The seasonal reproduction number of dengue fever: impacts of climate on transmission.

Sittisede Polwiang

doi:10.7717/peerj.1069

Abstract

Background. Dengue fever is a mosquito-borne viral disease and a regular epidemic in Thailand. The peak of the dengue epidemic period is around June to August during the rainy season. It is believed that climate is an important factor for dengue transmission.Method. A mathematical model for vector–host infectious disease was used to calculate the impacts of climate to the transmission of dengue virus. In this study, the data of climate and dengue fever cases were derived from Chiang Mai during 2004–2014, Thailand. The value of seasonal reproduction number was calculated to evaluate the potential, severity and persistence of dengue infection.Results. The mosquito population was increasing exponentially from the start of the rainy season in early May and reached its the peak in late June. The simulations suggest that the greatest potential for the dengue transmission occurs when the temperature is 28.9 °C. The seasonal reproduction numbers were larger than one from late March to end of August and reaching the peak in June. The highest incidences occurred in August due to the delay of transmission humans-mosquito-humans. Increasing mean temperature by 1 °C, the number of incidences increases 28.1%. However, a very high or very low temperature reduces the number of infection.Discussion and Conclusion. The results show that the dengue infection depends on the seasonal variation of the climate. The rainfall provides places for the mosquitoes to lay eggs and develop to the adult stage. The temperature plays an important role in the life cycle and behavior of the mosquitoes. A very high or very low temperature reduces the risk of the dengue infection.

Highlights

Dengue fever is the most frequent mosquito-borne viral disease in the humans and has become a major international public health concern in recent decades
It is important to note that the asymptomatic dengue fever represents 75.7%–90.2% of total dengue infections (Seyler, Grandesso & Le Strat, 2009)
The temperature plays a significant role in the dengue transmission and influences the dynamic modelling of vector–host interaction

Summary

Introduction

Dengue fever is the most frequent mosquito-borne viral disease in the humans and has become a major international public health concern in recent decades. Infected individuals may be asymptomatic or have high fevers, headache, muscle and joint pain, and a characteristic skin rash similar to measles. These symptoms can develop into the life-threatening dengue hemorrhagic fever and into the dengue shock syndrome. How to cite this article Polwiang (2015), The seasonal reproduction number of dengue fever: impacts of climate on transmission. Dengue fever is a mosquito-borne viral disease and a regular epidemic in Thailand. The seasonal reproduction numbers were larger than one from late March to end of August and reaching the peak in June. A very high or very low temperature reduces the number of infection. A very high or very low temperature reduces the risk of the dengue infection

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