How Is Hand, Foot And Mouth Disease Spread?

Background

Hand, Foot and Mouth Disease (HFMD) was first described by Robinson and Rhodes in 1957 following an outbreak in Toronto which affected 60 patients from 27 families.

The first major outbreak occurred in Malaysia in 1997 followed by another one in India in 2007 during which 38 cases were reported in the region of Kolkata.

The largest outbreak was reported in China in 2008 which saw a large number of complications with a total number of 200 cases reported and 193 deaths due to the disease. During the last two decades, a sharp rise has been observed in the incidence, severity, complications and fatalities in South-East Asian countries due to viruses causing hand Foot and Mouth disease.

In India, it is assumed that development of Hand Foot and Mouth disease is related to eradication of polio because of mass immunization.

What Is Hand, Foot and Mouth Disease?

Hand, Foot and Mouth disease is the most commonly occurring and highly infectious viral disease occurring among children, caused primarily by the Coxsackie virus A16 (CV-A16) and Human Enterovirus 71 (EV-A71).

Infection with EV-A71 is of particular concern because it causes a severe disease among children, even leading to death.

Although this disease affects a large number of children all over the world, it is rarely seen among Indian children.
This disease usually occurs during summers and usually affects children below 10 years of age. It can also be seen in immune compromised patient and very rarely in adults.

“The Incubation Period For the Virus is 3-7 Days“

Complications and secondary infections from Hand, Foot and Mouth disease are rare and patients generally recover completely. Most patients do not even require hospitalization unless the neurological system gets involved.

Clinical Features of Hand, Foot and Mouth Disease

1. Disease presentation is very characteristic. It is a combination of rash both inside the body, that is, on the mucous membranes and outside the body, on the skin (both exanthema and enanthem). The rash becomes prominent after the onset of fever.
2. Males have a higher incidence rate of hand, foot and mouth disease as compared to
   females.
3. Prodromal Phase
   • Low grade fever along
   • Constitutional symptoms like malaise, weight loss and reduced appetite.
4. Lesions in Mouth and Throat
   • They begin as small red spots which develop into blisters measuring 2-10 mm in diameter. They later develop into vesicles which ulcerate rapidly.
   • Lesions on an inner side of cheeks, gums and on the tongue appear 1-2 days after onset of fever.
   • Lesions are painful because of which patients have reduced appetite.
   • There is difficulty in chewing and eating food because of the lesions.
   • The ulcers formed by these lesions appear greying in color surrounded by a reddish border.
   • Oral lesions are often misdiagnosed as aphthous ulcers, varicella or herpangina infection.
5. Lesions On The Skin
   • Skin lesions appear 1-3 days after onset of oral lesions.
   • Skin lesions develop as small red spots and later develop into blisters measuring 3-10 mm in diameter.
   • The rash is commonly seen on palms, soles, knees and elbows.
   • In infants, the rash develops on the buttocks and progresses to vesicles which dry up within an hour or two.
6. The lesions disappear within 10-14 days.

How Is Hand, Foot and Mouth Disease Spread?

Humans are the only known natural hosts for Coxsackie virus. An infected person continues to shed the virus through feces and saliva or mucus for several weeks after recovery. Therefore, the spread of hand, foot and mouth disease can occur during the acute phase and even after recovery.

Studies were done in Taiwan to evaluate the cause of epidemic and sporadic outbreaks of Hand Foot and Mouth disease suggested that household transmission of EV-71 played an important role in spreading the disease. In the study conducted, it was found that siblings of an infected person showed sero-positivity for EV-71.

“The Primary Mode of Spread of Viruses Causing Hand, Foot and Mouth Disease is the Fecal-Oral Route”

• Study of a pattern of occurrence and spread shows that warmer temperatures and humidity
  are favourable environments for the viruses to spread.
• In patients affected with Hand Foot and Mouth disease, the infection spreads rapidly within the body from oral lesions to the lymphatic system.
• Within the infected person, the causative virus can cross the blood-brain barrier and
  spread to the central nervous system.
• Hand, Foot and Mouth disease is spread from one person to another if one comes in direct contact with the oral or nasal secretions or feces of the affected child.
• This disease is spread when a person comes in direct contact with the fluid inside blisters or vesicles.
• It is commonly spread via droplets, that is, when a patient coughs or sneezes, the infected droplets are released which can be inhaled by other healthy people.
• The disease can be contracted by sharing contaminated food, drink and toys of an infected person.
• Enterovirus can be transmitted to the fetus if infection occurs during pregnancy. The newborn may suffer serious complications like hepatitis, meningoencephalitis, cardiomyopathy, and thrombocytopenia and disseminated intravascular coagulation.

Diagnosis of Hand, Foot and Mouth Disease

1. Swab samples of throat and vesicles can detect the causative virus.
2. EV-71 is shed through stools for several weeks. So stool samples can also detect or isolate the virus.
3. Isolation of virus from cerebro-spinal fluid and serum are less valuable.
4. EV-71 specific polymerase chain reaction (PCR) is a more reliable and relatively cost effect test for detection of enterovirus.
5. Indirect immune-fluorescence assay can rapidly identify E-71 virus.
6. CSF pleocytosis is a marker of central nervous system involvement. It has been universally observed among fatal cases of hand, foot and mouth disease.

How to Prevent HFMD?

No pharmacological intervention has been proven to prevent or control the spread of Hand Foot and Mouth disease.

Yet, It Can Be Prevented by Following Simple Hygiene Practices Like

• Washing hand before and after meals
• Washing hands after passing feces or after contacting skin lesions
• Maintain cleanliness of utensils and water used for consumption
• Cover up mouth and nose when in close contact with an infected person.
• Avoid sharing food, water, utensils and toys of an infected person.
• Surveillance has helped to prevent larger outbreaks in other countries.
• Live-attenuated enterovirus vaccines have reduced the chances of recurrent infection.
• The largest outbreak in India occurred and saw many cases due to lack of awareness among the masses as well as public healthcare workers.

Therefore, educating the general public regarding sanitation and general hygiene about plays an even greater role in the prevention of hand Foot and Mouth disease.

Complications of Hand, Foot and Mouth Disease

1. Cardio Pulmonary Complications – Tachycardia, dyspnea, tachypnea and poor peripheral circulation. Cardiac dysfunction and pulmonary edema may cause sudden death.
2. Neurological Complications – Aseptic meningitis, encephalitis, seizures, neurogenic bladder
3. Neurogenic Pulmonary Edema – Stage III encephalitis that damages the midbrain, pons and medulla oblongata.