Serum arginase, a biomarker of treatment efficacy in human African trypanosomiasis.

Arginase serum levels were increased in human African trypanosomiasis patients and returned to control values after treatment. Arginase hydrolyzes l-arginine to l-ornithine, which is essential for parasite growth. Moreover, l-arginine depletion impairs immune functions. Arginase may be considered as a biomarker for treatment efficacy.

Invasive fungal diseases in patients with autoimmune diseases: a case series from the French RESSIF network.

OBJECTIVES: We aimed to describe patients with autoimmune diseases (AID) developing invasive fungal disease (IFD) and identify factors associated with short-term mortality. METHODS: We analysed cases of IFD associated with AID from the surveillance network of invasive fungal diseases (Réseau de surveillance des infections fongiques invasives, RESSIF) registry of the French national reference centre for invasive mycoses. We studied association of AID-specific treatments with 30-day mortality. We analysed total lymphocyte and CD4-T cell counts in patients with Pneumocystis jirovecii pneumonia (PCP). RESULTS: From 2012 to 2018, 549 individuals with IFD and AID were included, mainly with PCP (n=227, 41.3%), fungemia (n=167, 30.4%) and invasive aspergillosis (n=84, 15.5%). Rheumatoid arthritis (RA) and anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV) were the most frequent AID in PCP (n=55 and 25, respectively) and invasive aspergillosis (n=15 and 10, respectively), inflammatory bowel diseases (IBDs) were predominant in fungemia (n=36). At IFD diagnosis, 365 (66.5%) patients received glucocorticoids (GCs), 285 (51.9%) immunosuppressants, 42 (7.7%) tumor necrosis factor (TNF)-α blockers, 75 (13.7%) other biologics. Mortality at 30 days was 28.1% (143/508). Fungemia and high-dose GCs were independently associated with higher 30-day mortality. In PCP patients, lymphopenia <1500/mm3 was frequent (132/179, 73.7%) even if CD4+T cell count exceeded 200/mm3 in 56/78 patients (71.8%) (median 472.5/mm3, IQR 160-858). CONCLUSION: IFD associated with AID occurs primarily in RA, AAV and IBD, especially when treated with GCs and immunosuppressants. Mortality is high, especially for patients on high-dose GCs. Lymphopenia may help identify risk of PCP, but normal CD4+T cell count does not rule out the risk. Further studies are needed to assess the individual risk factors for IFD.

Active Surveillance Program to Increase Awareness on Invasive Fungal Diseases: the French RESSIF Network (2012 to 2018).

The French National Reference Center for Invasive Mycoses and Antifungals leads an active and sustained nationwide surveillance program on probable and proven invasive fungal diseases (IFDs) to determine their epidemiology in France. Between 2012 and 2018, a total of 10,886 IFDs were recorded. The incidence increased slightly over time (2.16 to 2.36/10,000 hospitalization days, P = 0.0562) in relation with an increase of fungemia incidence (1.03 to 1.19/10,000, P = 0.0023), while that of other IFDs remained stable. The proportion of ≥65-year-old patients increased from 38.4% to 45.3% (P < 0.0001). Yeast fungemia (n = 5,444) was due mainly to Candida albicans (55.6%) with stable proportions of species over time. Echinocandins became the main drug prescribed (46.7% to 61.8%), but global mortality rate remained unchanged (36.3% at 1 month). Pneumocystis jirovecii pneumonia (n = 2,106) was diagnosed mostly in HIV-negative patients (80.7%) with a significantly higher mortality than in HIV-positive patients (21.9% versus 5.4% at 1 month, P < 0.0001). Invasive aspergillosis (n = 1,661) and mucormycosis (n = 314) were diagnosed mostly in hematology (>60% of the cases) with a global mortality rate of 42.5% and 59.3%, respectively, at 3 months and significant changes in diagnosis procedure over time. More concurrent infections were also diagnosed over time (from 5.4% to 9.4% for mold IFDs, P = 0.0115). In conclusion, we observed an aging of patients with IFD with a significant increase in incidence only for yeast fungemia, a trend toward more concurrent infections, which raises diagnostic and therapeutic issues. Overall, global survival associated with IFDs has not improved despite updated guidelines and new diagnostic tools. IMPORTANCE The epidemiology of invasive fungal diseases (IFDs) is hard to delineate given the difficulties in ascertaining the diagnosis that is often based on the confrontation of clinical and microbiological criteria. The present report underlines the interest of active surveillance involving mycologists and clinicians to describe the global incidence and that of the main IFDs. Globally, although the incidence of Pneumocystis pneumonia, invasive aspergillosis, and mucormycosis remained stable over the study period (2012 to 2018), that of yeast fungemia increased slightly. We also show here that IFDs seem to affect older people more frequently. The most worrisome observation is the lack of improvement in the global survival rate associated with IFDs despite the increasing use of more sensitive diagnostic tools, the availability of new antifungal drugs very active in clinical trials, and a still low/marginal rate of acquired in vitro resistance in France. Therefore, other tracks of improvement should be investigated actively.

Human neurocysticercosis: comparison of different diagnostic tests using cerebrospinal fluid.

Neurocysticercosis (NC), caused by the larval stage of Taenia solium, is one of the most common parasitic diseases of the central nervous system. The diagnosis of NC is mostly based on costly brain neuroimaging (computed tomography and/or nuclear magnetic resonance), which is rarely accessible in most affected areas. The most sensitive and specific tools for NC diagnosis are imagery techniques. The identification of specific antibodies and antigens is currently used only to support NC diagnosis due to their limited specificity and sensitivity. This study was performed to compare immunodiagnostic assays (antibody detection by enzyme-linked immunosorbent assay [ELISA] and enzyme-linked immunoelectrotransfer blotting [EITB] and HP10 antigen detection by ELISA) with the detection of parasite DNA by PCR amplification of a repetitive element of the parasite genome in the cerebrospinal fluid (CSF) of 121 radiologically and clinically characterized NC patients. Patients were divided into six groups according to the stage of the parasites and their localization. The CSF cellularity of each patient was also recorded. When all patients were considered, PCR exhibited the highest sensitivity (95.9%) and variable specificity (80% or 100%) depending on the controls used. The sensitivities of antibody detection by ELISA and EITB were not significantly different, and ELISA identified HP10 antigen mostly when vesicular cysticerci were located in the subarachnoideal basal cisterns. These results can help in the selection of different individual assays or combinations of assays to be used in NC diagnosis according to different requirements.

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

OBJECTIVES: In human African trypanosomiasis (HAT, sleeping sickness), staging of disease and treatment follow-up relies on white cell count in the cerebrospinal fluid (CSF). As B lymphocytes (CD19 positive cells) are not found in the CSF of healthy individuals but occur in neurological disorders such as multiple sclerosis, B lymphocyte count may be useful for field diagnosis/staging and therapeutic follow-up in HAT. METHODS: Seventy-one HAT patients were diagnosed and 50 were followed-up 6-24 months after treatment. White cell counts were used for conventional staging (stage 1, < or =5 cells/microl CSF, n = 42; stage 2, > or =20 cells/microl, n = 16) and intermediate stage (6-19 cells/microl, n = 13). Slides containing 1 microl of CSF mixed with Dynabeads CD19 pan B were examined microscopically to detect B cell rosettes (bound to at least four beads). RESULTS: Stage 1 patients exhibited zero (n = 37) or one CSF rosette/microl (n = 5), contrary to most stage 2 patients (14/16: > or =2 rosettes/microl). Intermediate stage patients expressed 0 (n = 9), 1 (n = 3) or 2 (n = 1) rosettes/microl of CSF. During follow-up, rosette counts correlated with white cell count staging but were much easier to read. CONCLUSION: B cell rosettes being easily detected in the CSF in field conditions may be proposed to replace white cell count for defining HAT stages 1 and 2 and limit uncertainty in treatment decision in patients with intermediate stage.

Endothelial cell signalling induced by trans-sialidase from Trypanosoma cruzi.

The protozoan responsible for Chagas' disease, Trypanosoma cruzi, expresses on its surface an unusual trans-sialidase enzyme thought to play an important role in host-parasite interactions. Trans-sialidase is the product of a multigene family encoding both active and inactive proteins. We have demonstrated that despite lacking enzymatic activity due to a single mutation, Tyr342-His, inactive trans-sialidase displays sialic acid binding activity, with identical specificity to that of its active analogue. In this work we demonstrate that binding of a recombinant inactive trans-sialidase to molecules containing alpha2,3-linked sialic acid on endothelial cell surface triggers NF-kappaB activation, expression of adhesion molecules and upregulation of parasite entry into host cells. Furthermore, inactive recombinant trans-sialidase blocks endothelial cell apoptosis induced by growth factor deprivation. These results suggest that inactive members of the trans-sialidase family play a role in endothelial cell responses to T. cruzi infection.

Increased CXCL-13 levels in human African trypanosomiasis meningo-encephalitis.

OBJECTIVES: To determine the role of the B-cell attracting chemokine CXCL-13, which may initiate B-cell trafficking and IgM production in diagnosing HAT meningo-encephalitis. METHODS: We determined CXCL-13 levels by ELISA on paired sera and CSF of 26 patients from Angola and of 16 controls (six endemic and ten non-endemic). Results were compared to standard stage determination markers and IgM intrathecal synthesis. RESULTS: CXCL-13 levels in patients' sera had a median value of 386.6 pg/ml and increased levels were associated with presence of trypanosomes in the CSF but not with other stage markers. CXCL-13 levels in patients' CSF had a median value of 80.9 pg/ml and increased levels were associated with all standard stage determination markers and IgM intrathecal synthesis. CONCLUSION: CXCL-13 levels in CSF increased significantly during the course of HAT. Hence the value of CXCL-13 for diagnosis, follow-up or as a marker of disease severity should be tested in a well-defined cohort study.

Cerebral inducible nitric oxide synthase protein expression in microglia, astrocytes and neurons in Trypanosoma brucei brucei-infected rats.

To study the anatomo-biochemical substrates of brain inflammatory processes, Wistar male rats were infected with Trypanosoma brucei brucei. With this reproducible animal model of human African trypanosomiasis, brain cells (astrocytes, microglial cells, neurons) expressing the inducible nitric oxide synthase (iNOS) enzyme were revealed. Immunohistochemistry was achieved for each control and infected animal through eight coronal brain sections taken along the caudorostral axis of the brain (brainstem, cerebellum, diencephalon and telencephalon). Specific markers of astrocytes (anti-glial fibrillary acidic protein), microglial cells (anti-integrin alpha M) or neurons (anti-Neuronal Nuclei) were employed. The iNOS staining was present in neurons, astrocytes and microglial cells, but not in oligodendrocytes. Stained astrocytes and microglial cells resided mainly near the third cavity in the rostral part of brainstem (periaqueductal gray), diencephalon (thalamus and hypothalamus) and basal telencephalon. Stained neurons were scarce in basal telencephalon, contrasting with numerous iNOS-positive neuroglial cells. Contrarily, in dorsal telencephalon (neocortex and hippocampus), iNOS-positive neurons were plentiful, contrasting with the marked paucity of labelled neuroglial (astrocytes and microglial) cells. The dual distribution between iNOS-labelled neuroglial cells and iNOS-labelled neurons is a feature that has never been described before. Functionalities attached to such a divergent distribution are discussed.

Onchocerciasis-related epilepsy? Prospects at a time of uncertainty.

Epilepsy and onchocerciasis (river blindness) constitute serious public health problems in several tropical countries. There are four main mechanisms that might explain a relationship between these two diseases: (i) the presence of Onchocerca volvulus in the central nervous system; (ii) the pathogenicity of various O. volvulus strains; (iii) immunological mechanisms involving cross-reactive immunization or cytokine production during infection; and (iv) the triggering role of insomnia due to itching.

A link between chemokine levels and disease severity in human African trypanosomiasis.

Trypanosoma brucei gambiense infection is an important public health challenge in sub-Saharan Africa. This parasitic disease is difficult to diagnose due to insidious clinical signs and transient parasitaemias. The clinical course is marked by two stages of increasing disease severity. An early systemic parasitic invasion is followed by the development of a progressive meningo-encephalitis. During this latter stage, a broad spectrum of neurological signs appears, which finally lead to a demyelinating and fatal stage if untreated. Treatment is toxic and difficult to administer when the CNS is invaded. Therefore, accurate diagnostic methods for stage determination are needed. The classically used criteria are not sufficiently specific and mechanisms of parasite invasion through the blood-brain barrier remain poorly understood. As cytokines/chemokines are involved in the early recruitment of leukocytes into the CNS, this study has focused on their potential value to define the onset of CNS involvement. Levels of monocyte chemoattractant protein-1/CCL-2, macrophage inflammatory protein-1alpha/CCL-3, IL-8/CXCL-8, regulated upon activation T cell expressed and secreted (RANTES)/CCL-5 and IL-1beta were measured in paired sera and CSF from 57 patients and four controls. Patients were classified into three groups (stage 1, intermediate and stage 2) according to current field criteria for stage determination (CSF cell count, presence of trypanosomes in CSF and neurological signs). In sera, cytokine/chemokine levels were poorly related to disease stage. Only CXCL-8 was higher in stage 1 patients when compared with stage 2 and CCL-5 was higher in controls when compared with patients. In contrast, in CSF the expression of the selected cytokines, except CCL-5, was associated with the presence of neurological signs, demonstrating their diagnostic value. We observed a relationship between the presence of trypanosomes or trypanosome-related compounds in CSF and levels of IL-1beta, CXCL-8, CCL-2 and CCL-3. These cytokines and chemokines may be triggered by the parasite and hence are potential markers of CNS invasion.

[Trypanosomiases]. / Les trypanosomoses.

Trypanosomiases are imported and rare parasitosis on the French metropolitan territory. They are re-emerging in some endemic areas, and their mode of transmission can lead to an increase of imported cases in a near future. They can be responsible for serious disease. In this paper, we describe the basic data concerning epidemiology, clinical features, diagnosis, treatment and prevention of sleeping sickness (Africa) and Chagas disease (Latin America).

Endothelial cell activation in the presence of African trypanosomes.

During human African trypanosomiasis, trypanosomes (Trypanosoma brucei gambiense or T. b. rhodesiense) invade the central nervous system (CNS). Mechanisms of blood-brain barrier and blood-cerebrospinal fluid barrier leakage remain unknown. To better understand the relationships between trypanosomes and endothelial cells, the principal cell population of those barriers, we cultured a human bone marrow endothelial cell (HBMEC) line in the presence or absence of T. b. gambiense, to study cell activation. As indicated by NF-kappaB translocation to the nucleus, cells were activated in the presence of trypanosomes. The expression of the adhesion molecules ICAM-1, E-selectin and VCAM-1 increased in co-culture. The parasites induced the synthesis of the pro-inflammatory cytokines TNF-alpha, IL-6 and IL-8, and of nitric oxide (NO) by HBMEC. Cells were also cultured in the presence of parasite variant surface glycoproteins (VSGs), and an increase in TNF-alpha, IL-6, IL-8, and NO synthesis was also observed. Soluble VSGs induced NF-kappaB translocation, and the expression of adhesion molecules, indicating that they could possibly be the molecular soluble factor responsible for endothelial cell activation. The permeability coefficient of HBMEC layer increased when cells were cultured in the presence of trypanosomes, parasite culture supernatant, or VSGs. Thus, T. b. gambiense can activate endothelial cells in vitro, through the release of soluble activating factors. Consequences of endothelial cell activation by parasite products may include a potentiation of the inflammatory reaction, leukocyte recruitment, passage of trypanosomes into the CNS, and barrier dysfunction observed during CNS involvement of HAT.

Oral nystatin prophylaxis of Candida spp. colonization in ventilated critically ill patients.

OBJECTIVE: Colonization of multiple body sites is a leading risk factor for Candida spp. infection in intensive care unit (ICU) patients. We evaluated whether oral nystatin prophylaxis reduces Candida spp. colonization in ventilated ICU patients. DESIGN AND SETTING: Prospective, randomized, open-label study with blinded assessment of the objective primary evaluation criterion in the medical-surgical ICU of a teaching hospital. PATIENTS: The study included 98 consecutive patients mechanically ventilated for at least 48 h (mean age 58+/-19 years; mean SAPS II 40+/-11), assigned to either treatment group (n=51) or control group (n=47). Study groups were comparable for age, SAPS II, reason for admission, and immune status. INTERVENTIONS: Patients were randomized to receive oral nystatin (treatment group; 3x10(6) U per day) or no nystatin (control group). Multiple body sites (trachea, stomach, rectum, urine, groin, and blood) were tested for Candida spp. on admission and then every 3 days by mycologists blinded to group assignment, and the colonization index was determined. RESULTS: Colonization by Candida spp. developed in 25% of controls but in none of the treated patients. In multivariate analysis, the absence of nystatin prophylaxis and ICU length of stay were independently associated with Candida spp. colonization. No invasive candidiasis was diagnosed in either study group. CONCLUSIONS: Oral nystatin prophylaxis efficiently prevented Candida spp. colonization in ICU patients at low risk of developing invasive candidiasis. Further studies are needed to determine whether this strategy remains efficient in reducing Candida spp. infections in higher risk ICU patients.

Synthesis and biological activity of nitro heterocycles analogous to megazol, a trypanocidal lead.

As part of our efforts to develop new compounds aimed at the therapy of parasitic infections, we synthesized and assayed analogues of a lead compound megazol, 5-(1-methyl-5-nitro-1H-2-imidazolyl)-1,3,4-thiadiazol-2-amine, CAS no. 19622-55-0), in vitro. We first developed a new route for the synthesis of megazol. Subsequently several structural changes were introduced, including substitutions on the two rings of the basic nucleus, replacement of the thiadiazole by an oxadiazole, replacement of the nitroimidazole part by a nitrofurane or a nitrothiophene, and substitutions on the exocyclic nitrogen atom for evaluation of an improved import by the glucose or the purine transporters. Assays of the series of compounds on the protozoan parasites Trypanosoma brucei, Trypanosoma cruzi, and Leishmania donovani, as either extracellular cells or infected macrophages, indicated that megazol was more active than the derivatives. Megazol was then evaluated on primates infected with Trypanosoma brucei gambiense, including late-stage central nervous system infections in combination with suramin. Full recovery was observed in five monkeys in the study with no relapse of parasitemia within a 2 year follow-up. Because there is a lack of efficacious treatments for sleeping sickness in Africa and Chagas disease in South America, megazol is proposed as a potential alternative. The mutagenicity of this compound is at present being reevaluated, and metabolism is also under investigation prior to possible further developments.

Twenty-four-hour disruption of the sleep-wake cycle and sleep-onset REM-like episodes in a rat model of African trypanosomiasis.

STUDY OBJECTIVES: Patients with human African trypanosomiasis (sleeping sickness) due to the inoculation of Trypanosoma brucei gambiense or rhodesiense show a major disruption of the 24-hour sleep-wake distribution, accompanied by the occurrence of sleep-onset rapid-eye-movement (REM) sleep episodes, proportional to the severity of the illness. Although animal models of human African trypanosomiasis have been developed to understand the pathogenic mechanisms leading to immune alterations, the development of an animal model featuring the alterations of endogenous biologic rhythms remains a necessity. ANIMALS: Sprague-Dawley rats (N = 10) entrained to a 12:12-hour dark-light regimen. INTERVENTIONS: Rats were infected with Trypanosoma brucei brucei AnTat 1.1E and instrumented with electrocorticographic and electromyographic electrodes. Polysomnography was recorded continuously from 2 days before infection until the animal's death. MEASUREMENTS AND RESULTS: The analysis of the spontaneous sleep-wake architecture revealed an increased proportion of slow-wave sleep (SWS) and a decreased amount of wakefulness 2 days before death. Considerable sleep fragmentation was observed in the infected rats, with numerous changes in sleep-wake stages and an increased number of episodes of wakefulness and SWS. Infected rats presented a fragmented pattern of SWS and a marked reduction in the mean paradoxical-sleep (PS) latency, resulting in a considerable disruption of the PS-SWS sequences. Abnormal transitions, particularly the appearance of sleep-onset REM episodes, marked the disruption of the internal sleep structure. The electrocorticogram traces were modified during SWS, with the occurrence of abnormal hypersynchronic slow waves and a disappearance of spindles. CONCLUSION: The Trypanosoma brucei brucei-infected rat is a good model of the syndrome seen in human African trypanosomiasis, ie, the 24-hour disruption of the sleep-wake cycle and the occurrence of sleep-onset REM-like sleep episodes.

Population genetic structure of Taenia solium from Madagascar and Mexico: implications for clinical profile diversity and immunological technology.

Taenia solium is a cestode parasitic of humans and pigs that strongly impacts on public health in developing countries. Its larvae (cysticercus) lodge in the brain, causing neurocysticercosis, and in other tissues, like skeletal muscle and subcutaneous space, causing extraneuronal cysticercosis. Prevalences of these two clinical manifestations vary greatly among continents. Also, neurocysticercosis may be clinically heterogeneous, ranging from asymptomatic forms to severely incapacitating and even fatal presentation. Further, vaccine design and diagnosis technology have met with difficulties in sensitivity, specificity and reproducibility. Parasite diversity underlying clinical heterogeneity and technological difficulties is little explored. Here, T. solium genetic population structure and diversity was studied by way of random amplified polymorphic DNA in individual cysticerci collected from pigs in Madagascar and two regions in Mexico. The amplification profiles of T. solium were also compared with those of the murine cysticercus Taenia crassiceps (ORF strain). We show significant genetic differentiation between Madagascar and Mexico and between regions in Mexico, but less so between cysticerci from different localities in Mexico and none between cysticerci from different tissues from the same pig. We also found restricted genetic variability within populations and gene flow was estimated to be low between populations. Thus, genetic differentiation of T. solium suggests that different evolutionary paths have been taken and provides support for its involvement in the differential tissue distribution of cysticerci and varying degrees of severity of the disease. It may also explain difficulties in the development of vaccines and tools for immunodiagnosis.

In vitro induction of microglial and endothelial cell apoptosis by cerebrospinal fluids from patients with human African trypanosomiasis.

In human African trypanosomiasis, trypanosomes first develop in the blood and lymph (Stage 1), then spread to the central nervous system (CNS) (Stage 2). Disruption of the blood-brain barrier of unknown mechanism occurs in Stage 2 disease. The hypothesis that cerebrospinal fluids (CSF) from African trypanosomiasis patients might contain factor(s) able to induce apoptosis in endothelial cells led us to evaluate this effect by two methods, the TdT-mediated dUTP nick end labelling (TUNEL) method and the measurement of soluble nucleosomes released by apoptotic cells in culture supernatant by ELISA. Apoptosis induction by CSF was also studied with microglial cells, the resident macrophages in the brain, which participate in the blood-brain barrier in the perivascular area. In contrast with control CSF, African trypanosomiasis patients' CSF induced apoptosis in both microglial and endothelial cells. The results obtained with the two methods correlated well, and showed that Stage 2 CSF induced apoptosis at higher levels in microglial cells, whereas the disease stage was not decisive for apoptosis induction in endothelial cells. We measured soluble Fas ligand (sFasL) and anti-Fas antibodies levels, two potent inducers of the Fas signalling pathway leading to apoptosis, in CSF from African trypanosomiasis patients and controls. CSF from African trypanosomiasis patients contained sFasL, and anti-Fas antibodies at higher levels than in controls. Stage 2 CSF contained more sFasL than Stage 1 CSF, and anti-Fas antibodies were detected only in Stage 2 CSF. Caspase-8 inhibitor effect and statistical data suggest that other pro-apoptotic factors may be involved in some CSF-induced apoptosis. Apoptosis induction may participate in the pathogenesis during African trypanosomiasis, and the presence of sFasL and anti-Fas antibodies may provide new tools for diagnosis and prognosis of the disease.

Treatment perspectives for human African trypanosomiasis.

Human African trypanosomiasis (HAT), or sleeping sickness, is currently on the rise. HAT develops in two stages, the first involving the hemolymphatic system, and the second, the neurological system. Left untreated, HAT is invariably fatal. There have been no therapeutic advances in more than 40 years. Stage 1 can be treated with pentamidine and suramin, but stage 2 can only be treated with melarsoprol, a toxic arsenic derivative that has a 2-12% incidence of fatal side-effects (encephalopathy). Eflornithine has never achieved widespread use because it is difficult to administer under field conditions. Nifurtimox has been used successfully in the treatment of American trypanosomiasis, or Chagas disease, but only in small studies or as a compassionate use treatment. There is little research and development for new drugs in this area: only one prodrug is in the clinical development phase, a pentamidine analog that offers hope for the replacement of injectable pentamidine with an orally administered drug. Current efforts appear to be focused on reevaluating older drugs. A course of treatment with melarsoprol for 10 days at 2.2 mg/kg/day is now in the multicenter evaluation phase. Orally administered eflornithine is also slated for reevaluation. In addition, studies of drug combinations are recommended to determine possible combined or synergistic effects and find ways to reduce toxicity.

Plasma kinetics and efficacy of oral megazol treatment in Trypanosoma brucei brucei-infected sheep.

Experimentally infected sheep have been previously developed as an animal model of trypanosomosis. We used this model to test the efficacy of megazol on eleven Trypanosoma brucei brucei-infected sheep. When parasites were found in blood on day 11 post-infection, megazol was orally administered at a single dose of 40 or 80mg/kg. After a transient aparasitaemic period, all animals except two relapsed starting at day 2 post-treatment, which were considerated as cured on day 150 post-treatment and showed no relapse after a follow-up period of 270 days. In order to understand the high failure of megazol treatment to cure animals, a kinetic study was carried out. Plasma concentrations of megazol determined, by reverse-phase high-performance liquid chromatography at 8h post-treatment in these animals, were lowered, suggesting slow megazol absorption, except in cured animals. However, megazol plasma profiles in uninfected sheep after a single oral dose of megazol showed a fast megazol lowered absorption associated with a short plasma half-life of drug. Inter-individual variation of megazol pharmacokinetic properties was also observed. These findings suggested that the high failure rates of megazol treatment were related to poor drug availability after oral administration in sheep. In conclusion, megazol could cure sheep with T. b. brucei infection but oral administration was not an effective route.