Discovery of parasite proteins in the urine of vivax malaria patients through mass spectrometry.

Malaria is an infectious disease that severely affects people worldwide. The detection of its causative organism, Plasmodium, is mainly based on microscopy, polymerase chain reaction, and rapid diagnostic tests, all relying on blood samples. Obtaining blood samples causes pain, poses a risk of infections, and leads to poor compliance in cases of repeated sampling. This highlights the need for non-invasive diagnostic alternatives. Several studies have explored the potential use of non-blood samples, such as saliva, urine, stool, and skin to detect Plasmodium. Urine accumulates changes from the body and thus is an appropriate source for biomarker discovery. A biomarker is a measurable change in the body that is associated with a disease or condition. In this study, the urine samples of Plasmodium vivax infected patients were analyzed through mass spectrometry. A comparison of the infected and control samples revealed several proteins present in one group but absent in the other, with some proteins showing altered levels. A total of 252 human proteins were found in the infected samples only. Gene ontology analysis and functional annotation revealed that these proteins are involved in key biological pathways and processes in both the human host and the parasite, and their presence in urine samples could aid in a deeper understanding of malaria biology. Twenty-eight P. vivax proteins were found in the mass spectrometric analysis of urine samples, including rifin-like protein, single-stranded DNA-binding protein, and profilin. These might serve as potential biomarkers for the non-invasive detection of Plasmodium infection.