Time series analysis of reported cases of hand, foot, and mouth disease from 2010 to 2013 in Wuhan, China

Abstract

BackgroundHand, foot, and mouth disease (HFMD) is an infectious disease caused by a group of enteroviruses, including Coxsackievirus A16 (CVA16) and Enterovirus A71 (EV-A71). In recent decades, Asian countries have experienced frequent and widespread HFMD outbreaks, with deaths predominantly among children. In several Asian countries, epidemics usually peak in the late spring/early summer, with a second small peak in late autumn/early winter. We investigated the possible underlying association between the seasonality of HFMD epidemics and meteorological variables, which could improve our ability to predict HFMD epidemics.MethodsWe used a time series analysis composed of a spectral analysis based on the maximum entropy method (MEM) in the frequency domain and the nonlinear least squares method in the time domain. The time series analysis was applied to three kinds of monthly time series data collected in Wuhan, China, where high-quality surveillance data for HFMD have been collected: (i) reported cases of HFMD, (ii) reported cases of EV-A71 and CVA16 detected in HFMD patients, and (iii) meteorological variables.ResultsIn the power spectral densities for HFMD and EV-A71, the dominant spectral lines were observed at frequency positions corresponding to 1-year and 6-month cycles. The optimum least squares fitting (LSF) curves calculated for the 1-year and 6-month cycles reproduced the bimodal cycles that were clearly observed in the HFMD and EV-A71 data. The peak months on the LSF curves for the HFMD data were consistent with those for the EV-A71 data. The risk of infection was relatively high at 10 °C ≤ t < 15 °C (t, temperature [°C]) and 15 °C ≤ t < 20 °C, and peaked at 20 °C ≤ t < 25 °C.ConclusionIn this study, the HFMD infections occurring in Wuhan showed two seasonal peaks, in summer (June) and winter (November or December). The results obtained with a time series analysis suggest that the bimodal seasonal peaks in HFMD epidemics are attributable to EV-A71 epidemics. Our results suggest that controlling the spread of EV-A71 infections when the temperature is approximately 20–25 °C should be considered to prevent HFMD infections in Wuhan, China.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-015-1233-0) contains supplementary material, which is available to authorized users.

Spatial-temporal heterogeneity of hand, foot and mouth disease and impact of meteorological factors in arid/ semi-arid regions: a case study in Ningxia, China

“…The increased HFMD in fall in Ningxia may be contributed to the climate conditions. As the temperature rises in spring, the risk of HFMD was increasing and reached the secondary peak, but as the temperature continued to rise, the HFMD risk dropped, similar to the threshold effect reported in Wuhan [33]. However, the exact conditions (range of temperature and humidity) that trigger this threshold effect are probably different as Wuhan is located in south China with humid climate.…”

“…However, the positive relation does not hold universally, it is only valid for limited temperature range. For example, a study conducted in Wuhan, the capital city of Hubei province located in south China showed that temperature ranging from 20 to 25°C prevent HFMD infections in Wuhan [33]. Other climate conditions may also have a threshold effect.…”

Inhibition of enterovirus 71 replication and viral 3C protease by quercetin

“…EV71 was first isolated in California, USA [1]. Subsequently, EV71-associated hand-foot-mouse disease (HFMD) outbreaks occurred around the world [2][3][4][5][6][7]. Clinical manifestations of EV71 infection range from mild HFMD to severe encephalitis, pulmonary edema, and even death [8,9].…”

Temperature and humidity affect the incidence of hand, foot, and mouth disease: a systematic review of the literature – a report from the International Society of Dermatology Climate Change Committee

“…The relationship between meteorological factors and HFMD outbreaks is often nonlinear in nature. In 23 of the 61 studies reporting a positive association with temperature, cases occurred most frequently within a specific temperature range, and extreme heat was associated with fewer case outbreaks . Whether or not this relates to viral biology or changes in human behavior at the extremes of temperature is unclear.…”

“…Given its incubation period of 3–7 days, it may be transmitted via asymptomatic hosts. Moreover, affected persons may remain infectious after symptoms resolve; EV71 has been identified in infected persons’ feces several weeks after symptom onset and in throat swabs for up to 2 weeks after infection . Diagnoses of HFMD are generally clinical, but a throat swab or stool specimen may be sent to the laboratory for diagnosis by culture or PCR.…”