Coxsackievirus A16

Etiology/Bacteriology

Taxonomy

ssRNA positive-strand viruses, no DNA stage | Order = Picornavirales | Family = Picornaviridae | Genus = Enterovirus | species = Enterovirus A
{|NCBI: Taxonomy Genome: Genome|}

Description

Coxsackievirus belongs in the Picornaviridae family that includes polioviruses and non-polioviruses. The Coxsackievirus is a non-poliovirus. Coxsackieviruses have two groups, group A and group B. Group A includes Coxsackievirus A16 (CA16), which is a common cause of hand, foot, and mouth disease (HFMD) in children under the age of 10. CA16 is a small, non-enveloped, icosahedral particle with a single positive-stranded genomic RNA. Some symptoms that might occur are fevers, rashes on hands and feet, and blister like sores in the mouth. The symptoms last around a week, and then disappear. CA16 is transmitted via the fecal-oral route, or oral-oral route. Although there are HFMD cases around the world, Asia currently has the most outbreaks. CA16 causes a mild and, sometimes, asymptomatic version of HFMD. Serious cases lead to meningitis, conjunctivitis, myocarditis, and pericarditis.

Clinical Features

Symptoms

CA16 is one of the most common causes of hand, foot, and mouth disease (HFMD). Initial symptoms are seen 3 to 6 days after exposure. The majority of CA16 infections in HFMD are asymptomatic, but some cause a fever, poor appetite, and a sore throat. Painful sores can develop in the mouth (herpangina). Rashes are mainly on the palms of hand and soles of feet, but can be on knees, elbows, buttocks, or genital areas. Dehydration is a major concern because of the pain experienced from swallowing. HFMD normally happens in children under 5, but adult cases have been recorded. HFMD is prominent during the warmer months, and the symptoms clear up in about a week without treatment. Although rare cases of HFMD lead to damage of the central nervous system, a CA16 infection is not linked with CNS damage at this time.[2]

Diagnosis

The majority of physicians diagnose HFMD based on the symptoms that are present. To diagnose a CVA16 infection, throat swabs and fecal specimen are collected. Viral tests can also be used to identify CVA16, but they are rarely done because they are expensive and it takes two weeks to get the results back. Since the symptoms clear in a week, viral tests are not done unless there are serious complications.[2]

Treatment

Because coxsackievirus A16 is self-limiting, the symptoms disappear after 7 to 10 days without any treatment. Physicians will prescribe symptomatic treatments for infected individuals. Acetominophen (Tylenol) can reduce the fever, and some pain. Sometimes Lidocain oral gel, benzydamine spray, mouthwash, or choline salicylate oral gels are recommended for mouth and throat ulcers. Preventing dehydration by adequate fluid intake is encouraged. An antiviral chemical used to treat herpes simplex, acyclovir, was used to successfully treat CA16, but the study was inconclusive.

Prevention

Currently, there is not a vaccine for any of the coxsackieviruses, but transmission of the virus can be avoided. To prevent infection of CVA16, good hygiene must be practiced. Hands need to be washed after using the toilet, changing diapers, before preparing food, etc. Children should be taught proper hygiene and hand washing to avoid infection of CA16. Other preventative measures include covering of one’s nose and mouth when coughing or sneezing, and not sharing cups, eating utensils, or towels with an infected person. Sterilization of toys, beds, changing tables, and eating utensils should be performed at child day cares and houses. Repeated infections are not typical, but they are possible because HFMD can also be caused by other strains of coxsackieviruses and enterovirus 71.