Epidemic Malaria Dynamics in Eastern Africa Highlands: The Role of Climate Change and Human Population Growth

Felipe Augusto Maurin Krsulovic,Timothy Peter Moulton,Fabian Jacksic,Mauricio Lima

doi:10.11648/j.eeb.20210601.15

Abstract

During the last two decades, researchers have suggested that the increase of the malaria incidence rate in tea plantations in the Kericho district in Kenya was driven by climate change. Critics suggested that others variables could be involved in the increase of the malaria burden, such as HIV and human population size. Population ecologists have developed a simple framework which helps to explore the contributions of endogenous (density-dependency) and exogenous processes on population dynamics. Both processes may operate to determine the dynamic behavior of a particular population through time. Briefly, density-dependency (endogenous process) occurs when the per capita population growth rate (R) is determined by its previous population sizes. An exogenous process occurs when some variable affects another but is not affected by the changes it causes. In this study we re-explore the dynamics of the malaria incidence rate in Kericho tea plantations taking into account the HIV incidence rate, rural population size, temperature and rainfall. We found that malaria dynamics showed signs of a negative endogenous process between R and malaria infectious class. We found that there was weak evidence to support the climate change hypothesis and that rural population size and the HIV incidence could interact to positively force malaria models parameters explaining the positive malaria trend observed at Kericho tea plantations in Kenya from 1979 to 2002.

Highlights

During the last two decades, researchers have suggested that the increase of the malaria incidence rate in tea plantations in the Kericho district in Kenya was driven by climate change [1,2,3,4,5,6,7,8,9,10]
Models with the interaction between rural population size and Human Immunodeficiency Virus (HIV) incidence rate performed better than models with climate variables and the model without exogenous variables (Table 3). These results suggest that these variables could be involved in the malaria increase burden as exogenous forcing on malaria endogenous model parameters leading to an increase in the malaria burden
The results suggest that other variables were more important than climate change in terms of the increase of malaria burden in Kericho tea plantations, as initially proposed in many studies from Kericho

Summary

Introduction

During the last two decades, researchers have suggested that the increase of the malaria incidence rate in tea plantations in the Kericho district in Kenya was driven by climate change [1,2,3,4,5,6,7,8,9,10]. These studies gave way to extensive debates about the importance of climate in the malaria burden in these locations. After three decades of decline, around 1980, malaria started to rise and once again became a major health problem, principally in Sub-Saharan Africa [16, 20, 21]

Methods

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Discussion

Conclusion