Enterovirus 71 (EV71) was first isolated and characterized from cases of neurological disease in California in 1969. It spread then to Europe with outbreaks in Bulgaria (1975) and Hungary (1978). It has since spread to various countries in Asia where it has been responsible for several serious outbreaks. EV71 is notable as one of the major causative agents for hand, foot and mouth disease (HF), and is sometimes associated with severe central nervous system diseases.

Much remains to be learned about the molecular mechanisms of EV71 replication and the host immune response. This special issue, published in Journal of Biomedical Science, presents reviews and primary research papers on EV71 that cover several topics: a clinical guideline on management of children with HF, epidemiology of EV71 in Thailand, the cell and tissue tropism and the regulation of gene expression, and finally animal models for EV71 and the developments of antiviral drugs.

Infection of retrovirus 71 (EV71) and associated hand, foot, and mouth disease (HF) are recognized as emerging public health issues worldwide. Hundreds of thousands of children are annually infected with EV71 and develop HF in China alone. Studies of EV71 infection are critical to the treatment and prevention of the associated HF outbreaks. In this report, we studied an outbreak of 105 HF cases in Shaw o Township of China between September to October 2012. More than 90% of cases were children younger than 9 years old, with over 50% of cases aged 3–6 years old. Laboratory studies detected a high prevalence of EV71 and suggested EV71 as the most common retrovirus causing HF in Shaw o. Sequencing analysis showed that the EV71 strains from Shaw o belong to the C4 phenotype, and are photogenically more related to those from the distant city of Nanchang than those from the nearby city of Wuhan with distinct variations. More girls were found to be associated with EV71 in Shaw o whereas more boys were associated with EV71 in Wuhan and Nanchang. Our studies further the understanding of the molecular epidemiological features of HF and infection by enteroviruses in China

Since the initial description of retrovirus 71 (EV71) in 1974 [ outbreaks of infection with this virus have occurred periodically throughout the world . EV71 infection manifests most frequently as the childhood ex anthem known as “hand, foot, and mouth disease” (HF), and it is clinically indistinguishable from HF caused by Coxsackie virus A16 (CA16). A molecular study of the evolution of human enteroviruses has shown that EV71 and CA16 have a close genetic relationship, and, together with CA7 and CA14, they form a distinct genetic subgroup within cluster A of the Enterovirus genus of the family Picornaviridae Despite the close genetic relationship between EV71 and CA16, EV71 has a propensity to cause neurological disease during acute infection a feature not observed in CA16 infections. Children <4 years of age are particularly susceptible to the most severe forms of EV71-associated neurological disease, including meningitis, brain-stem and/or cerebellar encephalitis, and poliomyelitis-like paralysis. The neurological complications of EV71 infection may occasionally cause permanent paralysis or death. Several large epidemics of severe EV71 infection in young children, including numerous cases of fatal brain-stem encephalitis, have recently been reported in Southeast Asia

Prevention

Vaccine to prevent EV71 infection is not available in Hong Kong at the moment. Good personal and environmental hygiene are the mainstay of prevention.

1. Maintain good personal hygiene

• Perform hand hygiene frequently, especially before touching the mouth, nose or eyes, before eating or handling food, after touching blister, and after using the toilet.
• Wash hands with liquid soap and water, and rub for at least 20 seconds. Then rinse with water and dry with a disposable paper towel or hand dryer. If hand washing facilities are not available, or when hands are not visibly soiled, hand hygiene with 70 to 80% alcohol-based hand rub is an effective alternative.
• Cover your mouth and nose with tissue paper when sneezing or coughing. Dispose of soiled tissue paper into a lidded rubbish bin, then wash hands thoroughly.
• Use serving chopsticks and spoons at meal time. Do not share food and drinks with others.
• Do not share towels and personal items with others.
• Avoid close contact (such as kissing, hugging) with infected persons.
• Refrain from work or attending class at school, and seek medical advice if feeling unwell. 
• Exclude infected persons from handling food and from providing care to children, elderly and immunocompromised people.

2. Maintain good environmental hygiene

• Regularly clean and disinfect frequently touched surfaces such as furniture, toys and commonly shared items with 1:99 diluted household bleach (mixing 1 part of 5.25% bleach with 99 parts of water), leave for 15 – 30 minutes, and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.
• Use absorbent disposable towels to wipe away obvious contaminants such as respiratory secretions, vomits or excreta, and then disinfect the surface and neighboring areas with 1:49 diluted household bleach (mixing 1 part of 5.25% bleach with 49 parts of water), leave for 15 – 30 minutes and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.
• Avoid group activities when HF outbreak occurs in the school or institution. Besides, minimize staff movement and arrange the same group of staff to take care of the same group of children as far as possible.