<em>Histoplasma capsulatum</em> and <em>Histoplasmosis:</em> Current Concept for the Diagnosis

Histoplasmosis is a global deep mycosis caused by Histoplasma capsulatum (Hc), a dimorphic fungus. It exists on two main varieties Hc capsulatum and Hc duboisii that could be distinguished by their epidemiology, their clinical presentation, and the morphological aspect of the fungus at direct examination of the sample. Laboratory diagnosis of Hc remains a real challenge as it required experience and equipment. Through a general review of literature, the different diagnosis tools for Histoplasma sp. are analyzed, and strengths and weaknesses are pointed according to the context-based value. Isolation of Hc on culture is the gold standard for diagnosis of histoplasmosis. However, it remains less sensitive (sensitivity: up to 77%) and implies long time to result, which can be inappropriate or in adapted for an emergency diagnosis. So, nonculture methods as antigen testing, serology, and molecular biology become available and allow a rapid diagnosis. However, the optimal diagnostic method depends on many parameters as the very wide range of symptomatology, the immune status. Indeed, Ag detection is the best diagnosis tool for PHD (sensitivity: 92–95%) and SCN histoplasmosis (sensitivity: 66%) and serology for the subacute/chronic form (sensitivity: 85–93%). Thus, the clinico-biological dialog is essential, and histoplasmosis management includes an integrated medical approach

Severe Acquired Toxoplasmosis Caused by Wild Cycle of Toxoplasma gondii, French Guiana

From 1998 through 2006, 44 cases of severe primary toxoplasmosis were observed in French Guiana in immunocompetent adults. Toxoplasma gondii isolates exhibited an atypical multilocus genotype. Severe disease in humans may result from poor host adaptation to neotropical zoonotic strains of T. gondii circulating in a forest-based cycle

Ecological niche modelling for predicting the risk of cutaneous leishmaniasis in the Neotropical moist forest biome

A major challenge of eco-epidemiology is to determine which factors promote the transmission of infectious diseases and to establish risk maps that can be used by public health authorities. The geographic predictions resulting from ecological niche modelling have been widely used for modelling the future dispersion of vectors based on the occurrence records and the potential prevalence of the disease. The establishment of risk maps for disease systems with complex cycles such as cutaneous leishmaniasis (CL) can be very challenging due to the many inference networks between large sets of host and vector species, with considerable heterogeneity in disease patterns in space and time. One novelty in the present study is the use of human CL cases to predict the risk of leishmaniasis occurrence in response to anthropogenic, climatic and environmental factors at two different scales, in the Neotropical moist forest biome (Amazonian basin and surrounding forest ecosystems) and in the surrounding region of French Guiana. With a consistent data set never used before and a conceptual and methodological framework for interpreting data cases, we obtained risk maps with high statistical support. The predominantly identified human CL risk areas are those where the human impact on the environment is significant, associated with less contributory climatic and ecological factors. For both models this study highlights the importance of considering the anthropogenic drivers for disease risk assessment in human, although CL is mainly linked to the sylvatic and peri-urban cycle in Meso and South America. © 2019 Chavy et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

The fight against HIV-associated disseminated histoplasmosis in the Americas: Unfolding the different stories of four centers

Disseminated histoplasmosis is a major opportunistic infection of HIV-infected patients, killing thousands in Latin America each year. Yet, it remains a neglected disease that is often confused with tuberculosis, for lack of simple, affordable, and rapid diagnostic tools. There is great heterogeneity in the level of histoplasmosis awareness. The purpose of this report was to describe how the historical “awakening” to the threat of histoplasmosis came to be in four different centers that have actively described this disease: In Brazil, the Sao José hospital in Fortaleza; in Colombia, the Corporación para Investigaciones Biológicas inMedellin; in French Guiana, Cayenne Hospital; and in Guatemala, the Association de Salud Integral in Guatemala city. In Brazil and French Guiana, the search for leishmaniasis on the buffy coat or skin smears, respectively, led to the rapid realization that HIV patients were suffering from disseminated histoplasmosis. With time and progress in fungal culture, the magnitude of this problem turned it into a local priority. In Colombia and Guatemala, the story is different because for these mycology centers, it was no surprise to find histoplasmosis in HIV patients. In addition, collaborations with the CDC to evaluate antigen-detection tests resulted in researchers and clinicians developing the capacity to rapidly screen most patients and to demonstrate the very high burden of disease in these countries. While the lack of awareness is still a major problem, it is instructive to review the ways through which different centers became histoplasmosis-aware. Nevertheless, as new rapid diagnostic tools are becoming available, their implementation throughout Latin America should rapidly raise the level of awareness in order to reduce the burden of histoplasmosis deaths. © 2019 by the authors

Outbreak of Leishmania braziliensis cutaneous leishmaniasis, Saül, French Guiana [letter]

New World cutaneous leishmaniasis (CL), a zoonotic disease, is increasingly seen among travelers returning from Latin American countries, particularly from Bolivia, Belize, and French Guiana (1). The epidemiology of CL in the Americas is heterogeneous and has complex variations in transmission cycles, reservoir hosts, and sandfly vectors. Changing human activities that affect these factors may have resulted in the emergence of species with distinct pathogenic potentials and responses to therapy. In the Guianan ecoregion complex, leishmaniasis is endemic, and 5 coexisting Leishmania parasite species are known to infect humans: L. guyanensis, L. braziliensis, L. amazonensis, L. naiffi, and L. lainsoni. Among these species, L. guyanensis accounts for ≈85% of CL cases (2). We report an outbreak of 7 cases of L. braziliensis CL that occurred among 24 scientists who participated in a field mission at Limonade Creek in Saül, French Guiana, during October 10–25, 2013. Saül is an isolated village in the Amazonian rainforest (3°55′18′′N, 53°18′02′′W)

Approche épidémiologique, clinique et biologique des formes sévères de toxoplasmose acquise du sujet adulte immunocompétent en Guyane française

This thesis in a focus on medical knowledge and scientific work which helped to describe since 1998 a special from of acquired toxoplasmosis especially reported in French Guiana and in a Surinamese border village. It presents as a clinical and pathophysiological approach of criteria of pathogenicity of Toxoplasma gondii that circulate in French Guiana. The document is organized into three main parts ; the first one reports the clinical, epidemiological and biological features of this form of toxoplasmosis, called Amazonian toxoplasmosis or AT ; the second part develops the arguments for the existence of a forest base cycle of atypical strains of T.gondii, and the third part determines the virulence criteria on mice for one T.gondii involved in AT.General review of published articles associated with the analysis of 35 cases of AT reported from 2002 to 2009 clearly highlight the experience of this clinical entity that is remarkable for its morbidity and its clinical heterogeneity. Ethnicity, place of residence and some biological parameters seems to be aggravating factors. The initial hypothesis that AT involves unsuitable T.gondii strains to humans led to study the circulation of the parasite in wildlife and recent studies confirms this hypothesis. The third part of this document really concretizes the virulence on mice of one atypical T.gondii strain involved in an AT case by the determination od the letal dose, LD50 and LD100 and the description of of the histological features. This part initiates a discussion about the pathophysiolgical mechanisms of this entityCette thèse fait une mise au point sur les connaissances médicales et les travaux scientifiques qui ont contribué à mettre en lumière depuis 1998 une forme particulière de toxoplasmose acquise décrite principalement en Guyane Française et à sa frontière Surinamaise. Elle s organise en une double approche clinique et physiopathologique des critères de pathogénicité des Toxoplasma gondii circulant en Guyane et se décline en 3 volets ; le premier rapportant les aspects cliniques, épidémiologique et biologiques de cette forme de toxoplasmose, dénommée toxoplasmose amazonienne ou TA ; le deuxième expose les arguments pour l existence d un cycle forestier impliquant des souches T.gondii atypiques et à l origine de ces formes ; et le troisième volet détermine des critères de virulence d une souche atypique responsable de TA chez la souris.Le travail de synthèse des articles publiés couplé à l exploitation de 35 cas entre 2002 et 2009 met bien en évidence l existence de cette entité clinique remarquable de part sa morbidité, sévérité et son hétérogénéité clinique. Le caractère ethnique et le lieu de résidence pourraient être des facteurs aggravants de même que certains paramètres biologiques. L hypothèse initiale d une inadaptation de souches de T.gondii à l homme à conduit à explorer la circulation du parasite dans la faune sauvage et les enquêtes réalisées sur ce biotope confortent cette idée. La troisième partie de ce document rapporte bien par i) des critères chiffrés au travers de la DL 50 et DL100, ii) par des critères anatomopathologiques, la virulence particulière d une souche. Elle initie une réflexion sur les mécanismes physiopathologiques de cette entité.CAYENNE-BU (973022101) / SudocSudocFranceFrench GuianaFRG

Hyperparasitaemia during bouts of malaria in French Guiana.

International audienceUNLABELLED: ABSTRACT: BACKGROUND: High circulating parasite load is one of the WHO criteria for severe falciparum malaria. During a period of 11 years (2000-2010), the frequency of hyperparasitaemia (HP) (≥4% infected erythrocytes) during bouts of malaria due to Plasmodium falciparum, Plasmodium vivax and Plasmodium malariae in patients referred to Cayenne General Hospital (CGH) in French Guiana and the frequency of their admission to the Intensive Care Unit (ICU) were evaluated. METHODS: A mean of 1,150 malaria cases were referred to the Parasitology Laboratory of CGH each year over the last decade. During this period, malaria diagnostic (microscopy) and parasitaemia evaluation have remained unchanged: determination of the parasitized erythrocytes percentage with asexual forms on thin blood smears for all cases of parasitaemia exceeding 0.1%. Patients admitted to the ICU can be counted by origin of the request for malaria testing. All the data collected retrospectively were anonymized in a standardized case report form and in database. RESULTS: Between 2000 and 2010, 12,254 bouts of malaria were confirmed at the Parasitology Laboratory of CHG: P. vivax: 56.2%, P. falciparum: 39.5%, co-infection with both species: 3.4%, P. malariae: 0.9%. HP was observed in 262 cases, at a frequency of 4.9% for P. falciparum and only 0.041% for P. vivax, with no recorded cases for P. malariae. The need for intensive care was correlated with P. falciparum parasite load: 12.3% of cases for parasitaemia of 4-9%, 21.2% for parasitaemia 10-19%, 50% for parasitaemia 20-29% and 77.8% for parasitaemia ≥30% (n=9). The patient with the highest parasitaemia (75% infected erythrocytes with asexual form) presented a major concomitant lupus flare-up treated with corticoids. He survived without obvious sequelae. CONCLUSIONS: In French Guiana during bouts of malaria, HP was observed at a frequency of ~ 5% for P. falciparum and two orders of magnitude less frequent for P. vivax. HP is a severity criterion for falciparum malaria in this endemic area. However, two of the patients with HP ≥30% were not admitted to the ICU and sequel-free cure in malaria patients with 75% parasitaemia is, therefore, possible