Abstract
Background: Malaria is one of the acute communicable diseases transmitted by Anopheline mosquitos to humans and is endemic in 108 countries worldwide. Most malaria epidemics in African highland countries are caused by Plasmodium falciparum (P. falciparum), and people residing in these highlands are said to have low immunity to malaria. The disease affects both children and adults. The City of Johannesburg, South Africa lies in a highland area of the country with an altitude of 1 753m above sea level.
Objective: The main aim of the study was to determine the spatial distribution of notifiable malaria cases in the City of Johannesburg during the period 2015-2019.
Methods: Data on malaria infections in the City was retrieved from the Johannesburg Public Health Unit and the Johannesburg Health District archives for the period 2015 to 2019. Global positioning system coordinates derived from captured addresses of individuals whose laboratory tests confirmed malaria diagnosis was used to evaluate malaria prevalence and clusters. Google maps was used to locate the coordinates for each address, which were then analysed in ArcGIS to identify possible clusters. This tool identifies statistically significant spatial clusters of high values (hot spots) and low values (cold spots). Data analysis was performed using the Statistical Package for Social Science (SPSS). The analysis included descriptive analysis, to generate frequency distribution of variables of study participants in connection with the outcome measure being malaria. For variables with two categories; imported cases, the independent t-test was performed to determine whether the means of the two groups were statistically significant.
Results: A total of 1 266 participants were included in the study. The majority of participants were male (826 (65%) and fewer participants were female (440 (35 %). Malaria cases in 2015 were n =389, 2016 n =333, 2017 n =217, 2018 n =310 and in 2019 n =166. The largest proportion of confirmed cased was attributed to age groups under 10 years 26,3 % (n =333), 21 – 30 years 21,9% (n =247) and 31 - 40 years 19,8% (n =251) respectively. Fewer participants 3.5% (n =44) were aged 61 and over. Spatial analysis showed that a statistically significant cluster of malaria cases was found in Soweto, a township of the City of Johannesburg in Gauteng. Therefore, there is a high probability that Soweto could be considered a malaria hotspot.
Conclusion: Imported malaria is a major obstacle to achieving infection elimination. Due to economic migration, imported malaria remains a significant health burden in non-endemic
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malaria areas. The study found that children and economic active populations were affected. Malaria prevalence was high in Soweto; therefore, malaria surveillance/monitoring should be intensified in this region. At the local level, mobile phone technology opens up a world of possibilities for disease surveillance and teaching on the go. Short messaging service (SMS) alerts sent to people migrating from endemic to non-endemic areas may encourage them to wear insecticide-treated bed nets and consult health facilities for prophylaxis, limiting onward transmission. Individuals with symptoms may be more vigilant and seek treatment as a result of SMS warnings.
Keywords: Spatial distribution, malaria prevalence, travel malaria, Plasmodium falciparum.