It is such a great relief to see the recent progress in Malaria control efforts. The World Health Organization reported that 212 million new cases and 429,000 deaths occurred (WHO, 2016). Malaria control efforts have focused on three major areas over the last decade: chemoprevention, vector control and use of malaria diagnostic testing. All three of these have shown impressive improvements over time. However surveillance efforts have not made any measurable strides.
According to the WHO, an estimated 19% of global malaria cases are detected using existing surveillance systems. But nearly 4 in 5 patients with malaria are not detected using current methods. This is not nearly good enough. The current gold standard for malaria detection requires identification using microscopy and a blood smear. This is time consuming, and only detects patients whose disease has spread beyond the liver. Dozens of rapid diagnostic tests (RDT) exist, but are not nearly sensitive enough. We really need a way to detect malaria at the earliest stages, when it matters the most.
Several barriers prevent infected patients from seeking treatment. Socioeconomic forces are the biggest barrier. Malaria disproportionately affects patients in the poorest and most rural settings in the world. In rural communities, patients simply don’t have the means to travel to cities to seek medical attention. The second barrier is trying to figure out who even has the disease. More than two-thirds of patients infected with Malaria may not even know it. A recent study found that in a tribal area of West Bengal 81 patients were infected with P. falciparum. Of these 81 patients, 66 (80%) were proven to be asymptomatic carriers (Ganguly, 2013). This is a big problem because these asymptomatic carriers serve as a huge reservoir and unknowingly continue to spread the disease.
I sought to address these fundamental issues using a low-tech approach. My goal was to create a small portable device that could amplify and detect malaria DNA using ordinary camping equipment. Laboratory based tests like polymerase chain reaction (PCR) are certainly sensitive enough to amplify sections of the malaria genome, however they are impractical to use in the developing world. I wanted to create something that could run on battery power, without the need for AC electricity, and would require only minimal training.
My system relies on a technique known as isothermal loop amplification (LAMP) and is similar to PCR, but does not require bulky lab equipment. Instead of using an expensive thermocycler, the portable LAMP system uses a flameless camping stove based on meals-ready-to-eat (MRE) heaters. The stove uses a magnesium alloy to generate an exothermic reaction — enough to power the LAMP reaction for up to 60 minutes. A smartphone camera is then used to detect color changes on a microfluidic chip which signifies the presence of malaria DNA. The LAMP reaction detects two genes which are found in malaria causing plasmodium species: aldolase and histidine rich protein II (HRP-2).
So when will this be ready for use in real patients? Unfortunately it will take some time. Results from this experiment were recently presented as a poster at the American Society of Parasitologists Annual Meeting in San Antonio TX (Gopal et al, 2017). In this first prototype, we amplified purified DNA from a P. falciparum stock. Further work needs to be done to compare the results from LAMP to a standard lab based PCR. After some more refinements, the device would then be ready for testing in real patients with endemic malaria. Then we could potentially submit the device for approval to health authorities for human use. Through the efforts of the scientific community, I hope a more refined device using this technology will be available within the next 3-5 years.
Ganguly, S., P. Saha, S. K. Guha, A. Biswas, S. Das, P. K. Kundu, and A. K. Maji. 2013. “High Prevalence of Asymptomatic Malaria in a Tribal Population in Eastern India.” Journal of Clinical Microbiology 51 (5):1439–44.
Gopal NS, Hayter J, Azaro M, Brzustowicz LM. Plasmodium Aldolase Quantification Using Portable Isothermal Loop Mediated Amplification (LAMP) and a Smartphone. Poster #148 presented at the American Society of Parasitologists Annual Meeting, San Antonio TX, July 2017.