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Owing to the sanitary importance of the tick Amblyomma parvum, this study evaluated the infection by Ehrlichia, Anaplasma and Rickettsia species of questing A. parvum collected in northwestern Argentina. Our results showed that A. parvum ticks in this region are infected with the recently reported Ehrlichia sp. strain San Luis, closely related to Ehrlichia chaffeensis. A high prevalence of Candidatus Rickettsia andeanae was observed. Most of the infected ticks presented rickettsial loads lower than those previously reported for other spotted fever group rickettsiae. The presence of Ehrlichia sp. strain San Luis in A. parvum is a potential risk for public health as the principal hosts of this tick are domestic mammals in rural areas and humans are frequently bitten by this tick species. Fil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Fernandez Basile, Camilo. Laboratorio de Ecología de Enfermedades; Argentina Fil: Percara, Alejandro Rubén César. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina

La ehrlichiosis monocitica canina (EMC) es una enfermedad causada por la bacteria Ehrlichia canis, de distribución mundial, alta mortalidad en caninos doméstico y síntomas inespecíficos, lo que dificulta su diagnóstico clínico. Ehrlichiacanises transmitida por la garrapata Rhipicephalus sanguineussensu lato a un hospedador, en Argentina se reconocen dos linajes (tropical y sensu stricto) de dicha especie. El objetivo del presente trabajo es reportar el primer caso confirmado de EMC por E. canisen un canino de la ciudad de Rafaela, Santa Fe, área endémica de R. sanguineuss.s. El 18/02/2019 llegó a la consulta privada un canino con síntomas inespecíficos como hipertermia tarde/noche, depresión, letargia, aplasia, inapetencia y pérdida de peso; más antecedente de parasitismo por garrapatas. La mascota presentaba anemia leve (4.730.000/mm3), enzimas hepáticas aumentadas (AST/ASA/GOT=72 U/l) y esplenomegalia. El test serológico in vitro y PCR para amplificar ADN E. canisfueronpositivos, por lo que la mascota recibe tratamiento para EMC con doxiciclina 10 mg/kg/día durante 30 días, antiinflamatorios durante 5 días y protector hepático. A los 60 días de iniciado el tratamiento la mascota recuperó su peso normal y a los 120 días se realiza PCR como monitoreo de la eficacia del tratamiento dando resultado negativo. Canine monocytic ehrlichiosis (CME) is a disease caused by Ehrlichia canisbacteria. It has a globally distributed and cause high mortality in domestic canines with nonspecific symptoms, which makes clinical diagnosis difficult. Eherlichiacanisis transmitted to a host by the tick Rhipicephalus sanguineussensu lato. In Argentina two lineages of this species are recognized (tropical and sensu stricto). The objective of this work is to report the first confirmed case of CME by E. canisin endemic area of R. sanguineuss.s from Rafaela, Santa Fe. On February 2, 2019 a canine arrived at the private clinic with non-specific symptoms such as late / night hyperthermia, depression, lethargy, aplasia, loss of appetite and weight loss, as well as, antecedent of tick parasitism. The pet had mild anemia (4,730,000/ m3), increased liver enzymes (AST/ASA/GOT = 72 U/l) and splenomegaly. The in vitro serological test and PCR to amplify E. canisDNA were positive, so the dog receivedtreatment for CME with doxycycline 10 mg/kg/day for 30 days, anti-inflammatory for 5 days and liver protector. After 60 days of starting the treatment, the animalregained its normal weight and after 120 days the PCR have given negative result, checking the effectiveness of the treatment. EEA Rafaela Fil: Tarragona, Evelina Luisa. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Flores, Fernando S. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Laboratorio de Ecología de Enfermedades; Argentina Fil: Herrera, Candelaria L. Actividad privada; Argentina Fil: Dalinger, Miriam. Actividad privada; Argentina Fil: Aguirre, Nerina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Fil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Laboratorio de Ecología de Enfermedades; Argentina Fil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

The current work evaluated road-killed Pampas foxes (Lycalopex gymnocercus) and their ticks for the presence of vector-borne agents in the ecoregion Esteros del Iberá in northeastern Argentina. Spleen, lung and blood samples and Amblyomma tigrinum adult ticks collected from the foxes were tested by polymerase chain reaction (PCR) assays targeting bacteria of the genera Ehrlichia, Anaplasma, and Rickettsia. All foxes tested were negative for the three genera, but evidence of Ehrlichia and Rickettsia infection was detected in the ticks. One A. tigrinum (out of 12 tested) was infected by an ehrlichial agent, here named Ehrlichia sp. strain Iberá, related to ehrlichial agents recently detected in platypuses in Tasmania (Ornithorhynchus anatinus) and in voles (Myodes rutilus and Myodes rufocanus) and shrews (Sorex araneus) in the Russian Far East. Regarding Rickettsia, all A. tigrinum ticks (100%) were infected by ´Candidatus Rickettsia andeanae´, a member of the spotted fever group rickettsia of unknown pathogenicity. Further research is necessary to unveil the ecology of Ehrlichia sp. strain Iberá as well as its zoonotic relevance. The species of the genus Ehrlichia are known to be pathogenic to mammals, including humans and domestic animals, thus the presence of this ehrlichial agent in A. tigrinum is a potential risk for veterinary and public health, as the adults of A. tigrinum are common parasites of dogs in rural and peri-urban environments, and humans are also frequently bitten by this tick species. Fil: Eberhardt, María Ayelen Teresita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Fernández, Camilo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Fargnoli, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina

To identify and predict situations of increased risk of orthohantavirus infection in humans, it is necessary to study the relationships between the virus and its rodent hosts. The present study investigated orthohantavirus infection in an assemblage of wild Sigmodontinae rodents of the Paraná Delta, Argentina, and providing new evidence of host-switching events. Rodents belonging to the species Oxymycterus rufus (n=187), Akodon azarae (n=82), Oligoryzomys flavescens (n=80), Oligoryzomys nigripes (n=47), Scapteromys aquaticus (n=38), Deltamys kempi (n=7) and Holochilus brasiliensis (n=2) were captured at 4 sampling sites during 20 trapping sessions. Blood sampleswere analyzed by IgG ELISA and livers by a nested reverse transcription PCR for the diagnosis of orthohantavirus infection. The amplified products of the S and M orthohantavirus genomes were sequenced and analyzed to determine similarities with species of the Orthohantavirus genus. The species of the Oligoryzomys positive to the virus were confirmed by amplifying and sequencing thecomplete cyt b gene. Of the 443 serum samples analyzed by IgG ELISA, A. azarae presented the highest host-specific prevalence value (10/82, 12.2%) followed by Ol. nigripes (4/47, 8.5 %) and Ox. rufus (1/187, 0.5%). All the sero-positive Ol. nigripes (n= 4) were positive to the amplification of the S and M segments of the Lechiguanas genotype (98% nucleotide identity for both segments).This is surprising given that Ol. nigripes has been previously associated with Juquitiba genotype, not Lechiguanas. The latter is generally associated with Ol. flavescens, which in our study were all sero-negative. In addition, the association Ox. rufus ? Pergamino genotype found here is, to ourknowledge, novel and another potential evidence of host-switching considering that Pergamino has been originally associated with A. azarae. These findings contribute to the building evidence that contradicts the one-genotype-one-reservoir species premise in the association betweenrodent reservoirs and orthohantaviruses, and supports the hypothesis that the community structure of sympatric host species may contribute to orthohantavirus dynamics. Fil: Colombo, Valeria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Ciencias Veterinarias del Litoral; Argentina. Laboratorio de Ecología de Enfermedades; Argentina Fil: Brignone, Juan Jeronimo. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; Argentina Fil: Sen, Carina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; Argentina Fil: Previtali, Maria Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Martin, María Laura. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; Argentina Fil: Levis, Silvana del Carmen. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; Argentina Fil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Ciencias Veterinarias del Litoral; Argentina. Laboratorio de Ecología de Enfermedades; Argentina Fil: González Ittig, Raúl Enrique. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Ciencias Veterinarias del Litoral; Argentina. Laboratorio de Ecología de Enfermedades; Argentina

Rickettsia massiliae belongs to the spotted fever group and in the New World is commonly associated with the brown dog tick, Rhipicephalus sanguineus. Herein we investigate the presence of R. massiliae in Rh. sanguineus sensu lato ticks in a location near the Andean foothills (Mendoza, Argentina), to provide a prevalence estimate and to assess the infection intensity of this pathogen. Rickettsia massiliae infection was found in 5.1% of the Rh. sanguineus s.l ticks analyzed, all with high infection intensities. Molecular analysis determined that all R. massiliae-infected Rh. sanguineus s.l. ticks belonged to the temperate lineage. Fil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Linares, Maria Cielo. Instituto de Zoonosis Luis Pasteur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina

Wild birds may be considered a possible source of parasitic mesostigmatid mites for poultry, but only few studies explored this hypothesis. In addition, there is very little information about the parasitic mites present in commercial poultry systems from southern South America. To contribute with data on parasitic mesostigmatid mites at the domestic-wildlife interface, we conducted a study in which samples were systematically collected from laying hens and wild birds (adults and nestlings), for two years at three commercial laying hen farms. The occurrence of mesostigmatid mites were compared among hosts. A proportion of the collected mites were morphologically identified to the species level, finding that host preference varied greatly depending on mite species: laying hens were only parasitized by Ornithonyssus sylviarum, wild bird nestlings were mostly parasitized by Ornithonyssus bursa, and in small proportion, by O. sylviarum, while adult passerines were parasitized by both Ornithonyssus species, and sporadically by Pellonyssus cf. reedi and Dermanyssus cf. triscutatus. In laying hens, there was intra- and inter-annual variability in mite occurrence, but no consistent seasonal pattern, whereas in adult wild birds, mites showed the highest prevalence in spring and the lowest in summer. Not coinciding with this general pattern, the occurrence of O. bursa matched the reproductive activity of wild birds. A phylogenetic analysis based on a fragment of the 16S rRNA gene was carried out for a subsample of the mites collected, showing that the O. sylviarum mites present on adult wild birds and laying hens had the same haplotype (100% identity). Additionally, mites obtained from wild birds morphologically identified as O. bursa presented two distinctive haplotypes (89.8% identity), one phylogenetically related to O. sylviarum and the other to O. monteiroi. These findings show that in central Argentina commercial laying hens are parasitized mainly by O. sylviarum while wild birds are also hosts to other mite species. Adult wild passerines, especially house sparrows, may be a source of O. sylviarum for commercial poultry Fil: Arce, Sofía Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Antoniazzi, Leandro Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Sosa, Claudia Carina. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina Fil: Fasano, Agustín Alfonso. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina Fil: Quiroga, Martin Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Lareschi, Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina

A new species of Trichuris (Nematoda: Trichuridae) is described from the capybara, Hydrochoeris hydrochaeris (Rodentia: Caviidae), from two localities of Corrientes Province, based on morphological characteristics and ITS1 and ITS2 of nuclear rDNA region sequences. This species present morphological differences with 28 species of the genus described from North and South American rodents. Also, the new species is molecularly characterized and differentiated from those species from Muridae, Cricetidae and Myocastoridae rodents recorded from North and South America, Europe and Africa. Trichuris cutillasae n. sp. constitutes the ninth record from rodents of Argentina, and the second record for Caviidae. The phylogenetic analysis showed that the specimens of new species are in the same clade, and separated from specimens of T. myocastoris (ITS1and ITS2), T. navonae,T. bainae, Trichuris sp. and T. pardinasi (ITS2). Similarly, analysis of concatenated sequences ITS1 and ITS2 added further evidence that T. cutillasae n. sp. is a different species from those previously analyzed Fil: Eberhardt, María Ayelen Teresita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Robles, Maria del Rosario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina Fil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Callejón, Rocio. Departamento de Microbiología y Parasitología; España

In the present study, we report the first in vitro isolation and infection intensity of Rickettsia parkeri in Amblyomma triste ticks from Argentina. No genetic differences in the molecular targets evaluated were found between R. parkeri isolates from Argentina and those R. parkeri isolates reported in Uruguay and Brazil, both obtained from A. triste. Only a minor difference was observed when compared to R. parkeri isolated from Amblyomma maculatum from United States. Moreover, the prevalence of infection by R. parkeri in ticks collected from the vegetation in the Paraná Delta was high (20.4%). Interestingly, the distribution of R. parkeri infection intensity observed in A. triste ticks was distinctly bimodal, with approximately 60% of the infected ticks presenting high rickettsial loads (3.8×10E5-4.5×10E7 ompA copies/tick) and the remainder with low rickettsial levels (5.6×10E1-6.5×10E3 ompA copies/tick). This bimodality in R. parkeri infection intensity in ticks could determine not only differences in the severity of the disease, but also be important for the infection dynamics of this pathogen. Further research exploring the distribution of rickettsial infection levels in ticks, as well as its determinants and implications, is warranted. Fil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Cs.veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina Fil: Antoniazzi, Leandro Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Cs.veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Colombo, Valeria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Cs.veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Ciencias Veterinarias del Litoral; Argentina. Laboratorio de Ecología de Enfermedades; Argentina

The taxonomic identification of species in the genus Philornis Meinert (Diptera: Muscidae) has been based primarily upon analysis of morphological characters. However, relying solely on morphology has led to frequent species misidentification. This has been empirically demonstrated when specimens identified morphologically as Philornis seguyi have been reclassified as Philornis torquans based on DNA sequences of the second ribosomal internal transcribed spacer (ITS2), showing that the morphologic distinction between these 2 species is extremely challenging. Herein, new molecular data on specimens assigned to P. torquans and P. seguyi from the type locality of P. seguyi (Misiones province, Argentina) were analyzed. The ITS2 sequences obtained differed from those previously reported for Philornis, increasing to 3 the number of documented genotypes of flies morphologically indistinguishable from P. torquans. These results strongly suggest that subcutaneous Philornis spp. from southern South America could represent a species complex (P. torquans complex). La identificación taxonómica de especies del género Philornis Meinert (Diptera: Muscidae) ha estado basada principalmente en el análisis de los caracteres morfológicos. Sin embargo, el uso exclusivo de información morfológica ha llevado con frecuencia a errores en la identificación de las especies. Esto fue demostrado de forma empírica cuando especímenes morfológicamente identificados como P. seguyi fueron reclasificados como P. torquans utilizando secuencias del segundo espaciador interno ribosomal transcrito (ITS2), lo que demuestra que la distinción morfológica entre estas 2 especies es extremadamente complicada. En el presente trabajo se analizaron nuevos datos moleculares de especímenes identificados como P. torquans y P. seguyi provenientes de la región reportada como localidad tipo para P. seguyi (provincia de Misiones, Argentina). Las secuencias de ITS2 obtenidas fueron diferentes a aquellas previamente reportadas para otras especies de Philornis y se incrementa a 3 el número de genotipos documentados de moscas morfológicamente indistinguibles asignadas a P. torquans. Estos resultados indican que los organismos de Philornis spp. subcutáneos del sur de Sudamérica podrían representar un complejo de especies (complejo P. torquans). Fil: Quiroga, Martin Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina. Universidad Autónoma de Entre Ríos; Argentina Fil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Arrabal, Juan Pablo. Ministerio de Salud de la Nación; Argentina Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina

An Argentinian Dogo which suffered from anorexia, lymphadenopathy, cachexia and paresis of the hind limbs was diagnosed with trypanosomiasis in Argentina in 2013. In this study, we describe the clinical profile and its evolution as well as the molecular method employed to identify and quantify Trypanosoma evansi. Fil: Bono Battistoni, Maria Florencia. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina Fil: Orcellet, Viviana Mercedes. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina Fil: Peralta, J. L.. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina Fil: Marengo, R.. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina Fil: Plaza, D.. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina Fil: Brunini, A.. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina Fil: Ruiz, Marcelo Fabián. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina Fil: Widenhorn, Nelsa Ines. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina Fil: Sanchez, A.. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina Fil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Cignetti, Luciana. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina

Several cases of human rickettsiosis caused by Rickettsia parkeri were recently documented in the Paraná River delta of Argentina, where the tick vector is Amblyomma triste Koch. As cattle suffer recurrent A. triste infestations, they are at risk of becoming infected with R. parkeri. Herein we investigated the dynamics of R. parkeri and its A. triste vector in a herd of beef cattle. Cattle were followed for 18mo and samples were analyzed for the presence of antibodies against four Rickettsia species (R. parkeri, Rickettsia bellii, Rickettsia amblyommii, and Rickettsia felis) and also for the presence of rickettsial DNA. Additionally, cattle were examined for attached ticks and questing adult ticks were collected. All ticks were analyzed for the presence of rickettsial DNA. No evidence of rickettsemia was found in any cow, but the high R. parkeri infection rate documented in A. triste both questing in the study area (13.9%) and feeding on cattle (19.8%) and the identification of antibodies against R. parkeri antigen in 90% of cattle are evidence that infection is taking place. Altogether, our data suggest that A. triste ticks are capable of naturally exposing cattle to R. parkeri. However, the progress of R. parkeri infection and its impact on bovine health and production remain to be established. Fil: Monje, Lucas Daniel. Universidad Nacional del Litoral; Argentina Fil: Costa, F.B.. Universidade de Sao Paulo; Brasil Fil: Colombo, Valeria Carolina. Universidad Nacional del Litoral; Argentina Fil: Labruna, M.B.. Universidade de Sao Paulo; Brasil Fil: Antoniazzi, Leandro Raúl. Universidad Nacional del Litoral; Argentina Fil: Gamietea, I.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; Argentina Fil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; Argentina Fil: Beldomenico, Pablo Martín. Universidad Nacional del Litoral; Argentina

Trypanosoma evansi is a flagellated protozoan that parasitizes a wide variety of mammals, occasionally including humans. In South America, it infects horses, cattle, buffaloes, dogs and wild mammals, causing a disease known as "Mal de Caderas", which results in important economic losses due to a wide range of pathological expressions. Argentina represents the southern limit of its distribution. The capybara (Hydrochoerus hydrochaeris) is a large rodent found in tropical to temperate freshwater wetlands of South America. As capybaras infected with T. evansi present no clinical signs of disease, withstanding high parasitaemia, this species was proposed as a reservoir host. In this study we investigated the prevalence and parasitaemic intensity of T. evansi in samples obtained from 60 free-ranging capybaras of Esteros del Iberá (Corrientes province, northeastern Argentina) using smear microscopy and real-time PCR assays. All the cases of capybaras infected with T. evansi were found during one of the years studied, with no evidence of seasonality. The overall infection prevalence was 10%, but between years it ranged from 0% to 17% (in 2011). This is the first confirmation of T. evansi infection in Argentina by molecular biology techniques. Our results showed no differences between the methods used to detect the presence of T. evansi in capybaras, which indicates that simple methods like microscopy can generate important data on the ecoepidemiology of this parasite. Both techniques used in this study represent a viable tool for ecoepidemiological studies, and can be used to produce good estimates of prevalence and parasitaemic level of the infection, which inform for the implementation of strategies for the control of the disease. Fil: Eberhardt, María Ayelen Teresita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Cs.veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Cs.veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Zurvera, D. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Cs.veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Cs.veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina

Se determinaron las especies de garrapatas y ácaros mesostigmata parásitos de roedores sigmodontinos en una localidad del Delta del Paraná. Fueron registradas 38 asociaciones parásitohospedador entre dos especies de garrapatas y cinco especies de ácaros con seis especies de roedores, que mostraron una distribución agregada de sus parásitos. Dos de las asociaciones (Holochilus brasiliensis-Amblyomma triste y H. brasiliensis-Ixodes loricatus) son nóveles, siendo la asociación H. brasiliensis-Am. triste de importancia sanitaria ya que esta garrapata es vector de Rickettsia parkeri, patógeno que afecta a los humanos. La mayoría de las asociaciones se detectaron previamente sólo en la eco-región correspondiente a la localidad de estudio. Por el contrario, unas pocas asociaciones ya registraban antecedentes para otras regiones argentinas, el Brasil, Paraguay o el Uruguay, The species of ticks (Ixodida) and mites (Mesostigmata) parasites of sigmodontine rodents were determined in a locality of the Paraná River Delta. A total of 38 host-parasite associations between two species of ticks and five species of mites were found from six species of rodents. Aggregated distributions of parasites on hosts characterized those associations. Two associations (Holochilus brasiliensis-Amblyomma triste y H. brasiliensis-Ixodes loricatus) were not registered before, and the H. brasiliensis-Am.triste association is of sanitary importance because this tick is a vector of rickettsiosis to humans. The majority of the associations were previously found only in the ecoregion where the study site is located. In contrast a few of the associations reported have antecedents in other regions of Argentina, Brazil, Paraguay or Uruguay., Centro de Estudios Parasitológicos y de Vectores

The gene for estrogen receptor a (ERa) has been shown to be under complex hormonal control and its activity can be regulated by mRNA alternative splicing. Here we examined the regulation of ERa transcription and translation in the rat uterus by ovarian steroid hormones. We examined whether expression of ERa mRNA splic isoforms is hormonally regulated in ovariectomized (OVX) and cycling rats. Adult OVX female rats were treated daily with 17-estradiol (E2) (0·05 μg/rat or 5 μg/rat), progesterone (P4) (1 mg/rat) or a combination of both hormones for 4 days. Animals were killed 24 h after the last injection and uterine horns were removed. In order to determine whether ERa mRNA isoforms are differentially expressed under various physiological conditions, animals were evaluated at proestrus, estrus and diestrus. The ERa protein and mRNA were detected by immunohistochemistry and comparative RT-PCR analysis respectively. The presence of ERa mRNA isoforms was evaluated using a nested RT-PCR assay. In OVX control rats, ERa mRNA and protein levels were high, demonstrating a constitutive expression of the ERa gene in the uterus. When animals received P4 or the high dose of E2,a significant decrease in both ERa mRNA and protein was observed in the uterus. However, when rats were treated with the low dose of E2, only the ERa protein was down-regulated; no changes were observed in ERa mRNA expression. In addition to the full-length ERa mRNA, OVX control rat uteri expressed three shorter transcripts: a3, a4 and a3,4 (lacking exon 3, exon 4, or both 3 and 4 respectively). Surprisingly, when OVX animals were treated with P4, the low dose of E2 or a combination of both steroids, expression of the a3 isoform was completely abolished. During the estrous cycle, all ERa mRNA splicing variants were detected at proestrus and estrus. However, in diestrus, significant low levels of the a3 isoform were observed. In summary, our results suggest a dose-dependent relationship between E2 concentrations and the level of control in the ERa transcription–translation cascade. Moreover, the alternative splicing of the ERa imary transcript is influenced by the hormonal milieu, suggesting that these events could affect the estrogen responsiveness of the rat uterus during the estrous cycle. Fil: Varayoud Jorgelina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Fisiología. Laboratorio de Endocrinología y Tumores Hormonodependientes; Argentina Fil: Ramos J Guillermo. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Fisiología. Laboratorio de Endocrinología y Tumores Hormonodependientes; Argentina Fil: Monje, Lucas Daniel. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Fisiología. Laboratorio de Endocrinología y Tumores Hormonodependientes; Argentina Fil: Bosquiazzo, Veronica Lis. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Fisiología. Laboratorio de Endocrinología y Tumores Hormonodependientes; Argentina Fil: Muñoz de Toro, Monica Milagros. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Fisiología. Laboratorio de Endocrinología y Tumores Hormonodependientes; Argentina Fil: Luque, Enrique Hugo. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Fisiología. Laboratorio de Endocrinología y Tumores Hormonodependientes; Argentina