A large problem
Like the rest of Sub-Saharan Africa, malaria in Malawi continues to be one of the most important public health problems that our population faces; accounting for between 30 to 40% of hospital visits and 20 to 30% of hospital deaths, especially among children under the age of five years. Pregnant women are also susceptible to the devastating effects of malaria infection, although the major impact of malaria infection in pregnancy is not on the woman herself but on her unbom child, whose growth may be impaired as a consequence of the accumulation of parasites in the placenta. About 20% of Malawian babies are born with low birth weight (LBW), the most important predictor of neonatal and infant mortality, and malaria is the most important preventable cause of LBW.
Many schemes
It has been argued, correctly, that no African country is successfully controlling malaria, and that this is one reason why we have had so many “new” initiatives from WHO and other international bodies to try to tackle the immense problems caused by malaria. Beginning with The Accelerated Implerientation of Malaria Control in the early 90s, we moved through the African Malaria Initiative to the Roll Back Malaria (RBM) ‘movement’, spearheaded by WHO, World Bank, UNICEF and UNDP. There has been evidence in the African region of ‘strong political will’ to control malaria in the form of The Harare Declaration and recently The Abuja Declaration signed by our heads of State and Government. Malawi is a signatory to both these landmark declarations.
A resourceful enemy
In spite of all these efforts the malaria problem continues to escalate alarmingly. One of the major contributing factors to this escalation has been the increasing problem of parasite resistance to the commonly used first line antimalarial drugs. When malaria control programme managers from the sub-Saharan region meet to share country experiences, they show graphic slides or transparencies portraying in each country ever increasing levels of mortality and morbidity from malaria. Such experiences made us realise that our Control Programmes had turned into Malaria Mortality and Morbidity Monitoring Programmes, since in spite of the alarming data that were being gathered our main tool for control remained the same.
Diagnosis and treatment
WHO recommends three main arms to a malaria control strategy: case management personal protection (including the use of insecticide treated materials, ITM's ) and selective vector control; the main focus of our control efforts has been the first of these, namely early and appropriate case management. Case management by necessity requires the use of drugs. For this strategy to have an impact there is need for an effective and efficacious drug.
Malawi's Control Programme
Recognising this simple fact and seeing the escalating malaria problem, the Malawi Ministry of Health set up a Malaria Control Programme in 1984. Its mandate was to monitor the efficacy of the currently recommended first line treatment for uncomplicated malaria at the time, chloroquine (CQ), and also to study other alternative antimalarial drugs which included sulphadoxine pyrimethamine (SP), amodiaquine, mefloquine and halofantrine. Six sentinel sites were set up, three along the lakeshore and three inland for in-vivo drug efficacy studies. Amodiaquine was quickly deleted from the national formulary because of common problems with severe abdominal pains. The others were abandoned on the basis of unaffordable cost.
Drug resistance: the change to SP
After over eight years of systematic efficacy studies involving CQ and SP, it was clear that by 1990 over 80% of the Plasmodium falciparum infections were exhibiting the most severe form of resistance to CQ, i.e RII and RIII. In addition there were less than 5% of the parasites showing resistance to SP. These were systematic in-vivo studies on children under the age of 5 years. In parallel to the increasing CQ resistance of the parasites to CQ, there was also increasing resistance among the consumers - i.e mothers of sick children - to accept CQ treatment for their children. Consequently a national consensus meeting of stakeholders decided in 1991 to change from CQ to SP as first line treatment for uncomplicated malaria infection. The actual ‘launch’ of the new treatment policy was in 1993. The lag period was neccessitated by the logistics of procuring enough SP to trickle down to all health centres (we wanted to avoid the scenario where a ‘new’ drug is announced and patients find that it's not available at the health centre), training health workers and also to develop I.E.C materials for community information.
Other measures
Even though the most notable change was the switch from CQ to SP; there were other changes made for the management of malaria at the same meeting. A 20mg/kg loading dose of quinine was added to the management of severe malaria, parenteral quinine was introduced for intramuscular use at the health centre level (after recognising that patients with severe malaria need to be started on effective antimalarial treatment at the health centre prior to referral, a process which can sometimes take hours to achieve) and finally two doses of SP were introduced to replace weekly CQ for prophylaxis during pregnancy. This is now a practice that has now been adopted and promoted by WHO as Intermittent Presumptive Treatment (IPT) in pregnancy.
Research informing policy
It is important to note that changes made to malaria management were based on locally generated data, with good collaboration between malaria researchers, malaria control programme and policy makers within the Ministry of Health. An excellent example of applying research findings to programme policy and implementation. This collaboration continues to be implemented mainly through annual malaia research dissemination meetings. Since the change in 1993, SP efficacy has continued to be monitored at sentinel sites through in-vivo testing as before.
SP has done well
As is to be expected with the continued use of any antimicrobial (whether antibacterial, antiviral or antiparasitic), the more it is used the more likely it is that resistance will develop. This is what we are seeing with SP. The parasite resistance has increased from less than 5% in the early 90's to as high as 20% at some sites in 2001. The rate of increase of SP resistance has not been as rapid as had been predicted in certain circles. SP is still effective in more than 80% of the malaria cases treated and therefore remains the first choice for treatment of uncomplicated malaria in Malawi after about 10 years of widespread use - we should not forget that multitude of children's lives that have been saved by the use of a more effective drug than CQ during this period.
Being prepared
Realising however that at some stage in future SP will have to give way to another more effective drug or combination of drugs, the Programme is encouraging research in this area of alternatives to SP; one of the most advanced projects has been the study of Chlorproguanil-Dapsone or LAPDAP at Ndirande Health Centre (Blantyre). We are also looking at the possibility of studying compounds containing the artemisinin derivatives since WHO now recommends moving towards what is referred to as Combination Therapy or CT. This approach draws on the experience of treatment of malignancies, TB and HIV infection - it is designed to reduce the chances of a parasite developing resistance by using two or more drugs that have independent modes of action and different biochemical targets in the parasite. Using this definition, SP does not qualify as CT. The National Malaria Control Programme is also concerned about optimising the uptake of IPT-SP because there is now evidence that nationally only about 37% of pregnant women are taking the full two doses of SP in spite of high antenatal clinic attendance and also good knowledge about both the IPT regime and the safety of SP in pregnancy. Another problem is the mounting evidence that women who are HIV infected require more than the two doses of SP to achieve the same benefit of reduction of placental malaria and consequent reduction in LBW as those women who are not HIV infected. Studies will soon be underway to address this issue.
Working together
In conclusion, it is important to remember that Malawi has contributed significantly to the international malaria control effort by sharing her experience in managing a national antimalarial drug policy change. Malawi has also contributed a large body of knowledge in managing malaria in pregnancy and in the management of severe malaria - IPT-SP and the Blantyre Coma Score are visible such contributions. The articles in this edition of MMJ are further testimony of the excellent work done in this field. The history of malaria control in Malawi has been one of policy driven by locally generated relevant scientific data and this has been made possible by the good working relations between researchers and programme implementers. We will continue to nurture this relationship, which is ultimately beneficial to our people.