Hand, foot and mouth disease

Hand, foot and mouth disease (HFMD) is a common human syndrome caused by highly contagious intestinal viruses of the picornaviridae family typically characterized by a mild fever followed by a rash of flat discolored spots and bumps that may involve the skin of the hands, feet, and oral cavity. HFMD mainly affects infants and children, but can occasionally occur in immunocompetent adults.

Coxsackievirus A16 is the most common cause of HFMD while enterovirus 71 (EV-71) is the second most common cause of HFMD. Many other strains of coxsackievirus or enterovirus are also known to cause this viral syndrome. The viruses that cause HFMD are spread through direct contact with the mucus, saliva, or feces of an infected person. HFMD often occurs in small epidemics in nursery schools or kindergartens, usually during the summer and autumn months. Signs and symptoms normally appear 3-6 days after exposure to the virus. The syndrome goes away on its own, and most cases require no treatment other than symptomatic relief. No antiviral treatment or vaccine is currently available for HFMD, but development efforts are underway.

HFMD should not be confused with foot-and-mouth disease (also known as hoof-and-mouth disease) which affects livestock. Foot-and-mouth disease is caused by a different picornavirus which almost never infects humans.

Signs and symptoms

Common constitutional signs and symptoms of the HFMD include fever, feeling tired, generalized discomfort, loss of appetite, and irritability in infants and toddlers. Skin lesions frequently develop in the form of a rash of flat discolored spots and bumps followed by vesicular sores with blisters on palms of the hands, soles of the feet, buttocks, and sometimes on the lips. The rash is rarely itchy for children, but can be extremely itchy for adults. Painful facial ulcers, blisters, or lesions may also develop in or around the nose or mouth. HFMD usually resolves on its own after 7â€"10 days.

Diagnosis

A diagnosis usually can be made by the presenting signs and symptoms alone. If the diagnosis is unclear, a throat swab or stool specimen may be taken to identify the virus by culture. The common incubation period (the time between infection and onset of symptoms) ranges from three to six days.

Treatment

Medications are usually not needed as hand, foot and mouth disease is a viral disease that typically gets better on its own. Currently, there is no specific curative treatment for hand, foot and mouth disease. Disease management typically focuses on achieving symptomatic relief. Pain from the sores may be eased with the use of analgesic medications. Infection in older children, adolescents, and adults is typically mild and lasts approximately 1 week, but may occasionally run a longer course. Fever reducers and lukewarm baths can help decrease body temperature.

A minority of individuals with hand, foot and mouth disease may require hospital admission due to uncommon neurologic complications such as inflammation of the brain, inflammation of the meninges, or acute flaccid paralysis. Non-neurologic complications such as inflammation of the heart, fluid in the lungs, or bleeding into the lungs may also occur.

Complications

Complications from the viral infections that cause HFMD are rare, but require immediate medical treatment if present. HFMD infections caused by Enterovirus 71 tend to be more severe and are more likely to have neurologic or cardiac complications including death than infections caused by Coxsackievirus A16. Viral or aseptic meningitis can occur with HFMD in rare cases and is characterized by fever, headache, stiff neck, or back pain. The condition is usually mild and clears without treatment; however, hospitalization for a short time may be needed. Other serious complications of HFMD include encephalitis (swelling of the brain), or flaccid paralysis in rare circumstances.

Fingernail and toenail loss have been reported in children 4â€"8 weeks after having HFMD. The relationship between HFMD and the reported nail loss is unclear; however, it is temporary and nail growth resumes without treatment.

Prevention

No vaccine is currently available to protect individuals from infection by the viruses that cause HFMD, but such vaccines are being developed. HFMD is highly contagious and is transmitted by nasopharyngeal secretions such as saliva or nasal mucus, by direct contact, or by fecal-oral transmission. Preventive measures include avoiding direct contact with infected individuals (including keeping infected children home from school), proper cleaning of shared utensils, disinfecting contaminated surfaces, and proper hand hygiene. These measures have been shown to be effective in decreasing the transmission of the viruses responsible for HFMD.

Epidemiology

Hand, foot and mouth disease most commonly occurs in children under the age of 10 and tends to occur in outbreaks during the spring, summer, and fall seasons. HFMD is most commonly caused by infection with Coxsackievirus A16.

Major Outbreaks

• In 1998, there was an outbreak in Taiwan, affecting mainly children. There were 405 severe complications, and 78 children died. The total number of cases in that epidemic is estimated to have been 1.5 million.
• In 2008 an outbreak in China, beginning in March in Fuyang, Anhui, led to 25,000 infections, and 42 deaths, by May 13. Similar outbreaks were reported in Singapore (more than 2,600 cases as of April 20, 2008), Vietnam (2,300 cases, 11 deaths), Mongolia (1,600 cases), and Brunei (1053 cases from Juneâ€"August 2008)
• In 2009 17 children died in an outbreak during March and April 2009 in China's eastern Shandong Province, and 18 children died in the neighboring Henan Province. Out of 115,000 reported cases in China from January to April, 773 were severe and 50 were fatal.
• In 2010 in China, an outbreak occurred in southern China's Guangxi Autonomous Region as well as Guangdong, Henan, Hebei and Shandong provinces. Until March 70,756 children were infected and 40 died from the disease. By June, the peak season for the disease, 537 had died.
• The World Health Organization reporting between January to October 2011 (1,340,259) states the number of cases in China had dropped by approx 300,000 from 2010 (1,654,866) cases, with new cases peaking in June. There were 437 deaths, down from 2010 (537 deaths).
• In December 2011, the California Department of Public Health identified a strong form of the virus, coxsackievirus A6 (CVA6), where nail loss in children is common.
• In 2012 in Alabama, United States there was an outbreak of an unusual type of the disease. It occurred in a season when it is not usually seen and affected teenagers and older adults. There were some hospitalizations due to the disease but no reported deaths.
• In 2012 in Cambodia, 52 of 59 reviewed cases of children reportedly dead (as of July 9, 2012) due to a mysterious disease were diagnosed to be caused by a virulent form of HFMD. Although a significant degree of uncertainty exists with reference to the diagnosis, WHO report states, "Based on the latest laboratory results, a significant proportion of the samples tested positive for enterovirus 71 (EV-71), which causes hand foot and mouth disease (HFMD). The EV-71 virus has been known to generally cause severe complications amongst some patients."
• Hand, foot and mouth disease infected 1,520,274 people with 431 deaths reported up to end of July in 2012 in China.

History

Hand, foot and mouth disease cases were first described in New Zealand in 1957.

Research

Novel antiviral agents to prevent and treat infection with the viruses responsible for HFMD are currently under development. Preliminary studies have shown inhibitors of the EV-71 viral capsid to have potent antiviral activity.

References

External links

Media related to Hand, foot and mouth disease at Wikimedia Commons News related to Highly contagious Hand, foot and mouth disease killing China's children at Wikinews