Biology subjects

Giayetto, O.

Publications and source records attributed to Giayetto, O..

3 recordsLinked to original sources

bioRxiv2025

Integrated environmental drivers and evolutionary history reveal conserved patterns of avian exposure to West Nile and Saint Louis encephalitis viruses

The increasing threat of emerging vector-borne diseases, affecting both humans and wildlife, necessitates a nuanced understanding of the complex interactions among vectors, hosts, and pathogens. Focusing on West Nile Virus (WNV) and Saint Louis encephalitis Virus (SLEV) activity in avian communities of central and northern Argentina, this study delves into the intricate dynamics of exposure risk employing phylogenetic mixed models. Contrary to expectations, ecological traits displayed negligible influence on exposure risk. Instead, temperature seasonality and altitude, emerged as crucial predictors. The phylogenetic signal indicated a conserved susceptibility along the avian evolutionary tree, with Furnariidae, Turdidae and Columbidae families exhibiting higher exposure risk. These findings challenge prevailing notions about the dominant role of ecological traits in mosquito-borne pathogens. The study underscores the need for a holistic understanding, emphasizing the intricate interplay of environmental, phylogenetic, and ecological elements in shaping avian exposure to WNV and SLEV, offering vital insights for future research and public health strategies.

ecology↗

bioRxiv2023

Risk of urban Mayaro virus (Alphavirus: Togaviridae) transmission: is Aedes aegypti a competent vector?

Mayaro virus (MAYV) is an emerging pathogen endemic in Latin America and is the causative agent of fever and polyarthritis. Urban transmission depends on its ability to be transmitted by Aedes aegypti and to be amplified by humans. The aim of this study was to evaluate the susceptibility to infection and transmission and the presence of barriers to infection in different populations of Ae. aegypti for MAYV. Ae. aegypti eggs were collected from Cordoba, Buenos Aires and Rosario Cities (Argentina). Females were infected with five viral loads of MAYV strain (1 to 6 log10 PFU/ml) and maintained for 8 days. The presence of infectious viral particles in body, legs, and saliva was detected by plaquing assay in Vero cell monolayers. Through a bibliographic search, Ae. aegypti population data from Peru were incorporated and tested with different viral doses of MAYV. We build dose-response curves for Ae. aegypti populations to estimate infection (IR), dissemination (DR) and transmission (TR) based on MAYV viral loads detected in humans to estimate transmission risk occurring in an urban environment. The overall IR and DR were significantly associated with the viral doses and were not significantly affected by population origin. We found IR ranging for 3 to 84% (ID50% were higher than 5.5 log10 PFU/ml) and a DR reached 78% (DD50% higher than 6.0 log10 PFU/ml). The percentage of dissemination based on the infected mosquitoes ranged from 60 to 86% while the percentage of transmission based on disseminated mosquitoes ranged from 11 to 60%. Our results indicate that Ae. aegypti populations are not competent vectors for MAYV because they need higher viral doses than those developed by humans (3.9 - 4.5 log10 PFU/ml) to become infected. Only a very low proportion of infected mosquitoes with high 5 log10 PFU/ml are capable of transmitting it.

microbiology↗

bioRxiv2023

Ecological and life-history traits and their relationship with West Nile virus and Saint Louis Encephalitis virus exposure risk.

Host life-history traits can influence host-vector encounter rates, and so differentially determine the exposure risk of bird species. This modulation of host-virus encounters dynamics is especially important when facing "generalist" arboviruses like West Nile virus (WNV) and Saint Louis Encephalitis virus (SLEV). Using prevalence data collected by our laboratory since 2004, we tested several hypothesis that included birds ecological and life-history traits to determine which traits were better predictors of birds exposure risk to these arboviruses. By means of information-theoretic procedures and generalized mixed linear models, we observed that body mass was an important trait when predicting birds exposure risk to WNV and SLEV and migratory status significantly influenced birds exposure risk only to WNV. Our study highlights important traits to consider when studying the transmission system of these arboviruses, being useful to focus resources when characterizing viral transmission networks and discuss the repercussions of these traits over birds immune function throughout the pace of life syndrome and trade-offs theory.

ecology↗