As an avid observer of malaria transmission patterns, I am becoming worried about sustaining the advances that have developed over the past ten or so years. There is no doubt that the advent of insecticide treated bednets has provided a vehicle for various interested parties to exploit as a means of vector control, and this has happened in huge numbers. Tens of millions of LLINs have been delivered to various governments, NGOs and other interested parties, and this is still happening. But when it comes to monitoring the effects of this intervention, when it comes to careful evaluation of the programmes, there isn’t much to hear...
Most donors do not provide funds nor do they require any monitoring and evaluation. I am quite aware of the decline in the prevalence of malaria, there have been several papers on this since 2009 1,2 and still very recently2. But these are overall prevalence figures, some as parts of ongoing research projects, and others are based on variable data from national health reports. It would be nice to know how much of this is due to statistical variability and the focal nature of transmission, and how much is due to true interventions.
In the most case there are few if any epidemiologically designed evaluations of the impact of such interventions because the specific donor is more interested in getting nets and having them distributed than evaluating the effect. Not wanting to cast aspersions, it would be useful to know what proportion of funds allocated to procure bednets are earmarked for monitoring and evaluation. Data exist, but collecting such information and processing it for use requires training in epidemiology, something that is lacking in many NMCPs.
We have shown the value of this from our own work in Southern Province in Zambia. We have been doing numerous cross-sectional and longitudinal studies on the case positivity rate in the Macha area, with prevalence rate during the years 2008 to 2012 calculated by randomization. However these results are not at all in concordance with incidence calculated from weekly RDT positivity incidence detected at local rural health centres where people go when ill, and malaria is diagnosed by RDT and the information transmitted by SMS to the staff at the Macha Research Station. During those periods case incidence rates in health centres have indicated that malaria is still being transmitted.
How much more important are the records from the rural health centres where people with malaria are likely to visit when unwell? Our perception and analyses suggest that weekly case incidence rates from these RHC give a clear picture of the general whereabouts of foci of transmission, particularly during the low transmission season3. This demonstrates the importance of detection of asymptomatic cases and definition of parasite reservoirs during these times of low transmission4,5. This concept introduces a potential new strategy to detect transmission foci, particularly where past interventions have been successful in reducing transmission, and that will be to target interventions to eliminate these foci. Such a strategy could be integrated into the public health system, but will require specialized training in epidemiology and GIS – surely this could be directed to field vector biologists who one hopes will become part of the public health system. It certainly would be better than purchasing more and more LLINs that will continue selection for pyrethoid resistance!
The take home message from this can be summarized in point form:
• As expected, widespread use of a single insecticide group has selected for resistance, hence the increasing problem of spreading populations of the highly endophilic mosquito, An. funestus.
• This is a major concern, and strategies to deal with this situation need to be developed. There is no point in just sending more nets. Careful evaluation needs to be done, alternative insecticides must be used, and if nets are not amenable to the compound, then IRS needs to be emphasized.
• Programmes need to be correlated with data on transmission foci, where and when they are vulnerable to attack and what tools can be used. Appropriately trained personnel need to be recruited, paid appropriately and integrated into the control system (NMCP)
• There needs to be a method to coordinate activities, and donors need to agree to such coordination, because management across programmes is essential.
(1) Gething PW, Patil AP, Smith DL, Guerra CA, Elyazar IR, Johnston GL et al. A new world malaria map: Plasmodium falciparum endemicity in 2010. Malar J 2011;10:378.
(2) Gething PW, Battle KE, Bhatt S, Smith DL, Eisele TP, Cibulskis RE et al. Declining malaria in Africa: improving the measurement of progress. Malar J 2014;13(1):39.
(3) Davis RG, Kamanga A, Chime N, Castillo-Salgado C, Mharakurwa S, Shiff C. Early detection of malaria foci for targeted interventions on endemic southern Zambia. Malaria Journal 2011;10:260.
(4) Stresman G, Kamanga A, Moono P, Hamapumbu H, Mharakurwa S, Kobayashi T et al. A method of active case detection to target reservoirs of asymptomatic malaria and gametocyte carriers in a rural area in Southern Province, Zambia. Malaria Journal 2010;9(1):265.
(5) Stresman G, Kobayashi T, Kamanga A, Thuma P, Mharakurwa S, Moss W et al. Malaria research challenges in low prevalence settings. Malaria Journal 2012;11(1):353.
Clive Shiff, M.Sc. Ph.D. : Born, bred and educated in Rhodesia and South Africa. I started work as a Tsetse-Fly entomologist after leaving University but after a couple of years in the deep bush, I joined the Ministry of Health in the Malaria and Bilharzia Research Laboratory to work on malaria. I was sent to Zambia (then Northern Rhodesia) as medical entomologist (Zambia and Zimbabwe were one country then under the Central African Federation), and later was transferred to Southern Rhodesia where the scientific programmes were concentrated. I spent more than 20 years working on malaria and bilharzia, (schistosomiasis) in what is now Zimbabwe. Our malaria work was based on vector control with indoor residual spraying, and involved in mapping the homesteads of all people in the rural areas where the intervention was carried out. The spray teams were centrally controlled and supervised so that regular inspections were carried out and the mosquito populations regularly evaluated and where possible tested for susceptibility to the insecticide in use. Concurrently anti-malaria drugs were provided to the clinics and health centres and all clinical malaria was treated at no cost to the patient. The programme was successful and malaria became absent from the major part of the country, a situation that was maintained until the late 1990’s. Following the collapse of the Ministry of Health due to local corrupt government, malaria has returned and has become rampant again. I learned a great deal in this process and after moving to the US in 1979, and joining Johns Hopkins University in 1986 I had the opportunity to work in Tanzania in a USAID programme to test the efficacy of insecticide treated bed nets in the Bagamoyo area. Subsequently in 2003, though the establishment of the Johns Hopkins Malaria Research Institute, I was able to work in Zambia where I made many friends and my interest has spread to measuring malaria and studying the patterns of transmission in the Southern Province. I was one of the people that set up the Malaria Institute at Macha, and am still involved with the work there.
I have joined the Malaria World commentary group, and propose to bring topics of current importance to the attention of the entire MW community to stimulate thought and seek consensus as we continue to battle with this insidious disease.