Enteroviruses : Frequently Asked Questions?

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Data from Division of Acute Infectious Diseases, CDC, Taiwan

FAQ

  1. What are enteroviruses?

Enterovirus is a general term of a group of small RNA viruses which accounts for more than 70 viruses, including Coxsackieviruses A, Coxsackieviruses B, polioviruses, echoviruses, and enteroviruses.

  1. Can these enteroviruses only be found in Taiwan?

What are the epidemic seasons?

These kinds of viruses are usually epidemic in summer and early autumn all over the world. Because Taiwan is located in subtropics, the epidemics might take place throughout the year. According to the historical statistics, May to June and September to October are the two major epidemic peaks in Taiwan.

  1. How do enteroviruses spread?

Enteroviruses can be found on the respiratory secretions (e.g. saliva, sputum and nasal discharge) and stool of an infected person. People may get the infection by direct contact with secretions from an infected person or by indirect contact with contaminated surfaces or subjects. The virus may get into the body through respiratory tract or gastrointestinal tract.

Young children are often infected by direct or indirect contacts with adults who may have no symptom but still carry some viruses. They might also be infected by eating foods contaminated by virus-containing excrements. Toys are often the infecting intermediaries between young children, especially the hairy toys which cannot be cleaned routinely and have a higher risk of contaminated by potential pathogens.

Starting from several days before the appearance of symptom, patients who are infected by enteroviruses may transmit the virus to others and the peak of infectivity occurs within one week of disease onset. The virus can be found both in the throat and the stool. Patient may excrete the virus in the stools for several weeks. Enteroviruses transmitted easily among family members and the infection rate is especially high in crowded areas.

  1. What symptoms do enteroviruses cause?

The incubation period of the enteroviruses infection is about 2-10 days. Most of the infected persons have no or very mild symptoms. Most patients will be fully recovered spontaneously with a few days.

Symptoms of characteristic enterovirus infection include vesicles and ulcers in the oral cavity, vesicles or papules on the palm or sole. Fever is frequently observed. The course of illness is usually 7-10 days. A small proportion of cases may be complicated by aseptic meningitis, encephalitis, myocarditis, pericarditis, pneumonitis and paralysis.

  1. Under what kind of situations one has to see a doctor immediately?

Symptoms like “extreme sleepiness”, “myoclonic jerks”(repeated jerky-like movements similar to the startling response that involves abrupt muscle contractions of the whole body), and “persistent vomiting” may be early indicators of ongoing severe complicated illness. Such cases should be sent to a hospital immediately. Special attention should be paid to young infants within the first 5 days of illness because severe complications tend occur during this period. Patients should also search for an immediate medical help in cases of persistent fever, decreased activity, irritability, consciousness disturbance, coma, neck stiffness, limb paralysis, convulsions, shortness of breath, general weakness, increased heart rate, or irregular pulse.

  1. If a pregnant woman is infected with enterovirus, will she give birth of deformed babies?

There is no evidence suggesting that enterovirus infection of the pregnant woman may lead to congenital anomaly of the baby. However, the potential risk cannot be totally excluded and pregnant women should avoid being infected as possible.

  1. Is there any special drug to treat enterovirus infections?

Currently there is no drugs that can kill enteroviruses. Treatment strategies are mainly to support and stabilize the patient condition, and to relieve discomforts.

  1. Will one gain the immunity after being infected with the enterovirus?Will he be infected again later on?

There are more than 70 types of viruses in the group of enteroviruses. One will get a long-lasting immunity once being infected with some enterovirus and the protection against that specific type of enterovirus may last for several decades. One disease entity may be caused by several types of enteroviruses. Therefore, some people may get hand-foot-and-mouth disease or herpangina more than once.

  1. How high is the mortality rate of enterovirus infections?

Most patients with enterovirus infection have very mild or no symptoms. Although having not reached a general agreement, the fatality rate of enterovirus 71 infections has been estimated to be between 1/100,000 and 1/10,000 during the first outbreak of enterovirus 71 infection in Taiwan in 1998. In other words, after being infected with enterovirus 71, more than 99.9% of the patients will recover. However, it still caused quite a shock in Taiwan because the mortality rate of enterovirus 71 is higher than other common viral infections. Therefore, it is mandatory to have a thorough understanding of enteroviruses and the routes of their transmission to decrease the risk of infection.

  1. How to prevent enterovirus infections?

Currently there is no vaccine to prevent enterovirus infections except for polio viruses. Washing hands often and correctly, adopting good personal sanitation habits are measures to reduce the chances of getting infection.

(1) Wash your hands with soap and water frequently.

(2) Clean toys often and do not put them in the mouth.

(3) Don’t go to crowded public areas to avoid infections.

(4) Go to see doctors as soon as possible while being sick and take days off to get more rests.

(5) Watch for the cleaning and ventilation of the house.

(6) Always wash hands before touching children.

(7) All adults and children should keep sanitation.

More Information

  1. WHO|Hand, Foot and Mouth Disease (HFMD)
  2. USA CDC|Hand, Foot and Mouth Disease (HFMD)
  3. USA CDC|Non-Polio Enterovirus