Malaria epidemiology and key control interventions in the Democratic Republic of Congo

Malaria remains a major global public health problem causing over 400,000 deaths annually, mainly among children in sub Saharan Africa. The Democratic Republic of Congo (DRC), the second largest and the fourth most populated country in Africa, is one of the most malarious countries in the world. An estimated 97% of its 71 million inhabitants live in high transmission areas. Together with Nigeria, DRC accounts for about 40% of the total estimated malaria cases worldwide, and for more than 35% of the total estimated malaria deaths. The national malaria control programme (NMCP) is committed to reducing malaria and the associated morbidity and mortality in DRC through the implementation of specific proven interventions. The aim of this thesis was to contribute to the improvement of malaria control activities in the DRC, through the provision of new evidence on the epidemiology of malaria and key control interventions, to support evidence-based policy making.
Kinshasa, the capital of DRC, has been expanding very rapidly in the past 20 years (going from an estimated 3 million inhabitants to a current estimate of 10 million) and available evidence has shown that urbanization had a significant impact on the ecosystems and disease patterns, including malaria. However, in the context of scaling up of interventions, data on malaria distribution in Kinshasa are scarce; the latest epidemiological study was conducted in 2000. We conducted two cross-sectional surveys to update malaria risk stratification in Kinshasa, identify factors contributing to the distribution patterns, and update information on malaria control activities. Geo-referenced data for key parameters were mapped at the level of the health area (HA) by means of a geographic information system (GIS). The overall standardized malaria prevalence was 11.7%, showing a decline compared to previous studies. The spatial distribution showed higher malaria risk in the peri-urban areas compared to the more urban central areas. Compared to the Demographic and Health Survey 2007 (DHS-DRC, 2007), coverage of malaria control measures showed considerable progresses in a pattern inversely proportional to the malaria risk distribution: low LLIN coverage in the peri-urban areas and higher coverage in the centre of the city. The analysis of drivers of malaria in both children less than five years and individuals aged older than five years highlighted the variation of the effect of age and reported history of fever by level of endemicity. In low endemicity strata, a shift in the peak of malaria prevalence towards the older age groups was observed, while the history of fever in the last two weeks increased the risk of malaria in all age groups and regardless of the level of endemicity. Individual use of LLIN was associated with reduced risk malaria infection among children less than five years. The risk of malaria was lower among children less than five years of the wealthiest socio economic group. This risk map constitutes a strong basis for the planning of malaria control interventions in Kinshasa.
Following the publication of the results of two large open-label randomized controlled trials (SEAQUAMAT, AQUAMAT) that demonstrated the benefits of injectable artesunate over quinine in the treatment of severe malaria, and in line with the updated WHO guidelines, the NMCP changed the policy for treating severe malaria in children and adults from injectable quinine to injectable artesunate in 2012 A transition period of 3 years was set, including the need for operational research to support the national deployment. We conducted an operational comparative study of quinine and injectable artesunate for the treatment of severe malaria (MATIAS study) with the aims of assessing the operational feasibility of this introduction, providing national cost estimates, and assessing the acceptability of the new drug among both health care providers and patients. Our findings showed that all the operational parameters measured (time to discharge, interval between admission and the start of intravenous treatment, personnel time spent on patient management, and parasite clearance time) were equal or in favour of injectable artesunate. The mean total cost per patient treated for severe malaria in hospitals and health centres was also lower with injectable artesunate. There was a high acceptability by both health care providers and patients. These findings support the rapid scale up of injectable artesunate in the country.
Mass distribution campaigns of LLIN are accepted as the best approach to rapidly increase coverage and use. To promote correct and consistent use of distributed LLIN, the WHO recommends the integration of door-to-door visits with “hang up” activities into mass distribution campaigns. Integrating hang-up activities requires obviously additional human and financial resources. Since published data on the effects and cost of door-to-door visits with hang up activities on LLIN use are scarce, more evidence is still required to optimize the efficiency of national LLIN programmes. We used a LLIN mass distribution campaign in the province of Kasai Occidental that used two different approaches, a fixed delivery strategy and a door-to-door strategy including hang-up activities, to evaluate comparatively household LLIN ownership, access and individual use, and examine factors associated with LLIN use. We also compared the two delivery strategies with regard to the LLIN coverage achieved and the cost of implementation. Results showed that the mass distribution campaign was effective at achieving high LLIN ownership and use. Having sufficient numbers of LLIN to cover all residents in the household was the strongest determinant of LLIN use. Compared with the door-to-door strategy, the fixed delivery strategy achieved a higher LLIN coverage at lower delivery cost, and seems to be a better LLIN delivery option in the context of DRC.
Information on the number and distribution of malaria cases and deaths is fundamental for the design, implementation and evaluation of malaria control programmes. In many endemic areas, health facility-based data remain the only consistent and readily available source of information on malaria. Because of known inherent limitations, this source of date can underestimate the total burden of disease by a considerable fraction. In DRC, the use of rapid diagnostic tests has been expanded since 2010, leading to a marked increase in suspected malaria cases receiving a diagnostic test. Together with other management measures, this should improve the quality of the incidence rates obtained through the Health Monitoring Information System (HMIS). Based on household survey data, the Malaria Atlas Project (MAP) of the University of Oxford has produced estimates of clinical incidence of malaria for the years 2000-2015 for all African countries, providing something like a reference value on incidence rates. We compared the malaria incidence rates obtained from the HMIS data in the DRC from 2010 to 2014 to the MAP modelled incidence rates for the same time period, in order to assess the relative reporting of the HMIS system. Our preliminary results showed that due to the expansion of parasitological diagnosis, the number of confirmed malaria cases reported and hence the fraction of incident cases captured by the HMIS data had increased substantially over time. By contrast, the number of incident malaria cases predicted by the MAP model had progressively decreased. Because of inconsistencies in reporting, it has been difficult to establish trends in malaria morbidity, but the unchanged high values of test positivity rates suggest malaria transmission remains high and stable over time.