Polio

What is polio?

Poliomyelitis or polio, is an infection caused by the poliovirus leading to nerve damage and muscle paralysis. Transmission of the poliovirus occurs by contact with infected secretions from the nose and throat (airborne), or contact by the faeces (faeco-oral). The virus enters mouth and nose, multiplies in the throat or digestive tract, and spreads through the blood to the rest of the body.

What are the causes?

Poliovirus may infect a person who is not vaccinated against the disease. There are 3 types of polioviruses. All three can cause paralysis, but type 1 causes paralysis most often followed by types 3 and 2. Most epidemics

What are the symptoms?

Polio occurs in three forms: abortive, nonparalytic, and paralytic.
Abortive form is the most common and is a brief febrile illness that may go unnoticed. Symptoms are nonspecific and may include:

• Fever, sore throat, headache and muscle ache
  
• Malaise, general discomfort or uneasiness
  
• Loss of appetite, nausea, vomiting and constipation

In cases of nonparalytic poliomyelitis, the symptoms last one to two weeks and include:

• Moderate fever (38-390C) and headache
  
• Anxiety and excessive sweating
  
• Nausea and vomiting and constipation
  
• Excessive tiredness, weakness and irritability
  
• Soreness or stiffness of the muscles of back, arms, legs, and abdomen
  
• Muscle tenderness and spasm in any part of the body
  

In about one-third of cases this resolves in a week without developing paralysis. Approximately two thirds of these children have a short symptom free interlude between minor and major (CNS) illnesses.
The symptoms in cases of paralytic polio are:

• Fever, headache, irritability and stiff neck and back
  
• Rapid onset of weakness of one or more muscle groups leading to paralysis of any part of the body. Paralysis typically begins during fever. It is often the first symptom. Pattern of paralysis is asymmetrical involving usually only one limb, lower extremities more than upper extremities. Paralysed muscles atrophy over time.
  
• Abnormal (but not loss of) sensation: sensitivity to touch, mild touch may be painful
  
• Difficulty in passing urine
  
• Constipation and feeling of bloatedness in the abdomen
  
• Difficulty in swallowing and breathing
  
• Occasionally rapid deterioration with drowsiness, respiratory failure and sudden collapse.

How is it diagnosed?

Several diseases can be associated with muscular weakness. Polio is suspected in a patient who develops sudden paralysis on one side of the body following a short febrile illness. Rigidity of the neck and spine are the hallmarks of nonparalytic form. The virus can be easily cultured from stool, throat secretions and cerebrospinal fluid (CSF). Blood can be tested for antibodies against polioviruses. CSF tests help to confirm the diagnosis in cases with neurological involvement.

What is the treatment?

The aims of management are to allay fear, minimize skeletal deformities, anticipate and prevent complications and prepare the child and family for a prolonged treatment of the disability. Abortive and nonparalytic forms are treated similarly. They usually get better after few days of bed rest. The treatment generally includes pain relievers to treat the muscle spasm and pain, antipyretics for fever and sedatives with good diet. Avoid exertion for the next two weeks. Hot packs (warm water fomentation) for 10-15 minutes every 2-4 hours can relieve muscle stiffness and spasm.

A child with paralytic form of disease during acute stage requires complete bed rest. Stress on the affected muscles should be avoided. Massage and injections are contraindicated. Positioning of limbs using sand bags, splints or footboards helps in relaxation of affected muscles. Passive movements of joints within the range of pain are allowed. Hospitalisation is necessary for progressive paralysis, breathing difficulty and worsening sensorium. Once the virus is no longer active, physical therapy can improve muscle function.

FAQ’s

What is polio?

It is a highly infectious disease caused by one of 3 related polio viruses (type 1, 2 or 3), which belong to the group of enteroviruses (transient inhabitants of the intestines).

It mainly affects children under five years of age. Globally, there has been a decrease by 99.8% in polio cases since 1988 (from ~3,50,000 to 500 in 2001).

Can polio be cured?

There is no cure for polio. Giving multiple doses of oral polio vaccine (OPV) to children is the only way to prevent it.

Which are the countries at risk of polio?

Children in all countries remain at risk as long as even a single infected case of polio exists in the world. The virus can easily be imported into a polio-free nation. and can then rapidly spread amongst the unimmunised population.

Ten countries (polio-endemic) are still known to have ongoing poliovirus transmission (at the beginning of 2002). They are divided into areas with high-intensity and areas with low-intensity transmission.

Areas with high-intensity transmission
It includes India, Pakistan, Afghanistan, Nigeria and Niger and these countries account for more than 85% of new polio caseload in 2001. Some common characteristics of these regions are large populations, low routine immunization coverage, sub-optimal sanitation and relatively wide geographical distribution of the wild poliovirus.

Areas with low-intensity transmission
Account for less than 15% of the new caseload in 2001 and include Somalia, Sudan, Ethiopia, Angola and Egypt. They generally have lower-density populations and focal areas of wild poliovirus transmission.

What is the Global Polio Eradication Initiative?

Launch
The 41st World Health Assembly in 1988 (166 countries) launched a global initiative to eradicate polio by 2000 following the certification of smallpox eradication in 1980.

Progress
In the 14 years since its launch, the number of polio-infected countries has reduced from 125 to 10. In 1994 WHO Region of the Americas (36 countries) and in 2000 the WHO Western Pacific Region (37 countries and areas including China) were certified polio-free while this year the WHO European Region (51 countries) which has been polio free for over 3 years will receive the certification.

Objectives

• To interrupt transmission of the wild polio virus as soon as possible and certify all WHO regions polio-free by the end of 2005;
• To implement the polio endgame programme of work, including containment of wild poliovirus, global polio-free certification, and the development of a post-eradication immunization policy;
• To contribute to health systems development by strengthening routine immunization and surveillance for communicable diseases.
  

Strategies

• There are 4 core strategies to stop the transmission of wild poliovirus and certify all WHO regions polio-free by 2005:
• High infant immunization coverage with 4 doses of OPV in the first year of life
• Supplementary doses of OPV to all children under 5 years of ageduring national immunization days (NIDs)
• Surveillance for wild poliovirus through reporting and laboratory testing of all cases of acute flaccid paralysis among children under 15 years of age
• Targeted “mop-up” campaigns once wild poliovirus transmission is limited to a specific focal area.
  

What constitutes polio-free region?

Three conditions need to be satisfied:

1. at least 3 years of zero polio cases due to wild poliovirus
2. excellent certification standard surveillance
3. each country must illustrate the capacity to detect, report, and respond to “imported” polio cases. Laboratory stocks must be contained and safe management of the wild virus in Inactivated Polio Vaccine (IPV) manufacturing sites must be assured before the world can be certified polio-free
   

What are “polio endgame” strategies?
These include laboratory containment, certification of polio eradication and development of post-certification polio immunization policy

Laboratory containment
Before the world can be certified polio-free, all wild polioviruses in laboratories must be adequately contained. Wild poliovirus materials in laboratories must be identified and all remaining laboratory stocks are handled under appropriate biosafety conditions in the post-eradication era.

Global polio-free certification
This requires the maintenance of certification-standard acute flaccid paralysis surveillance for at least 3 years following the last polio case in any WHO region, and assurance that wild virus in the IPV manufacturing sites will be safely managed.

What has been the impact of Global Polio Eradication Initiative?

• From its launch in 1988 to target date of 2005, 5 million people, who would otherwise have been paralysed, will be walking.
• By preventing a debilitating disease, it will help in reducing poverty and give a greater chance to children and their families to lead healthy and productive lives.
• It has helped to provide key demographic data by accessing children in remote areas.
• Polio Eradication Initiative has extended the capacity of most countries to tackle other diseases by building effective disease-reporting and surveillance systems, training epidemiologists and establishing a global laboratory network.
• Routine immunization services have been strengthened by bolstering the cold-chain, transport and communication systems for immunizations. 
• In 2001, over 60 countries gave vitamin A drops during polio national immunization days.
• Many countries have established a new mechanism for coordinating major cross-border health initiatives aimed at reaching all people.