Biology subjects

Cecilio, P.

Publications and source records attributed to Cecilio, P..

4 recordsLinked to original sources

bioRxiv2026

The PEARL toolkit: Using sand flies to identify leishmaniasis animal reservoirs

Animal reservoirs remain unknown in emerging and most endemic leishmaniasis foci hindering control efforts. Here, we developed a field-applicable PERL (Phlebotomines Establish Reservoirs of Leishmania) toolkit using individual blood fed sand flies (IBF) to identify leishmaniasis reservoirs. Using IBF, we optimized DNA and RNA co-extraction and parasite detection of [≥]1 parasite/s by kDNA qPCR and ssu rRNA RT-qPCR. We then screened IBF for expression of two parasite genes, sherp and HPB, identified by RNAseq as having low-to-absent expression in IBF given a first Leishmania donovani-infected blood meal (IBF-iBM1) and high expression in specimens provided subsequent uninfected blood meals (IBF-BMS+). Linear discriminant analysis of target gene expression classified iBM1 parasites with a predictive accuracy of ~87% and ~82% in membrane- or naturally-fed on hamsters sand flies, respectively. By determining the blood source in specimens determined as IBF-iBM1, the PERL toolkit provides an innovative and practical approach to identification of leishmaniasis reservoirs.

Molecular Biology↗

bioRxiv2025

Discovery of an Adaptive Neuroimmune Response Driving Itch and Fast Tick Removal with Implications for Preventing Pathogen Transmission

Acquired tick resistance (ATR) is well characterized in tick-exposed animals, compromising tick fitness through antibody-mediated activation of basophils. Yet, anti-tick vaccines inducing ATR have had limited success. Here, we describe a neuroimmune event preceding ATR that leads to rapid host-mediated tick removal. Tick-sensitized guinea pigs mechanically remove ticks within 3-6 hours via an acquired neuroimmune-induced itch response that correlates with increased dermal expression of itch-associated genes like OSM and skin infiltration by T cells and macrophages, independently of IgG and IgE antibodies. When we expose humans to ticks, a similar immune response is observed. Blocking T cells before tick sensitization prevents immune cell infiltration to bite sites and abrogates scratching and tick removal. This neuroimmune response is independent of Trpv1 as tick-sensitized guinea pigs treated with resiniferatoxin remove ticks effectively. Itch-induced tick removal or IITR offers a novel approach to tick-borne disease prevention through early tick detection and removal.

neuroscience↗

bioRxiv2022

Genetic exchange in Leishmania is facilitated by IgM natural antibodies

Host factors mediating Leishmania genetic exchange are not well defined. Here, we demonstrate that IgM antibodies, but not IgG or IgA, facilitate parasite genetic hybridization in vitro and in vivo. IgM induces the gradual and transient formation of a structured parasite clump in a process essential for L. major and L. tropica hybridization in vitro. Parasite hybrids and 3-nucleated parasites were observed inside this structure, named the Leishmania mating clump. IgM was also required for or significantly increased Leishmania hybrid formation in vivo. At minimum, we observed a 12-fold increase in the proportion of hybrids recovered from sand flies provided a second blood meal containing IgM compared to controls. Notably, genetic backcross events in sand flies were only observed in the presence of IgM, and were reproducibly recovered, reinforcing the relevance of IgM for Leishmania genetic exchange in vivo. The in vitro and in vivo Leishmania crosses from these studies resulted in full genome hybrids. Leishmania co-option of a host antibody to facilitate mating in the insect vector establishes a new paradigm of parasite-host-vector coevolution that promotes parasite diversity and fitness through genetic exchange.

microbiology↗

bioRxiv2018

Whole-mouse in vivo bioluminescence imaging applied to drug screening against Leishmania infantum: a reliable method to evaluate efficacy and optimize treatment regimens

Leishmaniasis is an important vector-borne neglected tropical disease caused by Leishmania parasites. Current anti-Leishmania chemotherapy is unsatisfactory, justifying the continued search for alternative treatment options. Herein, we propose the use of a minimally invasive bioluminescence-based murine model for preliminary in vivo screening of compounds against visceral infection by Leishmania infantum. We demonstrate that luciferase-expressing axenic amastigotes, unlike promastigotes, are highly infectious to BALB/c mice and generate a robust bioluminescent signal in the main target organs, such as the liver and spleen. Finally, we validate the use of this technique to evaluate in vivo treatment efficacy using reference drugs amphotericin B and miltefosine.

microbiology↗