Hand, Foot and Mouth Disease Overview
Hand-foot-mouth disease (HFMD) is a common infectious disease caused by a variety of enteroviruses, mainly in infants and young children. Most patients have mild symptoms, characterized by fever and rashes or herpes on the hands, feet, mouth, etc. A small number of patients may be complicated by aseptic meningitis, encephalitis, acute flaccid paralysis, respiratory infections, and myocarditis. Individual severely ill children progress rapidly and are prone to death. Adolescents and adults are not infected after infection, but can transmit the virus. Enteroviruses that cause hand, foot and mouth disease include enterovirus 71 (EV71) and certain serotypes of CoxA, CoxA, and Echo. EV71 infection caused a large proportion of severe cases. Enteroviruses are highly contagious and can easily cause outbreaks or epidemics.
Relationship and difference between enterovirus EV71 infection and hand-foot-mouth disease
Enterovirus EV71 infection is a general term for diseases caused by human enterovirus 71 (EV71). It is clinically manifested as hand-foot-mouth disease. Some children with EV71 infection present with herpes angina and viral disease in severe patients. Encephalitis, viral encephalomyelitis, pulmonary edema, pulmonary hemorrhage, etc.
Hand-foot-mouth disease (HFMD) is a clinical syndrome caused by enterovirus infection. It has a variety of clinical manifestations. Most cases have mild clinical manifestations, such as fever and rash on the hands, feet, mouth, etc. Herpes is the main feature. A few cases show damage to the respiratory system and central nervous system, causing symptoms such as encephalitis, myocarditis, pulmonary edema, and flaccid paralysis. Individual severely ill children progress rapidly and cause death. There are more than 20 types of enteroviruses that cause hand, foot and mouth disease, including Coxsackievirus A group and enterovirus type 71.
Enterovirus EV71 infection is mainly manifested as hand-foot-mouth disease, but it can also be manifested as other diseases. Hand-foot-mouth disease can be caused by enterovirus EV71 infection, or by other enterovirus infections such as Coxsackie virus group A. There is a one-to-one relationship between you and me. However, according to data at home and abroad, compared with other hand, foot and mouth diseases caused by other enteroviruses, diseases caused by enterovirus 71 infection have a higher proportion of severe infections, a higher mortality rate, and a mortality rate of 10 in severe cases. % -25%.
Due to the diverse clinical manifestations of enterovirus EV71 infection and the lack of a simple and fast diagnostic method in clinic, the diagnosis of enterovirus EV71 infection is difficult.
Etiology
The major causes of hand, foot and mouth disease are Coxsackie virus of Coxsackie virus of the small RNA virus family and enterovirus genus type 16, 4, 5, 7, 9, and 10, and group B of type 2, 5, and 13; Viruses (ECHOviruses) and enterovirus 71 (EV71), of which EV71 and CoxAl6 are the most common.
Enteroviruses are suitable for survival and transmission in humid and hot environments. They are not sensitive to ether and dechlorocholate. 75% alcohol and 5% lysin cannot inactivate them, but they are sensitive to ultraviolet rays and dryness. Various oxidants (potassium permanganate, bleaching powder, etc.), formaldehyde, and iodine can inactivate the virus. The virus can be rapidly inactivated at 50 ° C, but a 1 mol concentration of divalent cation environment can improve the resistance of the virus to heat inactivation. The virus can survive for 1 year at 4 ° C and can be stored for a long time at -20 ° C. Long-term survival.
Epidemiology
Hand, foot and mouth disease is a global infectious disease, and the epidemic has been reported in most parts of the world. The disease was first reported in New Zealand in 1957. Coxsackie virus was isolated in 1958, and hand-foot-mouth disease was named in 1959. The pathogen of hand, foot and mouth disease detected early is mainly CoxA16, and EV71 was first confirmed in the United States in 1969. Since then, EV71 infection and CoxA16 infection have appeared alternately, becoming the main pathogens of hand, foot and mouth disease.
The disease was first reported in Shanghai in China in 1981. Since then, the disease has been reported in more than 10 provinces including Beijing, Hebei, Tianjin, Fujian, Jilin, Shandong, Hubei, Qinghai and Guangdong. An outbreak of hand, foot and mouth disease caused by CoxA16 occurred in Tianjin in 1983, and more than 7,000 cases occurred between May and October. After two years of low-level distribution, it broke out again in 1986. In 1995, EV71 was isolated from patients with hand, foot and mouth disease in Wuhan Institute of Virology, and in 1998, EV71 was also isolated from specimens of patients with hand, foot and mouth disease.
EV71 virus background information
- Hand-foot-mouth disease and EV71 infection in foreign countries
In the mid-1970s, EV71, with central nervous system infection as the main feature, broke out successively in Bulgaria and Hungary. There were more than 750 cases in Bulgaria alone, 149 were paralyzed, and 44 died. An outbreak of hand, foot and mouth disease caused by Coxsackie virus (CoxA16) occurred in the United Kingdom in the fourth quarter of 1994. The epidemic was spread across Wales and Wales. Most of the patients were 1-4 years of age and most patients had mild symptoms. The country's epidemiological data since 1963 show that the interval between hand-foot-mouth disease epidemics is 2-3 years. Japan is a country with a high incidence of hand-foot-mouth disease, and there have been many large-scale epidemics caused by CoxA16 and EV71 in history. In the late 1990s, EV71 began to spread in East Asia. A hand, foot and mouth disease epidemic mainly caused by EV71 occurred in Malaysia in 1997. A total of 2628 cases occurred from April to August, and 29 patients died in April to June alone. The average age of the deceased was 1.5 years and the course of the disease was only 2 days.
- Previous domestic hand-foot-mouth disease epidemic
Hand, foot and mouth disease has been prevalent in China. Since the 1980s, hand, foot and mouth disease has been reported in more than a dozen provinces (municipalities) in Beijing, Hebei, Tianjin, Fujian, Jilin, Shandong, Hubei, Xining, and Guangdong. In 1998, an outbreak of hand-foot-mouth disease and herpes angina was caused by EV71 infection in Taiwan Province of China. During the two epidemics in June and October, a total of 129 106 cases were monitored, of which 405 were critically ill and 78 died. Most are children under 5 years of age, and complications include encephalitis, aseptic meningitis, pulmonary edema or pulmonary hemorrhage, acute soft palsy, and myocarditis. From May to August 2000 in Zhaoyuan City, Shandong Province, there was an outbreak of hand-foot-mouth disease in children. The city's People's Hospital admitted 1698 children, the youngest was 5 months, the oldest was 14 years old, and 3 died of fulminant myocarditis. In 2007, 83,344 cases of hand-foot-mouth disease and 17 deaths were reported nationwide. There were 39,606 cases of hand-foot-mouth disease reported in Shandong Province alone, and tens of thousands of cases of hand-foot-mouth disease were reported in major cities such as Beijing and Shanghai.
- What are the difficulties in clinical diagnosis of enterovirus EV71 infection?
Enterovirus EV71 infection is characterized by a variety of clinical manifestations, ranging from asymptomatic recessive infections, mild hand, foot and mouth disease, and angina to severe cases such as neurogenic pulmonary edema and respiratory failure, and even death. . To diagnose enterovirus EV71 infection currently depends on virus nucleic acid detection and virus isolation and culture, and there is no condition for primary hospitals and disease prevention and control centers. In addition, some severe cases do not have typical clinical manifestations of hand, foot and mouth disease. Therefore, in In the early stages of an outbreak, severe cases are often difficult to diagnose, and pneumonia is often diagnosed. Only by combining the epidemiological investigation and clinical manifestations of the cases, especially the laboratory test results, a clear diagnosis is possible.
- Which groups are at high risk?
The general population is generally susceptible to enteroviruses and can gain immunity after infection. Due to the lack of cross-protection of antibodies after infection of different disease prototypes, the population can be infected with different types of enteroviruses and relapse. Most adults have acquired corresponding antibodies through recessive infection. Therefore, patients with enterovirus infection and hand-foot-mouth disease are mainly preschool children, especially children under 3 years old with a high incidence. According to foreign literature reports, it can be popular in the population every 2-3 years.
- The main cause of severe cases and deaths?
Most of the enterovirus infections and hand, foot and mouth diseases are mild cases. The main clinical symptoms are rashes on the hands, feet, mouth and perianal area, and herpes on the oral mucosa, accompanied by fever, sore throat, burnout, fatigue and other symptoms. The prognosis is good. . A few cases due to virus invasion of the nervous system, clinical manifestations of encephalitis, pneumonia, and neurogenic pulmonary edema, the disease progresses rapidly, and the mortality rate is high.
- Enterovirus disease transmission
Humans are the only source of infection for enteroviruses, including those with a recessive infection and a recessive infection with a dominant infection ratio of 100: 1. It is mainly transmitted through the gastrointestinal tract (fecal-mouth, water or food contamination) or the respiratory tract (droplets, coughing or sneezing), and can also be infected through contact with fluids from the patient's skin. A few days before the onset of the virus, the virus can be found in the throat and feces. At this time, the virus is contagious, and the infection is usually the strongest within one week after the onset of the disease. The patient excreted the virus from the pharynx within 1-2 weeks of onset, and excreted the virus from feces in about 3-5 weeks. The herpes fluid contained a large amount of virus, and the virus overflowed when it was broken. Therefore, the disease is easy to spread, easy to spread, and difficult to prevent and control.
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