Climate change and malaria incidence in South Africa

Goal To understand the impact of temperature and precipitation changes on the distribution of three Anopheles species mainly responsible for the transmission of malaria in Africa, and so prepare a prediction of malaria incidence over the next decades. Every year, malaria infects around 200 million and kills over one million people, most of whom are children and almost 90% of whom live in sub-Saharan Africa (Update on Malaria in Southern Africa, 2003). Malaria has serious economic impacts in Africa, slowing growth and development and perpetuating the vicious cycle of poverty, because it afflicts primarily the poor who tend to live in malaria-prone rural areas in poorly-constructed dwellings that offer few, if any, barriers against mosquitoes (UNICEF update, 2013). It is caused by several species of single-celled Plasmodium parasites transmitted by female mosquitoes, of which the most dangerous and most commonly found in Africa is P. falciparum. All mosquito species that transmit malaria belong to the genus Anopheles, and approximately 40 species are able to transmit malaria well enough to cause significant human illness and death (Malaria Atlas Project). Malaria transmission in tropical Africa is sustained by three main vectors which are A. gambiae, A. ara-biensis and A. funestus (Cinzia et al., 2011), while A. arabiensis and A. funestus are the main causes in South Africa (Yijun et al., 2010). In order to effectively combat the thriving effect of malaria transmission in a population, it is important to make a critical assessment of the existing malaria models, and study their evolution and efficacy in describing the host–parasite biology (Mandal et al., 2011). However, over the years, mathematical models have been greatly used to provide an explicit background to understand malaria transmission dynamics in human population. Several efforts have been made since 1970 to expand and develop the Ross-Macdonald model. Recently, Reiner et al. (2013) compiled a bibliography of 325 publications from 1970 through 2010 that included at least one mathematical model of malaria-borne pathogen transmission and used a 79-part questionnaire to classify each of 388 associated models according to its biological assumption. Their analyses revealed a growing acknowledgement of geographical, ecological and epidemiological complexities in modeling transmission, but also that most models during the past 40 years still resemble the Ross-Macdonald model. The questionnaire focuses on three essential components common to all of these models, which are: mosquitoes, hosts and encounters between them. Concerning mosquitoes, they found that 62% of the …