Detection of Rickettsia spp. in ectoparasites of cricetid rodents from Gran La Plata, Buenos Aires Province, Argentina

Rickettsia spp. are obligate intracellular Gram-negative bacteria, worldwide distributed. The genus includes more than 20 species, many of them causing a group of diseases in humans and animals known as Rickettsiosis, usually transmitted by arthropod vectors. Although in Argentina Rickettsiosis have a low prevalence, clinical cases have been reported in Gran La Plata area. Rodents are usual hosts of ectoparasites, some of which have been involved in the enzootic life cycle of rickettsial species. The aim of this work was to detect bacteria of the genus Rickettsia in fleas, mites and ticks associated with cricetids in Gran La Plata.Para acceder a la videoconferencia completa, hacer clic en "Enlace externo".Sociedad Latinoamericana de Ecología de Vectore

Broadening the spectrum of ivermectin: Its effect on Trypanosoma cruzi and related trypanosomatids

Chagas disease is an endemic American parasitosis, caused by Trypanosoma cruzi. The current therapies, benznidazole (BZN) and nifurtimox (NFX), show limited efficacy and multiple side effects. Thus, there is a need to develop new trypanocidal strategies. Ivermectin (IVM) is a broad-spectrum antiparasitic drug with low human and veterinary toxicity with effects against T. brucei and Leishmania spp. Considering this and its relatively low cost, we evaluate IVM as a potential repurposed trypanocidal drug on T. cruzi and other trypanosomatids. We found that IVM affected, in a dose-dependent manner, the proliferation of T. cruzi epimastigotes as well as the amastigotes and trypomastigotes survival. The Selectivity Index for the amastigote stage with respect to Vero cells was 12. The IVM effect was also observed in Phytomonas jma 066 and Leishmania mexicana proliferation but not in Crithidia fasciculata. On the epimastigote stage, the IVM effect was trypanostatic at 50 μM but trypanocidal at 100 μM. The assays of the drug combinations of IVM with BNZ or NFX showed mainly additive effects among combinations. In silico studies showed that classical structures belonging to glutamate-gated Cl channels, the most common IVM target, are absent in kinetoplastids. However, we found in the studied trypanosomatid genomes one copy for putative IMPα and IMPβ, potential targets for IVM. The putative IMPα genes (with 76% similarity) showed conserved Armadillo domains but lacked the canonical IMPβ binding sequence. These results allowed us to propose a novel molecular target in T. cruzi and suggest IVM as a good candidate for drug repurposing in the Chagas disease context

Primera detección de Rickettsia asembonensis en Ctenocephalides felis felis en Argentina : Un estudio epidemiológico en pulgas de animales de compañía y sinantrópicos en el trifinio del Noreste argentino

Las rickettsiosis son enfermedades zoonóticas causadas por bacterias del género Rickettsia y transmitidas a humanos por medio de artrópodos vectores. En este sentido, las pulgas son importantes en salud pública debido a su rol como parásitos y como vectores de bacterias patógenas.Trabajo publicado en Cagliada, Maria del Pilar Lilia y Galosi, Cecilia Mónica (comps.). I Congreso de Microbiología Veterinaria. Libro de resúmenes. La Plata: Facultad de Ciencias Veterinarias, 2021.Facultad de Ciencias Veterinaria

Diagnóstico molecular y genotipificación del agente etiológico de la Enfermedad de Chagas, <i>Tripanosoma cruzi</i>, en vectores triatominos : Material del Taller teórico-práctico

Diagnóstico molecular y genotipificación del agente etiológico de la Enfermedad de Chagas, Tripanosoma cruzi, en vectores triatominos. Protocolos y fundamentos para el procesamiento de muestras, purificación de ADN, PCR de punto final y electroforesis en gel de agarosa.Centro de Estudios Parasitológicos y de Vectore

<i>Amphimermis enzoni</i> n.sp. (Nematoda: Mermithidae) parasitizing dragonflies and damselflies in Argentina

A mermithid nematode was found parasitizing nymphs of dragonflies and damselflies. The host specimens were collected from the stream Cajaravilla, Magdalena, Buenos Aires state, Argentina. In this work, we described Amphimermis enzoni n. sp., a nematode new to science. Nematodes were identified through morphological and molecular methods. The combination of the following characters separates A. enzoni n. sp. from other members of the genus Amphimermis Steiner: long and S-shaped vagina, twisted spicules for proximal 34% of their length, untwisted for 12%, again twisted for 30%, and untwisted for the last 24%; genital papillae arranged in three rows, medial row marginally longer than sub-medial rows; medial row bifurcated immediately anterior and posterior to cloaca, with 111 genital papillae (73 pre-anals and 38 post-anals). The sequences of 18S rDNA regions from A. enzoni formed a well-supported monophyletic clade with two GenBank sequences of Amphimermis spp. (EF617354 and EF617355) with 0.63 to 1.26% divergence and two Mermithidae spp. (LC512371 and LC512370) with 0.63 to 1.1% divergence, respectively. To our knowledge, this is the first example of mermithid infection in nymphs of dragonflies and damselflies for South America.Centro de Estudios Parasitológicos y de VectoresInstituto de Limnología "Dr. Raúl A. Ringuelet