BackgroundCare for malaria patients in endemic areas has been improved through the increasing use of Rapid Diagnostic Tests (RDTs). Most RDTs target the histidine-rich protein-2 antigen (PfHRP2) to detect P. falciparum, as it is abundant and shows great heat stability. However, their use in South America has been widely questioned following a recent publication that pinpoints the high prevalence of Peruvian field isolates lacking the gene encoding this protein. In the remote rural health centers of French Guiana, RDTs are the main diagnosis tools. Therefore, a study of PfHRP2 RDT performances and pfhrp2 genotyping was conducted to determine whether a replacement of the current pLDH-based kit could be considered.MethodsThe performance study compared the SD Malaria Ag test P.f/Pan® kit with the current gold standard diagnosis by microscopy. The prevalence of pfhrp2 and pfhrp3 deletions were evaluated from 221 P. falciparum isolates collected between 2009 and 2011 in French Guiana.ResultsBetween January 2010 and August 2011, 960 suspected cases of malaria were analyzed using microscopy and RDTs. The sensitivity of the SD Malaria Ag test P.f/Pan® for detection of P. falciparum was 96.8% (95% CI: 90.9–99.3), and 86.0% (95% CI: 78.9–91.5) for the detection of P. vivax. No isolates (95% CI: 0–4.5) lacking either exon of the pfhrp2 gene were identified among the 221 P. falciparum isolates analyzed, but 7.4% (95% CI: 2.8–15.4) lacked the exon 2 part of the pfhrp3 gene.ConclusionsField isolates lacking either exon of the pfhrp2 gene are absent in this western part of South America. Despite its sensibility to detect P. vivax, the SD Malaria Ag test P.f/Pan® kit is a satisfying alternative to microscopy in remote health centers, where it is difficult to provide highly skilled microscopists and to maintain the necessary equipment.

Dermatophytosis is a superficial fungal infection of keratinized structures that exhibits an increasing prevalence in humans and is thus requesting novel prophylactic strategies and therapies. However, precise mechanisms used by dermatophytes to adhere at the surface of the human epidermis and invade its stratum corneum are still incompletely identified, as well as the responses provided by the underlying living keratinocytes during the infection. We hereby report development of an in vitro model of human dermatophytosis through infection of reconstructed human epidermis (RHE) by arthroconidia of the anthropophilic Trichophyton rubrum species or of the zoophilic Microsporum canis and Arthroderma benhamiae species. By modulating density of arthroconidia in the inoculum and duration of exposure to such pathogens, fungal infection limited to the stratum corneum was obtained, mimicking severe but typical in vivo situation. Fungal elements in infected RHE were monitored over time by histochemical analysis using periodic-acid Schiff-staining or quantified by qPCR-detection of fungal genes inside RHE lysates. This model brings improvements to available ones, dedicated to better understand how dermatophytes and epidermis interact, as well as to evaluate preventive and therapeutic agents. Indeed, miconazole topically added to RHE was demonstrated to inhibit fungal infection in this model.

Dermatophytosis is a superficial fungal infection of keratinized structures caused by specific filamentous fungi named dermatophytes. In humans, the incidence of dermatophytosis is elevated and continuously increasing, rendering it a public health concern. The pathogeny of dermatophytosis remains poorly understood, partly due to the difficulties to set up a relevant model allowing the study of both the invasion of keratinized structures by fungi, and its impact on host tissue architecture and functions. Recently, the development of human cultured skin equivalents has led to some advances. This review aims to summarize current knowledge about dermatophytosis and then focuses on in vitro models to investigate the alterations of the epidermal barrier in response to fungal infection. | DERMATOPHY TOS IS AND DERMATOPHY TE SDermatophytosis is an infection of superficial keratinized epidermal layers, as well as hairs and nails, which is caused by keratinolytic filamentous fungi named dermatophytes.[1] Numerous dermatophyte species are grouped according to their ecological Genome sequencing, especially analysis of the polymorphisms inside the variable rDNA regions known as internal transcribed spacers (ITS), has provided phylogenetic criteria for improved species identification.[4] A revised classification of dermatophytes was proposed, [5][6][7] based on DNA sequences of five different loci, including ITS, on morphology and physiology in culture, and on geo-, zoo-or anthropophilic ecology (Table 1). This review is concerned with anthropophilic and zoophilic dermatophytes frequently responsible for human infections.Dermatophytosis is responsible for 3%-4% of dermatological cases and is the most common fungal infection in humans, with a prevalence estimated around 20%-25%. [8,9] In addition, its prevalence is continuously raising due to increased risk factors such as sport activities, type 2 diabetes, vascular diseases or ageing. Modern mobility further increases the dissemination of anthropophilic dermatophytes that extend in previously poorly affected geographical areas. [10,11] Among the species capable of infecting human skin,Trichophyton rubrum is the most frequently involved, being responsible for 50%-90% of dermatophytoses in humans. [9,12] The annual health expense cost of dermatophytosis is estimated to more than 500 million of US dollars.[13] | Dermatophyte infections induce various clinical picturesThe clinical signs of dermatophytosis result from both the degradation of keratinized tissues caused by fungal processes, as well as from the specific immune response of the infected host.Zoophilic species, probably less adapted to human hosts, generate more severe inflammatory responses than anthropophilic species. [6,14] Usual signs include dryness, desquamation, cracks and erythema of the skin of the feet, scalp or other body locations.Infections in hairless areas and nails, principally due to Trichophyton rubrum and Trichophyton interdigitale, are the most frequent in industrialized countries. Scalp infections, ...

Despite the threatening incidence of dermatophytosis, information is still lacking about the consequences of infection on epidermal barrier functions and about the keratinocyte responses that alert immune components. To identify the mechanisms involved, arthroconidia of the anthropophilic dermatophyte Trichophyton rubrum were prepared to infect reconstructed human epidermis (RHE) in vitro. Integrity of the barrier was monitored during infection by measurements of transepithelial electrical resistance and dye-permeation through the RHE. Expression and release of pro-inflammatory cytokines and antimicrobial peptides by keratinocytes inserted into the RHE were assessed, respectively, by quantitative reverse transcriptaseePCR (to analyze mRNA content in tissue extracts) and by ELISA (to detect proteins in culture media). Results reveal that infection by T. rubrum is responsible for disruption of the epidermal barrier, including loss of functional tight junctions. It additionally causes simultaneous expression and release of cytokines and antimicrobial peptides by keratinocytes. Potential involvement of the p38 mitogen-activated protein kinase signaling pathway was evaluated during infection by targeted inhibition of its activity. Intriguingly, among several p38 mitogen-activated protein kinase inhibitors, PD169316 alone was able to inhibit growth of T. rubrum on Sabouraud agar and to suppress the process of infection on RHE. This suggests that PD169316 acts on a specific target in dermatophytes themselves.

Background Plasmodium vivax malaria is a major public health problem in French Guiana. Some cases of resistance to chloroquine, the first-line treatment used against P. vivax malaria, have been described in the Brazilian Amazon region. The aim of this study is to investigate a possible dispersion of chloroquine-resistant P. vivax isolates in French Guiana. The genotype, polymorphism and copy number variation, of the P. vivax multidrug resistance gene-1 (pvmdr1) have been previously associated with modification of the susceptibility to chloroquine.MethodsThe pvmdr1 gene polymorphism was evaluated by sequencing and copy number variation was assessed by real-time PCR, in P. vivax isolates obtained from 591 symptomatic patients from 1997 to 2013.ResultsThe results reveal that 1.0% [95% CI 0.4–2.2] of French Guiana isolates carry the mutations Y976F and F1076L, and that the proportion of isolates with multiple copies of pvmdr1 has significantly decreased over time, from 71.3% (OR = 6.2 [95% CI 62.9–78.7], p < 0.0001) in 1997–2004 to 12.8% (OR = 0.03 [95% CI 9.4–16.9], p < 0.0001) in 2009–2013. A statistically significant relationship was found between Guf-A (harboring the single mutation T958M) and Sal-1 (wild type) alleles and pvmdr1 copy number.ConclusionsFew P. vivax isolates harboring chloroquine-resistant mutations in the pvmdr1 gene are circulating in French Guiana. However, the decrease in the prevalence of isolates carrying multiple copies of pvmdr1 might indicate that the P. vivax population in French Guiana is evolving towards a decreased susceptibility to chloroquine.