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Trichinellosis is a zoonotic disease that has been studied mainly in domestic pigs (Sus scrofa domesticus). The cycle involves infection in domestic and wild fauna, which fulfill complex ecological roles, where Trichinella spiralis is reported in wild boar (Sus scrofa). The objective of this study was to determine the prevalence of trichinellosis in wild boar and evaluate the distance of positive animals to the nearest urbanization areas in Argentina Patagonia. Necropsies were carried out on wild boar hunted in the Nahuel Huapi and Lanín National Parks and surrounding areas. Skeletal muscle samples were collected from 1,694 wild boar and artificial digestion was performed on all samples. Trichinella spp. were found in 96 (5.8%) wild boar (0.2 to 424 Larvae/g). Parasitism in wild boar depends on the distribution of the population in natural and urban areas. Infected wild boar were found near peri-urban areas, demonstrating the importance of routine epidemiological surveillance and sanitary measures in and around cities. More research is needed to identify the Trichinella species that infect wild animals. We recommend the application of active and passive epidemiological surveillance in South America on exotic and native fauna that are hunted and consumed by humans.

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Trichinellosis is a zoonotic disease caused by Trichinella, with the main source of infection being the consumption of pork and pork-derived products. However, it can also be acquired from eating the meat from wild animals targeted for sport hunting. The objectives of this study were: 1) to develop and implement a molecular method for the identification of Sus scrofa (pig and wild boar) and Puma concolor (Puma) meat in sausages eaten raw, which were linked to trichinellosis outbreaks occurring in Córdoba, Buenos Aires and La Pampa provinces, Argentina, in 2010, 2021, and 2022, respectively; and 2) to identify the Trichinella species present in the food. Specific primers were designed for PCR amplification and nucleotide sequencing of a region of the mitochondrial cytochrome b gene from both host species. Samples from the mentioned outbreaks were analysed, and the molecular identification of Trichinella spp. larvae was also performed. Results of the species identification system revealed that sausages from Córdoba and Buenos Aires had a mixed composition of pork and puma meat, while those from La Pampa contained puma meat only. Trichinella spiralis was implicated in all three outbreaks. The species identification system developed and implemented in this study revealed two host species of Trichinella related to human cases, and alerts about the risk of zoonotic transmission to humans through infected puma meat.

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Abstract Anisakidosis is an infection caused by larval nematodes that belong to several genera within the family Anisakidae. Anisakidosis has about 20000 cases reported to date, the vast majority (90%) in Japan. Usually, human anisakiosis is more common than human pseudoterranovosis in Japan and Europe, although in North America Pseudoterranova spp. is the more frequent. Cases of human pseudoterranovosis have been reported from Chile and Peru. We here report one of the few cases of human infection by Pseudoterranova cattani by consumption of ``ceviche'' in Buenos Aires, Argentina.

Resumen La anisakidosis es una infección por larvas de nematodos que pertenecen a varios géneros dentro de la familia Anisakidae. Se han registrado aproximadamente 20.000 casos hasta la fecha, la mayoría (90%) en Japón. En Europa y Japón la anisakidosis es más frecuente en el humano que la pseudoterranovosis. En cambio, en América del Norte es más frecuente la infección humana por Pseudoterranova spp. También se han informado casos de pseudoterranovosis humana en Chile y en Perú. Informamos uno de los pocos casos de infección humana por Pseudoterranova cattani por consumo de ceviche en Buenos Aires, Argentina.

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Anisakidosis is an infection caused by larval nematodes that belong to several genera within the family Anisakidae. Anisakidosis has about 20000 cases reported to date, the vast majority (90%) in Japan. Usually, human anisakiosis is more common than human pseudoterranovosis in Japan and Europe, although in North America Pseudoterranova spp. is the more frequent. Cases of human pseudoterranovosis have been reported from Chile and Peru. We here report one of the few cases of human infection by Pseudoterranova cattani by consumption of "ceviche" in Buenos Aires, Argentina.

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Of the three Trichinella species described in South America, T. spiralis, T. pseudospiralis and T. patagoniensis, only the former has been implicated in human infections from consumption of pork-derived products. During a presumed trichinellosis outbreak in 2012 in Mendoza, Argentina, we evaluated the serological responses of three patients who had eaten the incriminated food and had signs and symptoms compatible with trichinellosis, using ELISA. We also analyzed potentially contaminated pork sausage by artificial digestion technique and recovered Trichinella muscle larvae, which were identified to the species level using a PCR multiplex assay and by sequencing a region of the mitochondrial gene coding cytochrome oxidase subunit I. No antibodies were detected in the sera of the patients, probably because the samples were collected during the immunological window period. According to molecular identification, all larvae from the sausage corresponded to T. britovi. Trichinella britovi is reported here for the first time in the American Continent, and represents the only cold-tolerant member of the genus in the Neotropics. This species was most likely introduced from Europe to South America during Spanish colonization through pigs, wild boars and/or rats.

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Se estudió el rol prospectivo de Rumina decollata como potencial hospedador paraténico de Toxocara cati para los gatos domésticos. Se recolectaron caracoles R. decollata y heces de gatos de un hospital de la Ciudad Autónoma de Buenos Aires. Se procesaron las heces y los caracoles fueron digeridos para identificar estadios de T. cati por análisis morfológico y molecular. El 23,5% (4/17) de las muestras de heces resultaron positivas a huevos larvados de T. cati. El 20% (5/25) de los pooles de caracoles fue positivo a larvas de tercer estadío (L3) de Toxocara spp. por PCR. El promedio de larvas totales recuperadas por gramo de caracol en todos los pooles positivos fue de 5.1, con un máximo de 33 L3/pool. Se trata del primer reporte de R. decollata como hospedador paraténico de T. cati, puesto que ha sido demostrada la infección en caracoles y gatos en un ambiente común

The prospective role of the land snail Rumina decollata as a potential paratenic host of Toxocara cati for domestic cats was studied. R. decollata specimens and cats' feces were collected from the open spaces of a Buenos Aires city hospital. Cats' feces were analyzed and snails were digested to identify T. cati stages, by morphological and molecular analyses. T. cati larval eggs were recovered from 23.5% (4/17) of the sampled feces. Twenty percent of snail pools (5/25) were confirmed to be positive for Toxocara spp. third larval stage (L3) by PCR. The mean value of total larvae recovered per gram of snail in all positive pools was 5.1, with a maximum 33 L3/pool. This is the first report of T. cati infective larvae in R. decollata domestic snail as a paratenic host, since the relationship between infection in snails and in cats' feces could be demonstrated in a common environment

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The prospective role of the land snail Rumina decollata as a potential paratenic host of Toxocara cati for domestic cats was studied. R. decollata specimens and cats' feces were collected from the open spaces of a Buenos Aires city hospital. Cats' feces were analyzed and snails were digested to identify T. cati stages, by morphological and molecular analyses. T. cati larval eggs were recovered from 23.5% (4/17) of the sampled feces. Twenty percent of snail pools (5/25) were confirmed to be positive for Toxocara spp. third larval stage (L3) by PCR. The mean value of total larvae recovered per gram of snail in all positive pools was 5.1, with a maximum 33 L3/pool. This is the first report of T. cati infective larvae in R. decollata domestic snail as a paratenic host, since the relationship between infection in snails and in cats' feces could be demonstrated in a common environment.

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Since 1916 to date, it has been suspected that vertical transmission of parasites from the genus Trichinella could occur in pregnant or lactating women during the parenteral phase of infection. The aim of the present study was to evaluate the transmammary transmission of T. patagoniensis in BALB/c mice. Twenty 7-week-old BALB/c mice were distributed into two groups of 10 individuals each, depending on the time of gestation when they were infected, 15 or 18 days after detection of the vaginal plug. Each group was subdivided into two subgroups of 5 mice each, which were given an oral dose of 100 or 500 infective larvae respectively. Euthanasia and subsequent artificial digestion was performed in the pups and the dams. No T. patagoniensis L1 larvae were found in any of the offsprings analyzed. The observed results suggest that vertical transmission of T. patagoniensis would not be possible in BALB/c mice.

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Prior to this study, only encapsulated species of Trichinella had been found in South America, i.e., T. spiralis and T. patagoniensis. Here we report the molecular identification of a non-encapsulated isolate of Trichinella from a domestic pig in Argentina. The multiplex PCR technique and the analysis of mitochondrial and nuclear DNA sequences revealed that it belongs to T. pseudospiralis, which parasitises birds and mammals from Australian, Nearctic, and Palaearctic regions. Interestingly, the isolate is closely related to the Palaearctic population. This is the first report of a non-encapsulated species of Trichinella from the Neotropical region.

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Mansonella ozzardi is a tissue-dwelling parasitic nematode, the causative agent of mansonelliasis in almost all Latin American countries. It has been described along the Argentine Yungas region. The microscopic diagnosis can yield false-negative test results at low microfilaremia levels. The aim of this study was to optimize the molecular diagnostic technique and compare it with the Knott's method and standard blood smear procedures (thin blood films and thick smears) in 92 blood samples of individuals from an endemic area. The PCR technique followed by the sequencing of the amplified product yielded 100 % sensitivity compared to the Knott's test, which is considered a reference method. Seven more cases of this parasitosis could only be identified with the molecular technique.

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Until a few years ago, Trichinella spiralis was the only taxon of the genus Trichinella detected in both domestic and wild animals of South America. Recently, a new genotype, named Trichinella T12, was identified in cougars (Puma concolor) from Argentina, on the basis of molecular studies using mitochondrial and nuclear ribosomal markers. In the present study, cross-breeding experiments indicated that Trichinella T12 is reproductively isolated from all other encapsulated Trichinella spp. and suggested that it is biologically more similar to Trichinella britovi and Trichinella murrelli than to the other encapsulated species/genotypes. Biological assays revealed that the reproductive capacity index of Trichinella T12 was ~4 and >2000 times lower than those of T. spiralis in mice and rats, respectively. The reproductive capacity index of Trichinella T12 in domestic pigs ranged from 0.0 to 0.05. Larvae parasitising the muscles of carnivores were infective to mice after freezing at -5°C for 3 months, but they lost infectivity after freezing at -18°C for 1 week. The region within the rDNA, known as the expansion segment V, showed a unique sequence which differs from those of all other known Trichinella spp./genotypes. The biological, geographical and molecular data support the classification of the genotype Trichinella T12 as a new species widespread in the Neotropical region, for which we propose the name Trichinella patagoniensis n. sp.

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Mansonella ozzardi es un nematode parásito tisular, agente etiológico de mansonellosis en casi la totalidad de los países latinoamericanos. En Argentina la mansonellosis ha sido descrita a lo largo de la región de las yungas. Su diagnóstico microscópico puede dar resultados falsos negativos en microfilaremias bajas. El objetivo del presente estudio fue optimizar su diagnóstico molecular y comparar los resultados con los obtenidos mediante las pruebas microscópicas de Knott, de gota gruesa y de extendido hemático fino, en 92 muestras de sangre de pacientes de zona endémica. La técnica de PCR seguida de la secuenciación del producto amplificado presentó una sensibilidad del 100 % frente al método de Knott, considerado como referencia, e incluso permitió identificar 7 casos más de la parasitosis.

Mansonella ozzardi is a tissue-dwelling parasitic nematode, the causative agent of mansonelliasis in almost all Latin American countries. It has been described along the Argentine Yungas region. The microscopic diagnosis can yield false-negative test results at low microfilaremia levels. The aim of this study was to optimize the molecular diagnostic technique and compare it with the Knott's method and standard blood smear procedures (thin blood films and thick smears) in 92 blood samples of individuals from an endemic area. The PCR technique followed by the sequencing of the amplified product yielded 100 % sensitivity compared to the Knott's test, which is considered a reference method. Seven more cases of this parasitosis could only be identified with the molecular technique.

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Mansonella ozzardi es un nematode parásito tisular, agente etiológico de mansonellosis en casi la totalidad de los países latinoamericanos. En Argentina la mansonellosis ha sido descrita a lo largo de la región de las yungas. Su diagnóstico microscópico puede dar resultados falsos negativos en microfilaremias bajas. El objetivo del presente estudio fue optimizar su diagnóstico molecular y comparar los resultados con los obtenidos mediante las pruebas microscópicas de Knott, de gota gruesa y de extendido hemático fino, en 92 muestras de sangre de pacientes de zona endémica. La técnica de PCR seguida de la secuenciación del producto amplificado presentó una sensibilidad del 100 % frente al método de Knott, considerado como referencia, e incluso permitió identificar 7 casos más de la parasitosis.(AU)

Mansonella ozzardi is a tissue-dwelling parasitic nematode, the causative agent of mansonelliasis in almost all Latin American countries. It has been described along the Argentine Yungas region. The microscopic diagnosis can yield false-negative test results at low microfilaremia levels. The aim of this study was to optimize the molecular diagnostic technique and compare it with the Knotts method and standard blood smear procedures (thin blood films and thick smears) in 92 blood samples of individuals from an endemic area. The PCR technique followed by the sequencing of the amplified product yielded 100 % sensitivity compared to the Knotts test, which is considered a reference method. Seven more cases of this parasitosis could only be identified with the molecular technique.(AU)

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Natural infection with Trichinella has been described in more than 150 mammalian species. However, few reports of Trichinella infection in wild animals have come from Argentina. In this study, muscle tissue was obtained from wild animals in Argentina with the aim of evaluating the presence of Trichinella. A total of 169 muscle samples were collected to determine the presence of Trichinella larvae by artificial digestion. The 169 muscle samples originated from 12 species including 36 opossums (Didelphis albiventris), 19 armadillos (Chaetophractus villosus), 9 capybaras (Hydrocaeris hydrocaeris), 1 puma (Puma concolor), 3 grey fox (Lycalopex gymnocercus), 6 coypus (Myocastor coypus), 6 skunks (Conepatus chinga), 2 ferrets (Galictis cuja), 66 rats (Rattus norvegicus), 6 mice (Mus musculus), 12 wild boars (Sus scrofa), and 3 wild cats (Felis geoffroyi). Trichinella infection was detected in 1 puma [2 larvae per gram (LPG)], 3 wild boars (8-420 LPG), 3 armadillos (0.04-0.08 LPG), and 9 rats (0.1 to 150 LPG). Only 3 Trichinella isolates, of 1 rat and 2 wild boars from Neuquén, were identified as Trichinella spiralis by nested PCR. The presence of Trichinella infection among wild animal populations suggests a sylvatic cycle of transmission in Argentina, which can serve as a reservoir for humans and domestic animals. Further, evidence of high prevalence in rats emphasizes the need to improve pig management, mainly in small individual farms without adequate technology, to enhance the quality of feeds, and to improve veterinary services to avoid exposure of pigs to Trichinella.

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At present, Trichinella spiralis is the only species of this genus reported from South America. Herein, we detail a molecular analysis of a new encapsulated isolate of muscle larvae of Trichinella, found in a mountain lion (Puma concolor) coming from the Patagonia, Argentina. We studied three DNA regions previously probed to be useful for the identification of all eleven recognized Trichinella genotypes: expansion segment 5 (ES5), cytochrome c-oxidase subunit I (COI) and 5S ribosomal DNA intergenic spacer region (5S ISR). BLAST searches with these DNA sequences showed that the mitochondrial and nuclear ribosomal regions most closely resemble other Trichinella sequences available in GenBank. However, they did not exactly match any of the eleven recognized genotypes. The phylogenetic analysis from COI and 5S ISR sequences showed that the mountain lion isolate is grouped with encapsulated members, in concordance with morphological data. Furthermore, this new isolate was located at the base of the encapsulated genotypes, signifying that it is an old genotype that could have emerged earliest in this group. These data strongly suggest that this isolate from the Patagonia represents the twelfth genotype (T12) described in the genus Trichinella. Nevertheless, further studies are necessary to adequately establish this isolate as a unique genotype.

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