TY - JOUR
T1 - Non-linear effect of temperature variation on childhood rotavirus infection
T2 - A time series study from Kathmandu, Nepal
AU - Bhandari, Dinesh
AU - Bi, Peng
AU - Dhimal, Meghnath
AU - Sherchand, Jeevan Bahadur
AU - Hanson-Easey, Scott
N1 - Funding Information:
We would like to acknowledge all the members of the rotavirus surveillance team in Kathmandu, Nepal involved in data collection and the laboratory analysis of collected samples. The authors would like to acknowledge Department of Hydrology and Meteorology Nepal for providing climate dataset. In addition, many thanks to Ms Susanne Edwards (senior statistician), the University of Adelaide for her guidance with statistical analysis. D.B is supported by Adelaide Scholarship International provided by the University of Adelaide for his PhD study.
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2020/12/15
Y1 - 2020/12/15
N2 - Introduction: This study aimed to investigate the effects of temperature variability on rotavirus infections among children under 5 years of age in Kathmandu, Nepal. Findings may inform infection control planning, especially in relation to the role of environmental factors in the transmission of rotavirus infection. Methods: Generalized linear Poisson regression equations with distributed lag non-linear model were fitted to estimate the effect of temperature (maximum, mean and minimum) variation on weekly counts of rotavirus infections among children under 5 years of age living in Kathmandu, Nepal, over the study period (2013 to 2016). Seasonality and long-term effects were adjusted in the model using Fourier terms up to the seventh harmonic and a time function, respectively. We further adjusted the model for the confounding effects of rainfall and relative humidity. Results: During the study period, a total of 733 cases of rotavirus infection were recorded, with a mean of 3 cases per week. We detected an inverse non-linear association between rotavirus infection and average weekly mean temperature, with increased risk (RR: 1.52; 95% CI: 1.08–2.15) at the lower quantile (10th percentile) and decreased risk (RR: 0.64; 95% CI: 0.43–0.95) at the higher quantile (75th percentile). Similarly, we detected an increased risk [(RR: 1.93; 95% CI: 1.40–2.65) and (RR: 1.42; 95% CI: 1.04–1.95)] of rotavirus infection for both maximum and minimum temperature at their lower quantile (10th percentile). We estimated that 344 (47.01%) cases of rotavirus diarrhoea among the children under 5 years of age were attributable to minimum temperature. The significant effect of temperature on rotavirus infection was not observed beyond lag zero week. Conclusion: An inverse non-linear association was estimated between rotavirus incidence and all three indices of temperature, indicating a higher risk of infection during the cooler times of the year, and suggesting that transmission of rotavirus in Kathmandu, Nepal may be influenced by temperature.
AB - Introduction: This study aimed to investigate the effects of temperature variability on rotavirus infections among children under 5 years of age in Kathmandu, Nepal. Findings may inform infection control planning, especially in relation to the role of environmental factors in the transmission of rotavirus infection. Methods: Generalized linear Poisson regression equations with distributed lag non-linear model were fitted to estimate the effect of temperature (maximum, mean and minimum) variation on weekly counts of rotavirus infections among children under 5 years of age living in Kathmandu, Nepal, over the study period (2013 to 2016). Seasonality and long-term effects were adjusted in the model using Fourier terms up to the seventh harmonic and a time function, respectively. We further adjusted the model for the confounding effects of rainfall and relative humidity. Results: During the study period, a total of 733 cases of rotavirus infection were recorded, with a mean of 3 cases per week. We detected an inverse non-linear association between rotavirus infection and average weekly mean temperature, with increased risk (RR: 1.52; 95% CI: 1.08–2.15) at the lower quantile (10th percentile) and decreased risk (RR: 0.64; 95% CI: 0.43–0.95) at the higher quantile (75th percentile). Similarly, we detected an increased risk [(RR: 1.93; 95% CI: 1.40–2.65) and (RR: 1.42; 95% CI: 1.04–1.95)] of rotavirus infection for both maximum and minimum temperature at their lower quantile (10th percentile). We estimated that 344 (47.01%) cases of rotavirus diarrhoea among the children under 5 years of age were attributable to minimum temperature. The significant effect of temperature on rotavirus infection was not observed beyond lag zero week. Conclusion: An inverse non-linear association was estimated between rotavirus incidence and all three indices of temperature, indicating a higher risk of infection during the cooler times of the year, and suggesting that transmission of rotavirus in Kathmandu, Nepal may be influenced by temperature.
KW - Children
KW - Environmental factors
KW - Epidemiology
KW - Nepal
KW - Rotavirus
UR - http://www.scopus.com/inward/record.url?scp=85089267094&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2020.141376
DO - 10.1016/j.scitotenv.2020.141376
M3 - Article
C2 - 32798872
AN - SCOPUS:85089267094
SN - 0048-9697
VL - 748
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 141376
ER -
