Cerebrospinal fluid B lymphocyte identification for diagnosis and follow-up in human African trypanosomiasis in the field

The detection and treatment of human African trypanosomiasis

Human African trypanosomiasis (HAT) is caused by the injection of Trypanosoma brucei (T. b.) gambiense or T. b. rhodesiense by Glossina, the tsetse fly. Three historical eras followed the exclusive clinical approach of the 19th century. At the turn of the century, the "initial research" era was initiated because of the dramatic spread of HAT throughout intertropical Africa, and scientists discovered the agent and its vector. Two entities, recurrent fever and sleeping sickness, were then considered a continuum between hemolymphatic stage 1 and meningoencephalitic stage 2. Treatments were developed. Soon after World War I, specific services and mobile teams were created, initiating the "epidemiological" era, during which populations were visited, screened, and treated. As a result, by 1960, annual new cases were rare. New mass screening and staging tools were then developed in a third, "modern" era, especially to counter a new epidemic wave. Currently, diagnosis still relies on microscopic detection of trypanosomes without (wet and thick blood films) or with concentration techniques (capillary tube centrifugation, miniature anion-exchange centrifugation technique). Staging is a vital step. Stage 1 patients are treated on site with pentamidine or suramin. However, stage 2 patients are treated in specialized facilities, using drugs that are highly toxic and/or that require complex administration procedures (melarsoprol, eflornithine, or nifurtimox-eflornithine combination therapy). Suramin and melarsoprol are the only medications active against Rhodesian HAT. Staging still relies on cerebrospinal fluid examination for trypanosome detection and white blood cell counts: stage 1, absence of trypanosomes, white blood cell counts ≤ 5/µL; stage 2, presence of trypanosomes, white blood cell counts ≥ 20/µL; T. b. gambiense HAT intermediate stage, between these still controversial thresholds. Our group has proposed the use of noninvasive ambulatory polysomnography to identify sleep-wake abnormalities characteristic of stage 2 of the disease. Only patients with abnormal sleep-wake patterns would then undergo confirmative lumbar puncture.

New insights in staging and chemotherapy of African trypanosomiasis and possible contribution of medicinal plants

Human African trypanosomiasis (HAT) is a fatal if untreated fly-borne neuroinflammatory disease caused by protozoa of the species Trypanosoma brucei (T.b.). The increasing trend of HAT cases has been reversed, but according to WHO experts, new epidemics of this disease could appear. In addition, HAT is still a considerable burden for life quality and economy in 36 sub-Saharan Africa countries with 15-20 million persons at risk. Following joined initiatives of WHO and private partners, the fight against HAT was re-engaged, resulting in considerable breakthrough. We present here what is known at this day about HAT etiology and pathogenesis and the new insights in the development of accurate tools and tests for disease staging and severity monitoring in the field. Also, we elaborate herein the promising progresses made in the development of less toxic and more efficient trypanocidal drugs including the potential of medicinal plants and related alternative drug therapies.

Actigraphy in human African trypanosomiasis as a tool for objective clinical evaluation and monitoring: a pilot study

Background

Human African trypanosomiasis (HAT) or sleeping sickness leads to a complex neuropsychiatric syndrome with characteristic sleep alterations. Current division into a first, hemolymphatic stage and second, meningoencephalitic stage is primarily based on the detection of white blood cells and/or trypanosomes in the cerebrospinal fluid. The validity of this criterion is, however, debated, and novel laboratory biomarkers are under study. Objective clinical HAT evaluation and monitoring is therefore needed. Polysomnography has effectively documented sleep-wake disturbances during HAT, but could be difficult to apply as routine technology in field work. The non-invasive, cost-effective technique of actigraphy has been widely validated as a tool for the ambulatory evaluation of sleep disturbances. In this pilot study, actigraphy was applied to the clinical assessment of HAT patients.

Methods/Principal Findings

Actigraphy was recorded in patients infected by Trypanosoma brucei gambiense, and age- and sex-matched control subjects. Simultaneous nocturnal polysomnography was also performed in the patients. Nine patients, including one child, were analyzed at admission and two of them also during specific treatment. Parameters, analyzed with user-friendly software, included sleep time evaluated from rest-activity signals, rest-activity rhythm waveform and characteristics. The findings showed sleep-wake alterations of various degrees of severity, which in some patients did not parallel white blood cell counts in the cerebrospinal fluid. Actigraphic recording also showed improvement of the analyzed parameters after treatment initiation. Nocturnal polysomnography showed alterations of sleep time closely corresponding to those derived from actigraphy.

Conclusions/Significance

The data indicate that actigraphy can be an interesting tool for HAT evaluation, providing valuable clinical information through simple technology, well suited also for long-term follow-up. Actigraphy could therefore objectively contribute to the clinical assessment of HAT patients. This method could be incorporated into a clinical scoring system adapted to HAT to be used in the evaluation of novel treatments and laboratory biomarkers.

The clinical picture of the parasitic disease human African trypanosomiasis (HAT, also called sleeping sickness) is dominated by sleep alterations. We here used actigraphy to evaluate patients affected by the Gambiense form of HAT. Actigraphy is based on the use of battery-run, wrist-worn devices similar to watches, widely used in middle-high income countries for ambulatory monitoring of sleep disturbances. This pilot study was motivated by the fact that the use of polysomnography, which is the gold standard technology for the evaluation of sleep disorders and has greatly contributed to the objective identification of signs of disease in HAT, faces tangible challenges in resource-limited countries where the disease is endemic. We here show that actigraphy provides objective data on the severity of sleep-wake disturbances that characterize HAT. This technique, which does not disturb the patient's routine activities and can be applied at home, could therefore represent an interesting, non-invasive tool for objective HAT clinical assessment and long-term monitoring under field conditions. The use of this method could provide an adjunct marker of HAT severity and for treatment follow-up, or be evaluated in combination with other disease biomarkers in body fluids that are currently under investigation in many laboratories.