Abstract: Estimation of a Within-Herd Transmission Rate for African Swine Fever in Vietnam

Apr 14, 2023

We describe results from a panel study in which pigs from a 17-sow African swine fever (ASF) positive herd in Thái Bình province, Vietnam, were followed over time to record the date of onset of ASF signs and the date of death from ASF. Our objectives were to (1) fit a susceptible-exposed-infectious-removed disease model to the data with transmission coefficients estimated using approximate Bayesian computation; (2) provide commentary on how a model of this type might be used to provide decision support for disease control authorities. For the outbreak in this herd, the median of the average latent period was 10 days (95% HPD (highest posterior density interval): 2 to 19 days), and the median of the average duration of infectiousness was 3 days (95% HPD: 2 to 4 days). The estimated median for the transmission coefficient was 3.3 (95% HPD: 0.4 to 8.9) infectious contacts per ASF-infectious pig per day. The estimated median for the basic reproductive number, R0, was 10 (95% HPD: 1.1 to 30). Our estimates of the basic reproductive number R0 were greater than estimates of R0 for ASF reported previously. The results presented in this study may be used to estimate the number of pigs expected to be showing clinical signs at a given number of days following an estimated incursion date.

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Video: What Causes Ear Necrosis in Pigs? - Alison Jeffery

In this episode of The Swine it Podcast Show Canada, Alison Jeffery, a PhD candidate at the University of Saskatchewan, discusses emerging research on ear necrosis in pigs. She explains the role of Fusobacterium necrophorum, how ear biting may introduce bacteria into damaged tissue, and what researchers are learning about disease progression, welfare, prevention, and future management tools. Listen now on all major platforms!

"Ear necrosis is not only an infectious disease challenge, it is also a welfare issue shaped by behavior, tissue damage, and the farm environment."

Meet the guest: Alison Jeffery / alison-jeffery is a PhD candidate in Large Animal Clinical Sciences at the University of Saskatchewan. Her research focuses on improving swine health and welfare by understanding and mitigating ear necrosis in pigs. Her background includes swine research, producer support, laboratory work, and studies in animal science and veterinary microbiology. Learn more from Alison Jeffery on The Swine it Podcast Show Canada, available on all major platforms.