Question

3. Describe the outcomes of infection by the poliovirus including the immediate and long-term concerns. Briefly outline the quest to develop a vaccine for polio and the setbacks and successes that occurred once the vaccine was developed.

Answer 1

Answer -

Symptoms of Poliovirus -

Although polio can cause paralysis and death, the majority of people who are infected with the virus don't get sick and aren't aware they've been infected. Thus polio infection can of two types: Paralytic & Non - Paralytic.

Non-paralytic polio -

Some people who develop symptoms from the poliovirus contract a type of polio that doesn't lead to paralysis (abortive polio). This usually causes the same mild, flu-like signs and symptoms typical of other viral illnesses.

Signs and symptoms, which can last up to 10 days, include:

• Fever
• Sore throat
• Headache
• Vomiting
• Fatigue
• Back pain or stiffness
• Neck pain or stiffness
• Pain or stiffness in the arms or legs
• Muscle weakness or tenderness

Paralytic polio -

This most serious form of the disease is rare. Initial signs and symptoms of paralytic polio, such as fever and headache, often mimic those of nonparalytic polio. Within a week, however, other signs and symptoms appear, including:

• Loss of reflexes
• Severe muscle aches or weakness
• Loose and floppy limbs (flaccid paralysis)

Post-polio syndrome -

Post-polio syndrome is a cluster of disabling signs and symptoms that affect some people years after having polio. Common signs and symptoms include:

• Progressive muscle or joint weakness and pain
• Fatigue
• Muscle wasting (atrophy)
• Breathing or swallowing problems
• Sleep-related breathing disorders, such as sleep apnea
• Decreased tolerance of cold temperatures.

Polio is a incurable disease which can only be controlled by pre immunisation which prevents its infection. The conventional four-pronged strategy has succeeded in eradicating polio from a large part of the world. This strategy involves maintaining high coverage of vaccination with at least three doses of live oral polio vaccine (OPV), providing supplemental rounds of vaccination, establishing an effective mechanism for the surveillance of acute flaccid paralysis (AFP), and house-to-house OPV “mop-up” campaigns carried out at the final stage in a limited geographical region.

Success of polio vaccine is mentioned as follows -

• High-level political advocacy and mass mobilization have been used to optimum benefit in this programme. Simple management tools like nonmonetary incentives were used to a large extent.
• Polio eradication has been a dynamic programme in which strategies have been frequently adapted and modified to various extents.
• Supplementary immunization activities, house-to-house activities and enhanced surveillance were later additions to the programme.10 The administration of monovalent vaccine (which has enhanced efficacy, increasing the chances of seroconversion in immunized children by almost three times).
• An increased number of supplementary rounds of vaccination and transit strategies (vaccination at transit points, such as railway platforms and national borders) became part of the programme as late as 2005.11
• The number of countries in which polio is endemic has decreased from 125 countries in 1988 to four countries (Afghanistan, India, Nigeria and Pakistan) in three WHO regions at the present time.
• Nine other countries reported importation of polio virus in 2006.
• It is clear that sooner or later the world will be able to eradicate polio.