When the Hanor Family of Companies has a porcine reproductive and respiratory syndrome break, the veterinarians put together a two-person investigation team to go over the activities at that farm for the 30 days prior to onset of clinical signs.
The team then examines the various events that occurred and categorizes them as "low," "medium" or "high" for the likelihood of being responsible for the virus introduction.
Kate Dion, a Hanor veterinarian, and animal well-being and quality assurance manager, says while the team often doesn't expect to find the main cause of the outbreak, they have found there are certain events that happen on-farm that can make a farm more vulnerable to a break.
"Construction and maintenance events actually seem to be kind of the exception in my experience with outbreak investigations," Dion says. "I think it's just because they are big, one-time risk events where you can kind of associate some of the things that occurred with that, and just because there's a lot of moving parts, and sometimes there are outside people coming onto your farm."
Case No. 1
In October 2019, the Hanor system had a 10,000-head sow farm catch fire. Thankfully, it was contained to just one farrowing barn, but Dion says the company did lose 25% of its farrowing capacity at the site.
"So really at that point, the race is on," Dion says. "We've got to build and reconstruct this farrowing barn, because we don't have any extra farrowing space in a nearby farm where we can move animals to help deal with this fire."
Activity at the farm escalated, and many people from within and outside the Hanor organization were visiting the site each day.
By mid-January 2020, Dion says a number of abortions had started occurring on-site, in Gestation Barn 9, so the Hanor team decided to do an investigation. During the 30-day investigation period, there were 37 events in which non-Hanor employees were on-site. There was also an increase in internal maintenance staff working near the affected barn.
None of the outside workers used shoe covers or disinfected boots prior to working on-site. There were also numerous vehicles on-site during this time; however, non-Hanor vehicles were disinfected by Hanor maintenance staff prior to coming on the premises.
Prior to the break, a large shipping container with equipment was delivered to the farm and unloaded right outside Gestation Barn 9. While the items were eventually disinfected, they had not been prior to arrival.
There was cross-traffic between the farm staff and the outside crews working at the perimeter, and there was potential for a carrying agent to be brought into the farm office from an employee's shoes.
"Then the question really becomes, how did the virus enter the farm?" Dion says. "In theory, we didn't have any of the construction crews and the maintenance crews inside of the farm. They were limited to the outside of the farm. The interior of the farm was blocked off from where they were working, but the reality is, there's just a lot of people, a lot of moving parts."
Case No. 2
In June, the Hanor team detected PRRS at a farm during weekly surveillance tests on processing fluids. It was found in Barn 7, and at that point, there were no clinical signs in the breeding herd.
"This one was really frustrating for us, just because this is a relatively new farm for us and the system," Dion says. "From a facility standpoint, it was set up to have good biosecurity, as well as a farm manager and farm staff that were really diligent about the practices."
They compared the PRRS sequence to the Morrison Swine Health Monitoring Project database, and a similar virus was found within 50 to 100 miles of the farm in the last two years — and within 150 miles of the farm in the last month.
"At this point, we at least know that virus is in our region, in our area, so [there's] definitely some concern for whether it be outside construction or equipment that may have connections to another farm in our area," Dion says.
Over the course of the investigation, the team found there had been a pit discharge line break outside Barn 7, and an internal maintenance crew had dug the line up. An external crew also came on-site to take measurements for replacement pipe. Six days prior to the positive processing fluids, an external plumber returned to install the new pipe.
"We found that biosecurity had been discussed with this plumber, but one thing that didn't occur was, they didn't actually sign off on our visitor and vendor acknowledgment form," Dion says. "We found that their vehicle did enter the premise, and it had been washed as requested; but as far as the actual plumber working around the site, they didn't have any shoe covers that they used, or boot disinfection as they worked on that farm. But we did find that the equipment and the tools that they used to actually do that repair were from our internal maintenance shop."
While the plumber did not enter the farm, Dion says there could have been cross-traffic with farm employees performing outside tasks, or the internal maintenance staff. There is also the possibility the virus could have come through on someone's shoes or a breach through the outside door of Barn 7.
Dion says there was one incidental finding from the investigation.
"We did have one maintenance employee who did not follow the correct downtime for entering the farm during the investigation period. They had actually visited a nursery prior to visiting the sow farm," Dion says. "What we determined was, although this is a breach in procedure, this was unlikely to be the source of the virus as this nursery was being monitored for PRRS and it was testing negative — but it is a good reminder that mistakes do happen."
Case No. 3
In December, Hanor's Gestation Barn 305 started experiencing problems. Sows were off feed, and abortions soon followed. When the team looked at sequencing, they found it was 100% similar to a another PRRS outbreak at a Hanor farm 16.5 miles away.
"As you can imagine, with it being within the system, we're going to find likely multiple operational connections thus far — and so then we really have to focus in on which of those connections actually had some sort of event where a mitigation step wasn't followed and had the potential for the virus to actually enter the farm," Dion says.
The investigators found that seven to 11 days prior to the farm's outbreak, an internal maintenance crew was on-site for welding and water trough repair. The farm manager was on vacation that week, and the assistant manager thought they were following tool and supply biosecurity, but no one was overseeing them.
Metal trough pieces were sprayed with disinfectant at a vehicle station as they did not fit in the disinfection room. The trough repair occurred next to the barn where the sows were off their feed.
"We found that they entered the farm premise, they did their disinfection steps with the trough at the vehicle disinfection station, and then they proceeded to go park their vehicle very close — right outside of the barn door of that Gestation Barn 305," Dion says. "This allowed them to have tools right next to the barn there so that they could grab them. After they parked their vehicle, they went to the farm entry and did their shower-in procedure; but when we asked them about the disinfection process for those tools that they were bringing in, we didn't get a good answer."
While there was a weekend of downtime between farm visits, Dion says it is possible that the vehicle, tools and supplies were contaminated from the other farm and brought the virus in.
What has the Hanor team learned from these investigations? Dion says first and foremost, try to avoid construction projects during the peak of PRRS season.
"Try to really schedule that preventative maintenance stuff in the warm weather. That can at least try to stack the odds in our favor of when the virus is less likely to spread, just due to adding hot temperatures on our side," Dion says. "The reality is this isn't always feasible, and emergency needs happen, so you do still have to be prepared to do these type of events — even in cold weather when viruses are able to spread more readily."
Dion also recommends these guidelines:
Biosecurity. Establish and continue discussing biosecurity requirements with construction and maintenance crews. Have visitors sign the vendor acknowledgment form to ensure clarity of expectations and formalize the process. Continue to repeat and question construction repair personnel regarding downtime and their contact with pig premises.
Transportation. Establish an "outside" line of separation from construction personnel and vehicles. Try to minimize any vehicles that come close or next to the barns.
Footwear. Have a shoe-cover, shoe change or boot disinfection process for people working on the premises near the barns.
Cross-traffic. Avoid cross-traffic with on-farm staff parking and entry.
Disinfect. Ensure downtime and disinfection are followed for all supplies and tools that enter. Avoid direct deliveries close to barns. Disinfect before and after bringing items on-farm. Alternatively, have tools available to use on-farm.
Reminders. Remind farm employees of the high risk of cross-traffic. Entry procedures must be followed correctly. Reinforce an employee shoe-cover process when employees have cross-traffic.
"One thing that I've thought about is, it might be valuable to actually ask someone on-farm to oversee these construction and maintenance crews when big projects are being done, making sure that they're actually complying," Dion says. "You know, it seems like that might be a lot of time; but that time, compared to the cost of an outbreak, actually might be money well spent."