Tropical Health Matters

Many countries are updating their national malaria strategies because of changing global events. There has been a call for serious focus on malaria elimination by 2040. The United Nations has adopted the Sustainable Development Goals that calls for an end of epidemics and universal health coverage and the Global Fund is using national strategies as a basis for its new funding mechanism.

Kenya is no exception. Jhpiego’s Malaria technical Adviser, Augustine Ngindu, who also works with the USAID supported Maternal and Child Survival Program, reports on the launching of the revised version of Kenya’s National Malaria Strategy that takes us into 2018. His summary of the event follows:

Kenya over the last three decades has developed several malaria strategies, the first in 1981 to reduce malaria mortality and reduce prevalence among vulnerable groups; the second a national plan in 1992 to reduce morbidity and mortality by 30% by 2000; the third 2001-2010 to achieve the Abuja Declaration targets; fourth 2009-2017 with a performance monitoring plan to reduce the burden of malaria by use of combined effective interventions.

The revised Kenya Malaria Strategy 2009-2018 was launched by the Principal Secretary, Ministry of Health on 7^th November 2015. The KMS 2009-2018 is a product of the midterm review of the National Malaria Strategy 2009-2017. The midterm review was to address the emerging issues including devolution of health services from national to county governments, new initiatives like countries moving towards malaria elimination.

The revision of the KMS 2009 -2018 was informed by the Kenya Health Sector Strategic Plan 2014 -2018, the Kenya Health Policy 2012 – 2030, the Kenya Constitution of 2010. The revision was achieved through a series of consultative meetings involving multi-stakeholder and multi-sectoral participatory process led by national and county governments. Photos from the re-launching can be seen at the Kenya National Malaria Control Program’s Facebook Page.

The future KMS 2009-2018 strategic directions and priorities are –

1. Insecticide treated nets and indoor residual spraying to continue being the mainstay for vector control with an insecticide resistance management plan
2. Prevention of malaria in pregnancy to continue being provided only in malaria endemic counties
3. Increase in target population for case management from 80% -100% including development of a private sector case management strategy
4. Strategies for expanding surveillance for purposes of epidemic preparedness and response in seasonal and low risk malaria zones.

The main challenges remain human resource and health commodity security especially in a state of devolved health services.

The Star Newspaper of Kenya also informs us that, “It will cost the government Sh57 billion to implement its revised malaria strategy from this year to 2018.” They also note that, “The changes in the strategy include the adoption of universal access to testing and treatment and expansion of malaria epidemic preparedness.”

Fortunately, Kenya’s malaria burden has been falling and focal areas of higher transmission have been identified to strategic advantage. We look forward to learning more about other countries’ efforts to update their malaria strategies.

Herbs, soil and hard scientific work have yielded Nobel Prizes in Medicine/Physiology for three scientists whose results now save millions of lives from death and disability due to malaria, onchocerciasis (river blindness) and filariasis (elephantiasis), according to the New York Times. Two of the winners, “Dr. Campbell and Dr. Omura, developed Avermectin, the parent of Ivermectin, a medicine that has nearly eradicated river blindness and radically reduced the incidence of filariasis.” Dr Tu Youyou, “inspired by Chinese traditional medicine in discovering Artemisinin, a drug that is now part of standard anti-malarial regimens and that has reduced death rates from the disease.”

Community Case Management of Malaria in Rwanda using Rapid Diagnostic Tests and ACTs

The development of these chemicals into human medicines was a long time coming, and in the case of artemisinin, over 2000 years. The Guardian quotes the Deputy Director of the Liverpool School of Tropical Medicine as saying that, “Artemisinin was discovered when fatalities from malaria were rocketing and the world was terrified we’d be looking at a post-chloroquine era. It has been a real game-changer.”

In fact artemisinin in combination with other medicines or artemisinin-based combination therapy (ACT) rescued many lives in the face of parasite resistance to earlier first line drugs like chloroquine and sulfadoxine-pyrimentamine (though artemisinin resistance is now growing). ACTs are also made freely available to populations in malaria endemic countries through such programs as the Global Fund to fight against AIDS, TB and Malaria (GFATM), the US President’s Malaria Initiative, the World Bank and others.

Avermectin began its medical role as a veterinary drug that killed parasites in livestock. Eventually research by Merck based on the similarities between animal and human filarial worms led to the testing and development of ivermectin to control onchocerciasis through annual doses that killed microfilariae.

Not only are both ACTs and ivermectin on WHO’s essential medicines list, but they form the basis of global efforts to eliminate disease. Once Merck determined that ivermectin was safe and effective in humans, it began donations of the drug to what has become the African Program for Onchocerciasis Control (APOC) and its counterpart that is working to eliminate the disease in the Americas. APOC and its national counterparts now reache people in over 200,000 endemic villages in 18 African countries with annual doses.

Community Directed Distribution of Ivermectin in Cameroon

While we celebrate the recognition that the drugs and their discoverers are receiving, we should not lose sight of the fact that without good delivery mechanisms these life saving medicines would not reach the poor, neglected, often remote populations who need them.

Beginning in 1995, APOC and the Tropical Disease Research Program of WHO and partners pioneered what has now become known as Community Directed Interventions (CDI) where the thousands of communities “beyond the end of the road” and their selected volunteers organize the annual ivermectin distributions. This community directed approach works for community case management of malaria, too.

Hopefully in the future, groups like APOC will receive Nobel Prize recognition for ensuring that those in need actually receive the medicines they require. In the meantime we encourage more countries to adopt the CDI approach to reduce malaria deaths and work toward the elimination of malaria, onchocerciasis and filariasis.

Mufaro Kanyangarara and her PhD thesis adviser, Luke Mullany of the Johns Hopkins Bloomberg School of Public Health Department of International Health, have been looking into the challenges of controlling and eventually eliminating malaria in a multi-country context in southern Africa. We are sharing abstracts from her pioneering work including the following which explores indoor residual spraying in Zimbabwe in a District near the Mozambique border.

In order to reduce the vector population and interrupt disease transmission, IRS with appropriate insecticides is essential. In response to local vector resistance, the Zimbabwe NMCP with support from PMI began a large-scale IRS campaign with organophosphates in four high transmission districts in Manicaland province – Chimanimani, Mutare, Mutasa and Nyanga. Using HMIS data, the present study reports on the effect of switching from pyretheroids to OP on malaria morbidity in one of the four high transmission districts selected. In the subsequent high transmission season following the switch from pyretheroids to organophosphates, there was evidence of a 43% decline in malaria incidence reported by health facilities from wards in Mutasa District treated with organophosphates, after accounting for possible confounding by environmental variables. Previous research shows that switching to organophospates effectively reduced biting rates and vector densities in areas with pyretheroid resistant strains in Ghana, Benin and Tanzania. Although previous research focused on using entomological data to show the reduction in the vector population following application of Actellic, organophosphates, this study adds to the literature by showing a decline in malaria transmission using health facility surveillance data.

In the present study, there were variations in rainfall and temperature over the study period, and these changes were associated with changes in malaria incidence. The study results also indicated malaria transmission in Mutasa District was driven by rainfall, proximity to second order streams, elevation and temperature. These results concur with previous research, which found that elevation, temperature, and rainfall are positively associated with malaria incidence. After adjustment for climatic variables and seasonality, malaria incidence rates a downward trend following the 2014 IRS campaign and thus supporting the plausible conclusion that switching to organophosphates in this setting contributed to the observed public health benefits. No major political, socio-economic, or health-care changes with the potential to reduce malaria morbidity by almost half occurred in Mutasa District during the study period.

Typically data from health facilities only includes data on the number of suspected cases. The HMIS in Zimbabwe is more sophisticated in that it allows reports of confirmed malaria cases. In calculating of incidence rates, the denominator used was the catchment area population size. The reliability of this value has been questioned as this assumes that people will visit the closest health facility/health facility in their catchment area. It is noteworthy to mention that in the present study the main results did not chance after including an offset for catchment area population size. This indicates that in the Zimbabwean context, the reported catchment area population size may be a reliable estimate. The study also underscores the utility of HMIS data in the evaluation of population level interventions. The HMIS has the advantage of providing quality data quickly and easily, with minimal additional investment. Additionally, HMIS reflects the burden of disease on the health system. Results from this study further suggest that passive surveillance data from the HMIS in Zimbabwe was sufficiently sensitive to detect IRS related reduction in malaria morbidity among residents of Mutasa District.

There are several important limitations of this study that should be highlighted. Causal inferences between spraying and improvements in malaria incidence should be made with caution as spraying was not implemented as an intervention in a randomized control trial. However, data from 14 health facilities located in unsprayed wards were included in the analysis to serve as a comparison and help understand any possible changes in malaria morbidity unassociated with the 2014 IRS campaign. Although the univariate model indicated that health facilities in unsprayed wards carried a lower burden of malaria, the multivariable model showed no significant differences between health facilities in sprayed and unsprayed wards prior to the IRS pilot, suggesting that climatic variables included in the model adequately adjusted for differences. However, it should be noted that although the study adjusted for environmental factors, it did not account for other factors like population movement, changes in treatment seeking behaviors, changes in the coverage of ITNs during the study period. The model developed in this analysis assumed that these factors remained constant over the study period. This seems reasonable given that the rural population of Mutasa is relatively stable, with access to health facilities providing malaria diagnosis and treatment. Additionally, although the number of suspected malaria cases was not explicitly model, a descriptive analysis does not indicate changes in diagnostic practice over the study period (data not shown). The HMIS in Zimbabwe has been in place for decades and has previously been used to evaluate the impact of changes in malaria morbidity, construct empirical seasonality maps and describe the spatial and temporal distribution of malaria.

Despite these potential limitations, health surveillance systems provide a feasible and efficient means of collecting longitudinal data on measures of malaria morbidity. The pronounced decline in malaria morbidity observed in this study is evidence supporting the benefit of switching to an insecticide class with a different mode of action in response to pyretheroid resistance. Although the IRS strategy implemented by ZNMCP and PMI was successful, continued entomological monitoring will be necessary. Additionally, with emerging resistance to multiple insecticides, this approach may not be sustainable over time. There is need for the development of novel strategies to manage insecticide resistance.

Mufaro Kanyangarara and her PhD thesis adviser, Luke Mullany of the Johns Hopkins Bloomberg School of Public Health Department of International Health, have been looking into the challenges of controlling and eventually eliminating malaria in a multi-country context in southern Africa. We are sharing abstracts from her pioneering work including the following which explores high resolution risk mapping in Zimbabwe near the Mozambique border.

Background: In Zimbabwe, more than half of malaria cases are concentrated in Manicaland province, where malaria continues to rebound despite intensified control strategies. The objectives of this study were to develop a prediction model based on high-resolution environmental risk factors and obtain seasonal malaria risk maps for Mutasa District, one of the worst affected districts in Manicaland Province.

Methods: Household RDT status was obtained from ongoing community-based surveys in Mutasa District from October 2012 through April 2015. While environmental variables were extracted from remote sensing data sources and linked to household RDT status. Logistic regression was used to model the probability of household positivity as a function of the environmental covariates. Model prediction performance and overall model fit were examined. Model predictions and prediction standard errors were generated and inverse distance weighting was used to generate smoothed maps of malaria risk and prediction uncertainty by season.

Results: Between October 2012 and April 2015, 398 households participated in the household surveys. Ninety-six individuals representing 66 households tested RDT positive. Household malaria risk was significantly higher among households sampled during the rainy season and further from the Mozambique border, while malaria risk was lower in sparsely populated areas as well as households located at higher elevations during the rainy season. The resulting maps predicted elevated risk during the rainy season particularly in low-lying areas bordering with Mozambique. In contrast, the risk of malaria was low across the study area during the dry season with foci of malaria scattered along the northern, western and south-eastern peripheries of the study area.

Conclusion: This study provides evidence for the significant heterogeneity of malaria, which was strongly linked to elevation, house density and proximity to the Mozambique border. These findings underscore the need for strong cross-border malaria control initiatives to complement country specific interventions.