Plan for the worst; hope for the best. That’s good advice for many situations but particularly accurate when it comes to African swine fever (ASF). [Source: The Pig Site 21 July 2021]
So far, the US has kept the virus from reaching its swine herd, but that doesn’t mean producers, caregivers or swine veterinarians can temper their vigilance.
In fact, remaining vigilant is a key message that Keith Erlandson, DVM, Zoetis, wants to drive home to the US swine industry. "We need to keep reminding people that ASF is still out there, and it could get into the US," he told Pig Health Today.
Erlandson spent five years in China working with a range of integrated production sites and was involved with a sow farm that broke with ASF one month after the 3 August 2018 index case. Within a month, the virus had spread to five other provinces, and by year’s end ASF had infected the entire country. Over the course of nearly three years, he gained first-hand experience dealing with the disease from sow farms to finishing sites. Among the lessons learned was that the course of the disease, diagnosing cases, as well as control and eradication are all more complex than anticipated.
Not in the book
While you may have reviewed the clinical signs of ASF in recent years, the virus hasn’t. "I had believed that an ASF infection would be apparent as soon as I walked into the barn and saw tell-tale clinical signs listed in any edition of Diseases of Swine," Erlandson said.
Instead, ASF shares common signs with other swine diseases, at least in the critical early days. Most pronounced were sows off feed and some vomiting, which could suggest a number of diseases, including porcine reproductive and respiratory syndrome (PRRS), porcine epidemic diarrhea virus and even swine influenza virus.
In the case of ASF, sow or finishing-pig mortality will start to tick up but may be viewed as day-to-day variations. Erlandson relayed that one sow may die today, then none, with three or four dead a few days later. "It takes a couple of weeks for ASF to ramp up to where it’s glaringly obvious and triggers a reaction," he pointed out. "I was expecting the disease would move very quickly through the farm, but it takes longer than I expected."
That detail offers the opportunity to gain control over the virus by acting quickly, within a day or two. But it also allows the virus to continue to move undetected.
Read the rest of the story on The Pig Site.