Intrathecal immune response pattern for improved diagnosis of central nervous system involvement in trypanosomiasis

Disease-related data patterns in cerebrospinal fluid diagnostics: medical quality versus analytical quantity

Cerebrospinal fluid (CSF) diagnostics is characterized by the biologically relevant combination of analytes in order to obtain disease-related data patterns that enable medically relevant interpretations. The necessary change in knowledge bases such as barrier function as a diffusion/CSF flow model and immunological networks of B-cell clones and pleiotropic cytokines is considered. The biophysical and biological principles for data combination are demonstrated using examples from neuroimmunological and dementia diagnostics. In contrast to current developments in clinical chemistry and laboratory medicine, CSF diagnostics is moving away from mega-automated systems with a constantly growing number of individual analyses toward a CSF report that integrates all patient data. Medical training in data sample interpretation in the inter-laboratory test systems ("EQA schemes") has become increasingly important. However, the results for CSF diagnostics (EQAS from INSTAND) indicate a crucially misguided trend. The separate analysis of CSF and serum in different, non-matched assays and extreme batch variations systematically lead to misinterpretations, which are the responsibility of the test providers. The questionable role of expensive accreditation procedures and the associated false quality expectations are discussed. New concepts that reintegrate the medical expertise of the clinical chemist must be emphasized along with the positive side effect of reducing costs in the healthcare system.

Parasites causing cutaneous wounds: Theory and practice from a dermatological point of view

A wide range of parasites can infest open wounds, or cause wounds due to the effects of the infestation. Parasitic infestations can involve the skin and subcutaneous tissues, with various clinical manifestations. In case of cutaneous wounds related to infestations, protozoa, helminths and arthropods are the main groups of parasites involved and emerging new aspects have been recently reported. Treating the wound correctly is fundamental in these patients in order to reduce the development of pathological scars and prevent complications. In particular, a gentle debridement for devitalized/infested tissue removal, the appropriate use of topical antiseptics and dressings such as hydrogel, hydrocolloids and antimicrobial dressings can be useful to control superinfections, moisture balance, inflammation and to promote edge proliferation.

Neopterin and CXCL-13 in Diagnosis and Follow-Up of Trypanosoma brucei gambiense Sleeping Sickness: Lessons from the Field in Angola

Human African Trypanosomiasis may become manageable in the next decade with fexinidazole. However, currently stage diagnosis remains difficult to implement in the field and requires a lumbar puncture. Our study of an Angolan cohort of T. b. gambiense-infected patients used other staging criteria than those recommended by the WHO. We compared WHO criteria (cell count and parasite identification in the CSF) with two biomarkers (neopterin and CXCL-13) which have proven potential to diagnose disease stage or relapse. Biological, clinical, and neurological data were analysed from a cohort of 83 patients. A neopterin concentration below 15.5 nmol/L in the CSF denoted patients with stage 1 disease, and a concentration above 60.31 nmol/L characterized patients with advanced stage 2 (trypanosomes in CSF and/or cytorachia higher than 20 cells) disease. CXCL-13 levels below 91.208 pg/mL denoted patients with stage 1 disease, and levels of CXCL-13 above 395.45 pg/mL denoted patients with advanced stage 2 disease. Values between these cut-offs may represent patients with intermediate stage disease. Our work supports the existence of an intermediate stage in HAT, and CXCL-13 and neopterin levels may help to characterize it.

Cerebrospinal Fluid-Derived Microvesicles From Sleeping Sickness Patients Alter Protein Expression in Human Astrocytes

Human African trypanosomiasis (HAT) caused by the extracellular protozoon Trypanosoma brucei, is a neglected tropical disease affecting the poorest communities in sub-Saharan Africa. HAT progresses from a hemolymphatic first stage (S1) to a meningo-encephalitic late stage (S2) when parasites reach the central nervous system (CNS), although the existence of an intermediate stage (Int.) has also been proposed. The pathophysiological mechanisms associated with the development of S2 encephalopathy are yet to be fully elucidated. Here we hypothesized that HAT progression toward S2 might be accompanied by an increased release of microvesicles (MVs), sub-micron elements (0.1–1 μm) involved in inflammatory processes and in the determination of the outcome of infections. We studied the morphology of MVs isolated from HAT cerebrospinal fluid (CSF) by transmission electron microscopy (TEM) and used flow cytometry to show that total-MVs and leukocyte derived-CD45⁺ MVs are significantly increased in concentration in S2 patients' CSF compared to S1 and Int. samples (n = 12 per group). To assess potential biological properties of these MVs, immortalized human astrocytes were exposed, in vitro, to MVs enriched from S1, Int. or S2 CSF. Data-independent acquisition mass spectrometry analyses showed that S2 MVs induced, compared to Int. or S1 MVs, a strong proteome modulation in astrocytes that resembled the one produced by IFN-γ, a key molecule in HAT pathogenesis. Our results indicate that HAT S2 CSF harbors MVs potentially involved in the mechanisms of pathology associated with HAT late stage. Such vesicles might thus represent a new player to consider in future functional studies.

Clinical management of East African trypanosomiasis in South Africa: Lessons learned

BACKGROUND

East African trypanosomiasis is an uncommon, potentially lethal disease if not diagnosed and treated in a timely manner. South Africa, as a centre for emergency medical evacuations from much of sub-Saharan Africa, receives a high proportion of these patients, mostly tourists and expatriate residents.

METHODS

The cases of East African trypanosomiasis patients evacuated to South Africa, for whom diagnostic and clinical management advice was provided over the years 2004-2018, were reviewed, using the authors' own records and those of collaborating clinicians.

RESULTS

Twenty-one cases were identified. These originated in Zambia, Malawi, Zimbabwe, Tanzania, and Uganda. Nineteen cases (90%) had stage 1 (haemolymphatic) disease; one of these patients had fatal myocarditis. Of the two patients with stage 2 (meningoencephalitic) disease, one died of melarsoprol encephalopathy. Common problems were delayed diagnosis, erroneous assessment of severity, and limited access to treatment.

CONCLUSIONS

The key to early diagnosis is recognition of the triad of geographic exposure, tsetse fly bites, and trypanosomal chancre, plus good microscopy. Elements for successful management are rapid access to specific drug treatment, skilled intensive care, and good laboratory facilities. Clinical experience and the local stock of antitrypanosomal drugs from the World Health Organization have improved the chance of a successful outcome in the management of East African trypanosomiasis in South Africa; the survival rate over the period was 90.5%.

Knowledge-base for interpretation of cerebrospinal fluid data patterns. Essentials in neurology and psychiatry

The physiological and biophysical knowledge base for interpretations of cerebrospinal fluid (CSF) data and reference ranges are essential for the clinical pathologist and neurochemist. With the popular description of the CSF flow dependent barrier function, the dynamics and concentration gradients of blood-derived, brain-derived and leptomeningeal proteins in CSF or the specificity-independent functions of B-lymphocytes in brain also the neurologist, psychiatrist, neurosurgeon as well as the neuropharmacologist may find essentials for diagnosis, research or development of therapies. This review may help to replace the outdated ideas like "leakage" models of the barriers, linear immunoglobulin Index Interpretations or CSF electrophoresis. Calculations, Interpretations and analytical pitfalls are described for albumin quotients, quantitation of immunoglobulin synthesis in Reibergrams, oligoclonal IgG, IgM analysis, the polyspecific ( MRZ- ) antibody reaction, the statistical treatment of CSF data and general quality assessment in the CSF laboratory. The diagnostic relevance is documented in an accompaning review.

IgM, lgG and IL-6 profiles in the Trypanosoma brucei brucei monkey model of human African trypanosomiasis

Human African trypanosomiasis (HAT) patients manifest immunological profiles, whose variations over time can be used to indicate disease progression. However, monitoring of these biomarkers in human patients is beset by several limitations which can be offset by using chronic animal models. A recent improved monkey model of HAT using a Trypanosoma brucei brucei isolate has been developed but the immunological profile has not been elucidated. The objectives of the current study was to determine the IgM, IgG and IL-6 profiles in blood and cerebrospinal fluid (CSF) in vervet monkeys infected with T. b. brucei. Three vervet monkeys were infected intravenously with 10⁵T. b. brucei, monitored for disease development and subsequently treated 28days post infection (dpi) sub-curatively using diminazene aceturate (DA) to induce late stage disease and curatively treated with melarsoprol (Mel B) at 119 dpi, respectively. Matched serum and cerebrospinal fluid (CSF) samples were obtained at regular intervals and immunospecific IgM, immunoglobulin G (IgG) were quantified by ELISA while IL-6 was assayed using a cytometric bead array (CBA) kit. Results showed that following infection, CSF IgM, IgG, IL-6 and serum IL-6 were significantly (p<0.05) elevated with peak levels coinciding with relapse parasitaemia. The IgG levels increased to reach OD peak levels of 0.442±0.5 at 126 dpi. After curative treatment with MelB, the serum IgM and Ig G levels fell rapidly to attain pre-infection levels within 35 and 49days, respectively. This shows that the profile of these immunoglobulins can be used as an indicator of curative treatment. CSF IL-6 concentrations of infected vervet monkeys showed no significant change (P>0.05) between infection and 35 dpi but levels increased significantly (P<0.05) with the highest level of 55.53pg/ml recorded at112 dpi. IL-6 elevation from 35 dpi may be indicative of parasite neuroinvasion hence can be used as possible candidate marker for late stage disease in the monkey model. Further, the marker can also be used in conjunction with IgG and IgM as markers for development of test of cure for HAT.

Cerebrospinal fluid data compilation and knowledge-based interpretation of bacterial, viral, parasitic, oncological, chronic inflammatory and demyelinating diseases. Diagnostic patterns not to be missed in neurology and psychiatry

The analysis of intrathecal IgG, IgA and IgM synthesis in cerebrospinal fluid (CSF) and evaluation in combined quotient diagrams provides disease-related patterns. The compilation with complementary parameters (barrier function, i.e., CSF flow rate, cytology, lactate, antibodies) in a cumulative CSF data report allows a knowledge-based interpretation and provides analytical and medical plausibility for the quality assessment in CSF laboratories. The diagnostic relevance is described for neurological and psychiatric diseases, for which CSF analysis can't be replaced by other diagnostic methods without loss of information. Dominance of intrathecal IgM, IgA or three class immune responses give a systematic approach for Facial nerve palsy, Neurotrypanosomiasis, Opportunistic diseases, lymphoma, Neurotuberculosis, Adrenoleucodystrophy or tumor metastases. Particular applications consider the diagnostic power of the polyspecific antibody response (MRZ-antibodies) in multiple sclerosis, a CSF-related systematic view on differential diagnostic of psychiatric diseases and the dynamics of brain- derived compared to blood-derived molecules in CSF for localization of paracytes.

Equine Protozoal Myeloencephalitis: An Updated Consensus Statement with a Focus on Parasite Biology, Diagnosis, Treatment, and Prevention

Equine protozoal myeloencephalitis (EPM) remains an important neurologic disease of horses. There are no pathognomonic clinical signs for the disease. Affected horses can have focal or multifocal central nervous system (CNS) disease. EPM can be difficult to diagnose antemortem. It is caused by either of 2 parasites, Sarcocystis neurona and Neospora hughesi, with much less known about N. hughesi. Although risk factors such as transport stress and breed and age correlations have been identified, biologic factors such as genetic predispositions of individual animals, and parasite‐specific factors such as strain differences in virulence, remain largely undetermined. This consensus statement update presents current published knowledge of the parasite biology, host immune response, disease pathogenesis, epidemiology, and risk factors. Importantly, the statement provides recommendations for EPM diagnosis, treatment, and prevention.

Quantitation of intrathecal immunoglobulin synthesis - a new empirical formula

BACKGROUND AND PURPOSE

Intrathecal immunoglobulin (Ig) synthesis occurs in various chronic inflammatory neurological diseases. Different formulae have been developed for quantitative determination of Ig synthesis within the cerebrospinal fluid (CSF) compartment. The hyperbolic formula of Reiber is frequently used which, however, returns a considerable number of false positive results in empirical observations.

METHODS

A computerized database of more than 19 000 paired CSF and serum samples was screened for patients presumed negative for local Ig synthesis and a new formula characterizing this collective was calculated. The validity of this formula was confirmed by several validation steps.

RESULTS

A cohort of 1173 patients with normal CSF findings was used for quantile regression. The 97.5th quantile of the formula Qlim(IgX)=a×Qalbb was considered as the cut-off curve for intrathecal Ig synthesis using different constants a and b for IgG, IgA and IgM. Compared to the Reiber formula, a lower level of false positive results was produced especially for IgM and IgA which was confirmed in a separate clinically well defined validation cohort. In 77 patients with discrepant findings between Reiber and our formula no specific diagnoses were found confirming the low diagnostic value of borderline Ig synthesis.

CONCLUSIONS

A new approximation formula was developed for determination of intrathecal Ig synthesis which produces fewer false positive results without reducing diagnostic sensitivity.

Human African trypanosomiasis with 7-year incubation period: clinical, laboratory and neuroimaging findings

Human African trypanosomiasis (HAT), also referred to as "sleeping sickness", is caused by the parasite Trypanosoma brucei. Diagnosing imported HAT outside endemic areas is difficult and diagnosis is often delayed. We report a case of imported human African trypanosomiasis caused by Trypanosoma brucei gambiense with an unusually long incubation period of at least 7 years. A 33 year old male African patient, a former resident of Cameroon, presented with a 4-month history of progressive personality changes. A few weeks before presentation the patient had first been admitted to a psychiatric ward and received antidepressant treatment, until a lumbar puncture showed pleocytosis and then antibiotic treatment for suspected neuroborreliosis was initiated. The patient continued to deteriorate during antibiotic treatment and became increasingly lethargic. Under antiparasitic and anti-inflammatory treatment, the condition of the patient gradually improved over the following months and he recovered completely after 24 months of follow-up. This well-documented case illustrates typical difficulties in establishing the correct diagnosis outside endemic areas and provides an overview of typical clinical, neuropathological and neuroimaging findings in T. b. gambiense trypanosomiasis, guiding the clinician in establishing the correct diagnosis in this rare disease.

Neurological trypanosomiasis in quinapyramine sulfate-treated horses--a breach of the blood-brain barrier?

Trypanosoma evansi infection typically produces wasting disease, but it can also develop into a neurological or meningoencephalitis form in equids. Trypanosomiasis in horses was treated with quinapyramine sulfate, and all the 14 infected animals were recovered clinically. After clinical recovery, four animals developed a neurological form of the disease at various intervals. Two of these animals treated with diminazene aceturate recovered temporarily. Repeated attempts failed to find the parasite in the blood or the cerebrospinal fluid (CSF), but all of the animals were positive in enzyme-linked immunosorbent assay. The calculation of the antibody index (AI) in the serum and the CSF and polymerase chain reaction (PCR) analysis of the CSF and brain tissue were carried out to confirm the neuro-infection. We found PCR and AI analyses of the CSF to be useful tools in the diagnosis of the neurological form of trypanosomiasis when the organism cannot be found in the blood or CSF. The increased albumin quotient is indicative of barrier leakage due to neuroinflammation. The biochemical changes in the CSF due to nervous system trypanosomiasis include increases in the albumin quotient, total protein, and urea nitrogen. It seems to be the first report on relapse of the nervous form of trypanosomiasis in equids even after quinapyramine treatment in endemic areas.

False positivity of non-targeted infections in malaria rapid diagnostic tests: the case of human african trypanosomiasis

Background

In endemic settings, diagnosis of malaria increasingly relies on the use of rapid diagnostic tests (RDTs). False positivity of such RDTs is poorly documented, although it is especially relevant in those infections that resemble malaria, such as human African trypanosomiasis (HAT). We therefore examined specificity of malaria RDT products among patients infected with Trypanosoma brucei gambiense.

Methodology/Principal Findings

Blood samples of 117 HAT patients and 117 matched non-HAT controls were prospectively collected in the Democratic Republic of the Congo. Reference malaria diagnosis was based on real-time PCR. Ten commonly used malaria RDT products were assessed including three two-band and seven three-band products, targeting HRP-2, Pf-pLDH and/or pan-pLDH antigens. Rheumatoid factor was determined in PCR negative subjects. Specificity of the 10 malaria RDT products varied between 79.5 and 100% in HAT-negative controls and between 11.3 and 98.8% in HAT patients. For seven RDT products, specificity was significantly lower in HAT patients compared to controls. False positive reactions in HAT were mainly observed for pan-pLDH test lines (specificities between 13.8 and 97.5%), but also occurred frequently for the HRP-2 test line (specificities between 67.9 and 98.8%). The Pf-pLDH test line was not affected by false-positive lines in HAT patients (specificities between 97.5 and 100%). False positivity was not associated to rheumatoid factor, detected in 7.6% of controls and 1.2% of HAT patients.

Conclusions/Significance

Specificity of some malaria RDT products in HAT was surprisingly low, and constitutes a risk for misdiagnosis of a fatal but treatable infection. Our results show the importance to assess RDT specificity in non-targeted infections when evaluating diagnostic tests.

Rapid diagnostic tests (RDT) for malaria are currently rolled-out as the backbone of parasite-based diagnosis, and their diagnostic accuracy is sufficiently high to substitute microscopy. One decade ago, attention has been given to occurrence of limited false positivity in a number of malaria RDTs, but false positivity of RDTs has remained poorly documented since then. In the last years, the number of available RDT products has dramatically increased and test performance has improved. False positivity may therefore not be perceived as a problem anymore. In this manuscript, we demonstrate that specificities of malaria rapid diagnostic tests detecting parasite antigens are seriously affected by human African trypanosomiasis (sleeping sickness), with values down to 11%. Malaria constitutes the main differential diagnosis of human African trypanosomiasis, and the false-positive results for malaria RDTs increase the risk of misdiagnosis or delayed diagnosis of human African trypanosomiasis which is a fatal but treatable infection.

Neopterin is a cerebrospinal fluid marker for treatment outcome evaluation in patients affected by Trypanosoma brucei gambiense sleeping sickness

Background

Post-therapeutic follow-up is essential to confirm cure and to detect early treatment failures in patients affected by sleeping sickness (HAT). Current methods, based on finding of parasites in blood and cerebrospinal fluid (CSF) and counting of white blood cells (WBC) in CSF, are imperfect. New markers for treatment outcome evaluation are needed. We hypothesized that alternative CSF markers, able to diagnose the meningo-encephalitic stage of the disease, could also be useful for the evaluation of treatment outcome.

Methodology/Principal findings

Cerebrospinal fluid from patients affected by Trypanosoma brucei gambiense HAT and followed for two years after treatment was investigated. The population comprised stage 2 (S2) patients either cured or experiencing treatment failure during the follow-up. IgM, neopterin, B2MG, MMP-9, ICAM-1, VCAM-1, CXCL10 and CXCL13 were first screened on a small number of HAT patients (n = 97). Neopterin and CXCL13 showed the highest accuracy in discriminating between S2 cured and S2 relapsed patients (AUC 99% and 94%, respectively). When verified on a larger cohort (n = 242), neopterin resulted to be the most efficient predictor of outcome. High levels of this molecule before treatment were already associated with an increased risk of treatment failure. At six months after treatment, neopterin discriminated between cured and relapsed S2 patients with 87% specificity and 92% sensitivity, showing a higher accuracy than white blood cell numbers.

Conclusions/Significance

In the present study, neopterin was highlighted as a useful marker for the evaluation of the post-therapeutic outcome in patients suffering from sleeping sickness. Detectable levels of this marker in the CSF have the potential to shorten the follow-up for HAT patients to six months after the end of the treatment.

The reduction of the number of lumbar punctures performed during the follow-up of patients affected by sleeping sickness (HAT) is considered a research priority. Follow-up, consisting of the examination of cerebrospinal fluid (CSF) for presence of parasites and for the number of leukocytes, is necessary to assess treatment outcome. However, diagnosis of treatment failure is still imperfect and WHO encourages improvements in defining criteria. Many studies have attempted to standardize actual methods and to define a cut-off for the number of white blood cells in CSF to define relapses, while only few have proposed alternatives to current practice. Here we show that neopterin, already proven to be a powerful marker for staging T. b. gambiense HAT, is also useful in evaluating post-therapeutic outcome. The measurement of neopterin concentration in CSF during the follow-up may allow reduction in the number of lumbar punctures from five to three for the majority of cured patients.

New biomarkers for stage determination in Trypanosoma brucei rhodesiense sleeping sickness patients

Accurate stage determination is crucial in the choice of treatment for patients suffering from sleeping sickness, also known as human African trypanosomiasis (HAT). Current staging methods, based on the counting of white blood cells (WBC) and the detection of parasites in the cerebrospinal fluid (CSF) have limited accuracy. We hypothesized that immune mediators reliable for staging T. b. gambiense HAT could also be used to stratify T. b. rhodesiense patients, the less common form of HAT.

A population comprising 85 T. b. rhodesiense patients, 14 stage 1 (S1) and 71 stage 2 (S2) enrolled in Malawi and Uganda, was investigated. The CSF levels of IgM, MMP-9, CXCL13, CXCL10, ICAM-1, VCAM-1, neopterin and B2MG were measured and their staging performances evaluated using receiver operating characteristic (ROC) analyses.

IgM, MMP-9 and CXCL13 were the most accurate markers for stage determination (partial AUC 88%, 86% and 85%, respectively). The combination in panels of three molecules comprising CXCL13-CXCL10-MMP-9 or CXCL13-CXCL10-IgM significantly increased their staging ability to partial AUC 94% (p value < 0.01).

The present study highlighted new potential markers for stage determination of T. b. rhodesiense patients. Further investigations are needed to better evaluate these molecules, alone or in panels, as alternatives to WBC to make reliable choice of treatment.

Human African trypanosomiasis

Human African trypanosomiasis or sleeping sickness is a neglected tropical disease that affects populations in sub-Saharan Africa. The disease is caused by infection with the gambiense and rhodesiense subspecies of the extracellular parasite Trypanosoma brucei, and is transmitted to humans by bites of infected tsetse flies. The disease evolves in two stages, the hemolymphatic and meningoencephalitic stages, the latter being defined by central nervous system infection after trypanosomal traversal of the blood-brain barrier. African trypanosomiasis, which leads to severe neuroinflammation, is fatal without treatment, but the available drugs are toxic and complicated to administer. The choice of medication is determined by the infecting parasite subspecies and disease stage. Clinical features include a constellation of nonspecific symptoms and signs with evolving neurological and psychiatric alterations and characteristic sleep-wake disturbances. Because of the clinical profile variability and insidiously progressive central nervous system involvement, disease staging is currently based on cerebrospinal fluid examination, which is usually performed after the finding of trypanosomes in blood or other body fluids. No vaccine being available, control of human African trypanosomiasis relies on diagnosis and treatment of infected patients, assisted by vector control. Better diagnostic tools and safer, easy to use drugs are needed to facilitate elimination of the disease.

Clinical features, diagnosis, and treatment of human African trypanosomiasis (sleeping sickness)

Human African trypanosomiasis, or sleeping sickness, is caused by infection with parasites of the genus Trypanosoma, transmitted by the tsetse fly. The disease has two forms, Trypanosoma brucei (T b) rhodesiense and T b gambiense; and is almost always fatal if untreated. Despite a recent reduction in the number of reported cases, patients with African trypanosomiasis continue to present major challenges to clinicians. Because treatment for CNS-stage disease can be very toxic, diagnostic staging to distinguish early-stage from late-stage disease when the CNS in invaded is crucial but remains problematic. Melarsoprol is the only available treatment for late-stage T b rhodesiense infection, but can be lethal to 5% of patients owing to post-treatment reactive encephalopathy. Eflornithine combined with nifurtimox is the first-line treatment for late-stage T b gambiense. New drugs are in the pipeline for treatment of CNS human African trypanosomiasis, giving rise to cautious optimism.

Stage progression and neurological symptoms in Trypanosoma brucei rhodesiense sleeping sickness: role of the CNS inflammatory response

BACKGROUND

Human African trypanosomiasis progresses from an early (hemolymphatic) stage, through CNS invasion to the late (meningoencephalitic) stage. In experimental infections disease progression is associated with neuroinflammatory responses and neurological symptoms, but this concept requires evaluation in African trypanosomiasis patients, where correct diagnosis of the disease stage is of critical therapeutic importance.

METHODOLOGY/PRINCIPAL FINDINGS

This was a retrospective study on a cohort of 115 T.b.rhodesiense HAT patients recruited in Eastern Uganda. Paired plasma and CSF samples allowed the measurement of peripheral and CNS immunoglobulin and of CSF cytokine synthesis. Cytokine and immunoglobulin expression were evaluated in relation to disease duration, stage progression and neurological symptoms. Neurological symptoms were not related to stage progression (with the exception of moderate coma). Increases in CNS immunoglobulin, IL-10 and TNF-α synthesis were associated with stage progression and were mirrored by a reduction in TGF-β levels in the CSF. There were no significant associations between CNS immunoglobulin and cytokine production and neurological signs of disease with the exception of moderate coma cases. Within the study group we identified diagnostically early stage cases with no CSF pleocytosis but intrathecal immunoglobulin synthesis and diagnostically late stage cases with marginal CSF pleocytosis and no detectable trypanosomes in the CSF.

CONCLUSIONS

Our results demonstrate that there is not a direct linkage between stage progression, neurological signs of infection and neuroinflammatory responses in rhodesiense HAT. Neurological signs are observed in both early and late stages, and while intrathecal immunoglobulin synthesis is associated with neurological signs, these are also observed in cases lacking a CNS inflammatory response. While there is an increase in inflammatory cytokine production with stage progression, this is paralleled by increases in CSF IL-10. As stage diagnostics, the CSF immunoglobulins and cytokines studied do not have sufficient sensitivity to be of clinical value.

Cerebrospinal fluid neopterin as marker of the meningo-encephalitic stage of Trypanosoma brucei gambiense sleeping sickness

Background

Sleeping sickness, or human African trypanosomiasis (HAT), is a protozoan disease that affects rural communities in sub-Saharan Africa. Determination of the disease stage, essential for correct treatment, represents a key issue in the management of patients. In the present study we evaluated the potential of CXCL10, CXCL13, ICAM-1, VCAM-1, MMP-9, B2MG, neopterin and IgM to complement current methods for staging Trypanosoma brucei gambiense patients.

Methods and Findings

Five hundred and twelve T. b. gambiense HAT patients originated from Angola, Chad and the Democratic Republic of the Congo (D.R.C.). Their classification as stage 2 (S2) was based on the number of white blood cells (WBC) (>5/µL) or presence of parasites in the cerebrospinal fluid (CSF). The CSF concentration of the eight markers was first measured on a training cohort encompassing 100 patients (44 S1 and 56 S2). IgM and neopterin were the best in discriminating between the two stages of disease with 86.4% and 84.1% specificity respectively, at 100% sensitivity. When a validation cohort (412 patients) was tested, neopterin (14.3 nmol/L) correctly classified 88% of S1 and S2 patients, confirming its high staging power. On this second cohort, neopterin also predicted both the presence of parasites, and of neurological signs, with the same ability as IgM and WBC, the current reference for staging.

Conclusions

This study has demonstrated that neopterin is an excellent biomarker for staging T. b. gambiense HAT patients. A rapid diagnostic test for detecting this metabolite in CSF could help in more accurate stage determination.

Melarsoprol cyclodextrin inclusion complexes as promising oral candidates for the treatment of human African trypanosomiasis

Human African trypanosomiasis (HAT), or sleeping sickness, results from infection with the protozoan parasites Trypanosoma brucei (T. b.) gambiense or T. b. rhodesiense and is invariably fatal if untreated. There are 60 million people at risk from the disease throughout sub-Saharan Africa. The infection progresses from the haemolymphatic stage where parasites invade the blood, lymphatics and peripheral organs, to the late encephalitic stage where they enter the central nervous system (CNS) to cause serious neurological disease. The trivalent arsenical drug melarsoprol (Arsobal) is the only currently available treatment for CNS-stage T. b. rhodesiense infection. However, it must be administered intravenously due to the presence of propylene glycol solvent and is associated with numerous adverse reactions. A severe post-treatment reactive encephalopathy occurs in about 10% of treated patients, half of whom die. Thus melarsoprol kills 5% of all patients receiving it. Cyclodextrins have been used to improve the solubility and reduce the toxicity of a wide variety of drugs. We therefore investigated two melarsoprol cyclodextrin inclusion complexes; melarsoprol hydroxypropyl-β-cyclodextrin and melarsoprol randomly-methylated-β-cyclodextrin. We found that these compounds retain trypanocidal properties in vitro and cure CNS-stage murine infections when delivered orally, once per day for 7-days, at a dosage of 0.05 mmol/kg. No overt signs of toxicity were detected. Parasite load within the brain was rapidly reduced following treatment onset and magnetic resonance imaging showed restoration of normal blood-brain barrier integrity on completion of chemotherapy. These findings strongly suggest that complexed melarsoprol could be employed as an oral treatment for CNS-stage HAT, delivering considerable improvements over current parenteral chemotherapy.

Accuracy of five algorithms to diagnose gambiense human African trypanosomiasis

Background

Algorithms to diagnose gambiense human African trypanosomiasis (HAT, sleeping sickness) are often complex due to the unsatisfactory sensitivity and/or specificity of available tests, and typically include a screening (serological), confirmation (parasitological) and staging component. There is insufficient evidence on the relative accuracy of these algorithms. This paper presents estimates of the accuracy of five algorithms used by past Médecins Sans Frontières programmes in the Republic of Congo, Southern Sudan and Uganda.

Methodology and Principal Findings

The sequence of tests in each algorithm was programmed into a probabilistic model, informed by distributions of the sensitivity, specificity and staging accuracy of each test, constructed based on a literature review. The accuracy of algorithms was estimated in a baseline scenario and in a worst-case scenario introducing various near worst-case assumptions. In the baseline scenario, sensitivity was estimated as 85–90% in all but one algorithm, with specificity above 99.9% except for the Republic of Congo, where CATT serology was used as independent confirmation test: here, positive predictive value (PPV) was estimated at <50% in realistic active screening prevalence scenarios. Furthermore, most algorithms misclassified about one third of true stage 1 cases as stage 2, and about 10% of true stage 2 cases as stage 1. In the worst-case scenario, sensitivity was 75–90% and PPV no more than 75% at 1% prevalence, with about half of stage 1 cases misclassified as stage 2.

Conclusions

Published evidence on the accuracy of widely used tests is scanty. Algorithms should carefully weigh the use of serology alone for confirmation, and could enhance sensitivity through serological suspect follow-up and repeat parasitology. Better evidence on the frequency of low-parasitaemia infections is needed. Simulation studies should guide the tailoring of algorithms to specific scenarios of HAT prevalence and availability of control tools.

Gambiense human African trypanosomiasis (HAT, sleeping sickness) usually features low prevalence. The two stages of the disease require different treatments, and stage 2 is fatal if untreated. HAT diagnosis must therefore be highly sensitive (i.e., detect as many true cases as possible) and specific (i.e., minimize false positives). HAT diagnostic algorithms are complex and involve several tests to screen for, confirm and stage infection. We analyzed five algorithms used by Médecins Sans Frontières HAT programmes. We combined published data on the accuracy of each test in the algorithm with a computer program that simulates all possible algorithm branches. We found that all algorithms had reasonable sensitivity (85–90%); specificity was high (>99.9%) except for the Republic of Congo, where confirmation did not rely on microscopic evidence, resulting in frequent false positives (but also higher sensitivity). Algorithms misclassified about one third of stage 1 cases as stage 2, but stage 2 classification was highly accurate. The use of serology alone for confirmation merits caution. HAT diagnosis could be made more sensitively by following up serological suspects and repeating microscopic examinations. Computer simulations can help to adapt algorithms to local conditions in each HAT programme, such as the prevalence of infection and operational constraints.

Comparison of major immunoglobulins intrathecal synthesis patterns in Ecuadorian and Cuban patients with angiostrongyliasis

Angiostrongylus cantonensis meningitis was first reported in Cuba in 1981, and it was recently reported in South America. The aim of this paper is to evaluate the intrathecal immunoglobulin synthesis patterns from Cuba's and Ecuador's patients with angiostrongyliasis; 8 Ecuadorian patients from two different outbreaks and 28 Cuban patients were studied. Simultaneous blood and cerebrospinal fluid samples were taken. Immunoglobulin (Ig) A, IgM, IgG, and albumin were quantified by radial immunodiffusion. Corresponding Reibergrams were applied. A three-Ig pattern was the most frequent in the two groups, but IgM was presented in all Ecuadorian young mature patients; however, in the Cuban children, only 12 of 28 patients had intrathecal IgM, but about 90% had an IgA and IgG synthesis at time of later puncture. This indicates that, with a larger amount of parasites ingested, clinical symptoms are more severe, and a higher frequency of intrathecal IgM synthesis could be observed. This is discussed as a similarity with the intrathecal IgM synthesis in African trypanosomiasis.

Discovery and verification of osteopontin and Beta-2-microglobulin as promising markers for staging human African trypanosomiasis

Human African trypanosomiasis, or sleeping sickness, is a parasitic disease endemic in sub-Saharan Africa, transmitted to humans through the bite of a tsetse fly. The first or hemolymphatic stage of the disease is associated with presence of parasites in the bloodstream, lymphatic system, and body tissues. If patients are left untreated, parasites cross the blood-brain barrier and invade the cerebrospinal fluid and the brain parenchyma, giving rise to the second or meningoencephalitic stage. Stage determination is a crucial step in guiding the choice of treatment, as drugs used for S2 are potentially dangerous. Current staging methods, based on counting white blood cells and demonstrating trypanosomes in cerebrospinal fluid, lack specificity and/or sensitivity. In the present study, we used several proteomic strategies to discover new markers with potential for staging human African trypanosomiasis. Cerebrospinal fluid (CSF) samples were collected from patients infected with Trypanosoma brucei gambiense in the Democratic Republic of Congo. The stage was determined following the guidelines of the national control program. The proteome of the samples was analyzed by two-dimensional gel electrophoresis (n = 9), and by sixplex tandem mass tag (TMT) isobaric labeling (n = 6) quantitative mass spectrometry. Overall, 73 proteins were overexpressed in patients presenting the second stage of the disease. Two of these, osteopontin and β-2-microglobulin, were confirmed to be potential markers for staging human African trypanosomiasis (HAT) by Western blot and ELISA. The two proteins significantly discriminated between S1 and S2 patients with high sensitivity (68% and 78%, respectively) for 100% specificity, and a combination of both improved the sensitivity to 91%. The levels of osteopontin and β-2-microglobulin in CSF of S2 patients (μg/ml range), as well as the fold increased concentration in S2 compared with S1 (3.8 and 5.5 respectively) make the two markers good candidates for the development of a test for staging HAT patients.

Emerging trends in the diagnosis of Human African Trypanosomiasis

Human African trypanosomiasis (HAT) or sleeping sickness is caused by protozoan parasitesTrypanosoma brucei gambienseandT. b. rhodesiense. Despite the enormous technological progress in molecular parasitology in recent years, the diagnosis of HAT is still problematic due to the lack of specific tools. To date, there are two realities when it comes to HAT; the first one being the world of modern experimental laboratories, equipped with the latest state-of-the-art technology, and the second being the world of HAT diagnosis, where the latest semi-commercial test was introduced 30 years ago (Magnuset al.1978). Hence, it appears that the lack of progress in HAT diagnosis is not primarily due to a lack of scientific interest or a lack of research funds, but mainly results from the many obstacles encountered in the translation of basic research into field-applicable diagnostics. This review will provide an overview of current diagnostic methods and highlight specific difficulties in solving the shortcomings of these methods. Future perspectives for accurate, robust, affordable diagnostics will be discussed as well.

African trypanosomiasis and antibodies: implications for vaccination, therapy and diagnosis

African trypanosomiasis causes devastating effects on human populations and livestock herds in large parts of sub-Saharan Africa. Control of the disease is hampered by the lack of any efficient vaccination results in a field setting, and the severe side effects of current drug therapies. In addition, with the exception of Trypanosoma brucei gambiense infections, the diagnosis of trypanosomiasis has to rely on microscopic analysis of blood samples, as other specific tools are nonexistent. However, new developments in biotechnology, which include loop-mediated isothermal amplification as an adaptation to conventional PCR, as well as the antibody engineering that has allowed the development of Nanobody technology, offer new perspectives in both the detection and treatment of trypanosomiasis. In addition, recent data on parasite-induced B-cell memory destruction offer new insights into mechanisms of vaccine failure, and should lead us towards new strategies to overcome trypanosome defenses operating against the host immune system.

Human African trypanosomiasis

Human African trypanosomiasis (sleeping sickness) occurs in sub-Saharan Africa. It is caused by the protozoan parasite Trypanosoma brucei, transmitted by tsetse flies. Almost all cases are due to Trypanosoma brucei gambiense, which is indigenous to west and central Africa. Prevalence is strongly dependent on control measures, which are often neglected during periods of political instability, thus leading to resurgence. With fewer than 12 000 cases of this disabling and fatal disease reported per year, trypanosomiasis belongs to the most neglected tropical diseases. The clinical presentation is complex, and diagnosis and treatment difficult. The available drugs are old, complicated to administer, and can cause severe adverse reactions. New diagnostic methods and safe and effective drugs are urgently needed. Vector control, to reduce the number of flies in existing foci, needs to be organised on a pan-African basis. WHO has stated that if national control programmes, international organisations, research institutes, and philanthropic partners engage in concerted action, elimination of this disease might even be possible.

Trypanosomiasis and the brain

Neurological involvement following trypanosome infection has been recognised for over a century. However, there are still many unanswered questions concerning the mechanisms used by the parasite to gain entry to the CNS and the pathogenesis of the resulting neuroinflammatory reaction. There is a paucity of material from human cases of the disease therefore the majority of current research relies on the use of animal models of trypanosome infection. This review reports contemporary knowledge, from both animal models and human samples, regarding parasite invasion of the CNS and the neuropathological changes that accompany trypanosome infection and disease progression. The effects of trypanosomes on the blood-brain barrier are discussed and possible key molecules in parasite penetration of the barrier highlighted. Changes in the balance of CNS cytokines and chemokines are also described. The article closes by summarising the effects of trypanosome infection on the circadian sleep-wake cycle, and sleep structure, in relation to neuroinflammation and parasite location within the CNS. Although a great deal of progress has been made in recent years, the advent and application of sophisticated analysis techniques, to decipher the complexities of HAT pathogenesis, herald an exciting and rewarding period for advances in trypanosome research.

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.

Brucellosis presenting as pyrexia of unknown origin in an international traveller: a case report

Introduction

In this era of globalization frequent traveling across the world is common. It has resulted in exchange of knowledge and expertise among medical professionals around the world which has a visible positive impact. However, this predisposes the travelers to the risk of acquiring an ‘alien’ disease endemic to a particular country. This may be a great challenge for the treating physicians to manage such patients due to lack of facility for diagnosis and experience in handling such disease. We present a similar case scenario and problems we faced in managing that patient.

Case presentation

A 40-year-old man visited to Africa, developed a skin rash over ankle after an insect bite. This was followed by high grade fever. He was investigated in Kenya, however, returned to India pending results. Later he developed sleepiness and coarse tremors. Work up for the cause of fever was inconclusive. He was diagnosed with trypanosomiasis based on reports from Kenya. In absence of alternate diagnosis and clinical setting, we treated him for trypanosomiasis. This therapy resulted no improvement in patient’s condition. Finally, at request of the patient’s attendants he was referred to Belgium where he was diagnosed as brucellosis and treated successfully.

Conclusion

Our patient was indeed suffering from neurobrucellosis. Brucellosis is a frequently missed cause of pyrexia. Our case highlights that in this era, taking help from our professional colleagues over the globe is easy which can improve patient care greatly.

Immunospecific immunoglobulins and IL-10 as markers for Trypanosoma brucei rhodesiense late stage disease in experimentally infected vervet monkeys

OBJECTIVE

To determine the usefulness of IL-10 and immunoglobulin M (IgM) as biomarkers for staging HAT in vervet monkeys, a useful pathogenesis model for humans.

METHODS

Vervet monkeys were infected with Trypanosoma brucei rhodesiense and subsequently given sub-curative and curative treatment 28 and 140 days post-infection (dpi) respectively. Matched serum and CSF samples were obtained at regular intervals and immunospecific IgM, immunoglobulin G (IgG) and IL-10 were quantified by ELISA.

RESULTS

There was no detectable immunospecific IgM and IgG in the CSF before 49 dpi. CSF IgM and IgG and serum IgM were significantly elevated with peak levels coinciding with meningoencephalitis 98 dpi. The serum IL-10 was upregulated in both early and late disease stage, coinciding with primary and relapse parasitaemia respectively. CSF white cell counts (CSF WCC) were elevated progressively till curative treatment was given. After curative treatment, there was rapid and significant drop in serum IgM and IL-10 concentration as well as CSF WCC. However, the CSF IgM and IgG remained detectable to the end of the study.

CONCLUSIONS

Serum and CSF concentrations of immunospecific IgM and CSF IgG changes followed a pattern that mimics the progression of the disease and may present reliable and useful biomarkers of the disease stage. Due to rapid decline, serum IgM and IL-10 are, additionally, potential biomarkers of the success of chemotherapy.

A combined CXCL10, CXCL8 and H-FABP panel for the staging of human African trypanosomiasis patients

BACKGROUND

Human African trypanosomiasis (HAT), also known as sleeping sickness, is a parasitic tropical disease. It progresses from the first, haemolymphatic stage to a neurological second stage due to invasion of parasites into the central nervous system (CNS). As treatment depends on the stage of disease, there is a critical need for tools that efficiently discriminate the two stages of HAT. We hypothesized that markers of brain damage discovered by proteomic strategies and inflammation-related proteins could individually or in combination indicate the CNS invasion by the parasite.

METHODS

Cerebrospinal fluid (CSF) originated from parasitologically confirmed Trypanosoma brucei gambiense patients. Patients were staged on the basis of CSF white blood cell (WBC) count and presence of parasites in CSF. One hundred samples were analysed: 21 from stage 1 (no trypanosomes in CSF and 5 WBC/microL) patients. The concentration of H-FABP, GSTP-1 and S100beta in CSF was measured by ELISA. The levels of thirteen inflammation-related proteins (IL-1ra, IL-1beta, IL-6, IL-9, IL-10, G-CSF, VEGF, IFN-gamma, TNF-alpha, CCL2, CCL4, CXCL8 and CXCL10) were determined by bead suspension arrays.

RESULTS

CXCL10 most accurately distinguished stage 1 and stage 2 patients, with a sensitivity of 84% and specificity of 100%. Rule Induction Like (RIL) analysis defined a panel characterized by CXCL10, CXCL8 and H-FABP that improved the detection of stage 2 patients to 97% sensitivity and 100% specificity.

CONCLUSION

This study highlights the value of CXCL10 as a single biomarker for staging T. b. gambiense-infected HAT patients. Further combination of CXCL10 with H-FABP and CXCL8 results in a panel that efficiently rules in stage 2 HAT patients. As these molecules could potentially be markers of other CNS infections and disorders, these results should be validated in a larger multi-centric cohort including other inflammatory diseases such as cerebral malaria and active tuberculosis.

Tropical dermatology: Tropical diseases caused by protozoa

Protozoan infections are very common among tropical countries and have an important impact on public health. Leishmaniasis is the most widely disseminated protozoan infection in the world, while the trypanosomiases are widespread in both Africa and South America. Amebiasis, a less common protozoal infection, is a cause of significant morbidity in some regions. Toxoplasmosis and pneumocystosis (formerly thought to be caused by a protozoan) are worldwide parasitic infections with a very high incidence in immunocompromised patients but are not restricted to them. In the past, most protozoan infections were restricted to specific geographic areas and natural reservoirs. There are cases in which people from other regions may have come in contact with these pathogens. A common situation involves an accidental contamination of a traveler, tourist, soldier, or worker that has contact with a reservoir that contains the infection. Protozoan infections can be transmitted by arthropods, such as sandflies in the case of leishmaniasis or bugs in the case of trypanosomiases. Vertebrates also serve as vectors as in the case of toxoplasmosis and its transmission by domestic cats. The recognition of the clinical symptoms and the dermatologic findings of these diseases, and a knowledge of the geographic distribution of the pathogen, can be critical in making the diagnosis of a protozoan infection.

LEARNING OBJECTIVES

After completing this learning activity, participants should be able to recognize the significance of protozoan infections worldwide, identify the dermatologic manifestations of protozoan infections, and select the best treatment for the patient with a protozoan 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.

Traversal of human and animal trypanosomes across the blood-brain barrier

The neurological complications of human African trypanosomiasis (HAT) in man caused by the unicellular protozoan parasites Trypanosoma brucei gambiense and T. b. rhodesiense are a consequence of the penetration of the blood-brain barrier (BBB) by trypanosomes that enter the central nervous system (CNS). Yet the mechanisms by which African trypanosomes cross the true BBB comprised of brain microvascular endothelial cells (BMECs) remain unclear. Human BBB models used to determine how African trypanosomes initially interact in vitro with the human BBB proper suggest that parasites cross the human BBB in part by generating Ca(2+) activation signals in human BMECs through the activity of parasite cysteine proteases. In vivo murine models of HAT have suggested additional mechanisms of BBB traversal by trypanosomes, with recent compelling evidence for the important role of interferon-gamma in facilitating this process. A clear understanding of how trypanosomes enter the CNS is critical for both understanding the neuropathogenesis of HAT and in developing more effective drug therapies for late-stage disease.

The continuing problem of human African trypanosomiasis (sleeping sickness)

Human African trypanosomiasis, also known as sleeping sickness, is a neglected disease, and it continues to pose a major threat to 60 million people in 36 countries in sub-Saharan Africa. Transmitted by the bite of the tsetse fly, the disease is caused by protozoan parasites of the genus Trypanosoma and comes in two types: East African human African trypanosomiasis caused by Trypanosoma brucei rhodesiense and the West African form caused by Trypanosoma brucei gambiense. There is an early or hemolymphatic stage and a late or encephalitic stage, when the parasites cross the blood-brain barrier to invade the central nervous system. Two critical current issues are disease staging and drug therapy, especially for late-stage disease. Lumbar puncture to analyze cerebrospinal fluid will remain the only method of disease staging until reliable noninvasive methods are developed, but there is no widespread consensus as to what exactly defines biologically central nervous system disease or what specific cerebrospinal fluid findings should justify drug therapy for late-stage involvement. All four main drugs used for human African trypanosomiasis are toxic, and melarsoprol, the only drug that is effective for both types of central nervous system disease, is so toxic that it kills 5% of patients who receive it. Eflornithine, alone or combined with nifurtimox, is being used increasingly as first-line therapy for gambiense disease. There is a pressing need for an effective, safe oral drug for both stages of the disease, but this will require a significant increase in investment for new drug discovery from Western governments and the pharmaceutical industry.

Antibody index and specific antibody quotient in horses after intragastric administration of Sarcocystis neurona sporocysts

OBJECTIVE

To investigate the use of a specific antibody index (AI) that relates Sarcocystis neurona-specific IgG quotient (Q(SN)) to total IgG quotient (Q(IgG)) for the detection of the anti-S neurona antibody fraction of CNS origin in CSF samples obtained from horses after intragastric administration of S neurona sporocysts.

ANIMALS

18 adult horses.

PROCEDURES

14 horses underwent intragastric inoculation (day 0) with S neurona sporocysts, and 4 horses remained unchallenged; blood and CSF samples were collected on days - 1 and 84. For purposes of another study, some challenged horses received intermittent administration of ponazuril (20 mg/kg, PO). Sarcocystis neurona-specific IgG concentrations in CSF (SN(CSF)) and plasma (SN(plasma)) were measured via a direct ELISA involving merozoite lysate antigen and reported as ELISA units (EUs; arbitrary units based on a nominal titer for undiluted immune plasma of 100,000 EUs/mL). Total IgG concentrations in CSF (IgG(CSF)) and plasma (IgG(plasma)) were quantified via a sandwich ELISA and a radial immunodiffusion assay, respectively; Q(SN), Q(IgG), and AI were calculated.

RESULTS

Following sporocyst challenge, mean +/- SEM SN(CSF) and SN(plasma) increased significantly (from 8.8 +/- 1.0 EUs/mL to 270.0 +/- 112.7 EUs/mL and from 1,737 +/- 245 EUs/mL to 43,169 +/- 13,770 EUs/mL, respectively). Challenge did not affect total IgG concentration, Q(SN), Q(IgG), or AI.

CONCLUSIONS AND CLINICAL RELEVANCE

S neurona-specific IgG detected in CSF samples from sporocyst-challenged horses appeared to be extraneural in origin; thus, this experimental challenge may not reliably result in CNS infection. Calculation of a specific AI may have application to the diagnosis of S neurona-associated myeloencephalitis in horses.

Suramin and minocycline treatment of experimental African trypanososmiasis at an early stage of parasite brain invasion

The effect of treatment on relapses of Trypanosoma brucei (T. b.) brucei infections in mice in relation to passage of the parasites across the blood-brain barrier (BBB) as visualized by immunohistochemistry was studied. Three daily intraperitoneal injections of 20mg/kg suramin starting at 15 days post-infection (p.i.), when trypanosomes had begun to traverse the BBB, were curative, but not when starting at 21 days p.i. when parasite brain invasion was more pronounced. Relapses occurred in all mice after one or two daily injections of suramin starting at 15 days p.i., but they were delayed when treatment was supplemented with minocycline, which impedes penetration of T. b. brucei into the brain. This study supports the notion that suramin may be effective even when minor parasite neuroinvasion has appeared in African trypanosomiasis and it shows that minocyline can affect relapses of the disease.

Treatment failure related to intrathecal immunoglobulin M (IgM) synthesis, cerebrospinal fluid IgM, and interleukin-10 in patients with hemolymphatic-stage sleeping sickness

Human African trypanosomiasis treatment is stage dependent, but the tests used for staging are controversial. Central nervous system involvement and its relationship with suramin treatment failure were assessed in 60 patients with parasitologically confirmed hemolymphatic-stage Trypanosoma brucei gambiense infection (white blood cell count of or=1.9 mg/liter (OR, 11.7; 95% CI, 2.7 to 50), a CSF end titer by the LATEX/IgM assay of >or=2 (OR, 10.4; 95% CI, 2.5 to 44), and a CSF interleukin-10 concentration of >10 pg/ml (OR, 5; 95% CI, 1.3 to 20). The sensitivities of these markers for treatment failure ranged from 43 to 79%, and the specificities ranged from 74 to 93%. The results show that T. brucei gambiense-infected patients who have signs of neuroinflammation in CSF and who are treated with drugs recommended for use at the hemolymphatic stage are at risk of treatment failure. This highlights the need for the development and the evaluation of accurate point-of-care tests for the staging of human African trypanosomiasis.

African trypanosomiasis in a British soldier

BACKGROUND

Human African trypanosomiasis (sleeping sickness) is a parasitic infection transmitted by day-biting tsetse flies. The diagnostic gold standard is microscopy of blood, lymph node aspirates or CSF. The disease is invariably fatal, if not treated. There are over 300 000 new cases of sleeping sickness each year, and approximately 100,000 deaths.

CASE PRESENTATION

We describe a British soldier who acquired trypanosomiasis in Malawi. He gave no history of a painful insect bite but presented with classical early signs of sleeping sickness (a primary chancre, regional lymphadenopathy, circinate erythema and a cyclical fever pattern). His condition worsened in the next week and trypanosomes were observed in a blood sample. He was aeromedically evacuated to Johannesburg, where Stage One Trypanosoma brucei rhodesiense infection was confirmed; he also had renal and liver failure, pancytopenia and heart block. He was treated with intravenous suramin. He recovered fully over the next 5 months.

RECOMMENDATIONS

Medical officers deploying to eastern and southeastern Africa must be familiar with the common presenting signs and symptoms of T b rhodesiense sleeping sickness, and should have access to a reliable local microscopy service at all times. Confirmed sleeping sickness requires immediate transfer to a tertiary diagnostic and treatment centre, where suramin (for T b rhodesiense infection) or pentamidine (for T b gambiense) and also melarsoprol (for Stage Two disease) must be immediately available.