Case Report: Trypanosoma brucei Gambiense Human African Trypanosomiasis as the Cause of Fever in an Inpatient with Multiple Myeloma and HIV-1 Coinfection.

We report the case of a 64-year-old woman found to have urban-acquired Trypanosoma brucei (T.b.) gambiense human African trypanosomiasis (HAT) as the cause of sustained fever starting 9 months after returning to Canada from Democratic Republic of the Congo, in the context of concomitant multiple myeloma and HIV-1 coinfection. Approaches for the management of both clinical stages of T.b. gambiense HAT are well defined for endemic settings using current diagnostics and treatments. However, few data inform the diagnosis and management of patients with bone marrow suppression from active malignancy, recent anticancer therapy, or HIV coinfection. We discuss the implications of immunosuppression for diagnosis and management of T.b. gambiense HAT.

Coxiella burnetii associated with BVDV (Bovine Viral Diarrhea Virus), BoHV (Bovine Herpesvirus), Leptospira spp, Neospora caninum, Toxoplasma gondii and Trypanosoma vivax in reproductive disorders in cattle / Coxiella burnetii associada ao BVDV (Vírus da Diarreia Viral Bovina), BoHV (Vírus do Herpes Bovino), Leptospira spp, Neospora caninum, Toxoplasma gondii e Trypanosoma vivax em distúrbios reprodutivos em bovinos

Abstract This is a cross-sectional study to assess the presence of antibodies in ruminants against selected pathogens associated with reproductive disorders in cattle in four Brazilian states, including the zoonotic agent Coxiella burnetii. The used tests were Virus Neutralization Assay for IBR and BVD, Microscopic Agglutination Test for Leptospira spp., Indirect Fluorescent Antibody Test (IFAT) for C. burnetii and Toxoplasma gondii, and Enzyme-Linked Immunosorbent Assay for Neospora caninum and Trypanosoma vivax. Seropositivity for C. burnetii was 13.7% with titers from 128 to 131,072; 57.8% for BoHV-1, with titers between 2 and 1,024; 47.1% for BVDV-1a, with titers from 10 to 5,120; 89.2% for N. caninum; 50% for T. vivax; and 52.0% for Leptospira spp., with titers between 100 to 800 (the following serovars were found: Tarassovi, Grippotyphosa, Canicola, Copenhageni, Wolffi, Hardjo, Pomona and Icterohaemorrhagiae); 19.6% for T. gondii with titer of 40. This is the first study that has identified C. burnetii in cattle associated with BoHV and BVDV, N. caninum, Leptospira spp., T. gondii and T. vivax. Thus, future studies should be conducted to investigate how widespread this pathogen is in Brazilian cattle herds.

Resumo Este é um estudo transversal para avaliar a presença de anticorpos em ruminantes contra patógenos selecionados e associados a distúrbios reprodutivos em bovinos de quatro estados brasileiros, incluindo o agente zoonótico Coxiella burnetii. Os testes utilizados foram Teste de Vírus-Neutralização para BoHV e BVDV, teste de Aglutinação Microscópica para Leptospira spp., Reação de Imunofluorescência Indireta for C. burnetii e Toxoplasma gondii, e Ensaio de Imunoabsorção Enzimática para Neospora caninum e Trypanosoma vivax. A soropositividade para C. burnetii foi de 13,7% com títulos de 128 a 131.072; 57,8% para BoHV-1, com títulos entre 2 a 1.024; 47,1% para BVDV-1a, com títulos de 10 a 5.120; 89,2% para N. caninum; 50% para T. vivax; e 52,0% para Leptospira spp., com títulos entre 100 a 800 (sorovares encontrados: Tarassovi, Grippotyphosa, Canicola, Copenhageni, Wolffi, Hardjo, Pomona e Icterohaemorrhagiae) 19,6% para T. gondii com título de 40. Este é o primeiro estudo que evidencia a participação de C. burnetii em bovinos associada ao Vírus da Rinotraqueíte bovina infecciosa e da diarreia viral bovina, N. caninum, Leptospira spp., T. gondii e T. vivax em bovinos. Desta forma, futuros estudos devem ser conduzidos a fim de investigar o quão disseminado se encontra este patógeno em rebanhos bovinos brasileiros.

Role of cytokines in Trypanosoma brucei-induced anaemia: A review of the literature.

BACKGROUND: Anaemia is an important complication of trypanosomiasis. The mechanisms through which trypanosomal infection leads to anaemia are poorly defined. A number of studies have implicated inflammatory cytokines, but these data are limited and inconsistent. In this article, we reviewed the published literature on cytokines associated with Trypanosoma brucei infections and their role in the immunopathology leading to anaemia. METHODOLOGY: Articles were searched in PubMed through screening of titles and abstracts with no limitation on date of publishing and study design. Articles in English were searched using keywords "African trypanosomiasis", "sleeping sickness", "Trypanosoma brucei", in all possible combinations with "anaemia" and/or "cytokines". RESULTS: Twelve articles examining cytokines and their role in trypanosomeinduced anaemia were identified out of 1095 originally retrieved from PubMed. None of the articles identified were from human-based studies. A total of eight cytokines were implicated, with four cytokines (IFN-γ, IL-10, TNF-α, IL-12) showing an association with anaemia. These articles reported that mice lacking TNF-α were able to control anaemia, and that IFN-γ was linked to severe anaemia given its capacity to suppress erythropoiesis, while IL-10 was shown to regulate IFN-γ and TNF-α, providing a balance that was associated with severity of anaemia. IFN-γ and TNF-α have also been reported to work in concert with other factors such as nitric oxide and iron in order to induce anaemia. CONCLUSION: IFN-γ, IL-10, and TNF-α were the three major cytokines identified to be heavily involved in anaemia caused by Trypanosoma brucei infection. The anti-inflammatory cytokine, IL-10, was shown to counter the effects of proinflammatory cytokines in order to balance the severity of anaemia. The mechanism of anaemia is multifactorial and therefore requires further, more elaborate research. Data from human subjects would also shed more light.

Ly6C- Monocytes Regulate Parasite-Induced Liver Inflammation by Inducing the Differentiation of Pathogenic Ly6C+ Monocytes into Macrophages.

Monocytes consist of two well-defined subsets, the Ly6C+ and Ly6C- monocytes. Both CD11b+ myeloid cells populations have been proposed to infiltrate tissues during inflammation. While infiltration of Ly6C+ monocytes is an established pathogenic factor during hepatic inflammation, the role of Ly6C- monocytes remains elusive. Mice suffering experimental African trypanosome infection die from systemic inflammatory response syndrome (SIRS) that is initiated by phagocytosis of parasites by liver myeloid cells and culminates in apoptosis/necrosis of liver myeloid and parenchymal cells that reduces host survival. C57BL/6 mice are considered as trypanotolerant to Trypanosoma congolense infection. We have reported that in these animals, IL-10, produced among others by myeloid cells, limits the liver damage caused by pathogenic TNF-producing Ly6C+ monocytes, ensuring prolonged survival. Here, the heterogeneity and dynamics of liver myeloid cells in T. congolense-infected C57/BL6 mice was further dissected. Moreover, the contribution of Ly6C- monocytes to trypanotolerance was investigated. By using FACS analysis and adoptive transfer experiments, we found that the accumulation of Ly6C- monocytes and macrophages in the liver of infected mice coincided with a drop in the pool of Ly6C+ monocytes. Pathogenic TNF mainly originated from Ly6C+ monocytes while Ly6C- monocytes and macrophages were major and equipotent sources of IL-10 within myeloid cells. Moreover, Nr4a1 (Nur77) transcription factor-dependent Ly6C- monocytes exhibited IL-10-dependent and cell contact-dependent regulatory properties contributing to trypanotolerance by suppressing the production of TNF by Ly6C+ monocytes and by promoting the differentiation of the latter cells into macrophages. Thus, Ly6C- monocytes can dampen liver damage caused by an extensive Ly6C+ monocyte-associated inflammatory immune response in T. congolense trypanotolerant animals. In a more general context, Ly6C- or Ly6C+ monocyte targeting may represent a therapeutic approach in liver pathogenicity induced by chronic infection.

[Gustavo Pittaluga and the expedition to study sleeping sickness in the Spanish territories of the Gulf of Guinea (1909)]. / Gustavo Pittaluga y la expedición para el estudio de la enfermedad del sueño en los territorios españoles del golfo de Guinea (1909).

INTRODUCTION: Sleeping sickness, or human African trypanosomiasis, caused an important mortality at the beginnings of the twentieth century. For this reason the European colonial countries organized several scientific expeditions which contributed decisively to the knowledge of the disease. AIM: To study the first investigation performed in Spain on African trypanosomiasis and in the field of tropical medicine, which was accomplished by a scientific expedition to the Spanish territories in the Gulf of Guinea organized by Cajal in 1909. DEVELOPMENT: The parasitologist Gustavo Pittaluga, who became one of the most outstanding figures in Spanish medicine and public health during the first third of the twentieth century, commanded the expedition. Other members were Luis Rodriguez Illera and Jorge Ramon Fananas, Cajal's son. Along four months they travelled through the Spanish territories of Guinea, collecting clinical and epidemiological information on sleeping sickness and other diseases, and examining a great number of patients, who had hematological and parasitological studies performed. In the clinical description of the 14 cases of trypanosomiasis studied we have found the first description of the opsoclonus-myoclonus syndrome. A pathological study of the brain was performed in one case. In addition, important entomological studies and experimental investigations on trypanosomiasis were also performed. CONCLUSIONS: This expedition took place in the context of the impulse of renovation of Spanish science headed by Cajal through the Junta de Ampliacion de Estudios, recently created. In the investigations performed in Guinea, Pittaluga demonstrated a high scientific standard in the fields of clinical medicine, hygiene, parasitology and entomology, comparable with other contemporary European studies.

Effect of Trypanosoma brucei brucei on erythropoiesis in infected rats.

Anemia generated from African trypanosome infection is considered an important symptom in humans and in domestic animals. In order to recover from anemia, the process of erythropoiesis is essential. Erythropoiesis is affected by erythropoietin (EPO), an erythropoietic hormone, supplying iron and inflammatory and proinflammatory cytokines. However, the role of these factors in erythropoiesis during African trypanosome infection remains unclear. In the present study, we analyze how erythropoiesis is altered in anemic Trypanosoma brucei brucei (interleukin-tat 1.4 strain [ILS])-infected rats. We report that the packed cell volume (PCV) of blood from ILS-infected rats was significantly lower 4 days after infection, whereas the number of reticulocytes, as an index of erythropoiesis, did not increase. The level of EPO mRNA in ILS-infected rats did not increase from the third day to the sixth day after infection, the same time that the PCV decreased. Kidney cells of uninfected rats cultured with ILS trypanosome strain for 8 hr in vitro decreased EPO mRNA levels. Treatment of both ILS and cobalt chloride mimicked hypoxia, which restrained the EPO-production-promoting effect of the cobalt. Messenger RNA levels of ß-globin and transferrin receptor, as markers of erythropoiesis in the bone marrow, also decreased in ILS-infected rats. Levels of hepcidin mRNA, which controls the supply of iron to the marrow in liver, were increased in ILS-infected rats; however, the concentration of serum iron did not change. Furthermore, mRNA levels of interleukin-12, interferon-γ, tumor necrosis factor-α, and macrophage migration inhibitory factor in the spleen, factors that have the potential to restrain erythropoiesis in bone marrow, were elevated in the ILS-infected rats. These results suggest that ILS infection in rats affect erythropoiesis, which responds by decreasing EPO production and restraining its function in the bone marrow.

Low specificities of HIV diagnostic tests caused by Trypanosoma brucei gambiense sleeping sickness.

The accuracy of diagnostic tests for HIV in patients with tropical infections is poorly documented. Human African trypanosomiasis (HAT) is characterized by a polyclonal B-cell activation, constituting a risk for false-positive reactions to diagnostic tests, including HIV tests. A retrospective study of the accuracy of HIV diagnostic tests was performed with 360 human African HAT patients infected with Trypanosoma brucei gambiense before treatment and 163 T. b. gambiense-infected patients 2 years after successful treatment in Mbuji Mayi, East Kasai, Democratic Republic of the Congo. The sensitivities, specificities, and positive predictive values (PPVs) of individual tests and algorithms consisting of 3 rapid tests were determined. The sensitivity of all tests was 100% (11/11). The low specificity (96.3%, 335/348) and PPV (45.8%, 11/24) of a classical seroconfirmation strategy (Vironostika enzyme-linked immunosorbent assay [ELISA] followed by line immunoassay) complicated the determination of HIV status, which had to be determined by PCR. The specificities of the rapid diagnostic tests were 39.1% for Determine (136/348); 85.3 to 92.8% (297/348 to 323/348) for Vikia, ImmunoFlow, DoubleCheck, and Bioline; and 96.6 to 98.3% (336/348 to 342/348) for Uni-Gold, OraQuick, and Stat-Pak. The specificity of Vironostika was 67.5% (235/348). PPVs ranged between 4.9 and 64.7%. Combining 3 different rapid tests resulted in specificities of 98.3 to 100% (342/348 to 348/348) and PPVs of 64.7 to 100% (11/17 to 11/11). For cured HAT patients, specificities were significantly higher for Vironostika, Determine, Uni-Gold, and ImmunoFlow. T. b. gambiense infection decreases the specificities of antibody detection tests for HIV diagnosis. Unless tests have been validated for interference with HAT, HIV diagnosis using classical algorithms in untreated HAT patients should be avoided. Specific, validated combinations of 3 HIV rapid tests can increase specificity.

Scrutinizing the mechanisms underlying the induction of anemia of inflammation through GPI-mediated modulation of macrophage activation in a model of African trypanosomiasis.

In animal trypanosomiasis the severity of infection is reflected by the degree of anemia which resembles anemia of inflammation, involving a skewed iron homeostasis leading to iron accumulation within the reticuloendothelial system. Myeloid cells (M cells) have been implicated in the induction and maintenance of this type of anemia and modulation of M cells through the main trypanosome-derived glycosylphosphatidylinositol (GPI)-anchor could attenuate both anemia and trypano-susceptibility in Trypanosoma brucei-infected mice. Herein the GPI-based treatment, allowing a straightforward comparison between trypanotolerance and susceptibility in T. brucei-infected C57Bl/6 mice, was further adopted to scrutinize mechanisms/pathways underlying trypanosome-elicited anemia. Hereby, the following interlinkable observations were made in GPI-based treated (GBT) T. brucei-infected mice: (i) a reduced inflammatory cytokine production and increased IL-10 production associated with alleviation of anemia and restoration of serum iron levels, (ii) a shift in increased liver expression of iron storage towards iron export genes, (iii) increased erythropoiesis in the bone marrow and extramedullar sites (spleen) probably reflecting a normalized iron homeostasis and availability. Collectively, our results demonstrate that reprogramming macrophages towards an anti-inflammatory state alleviates anemia of inflammation by normalizing iron homeostasis and restoring erythropoiesis.

The central role of macrophages in trypanosomiasis-associated anemia: rationale for therapeutical approaches.

Bovine African trypanosomiasis causes severe economical problems on the African continent and one of the most prominent immunopathological parameters associated with this parasitic infection is anemia. In this report we review the current knowledge of the mechanisms underlying trypanosomiasis-associated anemia. In first instance, the central role of macrophages and particularly their activation state in determining the outcome of the disease (i.e. trypanosusceptibility versus trypanotolerance) will be discussed. In essence, while persistence of classically activated macrophages (M1) contributes to anemia development, switching towards alternatively activated macrophages (M2) alleviates pathology including anemia. Secondly, while parasite-derived glycolipids such as the glycosylphosphatidylinositol (GPI) induce M1, host-derived IL-10 blocks M1-mediated inflammation, promotes M2 development and prevents anemia development. In this context, strategies aimed at inducing the M1 to M2 switch, such as GPI-based treatment, adenoviral delivery of IL-10 and induction of IL-10 producing regulatory T cells will be discussed. Finally, the crucial role of iron-homeostasis in trypanosomiasis-associated anemia development will be documented to stress the analogy with anemia of chronic disease (ACD), hereby providing new insight that might contribute to the treatment of ACD.

Mechanisms controlling anaemia in Trypanosoma congolense infected mice.

BACKGROUND: Trypanosoma congolense are extracellular protozoan parasites of the blood stream of artiodactyls and are one of the main constraints on cattle production in Africa. In cattle, anaemia is the key feature of disease and persists after parasitaemia has declined to low or undetectable levels, but treatment to clear the parasites usually resolves the anaemia. METHODOLOGY/PRINCIPAL FINDINGS: The progress of anaemia after Trypanosoma congolense infection was followed in three mouse strains. Anaemia developed rapidly in all three strains until the peak of the first wave of parasitaemia. This was followed by a second phase, characterized by slower progress to severe anaemia in C57BL/6, by slow recovery in surviving A/J and a rapid recovery in BALB/c. There was no association between parasitaemia and severity of anaemia. Furthermore, functional T lymphocytes are not required for the induction of anaemia, since suppression of T cell activity with Cyclosporin A had neither an effect on the course of infection nor on anaemia. Expression of genes involved in erythropoiesis and iron metabolism was followed in spleen, liver and kidney tissues in the three strains of mice using microarrays. There was no evidence for a response to erythropoietin, consistent with anaemia of chronic disease, which is erythropoietin insensitive. However, the expression of transcription factors and genes involved in erythropoiesis and haemolysis did correlate with the expression of the inflammatory cytokines Il6 and Ifng. CONCLUSIONS/SIGNIFICANCE: The innate immune response appears to be the major contributor to the inflammation associated with anaemia since suppression of T cells with CsA had no observable effect. Several transcription factors regulating haematopoiesis, Tal1, Gata1, Zfpm1 and Klf1 were expressed at consistently lower levels in C57BL/6 mice suggesting that these mice have a lower haematopoietic capacity and therefore less ability to recover from haemolysis induced anaemia after infection.

Role of iron homeostasis in trypanosomiasis-associated anemia.

Anemia is a well-established infection-associated immunopathological feature of trypanosomiasis and the degree of the anemia is a reliable indicator of the severity of infection. Since infections with trypanosomes triggers a strong cytokine production and a type I immune response, the trypanosome-elicited anemia may be type I cytokine driven. This type of anemia termed anemia of chronic disease is characterized by an imbalance between erythrophagocytosis and erythropoiesis that is linked to a perturbed iron homeostasis including altered iron recycling by macrophages and iron sequestration. To further unravel the mechanisms underlying trypanosome-elicited anemia the expression profile of genes involved in erythrophagocytosis, uptake of iron-containing complexes and iron homeostasis was performed during the acute and chronic phase of experimental Trypanosoma brucei infections in a murine model. The results suggest that liver-associated erythrophagocytosis mediated by cytokine-activated macrophages (M1 cells) is the most likely main initiating event of aggressive anemia during the acute phase of infection. Persistence of strong type I cytokine production during the chronic phase of infection leads to hyper-activated M1 cells and a more progressive anemia. RT-PCR analysis of liver tissue demonstrates a strong increase of cell surface receptors involved in uptake of RBC and iron-containing compounds. For genes involved in iron processing we found an increase of ferroportin-1 (FPN-1), transferrin (Tf) and ceruloplasmin (CP) only in the acute phase, suggesting that export of iron is hampered in the chronic phase of infection. Our results suggest that in the chronic phase of trypanosomiasis, the iron-processing pathway is skewed towards iron sequestration, as evidenced by increased ferritin expression, while enhanced uptake of RBC/iron-containing compounds is maintained.

Bovine trypanotolerance: A natural ability to prevent severe anaemia and haemophagocytic syndrome?

Trypanotolerance is the capacity of certain West-African, taurine breeds of cattle to remain productive and gain weight after trypanosome infection. Laboratory studies, comparing Trypanosoma congolense infections in trypanotolerant N'Dama cattle (Bos taurus) and in more susceptible Boran cattle (Bos indicus), confirmed the field observations. Experiments using haemopoietic chimeric twins, composed of a tolerant and a susceptible co-twin, and T cell depletion studies suggested that trypanotolerance is composed of two independent traits. The first is a better capacity to control parasitaemia and is not mediated by haemopoietic cells, T lymphocytes or antibodies. The second is a better capacity to limit anaemia development and is mediated by haemopoietic cells, but not by T lymphocytes or antibodies. Weight gain was linked to the latter mechanism, implying that anaemia control is more important for survival and productivity than parasite control. Anemia is a marker for a more complex pathology which resembles human haemophagocytic syndrome: hepatosplenomegaly, pancytopenia and a large number of hyperactivated phagocytosing macrophages in bone marrow, liver and other tissues. Thus, mortality and morbidity in trypanosome-infected cattle are primarily due to self-inflicted damage by disproportionate immune and/or innate responses. These features of bovine trypanotolerance differ greatly from those in murine models. In mice, resistance is a matter of trypanosome control dependent on acquired immunity. However, a model of anaemia development can be established using C57BL/6J mice. As in cattle, the induction of anaemia was independent of T cells but its development differed with different trypanosome strains. Identification of the molecular pathways that lead to anaemia and haemophagocytosis should allow us to design new strategies to control disease.

Transverse myelitis due to trypanosomiasis in a middle aged Tanzanian man.

We report the case of a middle aged Tanzanian man who developed a spinal cord syndrome over 6 weeks, along with a mild encephalopathy. Investigations ruled out the usual major causes of such a syndrome in our setting in northern Tanzania. Examination of his cerebrospinal fluid revealed trypanosomes, and he made a slow but dramatic improvement after a full course of suramine and melarsoprol. We postulate that he had a transverse myelitis due to African trypanosomiasis, a rare and barely recognised cause.

Human African trypanosomiasis and human immunodeficiency virus co-infection in Western Kenya.

OBJECTIVE: To determine possible interaction between infections of Trypanosoma brucei rhodesiense sleeping sickness and HIV/AIDS in Western Kenya. DESIGN: Random selection and testing for HIV infections of serum samples from HAT patients using an indirect single phase enzyme linked immunosorbent assay (EAI-Immunocomb II, oragenics). SETTING: National Sleeping Sickness Referral Hospital-Alupe. RESULTS: Four (16%) of the HAT serum samples (n = 25) were found to be seropositive for HIV type 1 and 2 infections, while an additional four (16%) were sero-positive to HIV type 2 infections alone. In contrast, the patients from the local STD clinic showed that 52% (n = 53) were seropositive for both HIV type 1 and 2 infections. No patient from the STD clinic was seropositive for HIV type 2 alone. Calculated Yates Chi square value of 17.31 (P > 0.001) indicated a significant increase in HIV type 2 antibodies in T. brucei rhodesiense sleeping sickness patients. RESULTS: Sixteen percent of the HAT serum samples (n = 25) were found to be seropositive for HIV type 1 and 2 infections, while an additional 16% were sero-positive to HIV type 2 infections alone. In contrast, the patients from the local STD clinic showed that 52% (n = 53) were seropositive for both HIV type 1 and 2 infections. No patient from the STD clinic was seropositive for HIV type 2 alone. Calculated Yates Chi square value of 17.31 (P < 0.001) indicated a significant increase in HIV type 2 antibodies in T. brucei rhodesiense sleeping sickness patients. CONCLUSION: T. brucei rhodesiense sleeping sickness is an immuno-suppressive disease whose patients have shown a higher affinity to HIV type 2 infections more common in central and western Africa. Such patients when treated, appear to recover from HAT but later succumb to full-blown AIDS. It is recommended that CD4+ T cell numbers and CD4/CD8 T cell ratios be assessed toinvestigate response to treatment in HIV positive HAT patients.

Meningoencephalitic African trypanosomiasis: Brain IL-10 and IL-6 are associated with protection from neuro-inflammatory pathology.

The relationship of neuropathology to CNS inflammatory and counter-inflammatory cytokine production in African trypanosome-infected mice was studied using an infection model with a defined disease progression. The initial phase of CNS infection by trypanosomes, where only mild neuropathology is evident, was characterised by high levels of IL-10 and IL-6. In the later phase of CNS infection and in a post-drug treatment model, moderate to severe neuropathology was associated with high levels of IFN-gamma and TNF-alpha. The relationship of these cytokines to neuropathological grade suggests that IL-10 and IL-6 protect the CNS from inflammatory pathology when parasites first enter the brain and the data reconcile previously contradictory clinical measurements of CSF cytokines in meningoencephalitic patients with post-mortem histopathology observations.

Arsenicals (melarsoprol), pentamidine and suramin in the treatment of human African trypanosomiasis.

Human African trypanosomiasis (HAT), otherwise known as sleeping sickness, has remained a disease with no effective treatment. Recent progress in HAT research suggests that a vaccine against the disease is far from being successful. Also the emergence of drug-resistant trypanosomes makes further work in this area imperative. So far the treatment for the early stage of HAT involves the drugs pentamidine and suramin which have been very successful. In the second stage of the disease, during which the trypanosomes reside in the cerebrospinal fluid (CSF), treatment is dependent exclusively on the arsenical compound melarsoprol. This is largely due to the inability to find compounds that can cross the blood brain barrier and kill the CSF-residing trypanosomes. This review summarises our current understanding on the treatment of HAT.

Trypanosome hydrolases and the blood-brain barrier.

African trypanosomes cross the blood-brain barrier, but how they do so remains an area of speculation. We propose that proteases, such as the trypanopains and oligopeptidases that are released by trypanosomes, could mediate in this process. The trypanosomes also possess cell-surface-associated acid phosphatases that could play a role in invasion similar to that in advancing cancer cells. Such enzymes, perhaps acting in concert, have the potential to cause tissue degradation and ease the passage of the trypanosomes through various tissues in the host, including the blood-brain barrier.

[Disorders of awakening. Second part: secondary disorders]. / Troubles de l'éveil.

Secondary disorders of awakening should be distinguished from primary disorders, narcolepsy, idiopathic hypersomnia, recurrent hypersomnia, the causes of which are still unknown despite regular progress in the knowledge of the pathophysiology of narcolepsy. By definition secondary disorders of awakening are due to clearly identified causes of various origins. Two main types of secondary disorders of awakening have been distinguished: those depending on more or less voluntary sleep curtailment or on psychotropic or non psychotropic medications and those consecutive to different disorders, respiratory, neurologic, traumatic, psychotropic, infectious, metabolic, endocrinologic, and insomnia. Some of these disorders, frequent or very frequent, are polysomnographically investigated, night and day, enabling to assess in each case the type and severity of sleepiness. Others are only clinically evaluated. Disorders of awakening secondary to neurologic conditions and to a lesser extent to infectious conditions offer a special opportunity to study the anatomical basis of these disorders. They are granted more space.

Cytokines and the acute phase response in post-treatment reactive encephalopathy of Trypanosoma brucei brucei infected mice.

Stimulation of the acute phase response during infection of mice with Trypanosoma brucei brucei (T. b. brucei) was investigated in an experimental model of the post-treatment reactive encephalopathy (PTRE), a common side-effect of anti-trypanosome therapy. Plasma levels of the acute phase proteins (APP), haptoglobin (Hp) and serum amyloid P (SAP) increased by day 7 post-infection, but by day 20 had fallen to an intermediate level. This was accompanied by induction of the cytokines, interleukin (IL)-6 and tumour necrosis factor-alpha (TNFalpha) in both liver and brain. Treatment of mice on day 21 with a subcurative dose of diminazene aceturate (Berenil), a procedure known to induce a mild PTRE, cleared the parasite from the circulation with plasma APP and liver expression of mRNA for IL-6 and TNFalpha returning to the levels in the controls. Cytokine mRNA for both IL-6 and TNFalpha was detected in the brains of animals with developing PTRE although TNFalpha was not significantly greater than in the control group. A further subcurative dose of Berenil, leading to a more severe PTRE, was associated with elevated serum concentrations of Hp and SAP, increased TNFalpha mRNA in the liver and detectable IL-6 and TNFalpha mRNA in the brain. mRNA for IL-1alpha was expressed in brain and liver samples from all animals. A severe PTRE caused a systemic acute phase response which was not apparent with a mild PTRE. The pattern of cytokine mRNA induction was similar following both drug treatments. However, the difference in APP production could be caused by a breakdown in the blood-brain barrier during severe PTRE allowing cytokine synthesised in the brain to enter the circulation and maintain a systemic response.

Bone marrow response to acute and chronic Trypanosoma congolense infection in multimammate rats (Mastomys coucha).

The femoral bone marrow of multimammate rats (n=90), aged 3-8 weeks, experimentally infected with different doses of Trypanosoma congolense was examined by light and electron microscopy. Some animals died from trypanosomosis, but groups of 10 were killed at 4-8, 9-16, 20-24, 30, 40, 50 and 60 days post-infection (dpi). In the acute stage of infection (4-8 dpi) the bone marrow invariably showed a striking increase in erythropoiesis, characterized by an increase in the number of mitotic figures and erythroblastic islands and by a marked decrease in the myeloid:erythroid cell ratio. Later in the infection, erythropoietic activity decreased, while erythrophagocytosis, granulopoiesis, megakaryopoiesis and plasma cell population increased. In chronic infection (16-60 dpi), erythropoietic activity decreased, while intra- and extra-vascular erythrophagocytosis greatly increased. There was also an increase in the bone marrow stroma cells. Excessive erythrophagocytosis by these cells led to the formation of myelin figures and cytoplasmic telephagolysosomes. Degeneration and necrosis of neutrophils lining the adluminal surfaces of the blood sinuses were observed. It is concluded that in the acute stage of the infection, the bone marrow is responsive to the anaemia and that in the chronic stage, dyserythropoiesis and increased erythrophagocytosis by the expanded and activated cells of the mononuclear phagocytic system play an important role in the production of anaemia.