Biology subjects

Cardenas, N.

Publications and source records attributed to Cardenas, N..

4 recordsLinked to original sources

bioRxiv2024

Modeling the effects of vaccination against multiple strains of porcine reproductive and respiratory syndrome at the barn level

Porcine reproductive and respiratory syndrome (PRRSV) remains costly for the swine industry. Measures intended to irradicate or reduce the prevalence of PRRSV have limited effectiveness. Vaccination, the primary control strategy for PRRSV, has yet to be thoroughly investigated to ensure an optimal strategy is being implemented. Due to insufficient cross-immunity between strains, it is prudent to administer the most influential vaccine for the most dominant or threatening PRRSV strain in circulation at a given time. With this in mind, we demonstrated the benefits of targeted vaccination using metapopulation-based modeling. By using up-to-date data describing real farms to simulate the effects of variable vaccine efficacy in both a single and a double strain system, we showed that tailoring vaccines to prevalent PRRSV strains reduces infections, but using multiple vaccines may be more effective if strains vary in vaccine response. Therefore, the impact of the strain-specific effectiveness of market vaccines, paired with computational methods that allow tracking the effects on PRRVS dissemination at individual barns.

ecology↗

bioRxiv2022

Modeling foot-and-mouth disease dissemination in Brazil and evaluating the effectiveness of control measures

Foot-and-mouth disease (FMD) is known to infect multiple food-animal species and to spread among ungulate populations. We introduce a multiscale compartmental stochastic model that incorporates population dynamics, births, deaths, and species-specific transmission dynamics. The model integrates disease dynamics at both the between-farm and the within-farm levels. We developed four scenarios to evaluate the effectiveness of countermeasures, including movement standstill, vaccination, and depopulation. The base scenario involved vaccinating the animals on 20 farms and depopulating four infected farms. The three alternative control scenarios included increasing vaccination and depopulation capacities and no vaccination. Our findings indicate that bovines were the most frequently infected species, followed by swine and small ruminants. After ten days of initial spread, the number of infected farms ranged from 1 to 123, with most simulations (90.12%) predicting fewer than 50 infected farms. Most of the secondary spread occurred within a range of 25 km. Early response to initiating the control action reduces the number of days spent working on control actions while intensifying daily depopulation and vaccination capacity; this may be worth considering in decision-making processes for future control of FMD. Emergency vaccination proved to be efficient in reducing the magnitude and duration of outbreaks, whereas increasing depopulation without the use of vaccination also proved to be effective in eliminating the outbreaks.

ecology↗

bioRxiv2022

Towards transboundary networks of climate-smart marine reserves in the Southern California Bight

Climate-smart conservation addresses the vulnerability of biodiversity to climate change impacts but may require transboundary considerations. Here, we adapt and refine 16 biophysical guidelines for climate-smart marine reserves for the transboundary California Bight ecoregion. We link several climate-adaptation strategies (e.g., maintaining connectivity, representing climate refugia, and forecasting effectiveness of protection) by focusing on kelp forests and associated species. We quantify transboundary larval connectivity along [~]800 km of coast and find that the number of connections and the average density of larvae dispersing through the network under future climate scenarios could decrease by [~]50%, highlighting the need to protect critical steppingstone nodes. We also find that although focal species will generally recover with 30% protection, marine heatwaves could hinder subsequent recovery in the following 50 years, suggesting that protecting climate refugia and expanding the coverage of marine reserves is a priority. Together, these findings provide a first comprehensive framework for integrating climate resilience for networks of marine reserves and highlight the need for a coordinated approach in the California Bight ecoregion.

ecology↗

bioRxiv2019

Quantifying the dynamics of pig movements improve targeted disease surveillance and control plans

Tracking animal movements over time can fundamentally determine the success of disease control interventions throughout targeting farms that are tightly connected. In commercial pig production, animals are transported between farms based on growth stages, thus it generates time-varying contact networks that will influence the dynamics of disease spread. Still, risk-based surveillance strategies are mostly based on a static network. In this study, we reconstructed the static and temporal pig networks of one Brazilian state from 2017 to 2018, comprising 351,519 movements and 48 million transported pigs. The static networks failed to capture time-respecting movement pathways. Therefore, we propose a time-dependent network susceptible-infected (SI) model to simulate the temporal spread of an epidemic over the pig network globally through the temporal movement of animals among farms, and locally with a stochastic compartmental model in each farm, configured to calculate the minimum number of target farms needed to achieve effective disease control. In addition, we propagated disease on the pig temporal network to calculate the cumulative contacts as a proxy of epidemic sizes and evaluated the impact of network-based disease control strategies. The results show that targeting the first 1,000 farms ranked by degree would be sufficient and feasible to diminish disease spread considerably. Our finding also suggested that assuming a worst-case scenario in which every movement transmit disease, pursuing farms by degree would limit the transmission to up to 29 farms over the two years period, which is lower than the number of infected farms for random surveillance, with epidemic sizes of 2,593 farms. The top 1,000 farms could benefit from enhanced biosecurity plans and improved surveillance, which constitute important next steps in strategizing targeted disease control interventions. Overall, the proposed modeling framework provides a parsimonious solution for targeted disease surveillance when temporal movement data is available.

ecology↗