Investigating the Resurgence of Malaria Prevalence in South Africa Between 2015 and 2018: A Scoping Review


 
 Malaria remains a serious concern in most African countries, causing nearly one million deaths globally every year. This review aims to examine the extent and nature of the resurgence of malaria transmission in South Africa.
 
 
 
 Using the Arksey and O'Malley framework, this scoping review includes articles published between the years 2015 and 2018 on the resurgence of malaria occurrence in South Africa. Articles were searched between October 2018 to January 2019 using the following electronic databases: CINAHL, Pubmed, Science Direct and SCOPUS. Grey literature from Google Scholar was also hand searched. Key search terms and subject headings such as climate variables, climate changes, climatic factors, malaria resurgence, malaria reoccurrence and malaria increase over epidemic regions in South Africa were used to identify relevant articles. Three independent reviewers performed the selection and characterization of articles, and the data collected were synthesized qualitatively.
 
 
 
 A total number of 534 studies were identified. Among these, 24 studies met the inclusion criteria. The results were grouped by factors (four main themes) that influenced the malaria resurgence: Climatic, Epidemiological, Socio-economic, and Environmental factors. Climatic factors were found to be the major factor responsible for the resurgence of malaria, as more than 55% of the selected articles were climate-focused. This was followed by epidemiological, socio-economic and environmental factors, in that order. Grey literature from Google Scholar yielded no results.
 
 
 
 This study shows that malaria transmission in South Africa is more associated with climate. Climate-based malaria models could be used as early warning systems for malaria over the epidemic regions in South Africa. Since epidemiological factors also play significant roles in malaria transmission, regular and unrelaxed use of Indoor Residual Spraying (IRS) should be encouraged in these regions. Individuals should also be educated on the importance and the usefulness of these deliveries. While some studies have indicated that the vectors have developed resistance to insecticides, continuous research on developing new insecticides that could alter the resistance are encouraged. Furthermore, all efforts to eradicate malaria in South Africa must also target malaria-endemic neighbouring countries.


continuous research on developing new insecticides that could alter the resistance are ongoing. Individuals should also be educated on the importance and the usefulness of these deliveries. Furthermore, all efforts to eradicate malaria in South Africa must also target the epidemic neighbouring countries.

Background
Malaria continues to be a major threat in most African countries, claiming a significant number of lives every year [1]. Although, its burden has declined recently in sub-Saharan countries due to improvement in prevention, diagnosis, and treatment [1,2], the region still carries the largest share of the global malaria burden [1]. In South Africa, malaria is The recent resurgence initiated several studies to investigate the possible factors influencing malaria transmission over the nation. It has been established that malaria parasites being transmitted by mosquitoes are very sensitive to climatic conditions [9-12].
Consequently, the resulting epidemics is strongly dependent on climate variability. Also, since mosquitoes thrive better in a warm moist environments, there is a big concern that the projected global warming may make malaria parasites spread over more regions across the nation, thereby exposing more people to the deadly disease.

Methods
In this study, the Arksey and O'Malley (2005) framework for conducting scoping reviews was adopted [2]. This framework was considered appropriate for the aim of our study, and has been used in other studies [19,20].

Identifying relevant studies
The search was conducted by three (3) reviewers and using four (4) databases: CINAHL, PubMed, Science Direct, SCOPUS while grey literatures was searched from Google Scholar.
Terms that described climate variables combined using the Boolean operator (e.g. climate variable and climate factors) with terms that described malaria resurgence (e.g. malaria reoccurrence) were used. An initial search using all identified keywords and index terms were undertaken across all included databases. The text words contained in the title and abstract, and of the index and medical subject heading (MeSH) terms were used to ensure that all relevant materials were captured. Secondly, the reference list of all identified articles was searched for additional studies to identify studies that could not be located through this search strategy.
After key concepts were identified and databases selected, search terms were combined with Bloom operators and searches were run in selected databases. The articles were imported to Endnote reference manager where titles and abstracts were screened and fulltext articles were reviewed for eligibility based on the inclusion criteria (PICO). Grey literature search using Google Scholar with key words and search terms was also conducted. We used the "sort by relevance ranking" within Google Scholar to bring the most relevant results to the top of the list, we further set the page numbers to be screened to first ten pages of each search's results. This strategy ensures that the most relevant results are captured and also that a reasonable amount be screened. The results were further screened using the inclusion criteria for the review.

Selection of studies included
The inclusion criteria included; Articles focused on malaria epidemic regions in South Africa between 2015-2018.
Phenomenon of interest/Outcome: This review focused on malaria resurgence, malaria re-occurrence or malaria increase.
Type of study: This review considered empirical studies, but not limited to designs such as nonexperimental observational study, descriptive studies and case study conducted in South Africa, The search included published articles from 2015-2018 in South Africa on malaria resurgence during this period.
The search was restricted to English language papers and studies conducted in South Africa.

Extraction & charting of data from included studies
We reviewed articles for inclusion, manually extracted data from the selected articles using Microsoft Excel and summarized in a tabular form. Extracted data included: authors, article title, year of publication, study location, study population, aims of the study, methodology/instruments, outcome measure, importance of the result (see supplementary   table). The table enabled identification of differences, similarities and common themes in the studies. The extracted data were synthesized and summarized and presented in a narrative summary.

Results And Discussion
The initial 534 records and 4 from other sources are highlighted (  In general, climate variables play major roles in malaria transmission across all the epidemic provinces. For instance, four of the papers suggested that both temperature and rainfall are equally responsible for the transmission in KwaZulu-Natal, while two suggested similar findings over Limpopo. However, three additional papers concluded that the impact of temperature on the transmission is more significant than that of rainfall on KwaZulu-Natal and Mpumalanga provinces. This implies that effect of temperature is more pronounced over the two provinces. Rainfall is seen to be more significant than temperature over Limpopo province.

Conclusions And Recommendations
The inclusion criteria above show that climate variables (mainly, rainfall, temperature and relative humidity) are mostly mentioned but not solely responsible for the malaria resurgence in all the epidemic regions in South Africa. Environmental and socio-economic factors are also mentioned as vital elements to be considered in order to understand the dynamics of malaria transmission. Consequently, some preventive measures and interventions are suggested to minimize and gradually eradicate malaria from these regions.
Therefore, malaria models that integrate all variables could be used to monitor the progression of malaria and assist in intervention and prevention efforts with respect to malaria. These models could be implemented for developing methodology necessary to detect malaria pathogen, vector and habitat preference. More importantly, climate-based malaria models should be used as a framework for strengthening the institutional capacity of malaria surveillance by providing a malaria-risk management based on climate information and early warning system. Regular and unrelaxed use of indoor residual spraying (IRS) should be encouraged in these epidemic regions. Sufficient insecticides-impregnated bed nets should also be supplied to the communities in these regions, and more importantly, individuals should be educated on the importance and the usefulness of these deliveries. Furthermore, since it has been established that most malaria cases found in South Africa are imported from neighbouring countries [6], it is important to strengthen cross-border control of malaria to minimize its spread. All goals to eliminate malaria in South Africa must also target the epidemic neighbouring countries.