Novel ways for malaria prevention

                           Novel ways for malaria prevention

By Anesu Brighton Venge

 

Background

It was not until the late nineteenth century that the causative agent for malaria was identified as the Plasmodium parasite, and a few years later when the Anopheles mosquito was found as the transmitting vector. That is when we realized that a bite from a mosquito is not only annoying but potentially dangerous. Since then, several approaches have been developed to prevent onward malaria transmission through vector control and use of antimalarial medicines.

 

 

Introduction

Malaria is one of the leading causes of death in children under 5 in the WHO Sub-Saharan Africa region, and mainly affects the poor who can hardly afford the recommended treatment. About 90% of deaths due to malaria occur in Africa, with Nigeria and the Democratic Republic of Congo accounting for an estimated 40% of global malaria deaths. Several expanded malaria interventions were done between 2000 and 2013 resulting in a 47% reduction in global mortality rates and a substantial 58% decline in mortality in children under 5 in the WHO African region. This indicates a direct relationship between malaria interventions and a reduction in morbidity and mortality rates. As of 2015, 17 countries had managed to eliminate malaria, showing that the disease can be eradicated with proper efforts. Suffice to say malaria remains endemic in all WHO six regions. The progress made so far is sparse and fragile, hence the need for continual intervention against malaria towards a malaria free world. There are several factors that naturally impede the efforts against malaria. These include civil wars, natural disasters and disease outbreaks such as the recent Ebola virus which threaten existing heath structures and facilities and often lead to re-establishment and resurgence of the malaria endemic.

The modelling by WHO experts suggests that if current malaria interventions are not leveled up, incidence could increase due to the loss of malaria immunity in populations that have dramatically decreased case incidences.

Novel Methods/Interventions

Spatial aides and IRS

Indoor residual spraying (IRS) was used as a primary vector control intervention in the Global Malaria Eradication Programme (mid-twentieth century) and managed to eliminate malaria in a few countries. It is based on a communal effect, in that its effectiveness depends on the area covered such that low coverage IRS may not protect against malaria at all. This method relies on the knowledge of the number of households in an area, which is a challenge in rural and remote areas. Spatial aides make use of advances in satellite imagery, cellular access and other information technologies to plan, implement and monitor IRS. Spatial aides have been proven to be crucial in IRS and in the planning and monitoring of other malaria interventions.

[CAPTION FOR ‘VENGE2’ IMAGE] The figure shows from left to right, Enumerate—computer-based satellite enumeration, target—a map of enumerated structures (red dots) and target areas (green), implement—a tablet-based map to guide users to targeted structures where spatial data is collected, reported to a server and then visualized on intuitive interactive dashboards.

Another approach is stratification which is an implementation strategy based on surveillance data. It is the division of a country or area into smaller units where different combinations of interventions may be used as needed, taking into account the heterogeneity of malaria epidemiology.

A widely used but ever important approach is chemoprophylaxis using sub-therapeutic doses sufficient to prevent malaria disease in susceptible populations such as pregnant women and children under five as well as non-immune travelers. Whilst in suspected cases it is imperative to perform a diagnostic test before administering antimalarial (quality-assured) treatment. This reduces the drug pressure on parasites; provides accurate surveillance data, and gives way for the diagnosis of other febrile conditions that are usually assumed as malaria.

The national regulatory authorities have a major role to play in removing all inappropriate malaria medicines from the market and develop a thorough strategy to do away with ineffective antimalarial medicines from the public sector, private sector and pharmacies. This is a major step in preserving the efficacy of current artemisinin-based therapy. In places where there is little access to these facilities such as rural and remote areas, a scale up of interventions is required to increase coverage and access to recommended treatment. Measures should be put in place also to improve utilization in such areas where social and cultural factors play an important role in determining utilization of interventions.

The community health workers (aka village health workers) in rural and remote areas are important in providing surveillance data, detecting new cases and mitigating potential transmission. Large-scale malaria training of health workers is of great import especially in proactive case detection and treatment, thereby avoiding re-establishment.

Research and Innovation

Several studies are being done on new tools and approaches that shall be made available during the course of the WHO Global Technical Strategy for Malaria. These include transmission-blocking chemotherapy, malaria vaccines and markers of resistance. Researchers are also exploring the role of medicines in killing mosquitoes before they are able to transmit the disease and universal antimalarials. Whilst more research is being done on improved diagnostic tests for very low parasitaemia and P.vivax hypnozoites.

“We should act with resolve, and remain focused on our shared goal: to create a world in which no-one dies of malaria”

 

Email: [email protected]