arXiv subjects

Cesar A. Corzo

Publications and source records attributed to Cesar A. Corzo.

3 recordsLinked to original sources

arXiv2026

Descriptive and risk analysis of vehicle movements linked to porcine reproductive and respiratory syndrome and porcine epidemic diarrhea transmission in US commercial swine farms

Vehicle movements, including vehicle cabs and trailers, play a role in disseminating disease in swine production. However, there are many information gaps about vehicle movements patterns that increase the probability of disease transmission, which is crucial in developing better preventive strategies. In this study we described the movement pattern of vehicle cabs and trailers and identified risk factors for porcine reproductive and respiratory syndrome (PRRS) and porcine epidemic diarrhea (PED) farm's infectious status. We collected global positioning system (GPS) movement data from vehicle cabs and trailers for 18 months and basic information for 6621 farms in the U.S. For the vehicle movement data, we estimated 66 variables and evaluate their association with farms PRRS and PED status. Our univariate analysis showed that 56 variables were significant associated (p < 0.05) to PED and PRRS farm status. Within these variables, vehicle visit frequency and previous exposition to positive farms were the main risk factors for both diseases. Otherwise, increased vehicle cab and trailer loyalty for farm shipments and vehicle cleaning and disinfection events were protective factors. In the multivariate model, each additional weekly visit by a vehicle cab that had been exposed to a positive farm one day before the shipment was associated with a 234\% and 243\% increase in the odds of a farm testing PRRS- and PED-positive, respectively. Our analysis revealed that vehicle contact history play a crucial role in the transmission of PRRS and PED. These findings can provide insights to develop more target strategies aimed at reducing the transmission and outbreaks linked to vehicle movements in swine production.

q-bio.QM↗

arXiv2023

Spatiotemporal relative risk distribution of porcine reproductive and respiratory syndrome virus in the southeastern United States

Porcine reproductive and respiratory syndrome virus (PRRSV) remains widely distributed across the U.S. swine industry. Between-farm movement of animals and transportation vehicles, along with local transmission are the primary routes by which PRRSV is spread. Given the farm-to-farm proximity in high pig production areas, local transmission is an important pathway in the spread of PRRSV; however, there is limited understanding of the role local transmission plays in the dissemination of PRRSV, specifically, the distance at which there is increased risk for transmission from infected to susceptible farms. We used a spatial and spatiotemporal kernel density approach to estimate PRRSV relative risk and utilized a Bayesian spatiotemporal hierarchical model to assess the effects of environmental variables, between-farm movement data, and on-farm biosecurity features on PRRSV outbreaks. The maximum spatial distance calculated through the kernel density approach was 15.3 km in 2018, 17.6 km in 2019, and 18 km in 2020. Spatiotemporal analysis revealed greater variability throughout the study period, with significant differences between the different farm types. Sow farms were consistently categorized as high risk farm types, while downstream farms (i.e., finisher and nursery farms) had more susceptible farms within areas of significant-high relative risk. Factors associated with PRRSV outbreaks were farms with higher number of access points to barns, higher numbers of outgoing movements of pigs, and higher number of days where temperatures were between 4°C and 10°C. Results obtained from this study may be used to guide the reinforcement of biosecurity and surveillance strategies at farms and areas within the distance threshold of PRRSV positive farms.

q-bio.PE↗

arXiv2022

Modeling between-farm transmission dynamics of porcine epidemic diarrhea virus: characterizing the dominant transmission routes

The role of transportation vehicles, pig movement between farms, proximity to infected premises, and feed deliveries has not been fully considered in the dissemination dynamics of porcine epidemic diarrhea virus (PEDV). This has limited efforts for disease control and elimination restricting the development of risk-based resource allocation to the most relevant modes of PEDV dissemination. Here, we modeled nine modes of between-farm transmission pathways including farm-to-farm proximity (local transmission), contact network of pig farm movements between sites, four different contact networks of transportation vehicles (vehicles that transport pigs from farm-to-farm, pigs to markets, feed distribution and crew), the volume of animal by-products within feed diets (e.g. animal fat and meat and bone meal) to reproduce PEDV transmission dynamics. The model was calibrated in space and time with weekly PEDV outbreaks. We investigated the model performance to identify outbreak locations and the contribution of each route in the dissemination of PEDV. The model estimated that 42.7% of the infections in sow farms were related to vehicles transporting feed, 34.5% of infected nurseries were associated with vehicles transporting pigs to farms, and for both farm types, pig movements or local transmission were the next most relevant routes. On the other hand, finishers were most often (31.4%) infected via local transmission, followed by the vehicles transporting feed and pigs to farm networks. Feed ingredients did not significantly improve model calibration metrics. The proposed modeling framework provides an evaluation of PEDV transmission dynamics, ranking the most important routes of PEDV dissemination and granting the swine industry valuable information to focus efforts and resources on the most important transmission routes.

q-bio.PE↗