Childhood malaria remains a major global health problem affecting predominantly children in malaria-endemic countries. Children aged under five represent the majority of malaria cases and deaths; they account for two out of three malaria cases and three out of five malaria deaths, according to the World Health Organization. Early diagnosis is critical for treating malaria cases, especially in young children who exhibit non-specific symptoms such as fever. Early and accurate diagnosis is vital for prompt initiation of effective treatments that prevent severe outcomes. Over the past decade, two exciting developments in child malaria diagnostics have significantly improved the speed and accuracy of detecting and treating malaria infections. This article summarises these advancements, and the impact they have had on malaria control programs, and provides a brief outlook for the future of malaria diagnostics.
The Importance of Early Diagnosis in Malaria
Early diagnosis of malaria is essential for several reasons:
- Time is of the essence: Malaria can progress quickly and, without a prompt response, to severe disease or death. It can be diagnosed and treated early.
- Prevention of Transmission: Early case management of malaria reduces human-to-human transmission, especially in transmission hot spots.
- Reducing the burden of disease: The more accurate diagnosis is made, the easier it is to assess and control the levels of malaria prevalence in communities, reducing the overall burden on health systems.
Traditional Diagnostic Methods
Historically, malaria diagnosis relied on methods such as:
- Microscopy: a sample of blood is placed on a glass slide and stained in a specific way so that malaria parasites can be seen under a microscope. This technique is both highly specific and reliable but can require trained human personnel and is time-consuming.
- Rapid Diagnostic Tests (RDTs): these tests detect antigens of malaria parasites in blood samples and can yield results within 15-20 minutes. They are easy to use, do not need electricity or sophisticated equipment, and are suitable for highly rural settings.
- Clinical Diagnosis: Symptoms-based diagnosis alone, although less accurate than laboratory-based testing, also due to a higher risk of misdiagnosis especially in areas where febrile illnesses are prevalent.
Advancements in Malaria Diagnostics
The past few decades have seen major progress in the development of tools that can diagnose malaria quickly, accurately, and affordably. Here is a brief overview of the main developments:
Enhanced Rapid Diagnostic Tests (RDTs)
- Improved sensitivity and specificity: Malaria diagnosis using newer RDTs had improved sensitivity that can detect even low-density infections and specificity that helps to distinguish between different Plasmodium species.
- Combination Tests: some point-of-care RDTs combine the detection of malaria antigens with that of other pathogens, such as markers for anemia or secondary co-infections, into a single, more comprehensive diagnostic tool.
- Longer shelf life: Advances in RDT technology have extended shelf life, decreasing waste and making tests more reliable in resource-limited settings.
Polymerase Chain Reaction (PCR)
- Very High Sensitivity and Specificity: PCR-based methods allow for the detection of the ‘silent’ stages of parasite development that remain undetectable for months by RDTs or microscopy. Using this technology, it is possible to detect all four Plasmodium species in a single sample.
- Genotyping and drug resistance monitoring: the mapping of drug resistance and other useful genotyping information largely relies on the technique of PCR.
- Field-Deployable PCR Devices: advances in recent years have resulted in portable, user-friendly field-deployable PCR devices allowing for field diagnostic applications even under poor lab infrastructure.
Loop-Mediated Isothermal Amplification (LAMP)
- Fast and cheap: LAMP is another nucleic acid amplification test, but it works faster and cheaper than PCR and is less demanding on equipment. This technology can be used for field applications in low-resource settings.
- Field Adaptability: LAMP tests require little training and are very robust, making them a good candidate for field use in remote malaria-endemic areas.
Molecular Microscopy
- Enhance Detection – This involves using molecular methods in conjunction with light microscopy to increase the sensitivity of microscopic detection of the malaria parasites and allow these parasites to be discerned at very low densities to differentiate the species.
- Connected to Digital Technologies: New digital technologies including automated image analysis and machine learning are allowing the diagnosis of malaria with higher accuracy and speed.
Serological Tests
- Tracing past infections: Serological (ie, blood) tests look for antibodies produced in response to malaria infection and are useful in epidemiological studies or monitoring of past exposures. They aren’t helpful for active cases.
- Improved Assays for Screening: Recently developed serological tests are more sensitive and specific, enabling them to detect multiple antibodies associated with malaria.
Impact on Child Malaria Management
These advancements in malaria diagnostics have significant implications for managing malaria in children:
- Early Detection and Treatment: These should have seen children experiencing more timely and accurate detection, and less severe outcomes, due to early modelling-based diagnostic tools.
- Reduced Diagnostic Delays: with faster and more reliable tests, patients with a positive result can be diagnosed earlier; for young children, who are more susceptible to complications, decreasing delay could be vital.
- Improved Surveillance and Monitoring: Improved diagnostics contribute to improved surveillance and monitoring of trends in malaria, allowing for better-designed cross-sectional interventions and policies.
- Better Treatment: As a result of more advanced diagnostics, information about the kind of malaria and the severity of the infection becomes more precise, aiding in better treatment decisions and appropriate use of antimalarial medication.
Challenges and Future Directions
Despite these advancements, challenges remain:
- Accessibility and affordability: although the new diagnostic technologies are promising, ensuring that they are available and affordable in all settings where malaria is present will require considerable effort.
- Integrating with Health Systems: We must build technical capacity to integrate new diagnostic technologies into existing health systems, focusing on training, infrastructure, and support. It is essential to make sure health workers can use and interpret them properly.
- Sustainability: Ultimately, the long-term sustainability of diagnostic programs depends on committed funding, maintenance, and support. Certainly, we need to build sophisticated supply chain management and quality control systems to ensure malaria diagnostics remain effective.
- Resistance and New Strains: Ongoing monitoring and adjustments are vital to anticipate further resistance and the emergence of new malaria strains. We need diagnostics that can swiftly adapt to these developments.
Advances in child malaria diagnostics have made the screening and management of patients considerably quicker, more accurate, and easier to access. These new diagnostics have the potential to have a profound impact on the early detection and treatment of malaria cases in children in lower- and middle-income countries. This is because many malaria deaths – and indeed deaths from other causes, which can present as malaria – are preventable if treated promptly. Better diagnosis means better treatment, and that saves lives. As new technologies evolve, it’s ongoing work to address challenges to ensure that all who are at risk of malaria benefit, which in turn could lead to the reduction and ultimately the elimination of the disease. With these new rapid and accurate diagnostics in children and the continued improvement in both treatment and prevention measures, we are bringing ourselves closer to the goal of reducing, and hopefully, eventually eliminating malaria.
