentage of cases develop symptoms such as fever, headache, nausea, vomiting and diarrhoea.
He also says that a few patients can develop meningitis and acute flaccid paralysis – weakness or paralysis in one or more limbs.
Paralysis is most likely in type one polio, with type two being the least likely. Death can result through respiratory paralysis. Paralysis is brought about by the virus causing inflammation which destroys the motor neurons, which in turn leads to a loss of function in the nerves and eventually paralysis.
Parboosing says that the risk of paralysis is not the same for everyone and that it is “not possible to tell exactly which person infected with the virus will develop paralysis.”
He says that adults are more likely to develop paralysis than children and that anyone who exhibits sudden paralysis from an unknown cause should seek immediate medical attention.
At the moment there is no cure for polio, but the severity of the symptoms that may arise can be treated through medication. In terms of paralysis, not all patients are permanently paralysed and can with time recover movement. But, Parboosing says, the most effective way to avoid paralysis is to “get vaccinated and avoid the virus altogether.”
The last reported case in South Africa was in 1989, but there is still a risk for the re-emergence of polio here owing to a number of other countries where the virus is still prevalent such as Nigeria, the DRC, Sudan, Pakistan and India.