A new non-invasive test for malaria could alter the global test landscape dramatically, enabling reliable, safe, and sensitive testing for the deadly mosquito-borne malaria life in low and middle income countries that have been blighted by it, according to Yale School of Public Health epidemiologist Sunil Parikh, MD, MPH, and colleagues from Cameroon and the University of Arkansas for Medical Sciences, reporting in a new paper in Nature Communications.
The best part? The new test doesn’t require drawing a single drop of blood. In the study, Armstrong said, the test is run using a device called Cytophone, which exposes targeted lasers and ultrasound to detect circulating malaria infected cells in the bloodstream.
The Cytophone prototype, about the size of a tabletop printer, can detect whether infection is occurring within minutes, starting with a small noninvasive probe placed on the back of the person’s hand, on top of a targeted vein.
Shimmering crystals
Because hemozoin—an iron crystal—accumulates in infected red blood cells when malaria parasites thrive inside, ‘the Cytophone is able to detect that noninvasively,’ Armstrong said. When exposed to a laser, these nanocrystals heat up and absorb more light than normal haemoglobin, and can possess magnetic and optical properties, with the Cytpophone probe being able to detect them.
In 20 adult patients with symptomatic malaria in Cameroon, the Cytophone has 90% sensitivity and 69% specificity for detecting malaria infections comparable to and in some cases superior to the current gold standards for malaria screening, which require blood samples from patients.
Armstrong said the Cytophone was safe and comparable in diagnostic performance to the currently used point of care options when compared to highly sensitive quantitative PCR, which was used as the gold standard.
Collaboration key
Parikh and Armstrong praised the work of the Cameroonian collaborators, whom they said made the work of testing the device possible during the coronavirus pandemic. We tested this device with little advanced training because the trainees in Cameroon were amazing, said Parikh.
The “driving force” of the project, he said was Professor Yap Boum II, the director of the Medicine Sans Frontieres Epicentre in Cameroon’s capital city Yaounde and another co senior author of the study, who continued to test in Cameroon when the rest of the international team was unable to due to COVID-19 restrictions.
“The kind of transdisciplinary projects that can occur between engineers and epidemiologists I believe are essential to cut global disease burden.”
Through this collaboration the team hopes to build on a new generation of Cytophones they expect to be more sensitive, more advanced, even battery powered. Cytophone technology represents an exciting new point-of-care tool and may also aid in this effort by improving the ability to detect malaria cases and to initiate treatment.
Reference: Yadem AC, Armstrong JN, Mustafa Sarimollaoglu, Massa CK, Jean-Michel Ndifo, Menyaev YA, et al. Noninvasive in vivo photoacoustic detection of malaria with Cytophone in Cameroon.
Â
