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A pinboard by
Anja Ruether

Postdoc, Monash University

PINBOARD SUMMARY

A field study that brings ATR-FTIR for malaria diagnosis from the lab to where it is actually needed

In the current research project, we used attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy for field studies in Laos to diagnose malaria and determine the applicability of this method for the detection of asymptomatic carriers of malaria. Malaria is one of the most devastating diseases worldwide. Its distribution in Southeast Asia is hard to control as many patients have a very low number of the malaria parasite Plasmodium in their blood. These patients often do not show classical malaria symptoms. Thus they are called asymptomatic carriers. Due to the low parasitemia, they are often very hard to diagnose. Recent experiments using (ATR-FTIR) spectroscopy for the detection of Plasmodium in human red blood cells (RBCs) were carried out in our lab on RBCs that had been spiked with Plasmodium falciparum (3D7 strain) to different percentages of parasitemia. ATR-FTIR spectra of RBCs were recorded after fixation with methanol. This study enabled to detect the parasite down to 0.00001% parasitemia, a value that would cause asymptomatic malaria in humans. The previously developed protocols had to be adapted to be applied in the field. Warm temperatures and high humidity as well as limited capacity for the storage or cooling of chemicals characterize the tropical environment in malaria regions. Therefore, sample preparation should not require further chemicals such as methanol for fixation. Furthermore, in order to increase the number of samples that can be detected per time, as few sample preparation steps as possible were desired. Preliminary experiments: Whole blood samples that were spiked with P. falciparum infected RBCs were tested after lysis with distilled water. Lysing RBCs before drying them on a glass slide lead to increased sensitivity combined with uncomplicated sample preparation. Field study: Blood samples of 596 participants from six different villages in the province Champasak in Laos were tested for malaria using microscopy, rapid diagnosis tests, polymerase chain reaction and ATR-FTIR spectroscopy on lysed dried blood samples. The evaluation of the thus obtained data is currently in process.

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