General Malaria Information

This information was provided by
The Malaria Research Programme of the Medical Research Council, South Africa

Update on Malaria in Southern Africa 2003

"Malaria has slowed economic growth in African countries", to the extent that some countries are experiencing negative growth rates, and that since the 1960's the continent as a whole has sacrificed a third of its economic output (as GDP), for a loss now reaching $100 billion annually (Heads of State Meeting, African Summit on Roll Back Malaria, Abuja, Nigeria, 2000).

Historical malaria situation in South Africa

South Africa is not exempt from the potential ravages of malaria with its debilitating effects on communities and development. The areas affected can be seen from the continental distribution of the disease  (Box 1).

Box 1: Continental distribution of malaria. Since no continental atlas of malaria distribution, intensity and seasonality is available, the MARA/ARMA project is collecting and analysing all relevant published and unpublished malaria data from across Africa  ( http://www.mara.org.za ). An early product of this collaboration is a theoretical model of distribution of endemic malaria, based on continental long-term climate data . Red areas are those where climate is suitable and malaria probably endemic; blue and white areas have unsuitable climate and probably rarely epidemic or no malaria. This model agrees well with the few available country-level malaria maps.

Due to local climate, malaria transmission follows a distinctly seasonal pattern, and experiences marked inter-annual fluctuations leading to periodic epidemics.

Prior to its control from the late 1940's, malaria was endemic in the provinces of KwaZulu-Natal, Mpumalanga and Northern Province with recorded epidemics as far south as Durban and Pretoria on the highveld (Figure 1). Malaria mortality estimates by magistrates in KwaZulu-Natal from November 1931 to June 1932 totalled 22 132 (population at risk = 985 000), an exceptionally high mortality rate of 2.2%. In 1932, all the districts of KwaZulu-Natal Province, bar one, reported cases of malaria.

Figure 1: Malaria risk in South Africa in 1938, prior to the introduction of disease control.

Malaria Transmission

Malaria transmission is distinctly seasonal in South Africa with notifications generally increasing from November onwards (Figure 2). Peak rates in health facility malaria outpatients usually occur in April and decline by June.

Figure 2. Seasonal profile of malaria cases for the 1998/99 malaria season (Source Department of Health, South Africa)

Malaria is controlled in South Africa through mosquito vector control by intra-domiciliary spraying with a residual insecticide and parasite control by definitive diagnosis and treatment towards parasitological cure. Additional control measures include the use of focal larviciding and more recently insecticide impregnated bed nets as subsidiary control measures in specific areas.

There was a marked increase in malaria transmission in South Africa from 1996 to 2000 (Figure 3) with the situation being most pronounced in KwaZulu-Natal Province (Figure 4). 

Figure 3: Malaria case totals for South Africa aggregated by season (July to June) for July 1971 to June 2000.

The line is an exponential curve modelled on the season totals. The underlying reasons for the increase are difficult to quantify, but two proven factors were the rediscovery of Anopheles funestus in sprayed houses in the malaria areas, which were shown to be resistant to synthetic pyrethroids ( the insecticide used at the time to spray the houses) and the high levels of resistance to the then first line malaria treatment in KwaZulu-Natal (sulphadoxine / pyrimethamine) by the malaria parasite Plasmodium falciparum .

Figure 4. Notified malaria cases from the 3 malarious Provinces in South Africa.

The problem of insecticide resistance was addressed in KwaZulu-Natal by a prompt reversion to the use of DDT for intra-domiciliary spraying during the winter of 2000. This action should, as was the case in the past, eradicate Anopheles funestus from the targeted areas.

The situation with regard to parasite control is more complex. The community based in vivo studies (drug efficacy) conducted in KwaZulu-Natal during the 2000/2001 malaria season, showed parasitological resistance levels greater than 62% to sulphadoxine / pyrimethamine. A more effective treatment was essential to reduce morbidity, mortality and transmission. There is a global consensus that using a single drug (sequential monotherapy) should be replaced by combination therapy including an artemisinin derivative towards delaying the emergence and spread of drug resistance but also towards improved clinical cure rates and reduced transmission.  Based on these facts, the first line therapeutic drug for malaria had to be revised in KwaZulu-Natal and the decision was taken to change from monotherapy to a drug combination of artemisinin and lumafantrene (co-artemether) in mid-February 2001.

The resultant decrease in cases, after changes in drug and insecticide policy, can be seen in Figure 5, where cases dropped from over 40 000 for the 1999/2000 malaria season to less than 3500 in the 2001/2002 season.

Figure 5. Malaria cases by season, KwaZulu-Natal.

A regional approach to malaria control

The reduction in malaria cases in KwaZulu-Natal can be also be attributed to the creation of a regional malaria programme as part of the Lubombo Spatial Development Initiative (LSDI), which covers eastern Swaziland, southern Mozambique and north-eastern KwaZulu-Natal.

Malaria control cannot be viewed as a country specific problem, but is best viewed in a regional context as both mosquitoes and infected persons move across borders from non-controlled areas, thus limiting the effectiveness of control in South Africa. There is a high level of support for this regional approach to malaria control and the positive benefits this should have for tourism development in the Lubombo region. Sub-district malaria distribution maps are being developed towards dispensing appropriate malaria risk information to the tourism sector right down to the facility level.

A survey by the LSDI malaria programme showed infection rates in 1999 as high as 90% in children aged 2 to <15 years of age in the Mozambique sector and in close proximity to the highest risk areas in Ingwavuma district (Figure 6,7).

Figure 6. Plasmodium falciparum infections.

The LSDI malaria programme initiated a spraying programme in southern Mozambique in 2000. The overall prevalence of the disease in children had decreased by the 2001/2002 malaria season by 70% in Mozambique, while malaria incidence had reduced by 80% in Swaziland and a staggering 91% in KwaZulu-Natal.

The highest risk malaria areas in South Africa are border areas, specifically Ingwavuma, and these areas benefit positively from reductions in malaria transmission in southern Mozambique (Figure 7).

Figure 7. Malaria incidence at magisterial district level in South Africa during the 1988/89 and 1998/99 malaria seasons.

In conclusion: Given the commitment by government there is no reason to believe that malaria in South Africa cannot again be reduced to low levels by the effective use of appropriate insecticides and effective drugs, and sustained in the longer term through a regional approach to control. The latter is a first for the African continent and is timely in view of the World Health Organisation's "Roll Back Malaria" Initiative.