Poster Presentation First Malaria World Congress 2018

Infrared spectroscopy for point-of-care diagnosis of asymptomatic malaria – a field trial in remote villages in Laos (#376)

Anja Ruether 1 , Moritoshi Iwagami 2 , Paul Brey 2 , Christian Doerig 1 , Phil Heraud 1 , Bayden Wood 1
  1. Monash University, Melbourne, VICTORIA, Australia
  2. Institut Pasteur du Laos, Vientiane, Laos

Early, accurate and inexpensive diagnosis is critical for the eradication of malaria (1). Infrared (IR) spectroscopy can serve as a quick, easy and sensitive point-of-care (PoC) diagnostic tool. The chemical composition of a sample is interrogated by its interaction with IR light, which leads to a unique, wavenumber-dependent absorbance spectrum. In blood samples the spectrum is mainly characterised by IR bands from haemoglobin, proteins, lipids and carbohydrates. The chemical composition of human blood changes when a person is infected with malaria, and these changes can be detected with IR spectroscopy.  The present study aims at determining whether the technique can be used to diagnose asymptomatic carriers of malaria at PoC.

Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy has previously been established in our lab for the detection of P. falciparum cultured parasites in human red blood cells (2). In the current trial, we face the challenge of transferring this technique to the field. 595 patients from 5 villages in the province Champasak in Laos were tested for asymptomatic malaria using ATR-FTIR spectroscopy in a mobile pop-up lab, and the results were compared to those obtained with microscopy, rapid diagnosis tests (RDT) and polymerase chain reaction (PCR).

Combining ATR-FTIR with chemometric data analysis, asymptomatic carriers, which were established by PCR, were detected with a sensitivity and specificity of approximately 80%. Given the number of positive samples (n=28) and the number of cases with high parasitemia (n=7), this is an impressive outcome for a first field study. We showed that the portable ATR-FTIR methodology is logistically implementable in remote areas and shows potential for diagnosing asymptomatic carriers of malaria in the field, which is be a crucial feature of malaria elimination/eradication programmes.

  1. Zimmerman PA & Howes RE (2015) Malaria diagnosis for malaria elimination. Curr Opin Infect Dis 28(5):446-454.
  2. Khoshmanesh A, et al. (2014) Detection and quantification of early-stage malaria parasites in laboratory infected erythrocytes by attenuated total reflectance infrared spectroscopy and multivariate analysis. Anal Chem 86(9):4379-4386.