Morphological and molecular analysis of Ornithodoros hasei and Ornithodoros sp. cf. O. mimon (Acari: Argasidae) from northeastern Argentina

In this study two species of soft ticks belonging to the genus Ornithodoros were recorded in three areas in the province of Corrientes, Argentina. Four larvae were identified as Ornithodoros hasei (Schulze, 1935) on Molossus molossus (Molossidae) in Paraje Tres Cerros (Department of San Martín), while 56 larvae were identified as Ornithodoros sp. cf. O. mimon Kohls, Clifford & Jones, 1969 on Eptesicus furinalis and Myotis levis (Vespertilionidae) in Paraje Galarza (Department of Santo Tomé) and Colonia Carlos Pellegrini (Department of San Martín). These last two locations are found within the Esteros del Iberá eco-region. The known distribution range of O. hasei and O. cf. O. mimon is expanded to include the province of Corrientes. Two new ectoparasite-host associations were recorded for Argentina between O. hasei on M. molossus and O. cf. O. mimon on M. levis. The morphological differences together with the results of the phylogenetic analysis show that O. hasei presents genetic similarity with specimens from Brazil, and in Argentina, with ticks from Santa Fe. Instead, Ornithodoros sp. cf. O. mimon recorded in Corrientes and Uruguay belong to a different taxon than the O. mimon recorded in Brazil and Santa Fe, Argentina. Based on this, O. mimon should be considered a complex of species in which the specimens from Corrientes are provisionally considered as Ornithodoros sp. cf. O. mimon until their taxonomic status can be determined.

Identification and Evolutionary Characterization of Papillomavirus Sequences in New World Monkeys (Genera Sapajus and Alouatta) from Argentina

Objective: In this study, we investigated the occurrence of papillomavirus (PV) infection in non-human primates (NHP, Platyrrhine) of northeastern Argentina by using broad-spectrum PCR primers at the L1 gene. In addition, we conducted a phylogenetic and coalescence analysis of viral sequences to explore their evolutionary history and evaluate the co-speciation hypothesis in the context of primate evolution. Methods: We obtained samples of 57 individuals from wild and captive populations of Alouatta caraya, Sapajus nigritus and Sapajus cay. We assessed PV infection by PCR amplification with the CUT primer system and sequencing of 337 bp (112 amino acids) of the L1 protein. The viral sequences were analyzed by phylogenetic and Bayesian coalescence methods to estimate the age of the most common recent ancestor (tMCRA) with BEAST, v1.4.8 software. We evaluated viral/host tree congruence with TreeMap v3.0. Results: We identified two novel putative PV sequences of the genus Gamma- PV in Sapajus sp and Alouatta caraya (SPV1 and AcPV1, respectively). The tMRCA of SPV1 was estimated at 11,941,682 years before present (ybp) and that of AcPV1 at 46,638,071 ybp, both predating the coalescence times of their hosts: 6.4 million years (MYA) and 6.8 MYA, respectively. Based on the comparison of primate and viral phylogenies, we could not reject the null hypothesis that the PV tree is no more congruent with the host tree than a random tree would be (P>0.05). Thus, a model of virus-host coevolution was rejected. Conclusion: This study presents the first report of PV infection in Platyrrhine species from Argentina, expands the range of described hosts for these viruses, and proposes new scenarios for their origin and dispersal.

Antimicrobial and cytotoxic activity of green synthesis silver nanoparticles targeting skin and soft tissue infectious agents

Combining traditional medicine with nanotechnology therefore opens the door to innovative strategies for treating skin and soft tissue infections (SSTIs) and also contributes to the fight against the rise of antimicrobial resistance. Acanthospermum australe (Loefl.) Kuntze is a medicinal plant used by indigenous peoples in northeastern Argentina to treat SSTIs. Spherical and stable silver nanoparticles (AgNPs) of 14 ± 2 nm were synthesized from the aqueous extract of A. australe and silver nitrate. The antimicrobial activity against main species causing SSTIs and cytotoxicity on peripheral blood mononuclear cells of AgNP solution and its synthesis components were evaluated. Compared to its synthesis components, AgNP solution showed greater antimicrobial activity and lower cytotoxicity. The antimicrobial activity of AgNPs was due to the silver and not to the metabolites of the aqueous extract present on the surface of the nanoparticles. The plant extract played an important role in the formation of stable AgNPs and acted as a modulator of cytotoxic and immune responses.

Modeling of leptospirosis outbreaks in relation to hydroclimatic variables in the northeast of Argentina

The transmission of leptospirosis is conditioned by climatic variables. In northeastern Argentina leptospirosis outbreaks occur mainly in coincidence with periods of abundant precipitation and high hydrometric level. A Susceptible Infectious Recovered Epidemiological Model (SIR) is proposed, which incorporates hydroclimatic variables for the three most populated cities in the area (Santa Fe, Parana and Rosario), between 2009 and 2018. Results obtained by solving the proposed SIR model for the 2010 outbreaks are in good agreement with the actual data, capturing the dynamics of the leptospirosis outbreak wave. However, the model does not perform very well when isolated cases appear outside the outbreak periods, probably due to non-climatic factors not explicitly considered in the present version of the model. Nevertheless, the dynamic modeling of infectious diseases considering hydroclimatic variables constitutes a climatic service for the public health system, not yet available in Argentina.

Low reproductive success of the endangered Iberá Seedeater in its only known breeding site, the Iberá Wetlands, Argentina

Subtropical grasslands are highly susceptible to habitat conversion and number among South America’s most threatened ecosystems. The grasslands of northeastern Argentina have been identified as a priority conservation area for threatened capuchino seedeaters because they constitute the main breeding area of these migratory birds. The Iberá Seedeater (Sporophila iberaensis) is a newly described species in the Iberá Wetlands in Argentina whose biology is still poorly understood. The endangered species inhabits grasslands but has only been reported to breed in the Iberá Wetlands ecoregion of northeastern Argentina. To explore the species’ association with grassland vegetation, we studied the breeding biology (clutch size, hatching success, and fledgling production) of the Iberá Seedeater and the main parameters that influence nest survival and nest-site selection. We conducted nest searches and banded adults and nestlings in Iberá National Park during the breeding seasons of 2016–2018. The breeding season of the Iberá Seedeater was highly synchronous and the cumulative probability of nest survival was 0.16. The daily nest survival rate decreased as the breeding season advanced, survival was lower for nests supported by Rhynchospora corymbosa than Paspalum durifolium, the two main nest substrates, and the main causes of nest failure were nest predation and strong winds. Additionally, the population exhibited male-biased site fidelity and a low female return rate. In contrast to other capuchinos, whose breeding biology is associated with upland grasslands, the Iberá Seedeater nested exclusively in flooded lowland grasslands on marsh plants. Thus, effective lowland grassland management is key to maintain the vegetation structure required for reproduction in the Iberá Seedeater.

An annotated checklist of birds of Paraje Tres Cerros, Corrientes province, Argentina

We provide an updated checklist of birds of a unique landscape in northeastern Argentina, which is characterized by three isolated, rocky outcrops and their surrounding agroecosystem. We recorded 188 bird species, including nine that are globally or nationally threatened. We highlight the presence of several grassland-specialist birds of conservation concern. Of the species recorded, 80.6% are residents and 17.7% are migrants. The heterogeneity of the landscape and its structural complexity accounts the existence of a high avian species diversity, which includes both generalists and specialists. This study confirms the conservation value of this ecosystem, due both to the rocky outcrops and grassland matrix. Grasslands are one of the most threatened biomes in the world.