Hand-foot-mouth disease (HFMD) is a common childhood infectious disease caused by a variety of human enteroviruses, and is a category C infectious disease under statutory reporting management in China. Most patients have mild symptoms, with fever and rash or herpes on the hands, feet, and mouth as the main symptoms. A few patients may develop aseptic meningitis, encephalitis, acute flaccid paralysis, neurogenic pulmonary edema and myocarditis, etc. Individual children with severe disease progress rapidly and can lead to death. Hand, foot and mouth disease often appear outbreaks or epidemics, in order to guide the prevention and control of hand, foot and mouth disease around the work, the development of this guide.
I. Purpose
(a) to guide medical institutions, disease prevention and control agencies to carry out outbreak reporting and monitoring.
(B) guide the disease prevention and control agencies to carry out epidemiological investigation, pathogenetic surveillance.
(C) guide disease prevention and control institutions, medical institutions to carry out preventive control of key sites and the public.
Second, the disease overview
(A) pathogenesis.
The viruses causing HFMD belong to the genus Enterovirus of the family of small RNA viruses, including Coxsackievirus A (Coxasckievirus A, CVA) types 2, 4, 5, 7, 9, 10, 16, etc., Group B (Coxasckievirus B, CVB) types 1, 2, 3, 4, 5, etc.; Enterovirus 71 (Human Enterovirus 71, EV71); Echovirus (Echovirus, ECHO), etc. Echovirus (ECHO) and so on. Among them, EV71 and CVA16 are more common.
Enterovirus is suitable for survival and transmission in wet and hot environment, 75% alcohol and 5% lysol cannot inactivate it, and it is not sensitive to ether and dechlorinated bile salt; it is sensitive to ultraviolet light and drying, and various oxidizing agents (potassium permanganate, bleaching powder, etc.), formaldehyde, iodine and 56℃ for 30 minutes can inactivate the virus. The virus can survive for 1 year at 4℃, and can be stored for a long time at -20℃, and can survive for a long time in the external environment.
(B) Epidemiology.
1. Infectious source. Human is the only host of human intestinal virus, patients and recessive infections are the infectious source of the disease, recessive infections are difficult to identify and detect. The virus can be detected in the pharynx and feces of the infected person a few days before the onset of the disease, and is usually most infectious within a week after the onset of the disease.
2. Transmission route. Enterovirus can be transmitted through the gastrointestinal tract (fecal-oral route), as well as through the respiratory tract (droplets, coughing, sneezing, etc.), or through contact with the patient’s oral and nasal secretions, skin or mucosal herpes fluid, and contaminated hands and objects. It is not clear whether the disease can be transmitted through water or food.
3. Susceptibility. People are generally susceptible to human enterovirus. Different age groups can be infected with the disease, mainly children aged 5 years and younger, especially children aged 3 years and younger have the highest incidence. Specific immunity can be acquired after both overt and covert infections, and the neutralizing antibodies produced can remain in the body for a long time, resulting in relatively strong immunity to the same serotype of virus, but there is little cross-immunity between different serotypes.
4. Epidemic characteristics. The disease is not obvious regional epidemic, can occur throughout the year, generally May-July for the peak incidence. Childcare institutions and other susceptible people can occur in concentrated units outbreaks. Enterovirus is highly infectious, a large proportion of latent infection, complex transmission routes, rapid transmission, difficult to control, prone to outbreaks and a large range of epidemics within a short period of time.
(iii) Clinical manifestations.
The incubation period of hand, foot and mouth disease is 2-10 days, an average of 3-5 days, the course of the disease is generally 7-10 days.
Acute onset, fever, scattered herpes on the oral mucosa, maculopapular rash and herpes on the hands, feet and buttocks, there may be inflammatory redness around the herpes, and less fluid in the herpes. It may be accompanied by cough, runny nose, and loss of appetite. Some patients have no fever and present only with a rash or herpes. The prognosis is generally good; a few cases, especially children with EV71 infection, may develop meningitis, encephalitis, encephalomyelitis, neurogenic pulmonary edema, circulatory disorders, etc. The condition is dangerous and may lead to death or sequelae.
(D) Treatment principles.
There is no specific treatment method, mainly supportive therapy, the majority of patients can be self-healing. There is no specific vaccine. For the treatment of cases, refer to the Ministry of Health’s “Guidelines for the Treatment of Hand, Foot and Mouth Disease (2008 Edition)”.
III. Case definition
(A) Clinical diagnosis of cases.
Onset in the epidemic season, common in preschool children, infants and toddlers are more common.
1. Ordinary cases: fever with rash on hands, feet, mouth and buttocks, some cases may not have fever.
2. Severe cases: neurological involvement, respiratory and circulatory dysfunction, etc. Laboratory tests may include increased peripheral blood leukocytes, abnormal cerebrospinal fluid, increased blood sugar, and abnormal EEG, brain and spinal cord MRI, chest X-ray, and echocardiography.
In a very few severe cases, the rash is atypical and the clinical diagnosis is difficult and needs to be combined with laboratory tests to make a diagnosis.
If there is no rash, the clinical diagnosis of HFMD is not appropriate.
(B) Laboratory confirmed cases.
Clinical diagnosis of cases meeting one of the following conditions can be diagnosed as laboratory-confirmed cases.
1. Human enterovirus (human enterovirus including CVA16 and EV71 that have clear evidence of causing HFMD) is isolated from throat swab or throat wash, stool or anal swab, cerebrospinal fluid, herpes fluid, serum, and tissue specimens of brain, lung, spleen, lymph nodes, etc.
2. Specific nucleic acids of CVA16 or EV71 were detected from specimens such as pharyngeal swabs or throat lavage, stool or anal swabs, or human enteroviruses (human enteroviruses including CVA16 and EV71 that have clear evidence of causing HFMD) were detected from specimens such as cerebrospinal fluid, herpes fluid, serum, and tissue specimens such as brain, lung, spleen, and lymph nodes.
3. serum specimens with human enterovirus type-specific neutralizing antibody titers ≥ 1:256, or a 4-fold or more elevated serum enterovirus-specific neutralizing antibody in the acute and recovery phases.
(iii) Aggregate cases.
Within 1 week, 5 or more cases of HFMD occur in the same childcare institution or collective unit such as school; or 2 or more cases of HFMD occur in the same class (or dormitory); or 3 or more cases of HFMD occur in the same natural village; or 2 or more cases of HFMD occur in the same family.
Prevention and control measures for key populations and key institutions.
In order to reduce the incidence of hand, foot and mouth disease in the population, reduce the aggregation of cases, avoid hospital infections, around the key population mainly children living in the diaspora and child care institutions, medical institutions as the main focus of the prevention and control of the work of key places.
1. preventive and control measures for children living in the diaspora.
(1) before and after meals, after going home with soap or hand sanitizer to children to wash their hands; caregivers to wash their hands before contact with children, changing diapers for young children, after handling feces.
(2) Diapers for infants and young children should be washed, exposed to the sun or disinfected in a timely manner; pay attention to maintaining a hygienic home environment, frequent ventilation in the living room, and diligent drying of clothes and blankets.
(3) Bottles and pacifiers used by infants and children and tableware used by children should be fully cleaned and disinfected before and after use; do not allow children to drink raw water and eat cold food.
(4) Children should not be taken to public places with poor air circulation during the epidemic; avoid contact with sick children.
(5) Children with fever, rash and other related symptoms should be seen by a medical institution in a timely manner.
(6) Children treated at home should avoid contact with other children to reduce cross-infection; parents should dry or disinfect their children’s clothes and disinfect their children’s feces in a timely manner.
2. Preventive and control measures for childcare institutions.
(1) Conduct daily morning checkups and take measures such as immediate medical evacuation and home observation when suspicious children are found; disinfect items used by the children immediately.
(2) In case of serious illness or death, or in case of 2 or more cases in the same class within 1 week, it is recommended that the class in which the case is found be closed for 10 days; in case of 10 or more cases cumulatively in 1 week or 2 or more cases in each of 3 classes, after risk assessment, child care institutions may be recommended to close classes for 10 days.
(3) Education and guidance for children to develop good hygiene habits such as proper hand washing; teachers to maintain good personal hygiene.
(4) Maintain good ventilation in classrooms and dormitories and other places; regularly clean and disinfect toys, children’s personal hygiene utensils (water cups, towels, etc.), tableware, and other items.
(5) Regular wiping and disinfection of surfaces such as activity rooms, bedrooms, classrooms, door handles, stair handrails, desktops, etc.
(6) Child care institutions should clean and disinfect toilets daily, and staff should wear gloves and wash their hands immediately after work.
(7) Child care institutions should cooperate with the health department to take measures to prevent and control hand, foot and mouth disease.