[Sleeping sickness: end of the epidemic outbreak?]. / La maladie du sommeil, fin d'une épidémie ?

Sleeping sickness or human African trypanosomiasis is a parasitic disease transmitted by tsetse flies and therefore confined to its habitat, the central part of the African continent. Two disease forms are linked to two different parasites: T. b. gambiense and T. b. rhodesiense. Actual epidemiological data and precise and dynamic mapping of foci are in favor of a real decrease of the disease. Not all areas are under control and resurgence can still not be avoided from the remote areas where the disease is endemic. However, recent advances in knowledge in parasite genetics are giving hope of control. In 2009, for the first time since 50 years, less than 10,000 cases were declared to the World Health Organization. Clinical trials allowed revising some clinical concepts and linking them with parasite genetics: both disease forms can show variations from asymptomatic, chronic to acute and are linked to genetic differences in the host or the parasite. Parasitological diagnosis may be facilitated by the introduction of individual rapid tests and PCR-based field tests. Knowledge in mechanisms of brain invasion and screenings of inflammatory molecules allow new marker combinations for staging but they do not avoid lumbar puncture. Therapeutic options remain limited but there is hope to develop a new drug orally available in a near future.

High prevalence of hepatitis C virus infection and predominance of genotype 4 in rural Gabon.

Hepatitis C (HCV) molecular epidemiology is documented poorly in central African countries. In response to this, a population-based study of 319 consenting adults resident in a remote village of Gabon was undertaken (mean age: 38 years; age range: 13-85+; sex ratio: 0.74). Screening for anti-HCV antibodies was performed using ELISA and recombinant immunoblot assay. Seropositive samples were assessed further with viral load and genotyping techniques. Sixty-six (20.7%) individuals were HCV seropositive. Viral loads ranged from 600 to 24.9 million IU/ml (median: 372,500). Seroprevalence and viral loads increased significantly with age (P < 10(-5) and P < 0.003, respectively). HCV sequences of the 5'UTR genome region were obtained from 60 (90.9%) samples and NS5B region sequences were obtained from 22 (36.6%) samples. All strains belonged to subtypes of genotype 4: 4e (72.7%), 4c (13.6%), 4p (4.5%), 4r (4.5%) and one unclassified genotype 4 strain. Evolutionary analysis of the subtype 4e sequences indicates a period of raised transmission during the early twentieth century.

[Criteria for diagnosis of the neurological stage of human African trypanosomiasis: update and perspectives]. / Marqueurs du stade neurologique de la trypanosomose humaine africaine: actualités et perspectives.

Sleeping sickness or human African trypanosomiasis (HAT) is due to parasite infection by a sanguicolous flagellate protozoan of the Trypanosoma brucei genus. The disease is classically divided into two stages, i.e., the hemolymphatic stage and the CNS stage. Disease staging is currently a major challenge for therapeutic decision-making. In the field, diagnosis is based solely on white blood cell (WBC) count and detection of the parasite in the patient's cerebrospinal fluid (CSF). This technique is unreliable and invasive. Numerous studies are now under way to adapt staging to field conditions and to develop a reliable, low-cost, non-invasive test. This article describes the mechanisms underlying CNS involvement during HAT and reviews the different techniques now being studied to simplify and improve diagnosis of the CNS stage.

Apoptosis: a potential triggering mechanism of neurological manifestation in Plasmodium falciparum malaria.

Plasmodium falciparum infection can lead to a life threatening disease and the pathogenetic mechanisms of severe manifestations are not fully understood. Here, we investigated the capacity of P. falciparum-parasitized red blood cells (PRBC) from 45 children with clinical malaria to induce endothelial cell (EC) apoptosis. In all subjects, PRBC that cytoadhered to ECs could be found albeit to a variable degree. By contrast, PRBC that induce EC apoptosis were found only in nine (20%) subjects. Interestingly, children with neurological manifestations were significantly more likely to harbour apoptogenic strains. There was no quantitative relationship between the capacity of these isolates to cytoadhere and apoptosis induction. We hypothesize that P. falciparum-encoded molecules could be responsible for apoptosis induction and therefore suggest new insights in the pathogenesis of P. falciparum malaria. Further investigations are currently in progress to determine whether these results can be confirmed and to identify putative parasite apoptogenic factors.

Harbouring in the brain: A focus on immune evasion mechanisms and their deleterious effects in malaria and human African trypanosomiasis.

Malaria and human African trypanosomiasis represent the two major tropical vector-transmitted protozoan infections, displaying different prevalence and epidemiological patterns. Death occurs mainly due to neurological complications which are initiated at the blood-brain barrier level. Adapted host-immune responses present differences but also similarities in blood-brain barrier/parasite interactions for these diseases: these are the focus of this review. We describe and compare parasite evasion mechanisms, the initiating mechanisms of central nervous system pathology and major clinical and neuropathological features. Finally, we highlight the common immune mediated mechanisms leading to brain involvement. In both diseases neurological damage is caused mainly by cytokines (interferon-gamma, tumour necrosis factor-alpha and IL-10), nitric oxide and endothelial cell apoptosis. Such a comparative analysis is expected to be useful in the comprehension of disease mechanisms, which may in turn have implications for treatment strategies.

The vervet monkey (Chlorocebus aethiops) as an experimental model for Trypanosoma brucei gambiense human African trypanosomiasis: a clinical, biological and pathological study.

It has long been known that the vervet monkey, Chlorocebus (C.) aethiops, can be infected with Trypanosoma rhodesiense, but this model has not been described for T. gambiense. In this study, we report the development of such a model for human African trypanosomiasis. Twelve vervet monkeys infected with T. gambiense developed chronic disease. The duration of the disease ranged between 23 and 612 days (median 89 days) in five untreated animals. Trypanosomes were detected in the blood within the first 10 days post-infection and in the cerebrospinal fluid, with a median delay of 120 days (n = 4, range 28-348 days). Clinical changes included loss of weight, adenopathy, and in some cases eyelid oedema and lethargy. Haematological alterations included decreases in haemoglobin level and transitory decreases in platelet count. Biological modifications included increased gamma globulins and total proteins and decreased albumin. Pathological features of the infection were presence of Mott's cells, inflammatory infiltration of either mononuclear cells or lymphocytes and plasma cells in the brain parenchyma, and astrocytosis. These observations indicate that the development of the disease in vervet monkeys is similar to human T. gambiense infection. We conclude that C. aethiops is a promising experimental primate model for the study of T. gambiense trypanosomiasis.

[Sleeping sickness: forgotten research?]. / Maladie du sommeil: la recherche oubliée?

Has research on sleeping sickness, i.e., human African trypanosomiasis (HAT), been forgotten? To get an idea on funding, we consulted the Medline bibliographic database for the last 14 years. The number of publications on HAT was stagnant over the study period. By comparison there was a steady increase in the number of publications dealing with malaria. These findings suggest that interest in HAT research waned in favor of other endemics even though government or other funding agencies continued to finance research networks. To illustrate this situation, we present the funding and findings of our multidisciplinary working group in a wide range of domains including sleep, endocrine rhythms, identification of biological markers, research on physiopathologic mechanisms of the host-pathogen relationship, and development on new medications. Over the last 14 years, a total of 1 million Euros was spent to produce 68 publications on Medline, i.e., roughly 15000 [symbol: see text] per publication.

IgM quantification in the cerebrospinal fluid of sleeping sickness patients by a latex card agglutination test.

An increased IgM concentration in cerebrospinal fluid (CSF), occurring as a consequence of massive intrathecal IgM synthesis, is a marker of interest for diagnosis of the meningo-encephalitic stage in human African trypanosomiasis. However, in current practice, IgM in CSF is not determined because of the lack of a simple and robust test that is applicable in African rural regions where the disease prevails. We describe the development of a sensitive semiquantitative card agglutination test, LATEX/IgM, for IgM quantification in CSF. The test is simple and fast and the lyophilized reagent remains stable even at 45 degrees C. CSF end-titres obtained with LATEX/IgM parallel the IgM concentrations determined by nephelometry and enzyme-linked immunosorbent assay. Detection of intrathecal IgM synthesis is the most sensitive marker for CNS involvement in sleeping sickness. At a cut-off value of >or= 8, the sensitivity and specificity of LATEX/IgM for intrathecal IgM synthesis are 89.4 and 92.7%. As a consequence, patients with LATEX/IgM end-titres >or= 8 are likely to have intrathecal IgM synthesis, thus central nervous system involvement and therefore should be treated accordingly. Further studies should concentrate on the relationship between the LATEX/IgM end-titres, presence of intrathecal IgM synthesis and occurrence of treatment failures in patients treated with pentamidine.

Interleukin (IL)-6, IL-8 and IL-10 in serum and CSF of Trypanosoma brucei gambiense sleeping sickness patients before and after treatment.

Serum and cerebrospinal fluid (CSF) concentrations of interleukin (IL)-6, IL-8, IL-10, tumour necrosis factor-alpha and interferon-gamma were determined in 46 Trypanosoma brucei gambiense sleeping sickness patients in DR Congo, before and after treatment. According to their CSF cell number before treatment, patients were classified as early-stage (0-5 cells/microL), intermediate-stage (6-20 cells/microL) or late-stage patients (> 20 cells/microL). In serum, slightly higher IL-8 concentrations were found in early-stage patients compared to intermediate- or late-stage patients. These high IL-8 levels dropped after treatment. Higher IL-10 concentrations were detected in serum of patients in intermediate or late stage compared to early-stage patients. In both intermediate- and late-stage groups, serum IL-10 decreased after treatment. In CSF, elevated concentrations of IL-6, IL-8 and especially of IL-10 were observed in late-stage T. b. gambiense patients. After treatment, these concentrations dropped to levels similar to those of the other patients. Tumour necrosis factor-alpha was detected only in a few serum and CSF samples, which were scattered over the different patient groups. Interferon-gamma was detected in serum of 5 patients and remained undetectable in CSF.

Blood-cerebrospinal fluid barrier and intrathecal immunoglobulins compared to field diagnosis of central nervous system involvement in sleeping sickness.

Diagnosis of central nervous system (CNS) involvement in sleeping sickness is crucial in order to give an appropriate treatment regimen. Neurological symptoms occur late, therefore field diagnosis is based on white blood cell count, total protein concentration and presence of trypanosomes in cerebrospinal fluid (CSF). More sensitive and specific parameters are now available. Blood-CSF barrier (B-CSFB) dysfunction, intrathecal total and specific immunoglobulin synthesis were evaluated in 95 patients with and without obvious meningoencephalitis, and compared to field criteria.B-CSFB dysfunction is a rather late event in the course of CNS involvement and correlates with the presence of trypanosomes, neurological signs and intrathecal polyspecific and specific immune response. IgM intrathecal response and particularly IgM antibody index are early markers of CNS invasion. We showed that 29% of patients with CSF abnormalities but without trypanosome detection in the field had no neuro-immunological response. In contrast, patients with normal CSF according to field diagnosis showed an intrathecal immune response in 31% of the cases.Field diagnosis can therefore fail to determine neurological involvement but can also provide false positive results. Improved criteria including B-CSFB dysfunction and IgM detection are needed in order to provide an adapted treatment regimen.

[Sleeping sickness: major disorders of circadian rhythm]. / La maladie du sommeil: trouble majeur des rythmes circadiens.

At the meningoencephalitis stage, human African trypanosomiasis (HAT), sleeping sickness, causes dysregulation of the circadian rhythm of the sleep/wake cycle, rather than hypersomnia. In bedridden patients, total sleep time does not exceed 9 hours. The change in the 24-hour distribution of sleep and wakefulness is proportional to severity of clinical symptoms and laboratory abnormalities. The internal structure of sleep is also altered. All patients present sleep onset rapid eye movement periods (SOREMP), i.e., several sleep episodes beginning with rapid eye movement (REM) sleep. In mild cases, treatment with melarsoprol reverses circadian dysregulation, and SOREMP either decrease in number or disappear. Other circadian disturbances may be observed in HAT. These may include circadian dysrhythmia of hormonal secretions, but the relationship between hormonal pulses and sleep/wake states is preserved. The circadian rhythm of secretion of prolactin, renin, growth hormone and cortisol disappears in severe cases, but persists in mild ones. The amplitude and mean 24-hour value of plasma melatonin are normal with nocturnal peaks and no diurnal secretion. However, peak melatonin secretion occurs 2 hours earlier than in healthy African controls. In conclusion, HAT-induced dysregulation of circadian rhythm is proportional to disease severity. Presence of SOREMP and precocity of peak melatonin secretion support disturbance of the serotoninergic network rather than direct action on the biological clock.

Cross-reactivity of anti-galactocerebroside autoantibodies with a Trypanosoma brucei proteolipidic epitope.

Pathogenic mechanisms of the demyelinating encephalopathy featuring the nervous phase of human African trypanosomiasis (HAT) are largely unknown. They might include autoimmune disorders. A variety of autoantibodies is detected during the disease and we have previously evidenced anti-galactocerebroside (GalC) antibodies in the serum and cerebrospinal fluid (CSF) from patients in the nervous stage (stage II) of HAT. We now show that anti-GalC antibodies recognize an antigen located on the parasite membrane and common to different strains of trypanosomes. By using affinity chromatography with a rabbit anti-GalC antiserum, a 52-kD proteolipid was isolated from the membrane of Trypanosoma brucei (T. b.) brucei AnTat 1.9, AnTat 1. 1E, and T. b. rhodesiense Etat 1.2/R and Etat 1.2/S. Antibodies directed against this antigen were found in the CSF from patients with nervous stage HAT. These CSF also contained anti-GalC antibodies and adsorption with the proteolipid decreased anti-GalC reactivity. Immunization of mice with this antigen induced the production of antibodies which cross-reacted with GalC but no protection from experimental infection with T. b. brucei. These data support the hypothesis that anti-GalC antibodies detected in the CSF from HAT patients might be induced by molecular mimicry with a parasite antigen.

[Contribution of biochemical tests in the diagnosis of the nervous phase of human African trypanosomiasis]. / Apport des examens biochimiques dans le diagnostic de la phase nerveuse de la trypanosomose humaine africaine.

The stage of human African trypanosomiasis (HAT) is important to define precisely as far as it is directly related to the type of treatment used. The beginning of the neurological involvement is difficult to find out because there is no known specific clinical or biological sign. This study is trying to look for a precise marker and has been realized in Congo. 70 subjects with parasitologically confirmed HAT and 70 controls are included. The stage of HAT is determined according to the classical definition on the field using the cerebrospinal fluid (CSF) cell count: less than 5 cells/microliters for the first stage (P1), more than 5 cells/microliters for the second stage (P2). The blood analysis has included: glucose, urea, creatinine, sodium, potassium, calcium, chloride, phosphorus, uric acid, total bilirubin, unconjugated bilirubin, total cholesterol, triglycerides, total proteins, aspartate aminotransferase, alanine aminotransferase, creatinine phosphokinase, alkaline phosphatase, gamma-glutamyltransferase, immunoglobulins M and G, C3c fraction of complement, transferrin, seromucoid alpha 1, haptoglobin and albumin. In CSF we have analyzed IgM, IgG, protein levels and the bloodbrain barrier (BBB) impairment. The comparison between the subjects and their controls, the subjects in P1 and in P2, the CSF cell count and the other CSF alterations show the interest of the IgM level in CSF and the BBB impairment to identify subjects in P2. However there is a low gradation in the biological disturbances and not a precise threshold point. Nevertheless it seems reasonable to raise the CSF cell count level to 20 cells/microliters to define the beginning of the nervous involvement.

BalI and MspI polymorphisms of the dopamine D3 receptor gene in African Blacks and Caucasians.

An exonic BalI polymorphism and an intronic MspI polymorphism of the dopamine D3 gene were genotyped in 101 Caucasians from the Alsace and in 56 people from the Congo. This is the first study of the BalI polymorphism in sub-Saharan Africa and the first population study of the MspI site. BalI allele 1 was rare in the Congo (0.12) whereas it is the most frequent allele in all studies in Europe and Asia. MspI allele 1 was also significantly less frequent in the Congolese (0.24) than in Caucasians (0.52). D3 gene alleles show different frequencies in sub-Saharan Africa and may be useful for population studies.

[Explanatory factors of length of stay at the diagnosis-related group 129: common pneumonia and pleurisy, aged over 69 and/or associated co-morbidities]. / Facteurs explicatifs de la durée de séjour au sein du groupe homogène de malades 129: pneumonies et pleurésies banales, âge supérieur à 69 ans et/ou comorbidites associées.

BACKGROUND: Utilization of diagnosis related groups (DRGs) for hospital comparison, based on length of stay (LOS). OBJECTIVES: Inside a DRG (Pneumonia and pleurisy > 69 and/or associated comorbidities), to point out the explicative factors of LOS and the variables which could be recorded for a better description of these patients. SETTING: Pneumologic unit of Limoges' teaching hospital. METHODS: From 01-01-94 to 31-12-94, the DRG 129 was studied through the medical unit summary, the performance status at entrance, the social complexity, the characteristics of pneumonia (symptoms, temperature, arterial pressure...), the severity by American Thoracic Society (ATS) criteria, the procedures (chest X-ray, biology, fibroscopy...), the antibiotic treatments (intravenous and oral). Statistical tests associated univariate analysis, linear and logistic regressions. RESULTS: LOS was 15.53 d +/- 8.57 (m +/- SD). The mathematical model explains 69% of the variance of LOS logarithm. The logistic regression found 5 variables with a significant odds-ratio (OR) for an increased LOS: a high ATS score, repeated laboratory tests, a complex social situation, an increase length of antibiotic treatment (intravenous and oral). CONCLUSION: A better description of LOS, inside a DRG, needs supplementary variables. For pneumonia admitted in Limoges' hospital, the severity of the disease, the number of laboratory tests, the antibiotic treatment, the social complexity are the more significant indicators.

[The detection of anti-galactocerebroside autoantibodies in human African trypanosomiasis]. / Détection d'autoanticorps anti-galactocérébrosides au cours de la trypanosomose humaine africaine.

The pathogenesis of the central nervous system (CNS) damage in human african trypanosomiasis (HAT) is unknown. In view of an immunological mechanism, as in another trypanosomiasis, Chagas' disease, the causative agent of which is Trypanosoma cruzi, we have searched autoantibodies directed against glycosphingolipids of CNS. Detection and characterization of autoantibodies were performed by ELISA and detection after thin-layer chromatography of glycolipids with sera of an experimental model of HAT in sheep and sera of patients suffering of HAT from Côte d'Ivoire and Congo. The predominant reactivity of these sera, was characterized with galactocerebrosides, the major glycolipids of the myelin. Autoantibodies were detected in 42.8% and 25% of patients' sera, respectively from Côte d'Ivoire and Congo. The proportion of these antibodies increased dramatically to 72% in sera of patients with neurological symptoms. Anti-galactocerebroside antibodies were also found in CSF of 24.4% of Congolense patients. The pathogenic significance of these anti-galactocerebroside antibodies remains to be determined. They may constitute a predicative marker for the neurological improvement in HAT.

[An efficacy trial on Trypanosoma brucei brucei of molecules permeating the blood-brain barrier and of megazol]. / Essais d'efficacité sur Trypanosoma brucei brucei de molécules franchissant la barrière hématoméningée et du mégazol.

Human African trypanosomiasis (HAT) is a major public health problem in 36 sub-Saharan African countries and around 50 million people are classed as "at risk". About 25,000 new cases of the disease are reported annually by the World Health Organisation (WHO). This disease is fatal if untreated. As for now, chemotherapy is unsatisfactory and relies on a few drugs which show two major problems. The first is pharmacokinetics involving the passage through the blood-brain barrier. The second concerns toxicity and adverse side-effects of drugs used to treat this disease. New trypanocides should be safe, effective without toxicity. This study reports the action of 45 drugs, known to pass through the blood-brain barrier and belonging to different therapeutic classes, and also the megazol, a nitrothiadiazole derivative, on Trypanosoma brucei brucei AnTat 1-9 in vitro in acellular semi-defined medium. Results showed that some drugs did not modify the parasitic growth, and others were either trypanostatic or trypanocide. These last drugs were tested in vivo on T. b. brucei An-Tat 1-9 infected Swiss mice. Only megazol was shown to be effective and trypanocide. This compound might trigger the production of oxygen derivatives and free radicals-which have toxic effects on the trypanosome metabolism.