A stage structured mosquito model incorporating effects of precipitation and daily temperature fluctuations

Abstract

An outbreak of dengue fever in Guangdong province in 2014 was the most serious outbreak ever recorded in China. Given the known positive correlation between the abundance of mosquitoes and the number of dengue fever cases, a stage structured mosquito model was developed to investigate the cause of the large abundance of mosquitoes in 2014 and its implications for outbreaks of the disease.Data on the Breteau index (number of containers positive for larvae per 100 premises investigated), temperature and precipitation were used for model fitting.The egg laying rate, the development rate and the mortality rates of immatures and adults were obtained from the estimated parameters. Moreover, effects of daily fluctuations of temperature on these parameters were obtained and the effects of temperature and precipitation were analyzed by simulations. Our results indicated that the abundance of mosquitoes depended not only on the total annual precipitation but also on the distribution of the precipitation. The daily mean temperature had a nonlinear relationship with the abundance of mosquitoes, and large diurnal temperature differences can reduce the abundance of mosquitoes. In addition, effects of increasing precipitation and temperature were interdependent .Our findings suggest that the large abundance of mosquitoes in 2014 was mainly caused by the distribution of the precipitation. In the perspective of mosquito * Corresponding author. Tel: +86 29 85310232Email addresses: xiawang@snnu.edu.cn (Xia Wang), sytang@snnu.edu.cn, sanyitang219@hotmail.com (Sanyi Tang) Preprint submitted to Journal of Theoretical BiologySeptember 26, 2016 control, our results reveal that it is better to clear water early and spray insecticide between April and August in case of limited resources.

A combination of climatic conditions determines major within-season dengue outbreaks in Guangdong Province, China

“…Also, the optimal temperature that maximises the ERN becomes larger with time (Fig. 2c-f), agreeing with the fact that the optimal mosquito survival temperature is relatively small (around 27 °C; [21]) but the optimum for dengue fever transmission is relatively large (around 32 °C; [25]). This is because at the start of the simulation there are few mosquitoes and only a single infected individual, so temperature initially mainly affects the growth of mosquitoes, then affects both the mosquito reproduction and the biting rate and transmission probability per bite with an increasing number of mosquitoes.…”

“…Parameters involved in the mosquito dynamics model were derived from a previous paper [21]. To estimate other unknown parameters in the transmission model, we assumed that the number of local incident cases follows a Poisson distribution, so that the likelihood function was obtained.…”

Climate variation drives dengue dynamics

“…The two highest mosquito peaks, in years 2007 and 2014, were not predictable from the model. The 2014 mosquito peak in Guangzhou has recently been associated with the seasonal distribution of precipitation, the daily temperature range, and nonadditive effects of temperature and precipitation (15), pointing to more complex species−environment relationships than accommodated by our model. As our focus was on prediction, we intentionally restricted model complexity to reduce the risk of overfitting.…”

Using the intrinsic growth rate of the mosquito population improves spatio-temporal dengue risk estimation

“…Temperature affects the growth, development and survival of mosquitoes ( Attaway et al., 2017 ) and is recognised as the most influential predictor of Aedes abundance ( Weetman et al., 2018 ), as for most ectotherms, warmer temperatures reduces the size but increases the development rate of Ae. aegypti in the aquatic stages ( Padmanabha et al., 2012 ) (within certain limits ( Wang et al., 2016 ; Whiten and Peterson 2016 )). Wet bulb temperature is a measure based on both temperature and humidity.…”