Analysis On Risk Factors Of Severe Cases Of Hand, Foot And Mouth Disease In Children Infected By Enterovirus71

1. BackgroundHand, foot, and mouth disease (HFMD) is a common acute infectious disease in children caused by a variety of enterovirus. And it mostly occurred in pre-school children, especially under3years old of age. HFMD is particularly caused by Enteroviruses71(EV71), Coxsackievirus A16(CA16) and some serotypes of Echovirus (Echo). Among them, EV71infection has been associated with more serious illness and higher fatalities, which can cause severe neurological complications and rapidly progress to fulminant cardiorespiratory failure, and death. Since the late90’s of the20th Century. EV71have a high prevalence in the Asia Pacific area with more death with neurological complications. After the poliovirus is controlled effectively, EV71has become the most important enterovirus to seriously affect the health of children. With the lack of safe and effective anti-EV71drugs and vaccine, the prevention and control of EV71become very hard in the present times. Therefore, it is important to conduct the researches about the risk factors and the early warning indicators of EV71infection for reducing the incidence of severe cases and the mortality of HFMD.2. ObjectiveTo analyze the risk factors of severe cases of HFMD in children infected by EV71, and identify the warning indicators in the clinical process of the severe cases as early as possible. This will contribute to reducing the incidence of severe cases and the mortality of HFMD greatly and provide the scientific evidence for prevention and control of the disease. 3. Methods3.1Survey in fieldThis survey was conducted by a case-control study based on the hospital. Severe (case group) and mild cases (control group) came from the hospitals appointed to treat the HFMD and were laboratory test confirmed infected by EV71. The questionnaires were used by trained investigators to interview the parents and supervisors of the kids.3.2Lab testing methodsThe specimens of cases were detected by reverse transcriptase-polymerase chain reactions (RT-PCR). Throat swab or stool specimens were collected from the cases within3days onset. RT-PCR are carried out with the virus RNA specific primers of human enterovirus, CA16, EV71, respectively. Then we determined the virus type of specimens.3.3Statistical methodThe databank was established by the software Epi data3.2, and the questionnaire information was doubly inputted. The data was analyzed by the software SAS8.0. The Chi-square (χ2) test, T test or Rank-sum test was performed for the single factor analysis. The significant variables were performed for multi-factor non-conditional logistic regression model to analyze the risk factors to the sever hand food and mouth disease. The backward method was used to screening the variables. Hosmer-Lemeshow statistic was applied to test good-fitness of the model.4. Results4.1Basic situation60severe cases (case group) and60mild cases (control group) infected by EV71confirmed by the laboratory were collected. The differences on age and gender between case group and control group were not statistically significance.4.2Single factors analysisRisk factors of severe cases:symptoms of fever during the entire course of illness (OR=4.67,95%IC:1.45～15.05), first symptom was fever (OR=9.04,95%IC:3.95～20.68), peak temperature≥38.5℃(OR=4.94,95%IC:2.10～11.61), the type of rash was macula (OR=3.03,95%IC:1.22～7.55), herpes in pharyngeal isthmus (OR=3.09,95%IC:1.37～6.97), vomiting (OR=4.64,95%IC:1.94～11.09) convulsion (OR=5.32,95%IC:2.16～13.10), listlessness (OR=3.25, 95%IC:1.30～8.14), self-medication before seeing the doctor (OR=4.00,95%IC:1.78～8.99), febrifuge used before seeing the doctor (OR=4.97,95%IC:2.02～12.26), first treatment in village clinic(OR=3.31,95%1C:1.55～7.07), seeing village doctors during the course of illness (OR=3.05,95%IC:1.44～6.47), contacting with sick children (OR=2.32,95%IC:1.05～5.13)Protective factors of severe cases:children in kindergarten (OR=0.20,95%IC:0.04～0.95), symptoms of rash during the entire course of illness (OR=0.10,95%IC:0.01～0.80), first symptom was rash (OR=0.09,95%IC:0.04～0.22), diagnosis was confirmed or suspected cases at the first treatment (OR=0.38,95%IC:0.18～0.80)4.3Multi-factor non-conditional logistic regression analysis:The results showed that some factors increased the risk of severe cases including first symptom was fever(OR=5.85,95%IC:1.58～21.67), peak temperature≥38.5℃(OR=9.45,95%IC:2.07～43.11), the type of rash was macula (OR=8.12,95%IC:1.50～43.94), herpes in pharyngeal isthmus (OR=8.08,95%IC:1.59～40.99), bad spirit (OR=10.96,95%IC:1.85～64.85), first treatment in village clinic(OR=4.72,95%IC:1.15～19.45) and contacting with sick children (OR=8.14,95%IC:1.66～39.97)5. Conclusions5.1The warning indicators in the clinical process of the severe cases of HFMD infected by EV71are getting severe fever, herpes in pharyngeal isthmus, listlessness, vomiting, convulsion, so the parents and clinicians should attach great importance to these symptoms to achieve finding, diagnosis and treatment the severe cases as early as possible.5.2Contacting with sick children is an important route of transmission of this disease, so health education should be carried out and strengthen for the children’s parents and supervisor to grasp the common sense of HFMD and develop healthy living and individual hygiene habits.5.3Some severe cases haven’t seen doctors as soon as possible after illness, and some of them take medicine at home without doctors’guidance. Education should be carried out and strengthen for the rural residents to increase consciousness of autonomic medical treatment.5.4Some severe cases aren’t diagnosed in the rural clinics, which may delay treatment. The construction of basic medical institutions and the training of the primary health professionals should be taken to improve their professional skills and ability of dealing with the EV71infection.5.5The logistic regression model that this study obtains can be used to predict the probability of occurrence of severe cases.