Sleeping sickness could be diagnosed faster in the near future after a new study by researchers from Imperial College of London and their colleagues in Switzerland and the USA revealed that the condition leaves a metabolic fingerprint in the blood and urine.
Currently, it is difficult to detect sleeping sickness as most of its symptoms in its first stage including headache, weakness, and joint pain, are common in many other conditions.
It is passed on through a bite from an infected tsetse fly, which transmits a subspecies of a parasite known as Trypanosoma brucei into the bloodstream.
The researchers conducted the study using a mouse model. They examined the metabolic profiles of twelve mice infected with the parasite Trypanosoma brucei brucei, using blood and urine samples with the help of NMR spectroscopy.
They carried out their analyses two days before infection and at a series of points over a 33-day period after infection.
However, Trypanosoma brucei brucei cannot infect humans with sleeping sickness but it is very closely related to the parasites Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense, which do.
The findings revealed that the infection with the parasite created distinct metabolic 'fingerprints' in the blood and urine and that these fingerprints are different at different stages of the disease. They were visible in the blood as early as one day after infection.
Presently, to detect the disease Doctors have to use both a blood test and a lymphatic fluid test, using a needle inserted into the lymph node.
They then use a painful and invasive lumbar puncture to work out which stage the disease has reached, in order to select the best drug for treatment.
It is important to catch the disease as early as possible because once it enters the second stage, the parasite progresses into the patient's brain, doctors have to use a different, less effective set of drugs that can cause devastating side-effects, such as a brain disease, or encephalopathy.
"Sleeping sickness is a shattering disease and it is often not spotted until it is too late," said Professor Elaine Holmes, corresponding author of the research from the Department of Biomolecular Medicine at Imperial College
"Its initial symptoms can be quite mild and non-specific and doctors in sub-Saharan Africa don't usually have the time or money to carry out the tests to check if someone has it.
"Our research is at a very early stage, but our results suggest that scientists could in the future create a better way to test for sleeping sickness.
"So far we have only looked at a mouse model, and we have not yet investigated what happens when there are multiple parasites in the body, but these are promising findings," she added.
Researchers are conducting further studies to determine whether the findings in mouse models can be replicated in humans.
The study appears in the journal Proceedings of the National Academy of Sciences.