Towards the elimination of malaria in South Africa: a review of surveillance data in Mutale Municipality, Limpopo Province, 2005 to 2010

Abstract

Background: South Africa has targeted to eliminate malaria by the year 2018. Constant monitoring of malaria morbidity and mortality trends in affected subpopulations is therefore crucial in guiding and refining control interventions. Mutale Municipality in Limpopo Province is one of the areas with the highest risk of malaria in the country. This paper describes trends in malaria incidence, case fatality and household indoor residual spraying (IRS) coverage in Mutale Municipality, during the period 2005 to 2010.

Methods: A retrospective descriptive analysis was conducted on malaria data routinely collected through the Limpopo provincial malaria information system between July 2005 and June 2010. Five malaria seasons were defined. Annualized malaria incidence rates, case fatality rates (CFR) and IRS coverage rates were calculated.

Results: Cumulatively, 4,663 malaria cases and 21 malaria deaths were reported in Mutale between July 2005 and June 2010. Investigation of likely origin of the malaria in 3,517 patients revealed that 6.6% were imported cases, mostly from neighbouring Zimbabwe (222/231). Malaria incidence rates fell from 13.6 cases per 1,000 person-years in the 2005-2006 season to 2.7 cases per 1,000 person-years in the 2009-2010 season. The mean malaria CFR was stable between 0.3 and 0.6% during the first four seasons, and increased sharply to 2.1% in the 2009-2010 season. The median age of the 21 malaria deaths was 34 years (range: 16 to 60 years). CFRs were 0% in children below 15 years and above 0.5% in patients more than 24 years old. Regular IRS achieved coverage above 80% in all five seasons.

Conclusion: Malaria control interventions implemented in Mutale significantly reduced the incidence of malaria in the population. In order to accurately monitor progress towards the elimination goal, the malaria control programme should strengthen the reporting and capturing of the data in the provincial malaria information system; all patients diagnosed with malaria should be investigated to determine the likely source of the malaria, and malaria related deaths should be audited to improve case detection and management. Furthermore, the country should strengthen cross border malaria control collaborations in order to minimize malaria importation.

Figure 1

Map showing the geographical location of Limpopo Province in South Africa and Mutale Local Municipality in Limpopo Province. The top insert shows the location of Limpopo Province in South Africa (in blue circle). The bigger map shows the location of Mutale Municipality in Limpopo Province, in relation to neighbouring countries of Zimbabwe and Mozambique. The map was adapted from the Wikipedia website [http://en.wikipedia.org/wiki/File:Map_of_Limpopo_with_Mutale_highlighted_(2011).svg] as an open source document published under the GNU Free Documentation License and the copyright holder grants permission to copy, distribute and/or modify the document.

Figure 2

Distribution of malaria incidence rates and case fatality rates per malaria season, Mutale Municipality, Limpopo Province, July 2005 to June 2010. The blue line graph shows the incidence of malaria per 1,000 persons at risk each malaria season. The red line graph is showing the malaria case fatality rate (percentage) for each malaria season. Incidence calculations excluded imported and untraceable malaria cases (these were assumed to have been infected out of Mutale).

Figure 3

Number of malaria cases by month and year of diagnosis, Mutale Municipality, Limpopo Province, July 2005 to June 2010. Untraceable cases are those that were investigated/followed up by the malaria case investigators but the patients could not be located. For undocumented cases there was no information recorded to indicate whether the patient was investigated/followed up or not.