We're Not Fatal!

For our final installment we will review the work of Jamonneau et. al., (2012). Possibly, this is the most pertinent discovery of species of Trypanosoma we have come across thus far. As the title of this article implies, and as the authors have reviewed, it was previously assumed that if Human African Trypanosomiasis (HAT) was left untreated, it would result in 100% fatality. The authors attribute this previously assumed fatality rate to a few pieces of information which researchers have acquired in the past: sleeping sickness can have either chronic or more severe neurological symptoms, and the approximate one million deaths that the disease has already caused during three epidemic outbreaks on the African Continent. 

Previous reports of possible asymptomatic disease carriers and independent disease cures lead the researches to gather information through a longitudinal study on 50 patients who had been confirmed to be infected with Trypanosoma brucei gambiense in the past 5-15 years and either received treatment or refused treatment. Serological tests as well as parasite microscopy was used in order to detect the presence of parasites in individuals who had either been treated or refused treatment.  

Results showed that there were no neurological symptoms exhibited in any patients characteristic to the more severe second stage of infection, however 58% of patients who had been treated and 68% of patients who had not been treated exhibited symptoms such as headaches and fever which cannot be attributed to trypanosomiasis. 

Overall, the study provided information that supported the hypothesis that HAT was not 100% fatal when it was left untreated. Parasitological and serological tests supported the claim that self-cure can and did occur in some patients, while the same tests also argue that other patients can be asymptomatic carries of HAT but can control the disease at very low levels of parasitemia. Jomonneau et al., note however that chronically and experimentally infected pigs and cattle may possess undetectable levels of T. b. gambiense in the blood, but may still be able to infect the tsetse fly vectors and therefore humans may also present similar issues.  

All in all, the information presented is extremely valuable as it shows that the disease is not as fatal as it was previously thought. It may also even be possible for medical researchers to identify immune system defense mechanisms (Jamonneau et. al., 2012)! 

Jamonneau, V., H. Ilboudo, J. Kabore, D. Kaba, M. Koffi, P. Solano, A. Garcia, D. Courtin, C. Lavissiere, K. Lingue, P. Buscher, B. Bucheton. 2012. Untreated human infections by Trypanosoma brucei gambiense are not 100% fatal. PLOS Neglected Tropical Diseases. 6(6): pp. 1-8.