Bugs – Poliomyelitis
Poliomyelitis is a viral disease which is presently controlled throughout the world by massive vaccination programmes. The global incidence of this disease is dropping significantly and WHO hoped to declare the planet free of polio by the year 2005.
Mode of Infection
The virus enters through the oropharynx or the nasopharynx and infects via the gastrointestinal tract. The main method for infection is through contact with contaminated oral-faecal contact.
Many patients infected with the polio virus are asymptomatic. Under these circumstances they may be capable of transmitting the disease to others even though they themselves remain asymptomatic. It is estimated that between 90 to 95% of all infections are in apparent. Fatal cases associated with this condition are probably in the region of 5%. Patients may complain of fever, sore throat, headaches, nausea and vomiting and generalised muscular pains. Diarrhoea may be a presenting symptom. In those with progressive disease paralysis may develop. This is flaccid (floppy) and typically asymmetric with only one side of the body involved. In those with higher infection full bulbar paralysis may develop with respiratory failure and rapid death. In others the paralysis may be permanent or temporary lasting over 6 months.
In India one one million children have been vaccinated against this disease on a number of occasions during the last few years. In Africa, agreement has been reached in quite a number of countries to halt hositilities for a number of days to allow the vaccination programme entrance to some of the more isolated areas. The disease remains most prevalent in third world countries with poor sanitation measures.
Transmission occurs through an infected nappy, through oral sexual practices or most commonly, through contaminated food and water sources. Potentially the disease can be coughed from person to person though this would be extremely uncommon.
Clinical diagnosis is essential in this condition though it may be possible to isolate the virus from stool samples as well as from throat swabs.
There is no specific treatment for this condition. Barrier nursing may be required to lessen the risk of others being infected and ventilatory support may be required if the viral effects are showing high along the spinal chord.
Vaccination is the single most important measure for preventing Poliomyelitis.
There are two main vaccines used against this disease both of which work very well. One version is given as drops (sometimes on a sugar cube to hide the bitter taste) with the other given by injection. There is a mild risk when the oral version is used that contacts of the vaccinated person may become exposed through faecal exposure. The virus may be excreted in faecal matter for at least 6 weeks following vaccination and so extra care is required to ensure that contamination risk is contained.