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The rabies virus (RABV) is the exclusive lyssavirus affecting both wild and domestic mammalian hosts in the Americas, including humans. Additionally, the Americas stand out as the sole region where bat rabies occurs. While carnivore rabies is being increasingly managed across the region, bats are emerging as significant reservoirs of RABV infection for humans and domestic animals. Knowledge of the bat species maintaining rabies and comprehending cross-species transmission (CST) and host shift processes are pivotal for directing surveillance as well as ecological research involving wildlife reservoir hosts. Prior research indicates that bat RABV CST is influenced by host genetic similarity and geographic overlap, reflecting host adaptation. In this study, we compiled and analyzed a comprehensive nucleoprotein gene dataset representing bat-borne RABV diversity in Argentina and the broader Americas using Bayesian phylogenetics. We examined the association between host genus and geography, finding both factors shaping the global phylogenetic structure. Utilizing a phylogeographic approach, we inferred CST and identified key bat hosts driving transmission. Consistent with CST determinants, we observed monophyletic/paraphyletic clustering of most bat genera in the RABV phylogeny, with stronger CST evidence between host genera of the same family. We further discuss Myotis as a potential ancestral spreader of much of RABV diversity.

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Exploitation of the symbiotic relationship between endophytic fungi and ryegrass is a crucial technique for reducing the incidence of insect pests. This is primarily due to the production of alkaloids, such as peramine, by the fungi. This alkaloid has been reported as both a deterrent and toxic to a variety of insects. However, insects have developed various strategies to counteract plant defenses. One of the most studied methods is their ability to sequester toxic compounds from plants. In this study, we examined the feeding preferences and adaptation to peramine in Chilesia rudis, a native Chilean larva. Using a no-choice assay, we assessed larval feeding preferences and mass gain on seven experimental lines and two commercial cultivars of endophyte-infected and non-infected ryegrass. Pupal development time and adult performance were evaluated post-assay. Additionally, we measured peramine content in larval carcasses, feces, and ryegrass leaves. Jumbo was the most preferred cultivar with 32 mm2 of leaf tissues consumed. The longest pupal development time was observed in L161 and ALTO AR1, both at 28 days. Wing length in adults was greatest in the Jumbo and L163 cultivars, measuring 1.25 cm and 1.32 cm, respectively. Peramine concentrations were detected in the bodies of C. rudis. In conclusion, this larva can adapt to endophyte-infected ryegrass and develop counter-adaptation mechanisms to mitigate the effects of peramine.

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One of the primary supports for extensive agriculture is pasture, which can suffer severe damage from insects including the Argentine stem weevil, Listronotus bonariensis. The main control method has been the infection of ryegrass with an endophyte fungus, forming a symbiotic association that produces alkaloids. In this study, we evaluated the impact of endophyte and peramine production on the weight of L. bonariensis across seven unnamed lines (LE161-LE167), and two Lolium perenne cultivars: Jumbo and Alto AR1. L. bonariensis adults fed on leaves from LE164, LE166, and ALTO AR1 showed weight losses of 13.3%, 17.1% and 18.2%, respectively. Similarly, the corresponding alkaloidal extract from LE164, LE166, and ALTO AR1 exhibited an antifeedant effect on L. bonariensis adults in laboratory assays, as observed through weight loss or low weight gain (-12.5%, 8.8% and 4.9%, respectively). Furthermore, one alkaloid, peramine, also elicited an antifeedant effect when incorporated into an artificial diet. Liquid chromatographic analysis of the alkaloid extract revealed that peramine was present in LE164, LE166 and ALTO AR1 in amounts ranging from 46.5-184.2 ng/g. Peramine was not detected in Jumbo and the remaining experimental lines. These data suggest that L. bonariensis were susceptible to peramine produced from endophyte infection in experimental lines LE164 and LE166, as well as ALTO AR1, affecting their feeding behavior.

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Until now, Molossus melini was known only from its type locality, in the south of Santa Fe province, Argentina. Specimens of this species were collected in 2021 from a roost in a Fraxinus tree of the urban woodland of Paraná city, Entre Ríos province, Argentina. Bat identification was made by comparing external and cranial characters and measurements with those reported in the bibliography and corroborated by a phylogenetic analysis based on the cytochrome b gene. Also, multivariate morphometric analyses showed that cranial measurements, but not external ones, are informative enough to discriminate M. melini from the other Molossus species in Argentina (M. currentium, M. fluminensis, and M. molossus). This new record extends the distribution of M. melini from the south of Santa Fe province by 230 km to the northeast and represents the first record of the species in the Espinal ecoregion. Supplementary information: The online version contains supplementary material available at 10.1007/s13364-023-00679-1.

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ABSTRACT Perennial ryegrass is one of the most important food sources in animal production. However, several pests affect this crop, and one of the primary control strategies is the symbiotic relationships between ryegrass endophyte fungi. This fungus produces alkaloids that exhibit toxic activity against arthropods. Furthermore, the effect of fungi may extend to higher trophic levels, including predators (spiders and/or insects), decreasing their abundance and diversity. Given the importance of spiders and insects as predators, whether the symbiotic interaction between perennial ryegrass and endophyte fungus reduces the abundance and diversity of predators pose an important question. To address this question, natural enemies in perennial ryegrass were collected and analyzed over a year, and the percentage of endophyte fungus was evaluated by the presence of hyphae from two ryegrass cultivars, Jumbo (E-) and Alto AR1 (E+). We observed an 80% endophyte infection rate for (E+) and 0% for (E-). Moreover, 222 individual spiders corresponding to 10 families were identified in both perennial ryegrasses, including 209 individuals for (E-) and 13 for (E+). The most abundant spider family was Lycosidae, representing 71.17% of the total spiders. In addition, 65 insects were collected, corresponding to 6 families, with Carabidae being the most abundant. Furthermore, the Simpson index indicated the dominance of the family Lycosidae. Overall, spider and insect abundance and diversity were reduced in (E+), suggesting a negative effect of the endophyte on predator populations.

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Bats are reservoirs of diverse coronaviruses (CoVs), including progenitors of severe acute respiratory syndrome CoV (SARS-CoV) and SARS-CoV-2. In the Americas, there is a contrast between alphacoronaviruses (alphaCoVs) and betaCoVs: while cospeciation prevails in the latter, alphaCoV evolution is dominated by deep and recent host switches. AlphaCoV lineages are maintained by two different bat family groups, Phyllostomidae and Vespertilionidae plus Molossidae. In this study, we used a Bayesian framework to analyze the process of diversification of the lineages maintained by Molossidae and Vespertilionidae, adding novel CoV sequences from Argentina. We provide evidence that the observed CoV diversity in these two bat families is shaped by their geographic distribution and that CoVs exhibit clustering at the level of bat genera. We discuss the causes of the cocirculation of two independent clades in Molossus and Tadarida as well as the role of Myotis as the ancestral host and a major evolutionary reservoir of alphaCoVs across the continent. Although more CoV sampling efforts are needed, these findings contribute to a better knowledge of the diversity of alphaCoVs and the links between bat host species. IMPORTANCE Bats harbor the largest diversity of coronaviruses among mammals. In the Americas, seven alphacoronavirus lineages circulate among bats. Three of these lineages are shared by members of two bat families: Vespertilionidae and Molossidae. Uncovering the relationships between these coronaviruses can help us to understand patterns of cross-species transmission and, ultimately, which hosts are more likely to be involved in spillover events. We found that two different lineages cocirculate among the bat genera Molossus and Tadarida, which share roosts and have common viral variants. The bat genus Myotis functions as a reservoir of coronavirus diversity and, as such, is a key host. Although there were some spillovers recorded, there is a strong host association, showing that once a successful host jump takes place, it is transmitted onward to members of the same bat genus.

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We report detection of cases of monkeypox virus infection in Argentina in the context of a marked increase in confounding cases of atypical hand-foot-and-mouth syndrome caused by enterovirus coxsackie A6. We recommend performing an accurate differential virological diagnosis for exanthematous disease in suspected monkeypox cases.

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Rabies is a zoonotic disease caused by the rabies virus (RABV) that causes fatal encephalitis in mammals. Bats can transmit the disease to urban canines and felines, which rarely infect humans, establishing a secondary link. The last case of human rabies in Argentina was transmitted by a dog in 2008. We present the first case of human rabies originating from an insectivorous bat, Tadarida brasiliensis, transmitted by a feral cat in Buenos Aires province, Argentina.

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The rabies virus (RABV) is characterized by a history dominated by host shifts within and among bats and carnivores. One of the main outcomes of long-term RABV maintenance in dogs was the establishment of variants in a wide variety of mesocarnivores. In this study, we present the most comprehensive phylogenetic and phylogeographic analysis, contributing to a better understanding of the origins, diversification, and the role of different host species in the evolution and diffusion of a dog-related variant endemic of South America. A total of 237 complete Nucleoprotein gene sequences were studied, corresponding to wild and domestic species, performing selection analyses, ancestral states reconstructions, and recombination analyses. This variant originated in Brazil and disseminated through Argentina and Paraguay, where a previously unknown lineage was found. A single host shift was identified in the phylogeny, from dog to the crab-eating fox (Cerdocyon thous) in the Northeast of Brazil. Although this process occurred in a background of purifying selection, there is evidence of adaptive evolution -or selection of sub-consensus sequences- in internal branches after the host shift. The interaction of domestic and wild cycles persisted after host switching, as revealed by spillover and putative recombination events.

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The aim of this study was to set up a simple protocol to concentrate SARS-CoV-2 from sewage, which can be implemented in laboratories with minimal equipment resources. The method avoids the need for extensive purification steps and reduces the concentration of potential inhibitors of RT-qPCR contained in sewage. The concentration method consists of a single step, in which a small volume (40 mL) of sewage sample is incubated with polyaluminum chloride (PAC)(0.00045 N Al3+ final concentration). Virus particles adsorbed to the precipitate are collected by low-speed centrifugation, after which the recovered pellet is resuspended with a saline buffer. PAC-concentrated samples are stable for at least one week at 4 °C. Therefore, they may be sent refrigerated to a diagnosis center for RNA extraction and RT-qPCR for SARS-CoV-2 RNA detection if the lab does not have such capabilities. The PAC concentration method produced an average shift of 4.5-units in quantification cycle (Cq) values compared to non-concentrated samples, indicating a 25-fold increase in detection sensitivity. The lower detection limit corresponded approximately to 100 viral copies per ml. Kappa index indicated substantial agreement between PAC and polyethylene glycol (PEG) precipitation protocols (k = 0.688, CI 0.457-0.919). This low-cost concentration protocol could be useful to aid in the monitoring of community circulation of SARS-CoV-2, especially in low- and middle-income countries, which do not have massive access to support from specialized labs for sewage surveillance.

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Lynch-like syndrome (LLS) is an increasingly common clinical challenge with an underlying molecular basis mostly unknown. To shed light onto it, we focused on a very young LLS early-onset colorectal cancer (CRC) cohort (diagnosis ≤ 40 y.o.), performing germline and tumor whole-exome sequencing (WES) of 15 patients, and additionally analyzing their corresponding tumor mutational burden (TMB) and mutational signatures. We identified four cases (27%) with double somatic putative variants in mismatch repair (MMR) core genes, as well as three additional cases (20%) with double MSH3 somatic alterations in tumors with unexplained MSH2/MSH6 loss of expression, and two cases (13%) with POLD1 potential biallelic alterations. Average TMB was significantly higher for LLS cases with double somatic alterations. Lastly, nine predicted deleterious variants in genes involved in the DNA repair functions and/or previously associated with CRC were found in nine probands, four of which also showed MMR biallelic somatic inactivation. In conclusion, we contribute new insights into LLS CRC, postulating MSH3 and POLD1 double somatic alterations as an underlying cause of a microsatellite instability (MSI) phenotype, proposing intrinsic biological differences between LLS with and without somatic alterations, and suggesting new predisposing candidate genes in this scenario.

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Our aim was to evaluate the analytical and clinical performance of the SARS-CoV-2 molecular detection kits used in Argentina. Nine real-time reverse-transcription polymerase chain reaction (RT-qPCR) and three reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assays were evaluated using the World Health Organization (WHO) recommended test as reference method. A secondary standard calibrated for the E, N and RdRp genes against the Pan American Health Organization-World Health Organization-International Standard was used to calculate the limit of detection (LoD). A panel of artificial clinical samples, 32 positive and 30 negative for SARS-CoV-2, were analyzed to estimate the kappa concordance (κ) and the diagnostic performance. Differences among the LoD values for the target genes amplified by each kit were >1 log copies/reaction. The κ for the RT-qPCR kits was greater than 0.9, whereas that for the RT-LAMP assays ranged from 0.75 to 0.93. The clinical performance of RT-qPCR kits showed 100% specificity and high sensitivity, although with variations according to the gene analyzed. The E and N genes provided greater clinical sensitivity, whereas the RdRp gene increased the clinical specificity. The RT-LAMP assays revealed a variable diagnostic performance. The information provided can be useful to choose the most appropriate diagnostic test and may contribute to the establishment of a consensus in the diagnosis of SARS-CoV-2 in Argentina and the region.

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In terms of the domestication process in murtilla, studies have found changes in the concentration of phenolic compounds, with reduction of chemical defense of plants, depending on the change in the feeding behavior of insects. Thus, we hypothesized that the domestication of Ugni molinae decreases the content of phenolic compounds and modifies the feeding preference of Chilesia rudis larvae. Leaves of three parental ecotypes and four cultivated ecotypes were used in preference experiments to evaluate the mass gain and leaves consumption of larvae. Phenolic extracts from leaves of U. molinae were analyzed by HPLC. Identified compounds were incorporated in an artificial diet to assess their effect on mass gain, consumption, and survival of the larvae. The presence of phenolic compounds in bodies and feces was also evaluated. In terms of choice assays, larvae preferred parental ecotypes. Regarding compounds, vanillin was the most varied between the ecotypes in leaves. However, plant domestication did not show a reduction in phenolic compound concentration of the ecotypes studied. Furthermore, there was no clear relation between phenolic compounds and the performance of C. rudis larvae. Whether this was because of sequestration of some compounds by larvae is unknown. Finally, results of this study could also suggest that studied phenolic compounds have no role in the C. rudis larvae resistance in this stage of murtilla domestication process.

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Cosaviruses (CoSV) and Saffold cardiovirus (SAFV) are novel members of the Picornaviridae family. The Matanza-Riachuelo river basin covers a total area of 2200 km2 with approximately 60 km long. Its last section is called Riachuelo River. The aim of this study was to describe the circulation of both picornaviruses and their relationship with the environmental situation of the Riachuelo River using 274 samples collected from 2005 to 2015. CoSV and SAFV were investigated in samples available by two periods: 2005-2006 and 2014-2015 (103 and 101, respectively). Physicochemical and bacteriological parameters confirmed very high levels of human fecal contamination during the 11 years evaluated. CoSV was detected in 85.7% (66/77) and 65.4% (17/26) of the samples collected in 2005-2006 and 2014-2015 periods, respectively. Species A and D were identified, the first one being widely predominant: 74.1% (20/27) and 75.0% (3/4) in both periods. SAFV virus was detected in 47.1% (32/68) and 52.6% (10/19) in periods 2005-2006 and 2014-2015, respectively. SAFV-6 was the most identified genotype in the entire study, while SAFV-3 was predominant in 2005-2006. The contribution of genotypes 1, 2, 4 and 8 was minor. The high prevalence of CoSV and SAFV suggests that both viruses have been circulating in Argentina at least since 2005. Our results show that a watercourse with high rates of human fecal contamination can become a persistent source of new viruses which capacity to produce human diseases is unknown.

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Bats are among the most diverse, widespread, and abundant mammals. In Argentina, 67 species of bats have been recorded, belonging to 5 families and 29 genera. These high levels of biodiversity are likely to complicate identification at fieldwork, especially between closely related species, where external morphology-based approaches are the only immediate means for a priori species assignment. The use of molecular markers can enhance species identification, and acquires particular relevance in capture-release studies. In this study, we discuss the extent of the use of the mitochondrial cytochrome b gene for species identification, comparing external morphology identification with a molecular phylogenetic classification based on this marker, under the light of current bat systematics. We analyzed 33 samples collected in an eco-epidemiological survey in the province of Santa Fe (Argentina). We further sequenced 27 museum vouchers to test the accuracy of cytochrome b -based phylogenies in taxonomic identification of bats occurring in the Pampean/Chacoan regions of Argentina. The cytochrome b gene was successfully amplified in all Molossid and Vespertilionid species except for Eptesicus, for which we designed a new reverse primer. The resulting Bayesian phylogeny was congruent with current systematics. Cytochrome b proved useful for species-level delimitation in non-conflicting genera (Eumops, Dasypterus, Molossops) and has infrageneric resolution in more complex lineages (Eptesicus, Myotis, Molossus). We discuss four sources of incongruence that may act separately or in combination: 1) molecular processes, 2) biology, 3) limitations in identification, and 4) errors in the current taxonomy. The present study confirms the general applicability of cytochrome b -based phylogenies in eco-epidemiological studies, but its resolution and reliability depend mainly, but not solely, on the level of genetic differentiation within each bat genus.

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In rabies diagnosis, it is essential to count on a rapid test to give a quick response. The combined sensitivity and robustness of the TaqMan RT-PCR assays (qRT-PCR) have made these methods a valuable alternative for rabies virus (RABV) detection. We conducted a study to compare the applicability of two widely used qRT-PCR assays targeting the nucleoprotein gene (LysGT1 assay) and leader sequences (LN34 qRT-PCR assay) of RABV genomes, in all variants circulating in Argentina. A total of 44 samples obtained from bats, dogs, cattle, and horses, that were previously tested for rabies by FAT and conventional RT-PCR, were used in the study. All variants were successfully detected by the pan-lyssavirus LN34 qRT-PCR assay. The LysGT1 assay failed to detect three bat-related variants. We further sequenced the region targeted by LysGT1 and demonstrated that the presence of three or more mismatches with respect to the primers and probe sequences precludes viral detection. We conclude that the LysGT1 assay is prone to yield variant-dependent false-negative test results, and in consequence, the LN34 assay would ensure more effective detection of RABV in Argentina.

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BACKGROUND: From November 2018 through February 2019, person-to-person transmission of Andes virus (ANDV) hantavirus pulmonary syndrome occurred in Chubut Province, Argentina, and resulted in 34 confirmed infections and 11 deaths. Understanding the genomic, epidemiologic, and clinical characteristics of person-to-person transmission of ANDV is crucial to designing effective interventions. METHODS: Clinical and epidemiologic information was obtained by means of patient report and from public health centers. Serologic testing, contact-tracing, and next-generation sequencing were used to identify ANDV infection as the cause of this outbreak of hantavirus pulmonary syndrome and to reconstruct person-to-person transmission events. RESULTS: After a single introduction of ANDV from a rodent reservoir into the human population, transmission was driven by 3 symptomatic persons who attended crowded social events. After 18 cases were confirmed, public health officials enforced isolation of persons with confirmed cases and self-quarantine of possible contacts; these measures most likely curtailed further spread. The median reproductive number (the number of secondary cases caused by an infected person during the infectious period) was 2.12 before the control measures were enforced and decreased to 0.96 after the measures were implemented. Full genome sequencing of the ANDV strain involved in this outbreak was performed with specimens from 27 patients and showed that the strain that was present (Epuyén/18-19) was similar to the causative strain (Epilink/96) in the first known person-to-person transmission of hantavirus pulmonary syndrome caused by ANDV, which occurred in El Bolsón, Argentina, in 1996. Clinical investigations involving patients with ANDV hantavirus pulmonary syndrome in this outbreak revealed that patients with a high viral load and liver injury were more likely than other patients to spread infection. Disease severity, genomic diversity, age, and time spent in the hospital had no clear association with secondary transmission. CONCLUSIONS: Among patients with ANDV hantavirus pulmonary syndrome, high viral titers in combination with attendance at massive social gatherings or extensive contact among persons were associated with a higher likelihood of transmission. (Funded by the Ministerio de Salud y Desarrollo Social de la Nación Argentina and others.).

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We present two groups of cases of atypical hand, foot, and mouth disease (HFMD) caused by Coxsackievirus A6 (CV-A6) detected in Argentina in 2015. The first group involved 14 patients from Chubut province and the second group affected 12 patients from San Luis province. Molecular analysis of the complete VP1 protein gene revealed the circulation of E2 sublineage, the most predominant worldwide. To our knowledge, this is the first report of CV-A6 infections associated with atypical HFMD in Argentina and South America.

Se describen dos grupos de casos de enfermedad de mano-pie-boca (HFMD) atípica causada por el virus Coxsackie A6 (Coxsackievirus A6, CV-A6) detectados en Argentina en el año 2015. El primero de los grupos involucró a 14 pacientes de Chubut y el segundo a 12 pacientes de San Luis. El análisis molecular del gen de la proteína VP1 completa reveló la circulación del sublinaje E2, el predominante a nivel global. Hasta donde sabemos, este es el primer reporte de infecciones CV-A6 asociadas con HFMD atípica en Argentina y Sudamérica.

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After a 2014 outbreak of severe respiratory illness caused by enterovirus D68 in the United States, sporadic cases of acute flaccid myelitis have been reported worldwide. We describe a cluster of acute flaccid myelitis cases in Argentina in 2016, adding data to the evidence of association between enterovirus D68 and this polio-like illness.

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Colorectal cancer (CRC) is one of the most common cancers in Latin America and the Caribbean, with the highest rates reported for Uruguay, Brazil and Argentina. We provide a global snapshot of the CRC patterns, how screening is performed, and compared/contrasted to the genetic profile of Lynch syndrome (LS) in the region. From the literature, we find that only nine (20%) of the Latin America and the Caribbean countries have developed guidelines for early detection of CRC, and also with a low adherence. We describe a genetic profile of LS, including a total of 2,685 suspected families, where confirmed LS ranged from 8% in Uruguay and Argentina to 60% in Peru. Among confirmed LS, path_MLH1 variants were most commonly identified in Peru (82%), Mexico (80%), Chile (60%), and path_MSH2/EPCAM variants were most frequently identified in Colombia (80%) and Argentina (47%). Path_MSH6 and path_PMS2 variants were less common, but they showed important presence in Brazil (15%) and Chile (10%), respectively. Important differences exist at identifying LS families in Latin American countries, where the spectrum of path_MLH1 and path_MSH2 variants are those most frequently identified. Our findings have an impact on the evaluation of the patients and their relatives at risk for LS, derived from the gene affected. Although the awareness of hereditary cancer and genetic testing has improved in the last decade, it is remains deficient, with 39%-80% of the families not being identified for LS among those who actually met both the clinical criteria for LS and showed MMR deficiency.

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