Temporins are anti-microbial peptides synthesized in the skin of frogs of the Ranidae family. The few studies to date that have examined their anti-viral properties have shown that they have potential as anti-viral therapies. In this work, we evaluated the anti-herpes simplex virus type 1 (HSV-1) activity of the temporin-SHa (SHa) and its synthetic analog [K³]SHa. Human cathelicidin LL-37 and temporin-Tb (Tb), previously demonstrated to have anti-HSV-1 properties, were used as positive controls. We observed that SHa and [K³]SHa significantly inhibit HSV-1 replication in human primary keratinocytes when used at micromolar concentrations. This anti-viral activity was equivalent to that of Tb, but lower than that of LL-37. Transcriptomic analyses revealed that SHa did not act through the modulation of the cell innate immune response, but rather, displayed virucidal properties by reducing infectious titer of HSV-1 in suspension. In contrast, pre-incubation of the virus with LL-37 suggests that this peptide does not act directly on the viral particle at non-cytotoxic concentrations tested. The anti-HSV-1 activity of LL-37 appears to be due to the potentiation of cellular anti-viral defenses through the induction of interferon stimulated gene expression in infected primary keratinocytes. This study demonstrated that SHa and [K³]SHa, in addition to their previously reported antibacterial and antiparasitic activities, are direct-acting anti-HSV-1 peptides. Importantly, this study extends the little studied anti-viral attributes of frog temporins and offers perspectives for the development of new anti-HSV-1 therapies.

We ascertain the in vitro Benznidazole (BZN) and Nifurtimox (NFX) susceptibility pattern of epimastigotes, trypomastigotes, and amastigotes of 21 T. cruzi strains, from patients, reservoir, and triatomine bugs of various geographic origins. Using this panel of isolates, we compute the Epidemiological cut off value (CO_wt). Then, the frequency of the susceptible phenotype (Wild type) towards benznidazole (BZN) and nifurtimox (NFX) within this set of strains belonging to three discrete typing units (DTUs), TcI, TcII, and TcV, was deduced. We observed that the susceptibility status of individual T. cruzi isolates toward BZN and NFX is related to the genetic background and underlying factors that are probably related to the individual life trait history of each strain. Analyzing drug susceptibility in this conceptual framework would offer the possibility to evidence a link between isolates expressing a low susceptibility level (not wild-type) as defined by the CO_wt value and none-curative treatment. It will also permit us to track drug-resistant parasites in the T. cruzi population.

Amphibian skin is a promising natural resource for antimicrobial peptides (AMPs), key effectors of innate immunity with attractive therapeutic potential to fight antibiotic-resistant pathogens. Our previous studies showed that the skin of the Sahara Frog (Pelophylax saharicus) contains broad-spectrum AMPs of the temporin family, named temporins-SH. Here, we focused our study on temporin-SHe, a temporin-SHd paralog that we have previously identified in this frog but was never structurally and functionally characterized. We synthesized and determined the structure of temporin-SHe. This non-amphipathic α-helical peptide was demonstrated to strongly destabilize the lipid chain packing of anionic multilamellar vesicles mimicking bacterial membranes. Investigation of the antimicrobial activity revealed that temporin-SHe targets Gram-negative and Gram-positive bacteria, including clinical isolates of multi-resistant Staphylococcus aureus strains. Temporin-SHe exhibited also antiparasitic activity toward different Leishmania species responsible for visceral leishmaniasis, as well as cutaneous and mucocutaneous forms. Functional assays revealed that temporin-SHe exerts bactericidal effects with membrane depolarization and permeabilization, via a membranolytic mechanism observed by scanning electron microscopy. Temporin-SHe represents a new member of the very limited group of antiparasitic temporins/AMPs. Despite its cytotoxicity, it is nevertheless an interesting tool to study the AMP antiparasitic mechanism and design new antibacterial/antiparasitic agents.

Isothermal amplification of nucleic acids has the potential to be applied in resource-limited areas for the detection of infectious agents, as it does not require complex nucleic purification steps or specific and expensive equipment and reagents to perform the reaction and read the result. Since human and animal infections by pathogens of the Tryponasomatidae family occur mainly in resource-limited areas with scant health infrastructures and personnel, detecting infections by these methodologies would hold great promise. Here, we conduct a narrative review of the literature on the application of isothermal nucleic acid amplification for Trypanosoma and Leishmania infections, which are a scourge for human health and food security. We highlight gaps and propose ways to improve them to translate these powerful technologies into real-world field applications for neglected human and animal diseases caused by Trypanosomatidae.

The implementation of sustainable control strategies aimed at disrupting the transmission of vector-borne pathogens requires a comprehensive knowledge of the vector ecology in the different eco-epidemiological contexts, as well as the local pathogen transmission cycles and their dynamics. However, even when focusing only on one specific vector-borne disease, achieving this knowledge is highly challenging, as the pathogen may exhibit a high genetic diversity and multiple vector species or subspecies and host species may be involved. In addition, the development of the pathogen and the vectorial capacity of the vectors may be affected by their midgut and/or salivary gland microbiome. The recent advent of Next-Generation Sequencing (NGS) technologies has brought powerful tools that can allow for the simultaneous identification of all these essential components, although their potential is only just starting to be realized. We present a metabarcoding approach that can facilitate the description of comprehensive host-pathogen networks, integrate important microbiome and coinfection data, identify at-risk situations, and disentangle the transmission cycles of vector-borne pathogens. This powerful approach should be generalized to unravel the transmission cycles of any pathogen and their dynamics, which in turn will help the design and implementation of sustainable, effective, and locally adapted control strategies.

Since the 20th century, numerous studies have detected or isolated parasites from the Trypanosomatidae family in various tick species. However, the status of ticks as vectors for medically or veterinary significant Trypanosoma and Leishmania remains unclear. We conducted a systematic review and meta-analysis to provide new insights into the potential vector status of these pathogens, which have significant medical and veterinary implications. We searched three databases (PubMed, Google Scholar, and Web of Science) from 1912 to June 30, 2023, resulting in 94 papers included in the qualitative analysis and 86 papers in the quantitative analysis. All identified field studies were conducted in endemic areas and investigated the presence of Trypanosoma and Leishmania parasites, DNA, or antigens in ticks. We recorded a pooled prevalence of Trypanosomatidae detection in ticks at 15.48 % [7.99–24.61 %], with significant variations depending on the year, detection method, and geographical area. Most of the infected tick species belonged to the genera Amblyomma, Hyalomma, Ixodes, and Rhipicephalus. Experimental laboratory work on transmission routes demonstrated potential vector competence in both the Argasidae and Ixodidae tick families. Although our systematic review and meta-analysis provide compelling evidence of the natural infection of ticks by Trypanosomatidae parasites, along with some evidence of non-traditional transmission routes, they do not offer conclusive evidence regarding the role of ticks as biological or mechanical vectors for Trypanosomatidae species of veterinary and medical interest. This highlights the urgent need for additional investigations to address this point.