Cedric P. Yansouni
McGill University Health Centre
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Publication
Featured researches published by Cedric P. Yansouni.
The New England Journal of Medicine | 2013
Chris Kenyon; Kim Bonorchis; Craig Corcoran; Graeme Meintjes; Michael Locketz; Hester F. Vismer; Preneshni Naicker; Hans Prozesky; Marelize Van Wyk; Colleen Bamford; Gail Imrie; Sipho Dlamini; Andrew M. Borman; Robert Colebunders; Cedric P. Yansouni; Marc Mendelson; Nelesh P. Govender
BACKGROUND The genus emmonsia contains three species that are associated with human disease. Emmonsia crescens and Emmonsia parva are the agents that cause adiaspiromycosis, and one human case of Emmonsia pasteuriana infection has been described. We report a fungal pathogen within the genus emmonsia that is most closely related to E. pasteuriana in human immunodeficiency virus (HIV)-infected adults in South Africa. METHODS Between July 2008 and July 2011, we conducted enhanced surveillance to identify the cause of systemic, dimorphic fungal infections in patients presenting to Groote Schuur Hospital and other hospitals affiliated with the University of Cape Town, Cape Town, South Africa. DNA sequencing was used to identify pathogenic fungi. RESULTS A total of 24 cases of dimorphic fungal infection were diagnosed, 13 of which were caused by an emmonsia species. All 13 patients were HIV-infected, with a median CD4+ T-cell count of 16 cells per cubic millimeter (interquartile range, 10 to 44), and all had evidence of disseminated fungal disease. Three patients died soon after presentation, but the others had a good response to a variety of antifungal agents and antiretroviral therapy. Phylogenetic analysis of five genes (LSU, ITS1-2, and the genes encoding actin, β-tubulin, and intein PRP8) revealed that this fungus belongs in the genus emmonsia and is most closely related to E. pasteuriana. CONCLUSIONS The findings suggest that these isolates of an emmonsia species represent a new species of dimorphic fungus that is pathogenic to humans. The species appears to be an important cause of infections in Cape Town.
BMC Infectious Diseases | 2013
Sören L. Becker; Jürg Vogt; Stefanie Knopp; Marcus Panning; David C. Warhurst; Katja Polman; Hanspeter Marti; Lutz von Müller; Cedric P. Yansouni; Jan Jacobs; Emmanuel Bottieau; Moussa Sacko; Suman Rijal; Fransiska Meyanti; Michael A. Miles; Marleen Boelaert; Pascal Lutumba; Lisette van Lieshout; Eliézer K. N’Goran; François Chappuis; Jürg Utzinger
BackgroundPersistent digestive disorders account for considerable disease burden in the tropics. Despite advances in understanding acute gastrointestinal infections, important issues concerning epidemiology, diagnosis, treatment and control of most persistent digestive symptomatologies remain to be elucidated. Helminths and intestinal protozoa are considered to play major roles, but the full extent of the aetiologic spectrum is still unclear. We provide an overview of pathogens causing digestive disorders in the tropics and evaluate available reference tests.MethodsWe searched the literature to identify pathogens that might give rise to persistent diarrhoea, chronic abdominal pain and/or blood in the stool. We reviewed existing laboratory diagnostic methods for each pathogen and stratified them by (i) microscopy; (ii) culture techniques; (iii) immunological tests; and (iv) molecular methods. Pathogen-specific reference tests providing highest diagnostic accuracy are described in greater detail.ResultsOver 30 pathogens may cause persistent digestive disorders. Bacteria, viruses and parasites are important aetiologic agents of acute and long-lasting symptomatologies. An integrated approach, consisting of stool culture, microscopy and/or specific immunological techniques for toxin, antigen and antibody detection, is required for accurate diagnosis of bacteria and parasites. Molecular techniques are essential for sensitive diagnosis of many viruses, bacteria and intestinal protozoa, and are increasingly utilised as adjuncts for helminth identification.ConclusionsDiagnosis of the broad spectrum of intestinal pathogens is often cumbersome. There is a need for rapid diagnostic tests that are simple and affordable for resource-constrained settings, so that the management of patients suffering from persistent digestive disorders can be improved.
Clinical Microbiology and Infection | 2013
François Chappuis; Emilie Alirol; V. d’Acremont; Emmanuel Bottieau; Cedric P. Yansouni
The recent roll-out of rapid diagnostic tests (RDTs) for malaria has highlighted the decreasing proportion of malaria-attributable illness in endemic areas. Unfortunately, once malaria is excluded, there are few accessible diagnostic tools to guide the management of severe febrile illnesses in low resource settings. This review summarizes the current state of RDT development for several key infections, including dengue fever, enteric fever, leptospirosis, brucellosis, visceral leishmaniasis and human African trypanosomiasis, and highlights many remaining gaps. Most RDTs for non-malarial tropical infections currently rely on the detection of host antibodies against a single infectious agent. The sensitivity and specificity of host-antibody detection tests are both inherently limited. Moreover, prolonged antibody responses to many infections preclude the use of most serological RDTs for monitoring response to treatment and/or for diagnosing relapse. Considering these limitations, there is a pressing need for sensitive pathogen-detection-based RDTs, as have been successfully developed for malaria and dengue. Ultimately, integration of RDTs into a validated syndromic approach to tropical fevers is urgently needed. Related research priorities are to define the evolving epidemiology of fever in the tropics, and to determine how combinations of RDTs could be best used to improve the management of severe and treatable infections requiring specific therapy.
Lancet Infectious Diseases | 2013
Cedric P. Yansouni; Emmanuel Bottieau; Pascal Lutumba; Andrea Sylvia Winkler; Lut Lynen; Philippe Büscher; Jan Jacobs; Philippe Gillet; Veerle Lejon; Emilie Alirol; Katja Polman; Jürg Utzinger; Michael A. Miles; Rosanna W. Peeling; Jean-Jacques Muyembe; François Chappuis; Marleen Boelaert
Infections are a leading cause of life-threatening neuropathology worldwide. In central African countries affected by endemic diseases such as human African trypanosomiasis, tuberculosis, HIV/AIDS, and schistosomiasis, delayed diagnosis and treatment often lead to avoidable death or severe sequelae. Confirmatory microbiological and parasitological tests are essential because clinical features of most neurological infections are not specific, brain imaging is seldom feasible, and treatment regimens are often prolonged or toxic. Recognition of this diagnostic bottleneck has yielded major investment in application of advances in biotechnology to clinical microbiology in the past decade. We review the neurological pathogens for which rapid diagnostic tests are most urgently needed in central Africa, detail the state of development of putative rapid diagnostic tests for each, and describe key technical and operational challenges to their development and implementation. Promising field-suitable rapid diagnostic tests exist for the diagnosis of human African trypanosomiasis and cryptococcal meningoencephalitis. For other infections-eg, syphilis and schistosomiasis-highly accurate field-validated rapid diagnostic tests are available, but their role in diagnosis of disease with neurological involvement is still unclear. For others-eg, tuberculosis-advances in research have not yet yielded validated tests for diagnosis of neurological disease.
Lancet Infectious Diseases | 2008
Anne-Marie Lowe; Cedric P. Yansouni; Marcel A. Behr
The gastrointestinal tract contains a complex mix of microorganisms. Therefore, the finding of a particular microbe in the gastrointestinal tract or stools of a patient with intestinal disease does not necessarily indicate that the clinical state resulted from the presence of this organism. For this reason, extending from epidemiological association to causality is particularly challenging for gastrointestinal diseases. Most established agents of acute bacterial gastroenteritis (eg, Escherichia coli, Campylobacter jejuni) have been shown to fulfil Kochs postulates of causality in human volunteer studies. For Helicobacter pylori, which can cause both acute and chronic disease, the organism was first linked to an acute syndrome through volunteer studies and then later assessed for a role in chronic disease by use of Hills epidemiological criteria of causation. However, for agents of chronic intestinal disease, this approach is not ethical and risks overlooking events occurring long after the exposure. We examine the criteria used to judge causality (Kochs postulates and Hills criteria) and their applicability for chronic gastrointestinal diseases (eg, Whipples disease and Crohns disease). We also identify crucial research questions required to advance towards assessing the causal role of candidate microbes in the aetiopathogenesis of Crohns disease.
Clinical Infectious Diseases | 2012
Cedric P. Yansouni; Emmanuel Bottieau; François Chappuis; Marie-France Phoba; Octavie Lunguya; Billy Bongoso Ifeka; Jan Jacobs
To THE EDITOR—We read with interest the editorial commentary by Crump [1], which emphasizes the need for a syndromic approach to fever in low-resource settings—citing 2 recent epidemics of Salmonella Typhi [2, 3], the decreasing proportion of malaria-attributable illness in many areas, and changing vaccination patterns as arguments. We strongly agree with this point and wish to emphasize the role of microbiologic diagnostic tests in this process. Although the benefits of parasitological diagnosis of malaria are widely emphasized [4], using malaria diagnosis alone as the cornerstone of linking febrile patients to appropriate care is dangerous. For example, the Institute of Tropical Medicine, Antwerp, was recently asked for assistance by colleagues in the remote Bwamanda health zone of the Democratic Republic of the Congo, which was facing an outbreak of severe malarial anemia in the second half of 2011. A dramatic increase in blood transfusion requirements and in-hospital mortality was observed among children <5 years of age with parasitologically confirmed malaria. Intensified surveillance of bloodstream infections in December 2011 via the national reference laboratory in Kinshasa recovered 57 nontyphoidal Salmonella isolates among 135 blood cultures in severely ill children (42%). This large unrecognized outbreak of severe disease from a clonal strain of Salmonella illustrates the pitfalls of focusing on a single pathogen, such as malaria, in patients presenting with febrile illnesses in low-resource settings. Further, widespread adoption of malaria rapid diagnostic tests (RDT) has resulted in dramatic increases in empiric antibacterial use among the three-quarters of febrile patients in whom no malaria is found [5]. This dichotomous diagnostic approach can only fuel emerging antimicrobial resistance in the settings that can least afford it [6]. Choosing rational empiric therapy for patients with febrile syndromes in lowresource settings is complicated by the fact that a large proportion of them may be caused by any of several geographically restricted infections and neglected tropical diseases, such as tick-borne borreliosis [7], visceral leishmaniasis [8], and human African trypanosomiasis. Such infections are severe and treatable but often clinically indistinguishable without confirmatory tests. Making matters worse, very little epidemiologic data underpin clinicians’ assessment of prior probability in vast areas of Africa and Asia. A syndromic approach to patients with fever that integrates relevant combinations of RDT is urgently needed in many parts of the world. This will require (1) comprehensive epidemiologic studies using reference standard techniques to determine the prevalence of priority diseases that are severe and treatable; (2) validation of existing RDT in field settings and development of new RDT for key pathogens of epidemiologic importance; and (3) evidence-based algorithms incorporating local epidemiological data and setting-specific RDT diagnostic contributions, because the latter can vary substantially by locality [9, 10]. We are working as part of the EUfunded NIDIAG (Neglected Infectious Disease dIAGnosis) consortium to develop such an approach to persistent fever in 4 low-resource countries, with the aim of achieving patient-centered care pathways that will accelerate diagnosis and improve outcomes.
Current Infectious Disease Reports | 2014
Cedric P. Yansouni; Joanna Merckx; Michael Libman; Momar Ndao
Microscopy has several limitations in the diagnosis of parasitic infection. New technologies have emerged to address some of these limitations. We review recent advances in three key areas. The detection of enteric protozoa is a commonly requested test, particularly with increasing travel to and migration from endemic countries. Microscopy is slow and labor intensive and requires a high level of technical expertise. It also lacks both sensitivity and specificity. Recently developed nucleic acid amplification tests are automated and rapid and show superior accuracy. Proteomics shows promise for both the diagnosis of infections where parasite detection is difficult and the potential for accurate assessment of cure in these cases. Finally, rapid and simple diagnostic tests suitable for use in low-resource settings are now allowing for improved study and control of infection in endemic regions.
Military Medicine | 2011
Annelies Aerssens; Daniel De Vos; Jean-Paul Pirnay; Cedric P. Yansouni; Joannes Clerinx; Alfons Van Gompel; Patrick Soentjens
The detection of schistosomiasis cases among Belgian military personnel returning from a mission in the Democratic Republic of Congo (DRC) prompted a nested case-control study of all military personnel deployed in the DRC between 2005 and 2008 to identify all infections and to start appropriate treatment. Of 197 patients exposed at Lake Tanganyika in the Kalemie area of DRC, 49 (24.9%) were diagnosed with schistosomiasis. Swimming was significantly more frequent than wading in the seropositive group than in the seronegative group (88.9% vs. 73.6%; odds ratio [OR], 2.86; 95% confidence interval [CI], 0.97-9.01). Thirty-one of 49 patients (63.3%) were symptomatic; including skin problems in 34.7%, respiratory symptoms in 12.2%, fever in 14.3%, and 51.0% with gastrointestinal problems. Median eosinophil counts were significantly higher in seropositive patients (375 vs. 138 per tL; Wilcoxon rank sum test [Ws] = 10,559.00; p < 0.01; r = -0.49). In total, 20 (40.8%) of the 49 patients were treated for symptomatic infections and the remainder for asymptomatic schistosomiasis. Our study emphasizes the need for active systematic post-tropical screening in military personnel after deployment to Schistosoma-endemic regions of the world.
Infection Control and Hospital Epidemiology | 2012
Cedric P. Yansouni; Nandini Dendukuri; Guoyuan Liu; Myriam Fernandez; Charles Frenette; Steven Paraskevas; Donald C. Sheppard
OBJECTIVE The significance of positive cultures of organ preservation fluid (OPF) in solid organ transplantation is not known. We sought to describe the microbiology and define the clinical impact of positive OPF cultures. DESIGN Retrospective cohort study. SETTING Tertiary care hospital. PATIENTS A consecutive sample of all solid organ transplantations at our center between July 2006 and January 2009 was reviewed. A total of 331 allografts (185 kidneys, 104 livers, 31 pancreases, and 11 hearts) met the inclusion criterion of having OPF cultures taken from the transplanted allograft. METHODS Organisms recovered from OPF were classified as high or low risk according to their virulence. Clinical outcomes were compared between recipients of organs with positive OPF cultures and recipients of organs with negative OPF cultures. RESULTS OPF cultures were positive in 62.2% of allografts and yielded high-risk organisms in 17.8%. Normal skin flora constituted the majority of positive OPF cultures, while Enterobacteriaceae spp. and Staphylococcus aureus made up the majority of high-risk organisms. Recipients of allografts with positive OPF cultures developed more frequent bacterial infections, regardless of allograft type (relative risk, 2.39; 95% confidence interval [CI], 1.61-3.54). Moreover, isolation of a given organism in OPF samples was associated with the development of a clinical infection with the same organism, regardless of allograft type. CONCLUSIONS Positive cultures of OPF are common events in solid organ transplantation, frequently involve high-risk organisms, and are associated with the development of postoperative clinical bacterial infections. Further study is required to determine the optimal strategies for their prevention and management.
Canadian Medical Association Journal | 2017
Andrea K. Boggild; Jennifer Geduld; Michael Libman; Cedric P. Yansouni; Anne McCarthy; Jan Hajek; Wayne Ghesquiere; Yazdan Mirzanejad; Jean Vincelette; Susan Kuhn; Pierre J. Plourde; Sumontra Chakrabarti; David O. Freedman; Kevin C. Kain
BACKGROUND: Widespread transmission of Zika virus in the Americas has occurred since late 2015. We examined demographic and travel-related characteristics of returned Canadian travellers with Zika infection acquired in the Americas to illuminate risk factors for acquisition and the clinical spectrum. METHODS: We analyzed demographic and travel-related data for returned Canadian travellers who presented to a CanTravNet site between October 2015 and September 2016 for care of Zika virus acquired in the Americas. Data were collected with use of the GeoSentinel Surveillance Network data platform. RESULTS: During the study period, 1118 travellers presented to a CanTravNet site after returning from the Americas, 41 (3.7%) of whom had Zika infection. Zika infection from the Americas was diagnosed at CanTravNet sites as often as dengue (n = 41) over the study period. In the first half of the study period, Zika virus burden was borne by people visiting friends and relatives in South America. In the latter half, coincident with the increased spread of Zika throughout the Caribbean and Central America, Zika virus occurred more often in tourists in the Caribbean. Forty (98%) of the travellers with Zika infection acquired it through probable mosquito exposure, and 1 had confirmed sexual acquisition. Congenital transmission occurred in 2 of 3 pregnancies. Two (5%) of those with Zika had symptoms resembling those of Guillain–Barré syndrome, 1 of whom also had Zika viral meningitis. INTERPRETATION: Even in this small cohort, we observed the full clinical spectrum of acute Zika virus, including adverse fetal and neurologic outcomes. Our observations suggest that complications from Zika infection are underestimated by data arising exclusively from populations where Zika is endemic. Travellers should adhere to mosquito-avoidance measures and barrier protection during sexual activity.