What Are Enteroviruses? Dr. Badran Answers

Enteroviruses

Enteroviruses are the most common viruses circulating worldwide and lead to a broad spectrum of clinical illnesses. In general, infants, children, and teenagers are most likely to get infected with enteroviruses and become ill. That’s because they do not yet have immunity from previous exposures to these viruses. Enteroviral infections are more frequent in summer and early fall but may occur at any time of year.

Routes of Transmission

Enteroviral infections are highly contagious and are a common cause of widespread outbreaks. Enteroviruses spread from person-to-person via oral–oral routes; for example, viruses are carried in respiratory droplets and transmitted when someone coughs and sneezes, oral–faecal transmission, direct contact with fluid from skin lesions and from mother to child in the peripartum period.

The incubation period for enteroviruses is usually 2–5 days. Once someone is infected, the enteroviruses implant and replicate in the alimentary tract. If the infection remains localized there are usually no symptoms. However, if the virus passes into the lymphatic system, generalized un-wellness may develop. If the virus spreads into the bloodstream more severe symptoms are experienced.

Aseptic Meningitis

Aseptic meningitis is an umbrella term for all of the causes of inflammation of the brain meninges that have negative cerebrospinal fluid bacterial cultures. It is one of the most common inflammatory disorders of the meninges.

Aseptic meningitis is most common among infants and children. More than half the cases encompassed enteroviruses (Coxsackie and ECHO viruses). In older children and adults, other enteroviruses as well as other viruses may cause aseptic meningitis.

Enterovirus D68

Enterovirus D68 (EV-D68) is one of more than 100 non-polio enteroviruses. Originally isolated in 1962 from respiratory specimens of children with severe pneumonia, enterovirus serotype D68, formerly classified as rhinovirus 87, belongs to the enterovirus D species. EV-D68 infection typically causes mild respiratory illness but occasionally may progress to more severe clinical syndromes (pneumonia, hepatitis, cardiomyopathy, and acute neurologic diseases including aseptic meningitis and poliolike paralytic disease).

Enterovirus D68 causes a respiratory illness, primarily in children; symptoms usually resemble those of a cold (e.g., rhinorrhea, cough, malaise, fever in a few children). Some children, particularly those with asthma, have more serious symptoms involving the lower respiratory tract (e.g., wheezing, respiratory distress).

Healthy adults can be infected, but they tend to have few or no symptoms. Immunocompromised adults may have severe respiratory disease.

Since EV-D68 causes respiratory illness, the virus can be found in an infected person’s respiratory secretions, such as saliva, nasal mucus, or sputum (mucus-like secretions from the lungs). EV-D68 likely spreads from person to person when an infected person coughs, sneezes, or touches a surface that is then touched by others. Children with asthma may have a higher risk for severe respiratory illness caused by EV-D68 infection.

Hemorrhagic Conjunctivitis

Acute hemorrhagic conjunctivitis) AHC (is an epidemic form of highly contagious conjunctivitis, characterized by conjunctival hemorrhages. The first AHC outbreak was described in 1969 in Ghana, West Africa, and was called Apollo disease, from the Apollo landing on the moon. This outbreak was caused by Enterovirus 70 (EV70) together with a Coxsackievirus A24 (CVA24v) variant, which are the major etiological agents involved in AHC outbreaks worldwide. AHC is known to be directly transmitted by close person-to-person contact or indirectly through soiled ophthalmological materials or unsafe recreational water. Recently, a possible airborne virus spread was suggested which could explain the high transmission rate of the disease.

Cardiac Infection

Myocarditis is an inflammation of the heart muscle (myocardium). The most common cause of myocarditis is viral infection (e.g., Enteroviruses), but it can also be caused by a bacterial infection, a reaction to a drug or an autoimmune disease

Group B enteroviruses are common causes of acute myocarditis, which can be a precursor of chronic myocarditis and dilated cardiomyopathy, leading causes of heart transplantation.

Cardiac infection due to enterovirus may occur at any age, but most patients are 20 to 39 years old. Patients may present with chest pain, arrhythmias, heart failure, or sudden death. Recovery is usually complete, but some patients develop dilated cardiomyopathy.

Neonatal Infection

Enteroviruses generally cause mild and self-limited diseases, but they have been found to affect neonates much differently, and often more severely than older children. Clinical manifestations are difficult to differentiate from those of bacterial sepsis, such as fever, poor feeding, lethargy, respiratory distress and cardiovascular collapse.

Severe life-threatening complications, including hepatic necrosis with coagulopathy, meningoencephalitis and myocarditis, usually present during the first week of life. Factors affecting severity and outcome include virus serotype, mode of transmission, and presence or absence of passively acquired serotype-specific maternal antibodies. Echoviruses and coxsackievirus B viruses are most common serotypes associated with the neonatal sepsis.

Recovery may occur within a few weeks, but death may result from circulatory collapse or, if the liver is involved, liver failure.

Respiratory Infections

These infections may result from enteroviruses. Symptoms include fever, coryza, pharyngitis, and, in some infants and children, vomiting and diarrhea. Bronchitis and interstitial pneumonia occasionally occur in adults and children. The course is usually mild.

Prevention Tips

Good hygiene is the best protection. Wash hands with soap and water after going to the toilet, before eating, after wiping noses, and after changing nappies or soiled clothing.

Wear a mask in public—especially if at high risk of serious illness from infections. Avoid kissing, hugging, and sharing cups or eating utensils with people who are sick. Disinfect frequently touched surfaces, such as toys and doorknobs, especially if someone is sick.

People should avoid sharing cups, eating utensils, items of personal hygiene (for example: towels, washers and toothbrushes) and clothing (especially shoes and socks). Thoroughly wash any soiled clothing and any surfaces that may have been contaminated by people with enterovirus infections.

Avoid touching, eyes, nose, and mouth with unwashed hands. Teach children about cough and sneeze etiquette, including covering coughs and sneezes with a tissue, or coughing into an elbow (not into your hands), disposing of used tissues in the bin straight away, and washing your hands afterwards with soap and water.

People who are unwell with colds, flu-like illness or gastro illness should stay away from small babies. If you are caring for a small baby and are unwell, wash your hands or use an alcohol-based hand rub before touching or feeding the baby.