Hand Foot and Mouth Disease

Viral Infection in Humans

Aug 14, 2007 Judy Arbique

Hand foot and mouth disease in humans is often confused with foot and mouth in animals. Although different viruses are responsible, both belong to the same family.

Although both produce painful blisters in the mouth and on the feet, foot and mouth disease that causes disease in livestock is not the same as hand, foot and mouth disease that infects humans. The viruses that cause foot and mouth disease and hand foot and mouth disease DO belong to the same family of viruses: Picornaviridae. However, foot and mouth disease is caused by Aphthovirus; hand foot and mouth disease is caused by an enterovirus.

The enterovirus group includes polioviruses, coxsackieviruses, echoviruses and others. Coxsackievirus A is the most common cause of hand foot and mouth disease.

Symptoms of hand foot and mouth disease usually appear 4-6 days from the time of exposure:

• Inflamed sores on the lips, tongue and mouth
• Fever
• Anorexia
• Malaise (unwell feeling)
• Sore throat
• Tender vesicles on the mucous membranes in the mouth and sides of the tongue and/or
• Tender vesicles on the palms, fingers and soles of the feet

Initially lesions begin as painful sores in the mouth: tongue, gums and inside of cheeks. The mouth sores blister and may become ulcers. A non-itchy skin rash also develops: rash begins as red spots which sometimes blister. Skin rash involves the palms of the hands, soles of the feet, and sometimes the buttocks.

Animals are not affected by hand foot and mouth disease.

How is hand foot and mouth disease transmitted?

• mainly through the oral-fecal route,
• contact with nose, throat, saliva and blister fluids,
• contact with contaminated items and surfaces.

Enteroviruses are highly infectious, especially during the first week of infection when viral shedding is greater: Relatively few viral particles are required for infection with attack rates close to 100%.

Hand foot and mouth disease is found worldwide, and usually affects children less than 10 years of age. Higher viral shedding rates found in children may help explain the higher incidence of hand foot and mouth disease in children and as vectors in spread of infection.

The higher incidence of hand foot and mouth disease in children can be partially explained by the greater risk of exposure related to poor hygiene and contact through play and contamination of shared items and surfaces.

Another factor in the higher infection rates in children is related to previous exposure that may protect adults from subsequent infection. Infants, children and adolescents are more susceptible to the virus because they are less likely to have built immunity through previous exposure to the virus causing hand foot and mouth disease.

Hand foot and mouth disease is usually self-limited. Treatment is supportive only: pain management and adequate fluid intake.

More serious infection has been reported in infection caused by enterovirus 71, a less common cause of hand foot and mouth disease.

Serious infection when it does occur includes:

• viral meningitis
• encephalitis
• paralysis

Good hygiene is essential to prevent spread of infection, which helps explain the higher incidence in children and their role as a vector in spreading infection to their families and other children.

Related articles:

Fingernails and Germs

Foot and Mouth Disease

Source:

Hand foot and mouth disease: Centers for Disease Control and Prevention

The copyright of the article Hand Foot and Mouth Disease in Microbiology is owned by Judy Arbique. Permission to republish Hand Foot and Mouth Disease in print or online must be granted by the author in writing.

Coxsackie virus

Coxsackie virus