70

■Bio-mathematics, Statistics and Nano-Technologies: Mosquito Control Strategies

5.2.9.2

Climatic driving effect on immunity acquisition .......

92

5.2.9.3

Effect of population dynamics on immunity acquisition

93

5.2.10 Summary of modelling approaches ................................

94

5.3

Discussion ................................................................

96

5.A

Methods for literature search ..............................................

101

5.A.1

Literature search strategy and selection criteria .....................

101

5.A.2

Outcome of literature search .......................................

101

5.B

Detailed model descriptions ...............................................

103

5.1

INTRODUCTION

Malaria is a considerable health threat to almost half of the world’s population, es-

pecially in sub-Saharan Africa [29]. According to WHO, the number of reported malaria

cases has not significantly changed from approximately 216 million cases in the periods

2015 to 2017. However, the global burden has significantly reduced over the last decade

as malaria mortality rates have globally declined by 60% since 2000 [2]. In 2017, malaria-

related deaths were estimated to be about 435 000 of which over 90% of the estimated

deaths occurred in Africa [1]. The burden posed by malaria is greater in Africa because the

majority of infections in Africa are caused by Plasmodium falciparum, the most dangerous

of the known human malaria parasites. Again, the most effective malaria vector Anophe-

les gambiae is the most widely spread in Africa [29]. The groups most vulnerable to this

pandemic are usually children below the age of five and pregnant women [132], [129],

which is far less true today because the effect of NAI has waned in older age groups. The

socio-economic impact of malaria is so high that it measurably contributes to poverty and

underdevelopment on national scales [207], [208].

A protozoan parasite, called Plasmodium, is the pathogen responsible for causing

malaria. However, P. falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium

ovale and Plasmodium knowlesi are the five species of Plasmodium known to cause malaria

in humans. Each of these species are subject to genetic polymorphism resulting to multi-

tude of variants which differ widely in virulence, response to treatment and tendency to

relapse, which is equally dependent on the interactions with individual hosts [88], [89].

The predominant cause of human infection in Africa is P. falciparum. It accounts for both

80 percent of all recorded malaria cases and 90% of malaria related deaths in Africa [8]. P.

vivax, is the second most significant species and is prevalent in Southeast Asia and Latin

America [9], [137]. Infectious female mosquitos of the genus Anopheles are responsible

for malaria transmission between humans.

The complete life cycle of malaria parasites involves two hosts: humans and the vector

(female Anopheles mosquitos). The sexual cycle takes place in mosquito after it ingests

the parasites (gametocytes) from a malaria-infected person during blood feeding which it

needs to nurture its eggs. The parasites reproduce sexually, and then develop inside the

mosquito gut, where they undergo meiosis and afterwards, migrate via the midgut wall