Overview

Acute flaccid paralysis (AFP) is a severe medical condition characterized by rapid onset of muscle weakness or paralysis and mainly affects children. The group of symptoms and signs, not a single disease, often affects muscles involved in breathing or swallowing. The condition, which often affects one leg or arm and is not typically linked to injury, primarily affects children under 15.

AFP is associated with a variety of causes, including viral infections such as poliovirus, enterovirus and adenovirus, Campylobacter infections, as well as autoimmune diseases such as Guillain-Barré syndrome (a disorder where the immune system attacks the nerves) and transverse myelitis (inflammation of the spinal cord).

Transmission

The virus is transmitted from person-to-person, mainly through the faecal-oral route and, less frequently, by a common vehicle such as contaminated water or food. It multiplies in the intestine from where it can invade the nervous system and cause paralysis and death.

Causes: In addition to poliovirus, a highly infectious virus that primarily affects the nervous system and can lead to severe paralysis and muscle weakness, potential causes range from other viral infections to autoimmune diseases and conditions, including transverse myelitis and Guillain-Barré syndrome.

Poliovirus: A highly infectious virus that primarily affects the nervous system and can lead to severe paralysis and muscle weakness, has historically been a significant cause of AFP and acute flaccid myelitis (AFM). Many cases were reported annually until the widespread adoption of polio immunization programmes reduced incidence rates.

Symptoms

Symptoms of AFP vary widely and may include:

Weakness and loss of muscle tone: Sudden onset of weakness or paralysis, usually affecting an arm or leg, accompanied by reduced muscle tone not caused by injury.

Facial weakness: Facial drooping, difficulty moving the eyes and drooping eyelids.

Speech and swallowing difficulties: Slurred speech and difficulty swallowing.

Sensory symptoms: Tingling or numbness in the limbs, indicating nerve involvement.

Respiratory issues: In severe cases of AFP difficulty breathing can lead to respiratory failure.

Disruption of autonomic functions: Problems controlling vital bodily processes such as heart rate and blood pressure.

Other signs and symptoms:

Fever and back pain may be present, suggesting that the condition could be affecting multiple systems in the body and is not localized to one area.

The sudden onset of uneven paralysis, along with fever or back pain, requires immediate medical consultation, especially if there are breathing difficulties.

Other common symptoms such as muscle wasting, fever, trouble breathing, tingling in the hands and feet, cramps, sensory loss and loss of bladder control should prompt immediate medical attention. It is necessary to urgently find the cause of these symptoms and begin treatment to prevent further nerve damage.

In cases of poliomyelitis, symptoms can include fever, neck stiffness, pain in the limbs, fatigue, headache, vomiting and stiffness. The illness can progress to flaccid paralysis with reduced deep tendon reflexes, often affecting the legs more than the arms. If the trunk and muscles of the chest and abdomen are involved, it can lead to paralysis in all four limbs. In the most severe cases, it causes difficulty swallowing and speaking. Patients do not lose sensation or experience changes in cognition.

Treatment and management

Treatments are available depending on the cause. Health care providers should consider consulting neurology and infectious disease experts to discuss possible treatments and recommend interventions on a case-by-case basis.

For poliomyelitis, there is no single treatment. Management focuses on symptom relief, hydration and specific treatments based on the underlying disease.

Physical or occupational therapy can help with arm or leg weakness caused by polio and may improve long-term outcomes, especially if started early in the illness.

Dehydration can make any illness worse, including those causing AFP, and it is crucial to ensure adequate hydration. This is especially important for conditions involving fever, vomiting and difficulty swallowing. Encourage the intake of safe water and the use of oral rehydration solutions – a mixture of clean water, salt and sugar to replace fluids lost through diarrhoea – when needed. Educate the community on the importance of staying hydrated.

Continuous medical follow-up and rehabilitation are essential for persistent cases to minimize long-term impacts.

Prevention

Health care workers should follow standard contact and droplet precautions

General prevention measures to reduce disease transmission:

Regularly wash hands with soap and warm water to remove germs and prevent the spread of infections.

Clean and disinfect frequently touched surfaces to reduce the risk of viral transmission. In settings with limited cleaning supplies, prioritize high-touch areas and use diluted bleach solutions or alcohol wipes if possible.

Use a disposable tissue to cover your mouth and nose when coughing or sneezing to prevent the spread of respiratory droplets. Dispose of the tissue immediately. If tissues are not available, cough or sneeze into your elbow not your hands.

AFP prevention measures in communities

Safe food and water practices:

Ensure that food is properly cooked and water is treated or boiled before consumption to prevent enterovirus (a virus affecting the intestines) and other infectious causes of AFP.

In areas with limited drinking water, use seawater or saline water for cleaning, toilet flushing and bathing to save drinking water. Inspect areas where seawater is collected to make sure it is safe to use. Seawater is not suitable for drinking.

Keeping safe while on the move: Constant moving makes following standard health practices challenging. Carry soap with you for hand cleaning if available and ensure safe water consumption to prevent diseases like AFP in transient living situations.

Prioritizing at-risk groups: Individuals with autoimmune disorders, weakened immune systems and those undergoing treatments that compromise immunity (e.g. chemotherapy), should be particularly careful about AFP exposure. Rigorous water and hygiene practices are essential for these groups to prevent infection. Whenever possible, ensure vaccination against diseases like poliovirus before exposure occurs.

Poliovirus vaccination

Maintaining high population-level polio vaccine uptake is essential to prevent poliovirus-related AFP.

In conflict or remote areas, health organizations can help conduct vaccination drives to ensure wider coverage.

Focus on securing and distributing polio vaccines, especially in areas with vulnerable populations like children, the elderly and those with compromised immune systems.

Community engagement and healthcare coordination

Immunization: Routine polio immunization programmes significantly lower the occurrence of paralytic poliomyelitis, a severe form of polio that leads to paralysis and disability. These programmes utilize vaccines that target the poliovirus, effectively preventing its transmission and the subsequent development of the disease, protecting populations, especially children, from one of the most disabling outcomes of viral infections.

Community engagement:

Building strong community awareness and education on AFP symptoms, transmission and prevention helps in early detection and control of outbreaks.

Engage community leaders and health care workers in outreach programmes to spread knowledge and enhance community readiness.

Share vital information about hygiene practices, symptom recognition and the importance of immediate health care consultation within your community.

Sources

Acute flaccid paralysis (AFP). Edinburgh: Public Health Scotland; 2024 (https://publichealthscotland.scot/our-areas-of-work/health-protection/infectious-diseases/acute-flaccid-paralysis-afp/overview/symptoms/).

Acute flaccid paralysis field manual. Geneva: World Health Organization and Republic of Iraq Ministry of Health; 2009 (https://applications.emro.who.int/dsaf/libcat/EMROPD_2009_105.pdf).

Acute flaccid paralysis (AFP). Johannesburg: National Institute for Communicable Diseases; 2023 (https://www.nicd.ac.za/diseases-a-z-index/acute-flaccid-paralysis-afp/).

Global guidelines for acute flaccid paralysis (AFP) surveillance in the context of poliovirus eradication. Geneva: World Health Organization and United Nations Children’s Fund; 2023 (https://polioeradication.org/wp-content/uploads/2023/03/Global-AFP-guidelines-pre-publiucation-version-2023.pdf).

Infection prevention and control and water, sanitation and hygiene measures in health-care settings and shelters/congregate settings in Gaza: technical note. Geneva: World Health Organization and United Nations Children’s Fund; 2024.