Enterovirus 71: Symptoms, Management, and Prevention.

Introduction

Enterovirus 71 (EV71) is a type of virus that belongs to the enterovirus genus in the Picornaviridae family. Enterovirus 71 is classified as an RNA virus (single-stranded) within the human enterovirus A species. It is one of the many enteroviruses that can cause human infections.

Enterovirus 71 was first identified in the year 1969 in California. Following severe outbreaks in Europe during the 1970s, enterovirus 71 has subsequently caused extensive epidemics in the Asia-Pacific region, resulting in multiple fatalities. The virus has also been reported in America and various European countries. Enterovirus 71 primarily targets young children, but adults can also contract the virus. However, adults generally experience milder symptoms compared to children.

How Does Enterovirus 71 Spread?

Enterovirus 71 can spread in the following ways:

• Direct Contact - Direct contact with respiratory secretions, saliva, or feces of an infected person can facilitate the spread of enterovirus 71. This can occur through activities such as hugging, kissing, or sharing contaminated items like utensils, cups, or toys.

• Contaminated Surfaces - Enterovirus 71 can survive on surfaces for a certain period. Touching surfaces such as doorknobs and bathroom fixtures or touching objects such as toys contaminated with the virus and then touching the mouth, nose, or eyes can lead to infection.

• Fecal-Oral Transmission - Ingesting food or water contaminated with enterovirus 71 can result in infection. This can happen when proper hygiene measures are not followed, especially after using the toilet or changing diapers.

• Respiratory Droplets - When an infected person coughs or sneezes, enterovirus 71 can get transmitted through respiratory droplets to a healthy individual. Inhalation of these droplets by individuals in close proximity can lead to infection.

What Are the Symptoms Associated With Enterovirus 71 Infection?

The duration between initial exposure to enterovirus 71 and the onset of the first noticeable symptoms usually ranges between three to five days. The symptoms associated with enterovirus 71 infection may vary but commonly include the following:

1. Hand, Foot, and Mouth Disease (HFMD) - Enterovirus 71 infection often presents as hand, foot, and mouth disease characterized by:

• Mild fever.

• Blisters or ulcers in the mouth, hands, and feet.

• Sore throat.

• Poor appetite.

• Fatigue.

2. Neurological Complications - In some cases, enterovirus 71 infection can lead to more severe neurological conditions, such as:

• Meningitis - It is characterized by inflammation of the brain lining and can result in symptoms like severe headaches, neck stiffness, and sensitivity to light.

• Encephalitis - It involves inflammation of the brain and can cause symptoms such as high fever, headaches, confusion, seizures, and in severe cases, coma.

• Paralysis - In rare instances, enterovirus 71 infection can cause paralysis resembling poliomyelitis, which involves muscle weakness or loss of muscle function.

How to Test for Enterovirus 71?

In order to test for enterovirus 71 (EV71) infection, the following methods are used:

• Molecular Tests -The most common and accurate method for enterovirus 71 detection is molecular testing, such as polymerase chain reaction (PCR). This test amplifies and detects the specific genetic material (RNA) of the virus. Clinical samples, including throat swabs, stool specimens, or cerebrospinal fluid (CSF), are collected and processed for PCR analysis.

• Viral Culture - In some cases, viral culture may be used to isolate and identify enterovirus 71. The collected samples, such as throat swabs or stool specimens, are used to grow and propagate the virus in a laboratory setting. This method requires more time and specialized expertise compared to molecular testing.

• Enzyme-Linked Immunosorbent Assay (ELISA) - In response to enterovirus 71 infection, the antibodies generated by the immune system can be detected by the ELISA test. These tests are useful for determining past exposure or evaluating population-level immunity but may not be suitable for diagnosing acute infections.

What Is the Treatment for Enterovirus 71 Infections?

At present, there is no antiviral treatment specifically available for infections caused by enterovirus 71. The main approach to treatment involves symptom management and providing supportive care.

• Medications (for example, Acetaminophen) can be used to alleviate symptoms such as fever, pain, and discomfort.

• Ensure adequate hydration, especially if there are difficulties in drinking or reduced oral intake. Offer frequent sips of water, oral rehydration solutions, or electrolyte-rich fluids to prevent dehydration.

• Encourage sufficient rest and provide a comfortable environment to support the body's recovery.

• Close monitoring of symptoms and seeking medical attention for severe or worsening symptoms is important. In severe cases with neurological complications, hospitalization may be necessary for specialized care and recovery.

How Can Enterovirus Infections Be Prevented?

In order to prevent enterovirus 71 infections, the following preventive measures are recommended:

• One must wash hands regularly with soap and water, especially before meals, after using the toilet, and after touching surfaces that may potentially be contaminated surfaces. Teach children proper handwashing techniques and encourage them to practice good hygiene habits.

• Individuals who are experiencing symptoms of enterovirus 71 infections or hand, foot, and mouth diseases should stay isolated from school, work, or public places until they have fully recovered to prevent transmission to others.

• Avoiding sharing utensils, cups, or other personal belongings. One must regularly clean and disinfect frequently touched surfaces and objects, such as toys, doorknobs, and countertops, using appropriate disinfectants.

• Encourage infected individuals to cover with the crook of the elbow while coughing or sneezing. While coughing or sneezing, one may also cover their mouth and nose using paper tissue to prevent the spread of respiratory droplets.

• Promote awareness and educate others, especially parents and caregivers, about the signs, symptoms, and preventive measures of enterovirus 71 infections.

• Stay updated on recommended vaccinations for common childhood illnesses, including vaccines for diseases associated with enteroviruses. While there is currently no specific vaccine for EV71 available globally, research and development for EV71 vaccines are ongoing.

What Are the Recent Advancements in Enterovirus 71 Vaccine?

Three companies have recently completed phase III clinical trials of inactivated enterovirus 71 whole-virus vaccines. These trials involved a large number of infants and children in China and were shown to be safe and effective. The vaccines showed over ninety percent protective efficacy against enterovirus 71-associated hand, foot, and mouth disease and over eighty percent of efficacy against other diseases associated with enterovirus 71. Fever was the most frequently reported adverse reaction, and no severe side effects were detected. However, studies and trials regarding the same continue.

Conclusion

Many cases of enterovirus 71 infection result in mild symptoms or no symptoms at all. At present, there is no antiviral treatment specific for enterovirus 71, and management focuses on symptom relief and supportive care. Severe cases can lead to neurological complications; hence close monitoring is a necessity. Keeping a distance from infected individuals and maintaining good overall hygiene is crucial in preventing enterovirus 71 infections. With the promising results from vaccine trials in preventing enterovirus 71-associated diseases, it is anticipated that the vaccine will become available in the near future.