Ecological and Seasonal Variations of Enteroviruses Infection in Taiwan, 2000-2004
Date Issued
2008
Date
2008
Author(s)
Chen, Hsiao-Yun
Abstract
Abstractackground:he global warming and climate change have a great impact on the ecology. The temperature-sensitive viruses infection such as non-polio enteroviruses infection appears more frequently in higher temperature seasons. Hand, foot and mouth disease (HFMD) and herpangina are diseases of enteroviral infection occurring mainly in children with high incidence in summer and autumn. The epidemic of HFMD and herpangina has been associated with temperature and vapor pressure. However, studies on the ecological and weather variations of the severe enteroviral cases epidemic remain limited. The present study analyzed the ecological, seasonal and temperature variations associated with severe cases of the enteroviral infection and the HFMD and herpangina cases reported by sentinel physicians at local hospitals and clinics. ethods:e used data obtained from the Centers for Disease Control, Executive Yuan epartment of Health to perform the study, including the surveillance data on severe cases of the enteroviral infection, database of HFMD and herpangina cases reported by sentinel physicians, and virology test results provided by virology laboratories. We measured the associations between demographic status and the severe cases, and the HFMD and herpangina cases of enteroviral infection. We also investigated the geographic differences in the incidences of enteroviral infection cases with severe complication, and the reported rates of HFMD and herpangina in Taiwan. Seasonal and monthly incidence rates were measured and the associations with the weather status such as temperature, precipitation, and sunshine were analyzed. Multivariate Poisson regression analysis was used to calculate the relative risk of the enteroviral infection associated with the above potential risk.esults:evere cases of enteroviral infection occurred mainly in children under 10 years of age, with 94% of cases occurred in children under 5 years of age. The highest incidence rate of enteroviral severe cases was in the southern Taiwan with the rate of 9.13/106, more than two times greater than that for children in the northern area (4.10/106). Results showed an apparent seasonal variation. The epidemic peak of enteroviral severe cases occurred in June in most areas, but a second peak occurred in October in the southern area. The multivariate Poisson regression analysis showed that infants and children of 1-year-old had the highest risk for severe complicated enteroviral infection, with a relative risk (RR) of 28.9 (95% confidence interval (CI) 22.0-38.1) for 1-year-old children compared with children of 5-9 years old. This study also showed that the risk of being severe cases was 43% grater for boys than for girls, 2.02 times grater (95%CI=1.72-2.37) for children in northern region than for children in the southern region. Cases of severe complication increased as the temperature increased, with the lowest rate in February and the highest rate in June. The rate of HFMD and herpangina cases reported by sentinel physicians was 3.5 times greater in the eastern region than in the northern region. In general, the HFMD and herpangina cases reported rates also increased as the temperature increased with the highest rate in May.onclusion: here was a distinctive seasonal variation in enteroviral infection in Taiwan. The epidemic is associated with not only the weather but also school activities; the risk is decrease when children have no school in the winter and summer breaks. The monthly variations of the incidence by area show that the epidemic may spread from other areas to the south. The elevated incidence in the fall in the southern area is likely associated with the local weather.
Subjects
Enterovirus
Type
thesis
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