by Stephen Wagner
PA Avian Influenza update
“This year so far we have had only four incidents that we’ve had to investigate,” said Dr. Nan Hanshaw, DVM, Pennsylvania Agriculture Department.“Last year we had mostly an H2/N2 [strain] we found with a lot of ducks in a lot of live bird markets.” H2/N2, she said, seems to be circulating largely in the New York market. Usually there are a couple of turkey flocks that do cause some concern.
She got a phone call one Friday night asking if Pennsylvania had high-path AI in turkeys. She checked to see and learned that Pennsylvania had an H2/N3 which, she said, “is sort of a swine-avian strain” that she had never dealt with. To her knowledge, the last time it was discussed was in Ohio in 2011.
There were two premises in East Berlin, PA that were tested. “Some of these turkeys are getting pretty big and are about 130 days old. We went out and swabbed them the other day [and] they were positive on serology, and they did come up PCR positive. We are perfectly willing to permit these turkeys to slaughter,” she said.
To permit, a biosecurity plan must be submitted. Those turkeys will be the last to be processed. The truck will be cleaned and disinfected, and they’re going to try to find a route that is safest with people on that road being alerted. “It’s a last-ditch effort if we need to do it,” Hanshaw said. Hanshaw was the lead-off speaker at Penn-Ag’s Keystone Pork Expo and Poultry Progress Day.
Infectious Bronchitis update
Dr. Sherrill Davison, DVM, University of PA, brought attendees up to speed on the infectious bronchitis aspect. She cited sophisticated terms like vaccinal infectious laryngotracheitis, blackhead (histomoniasis) and fowl cholera. “It’s not just infectious diseases that we’re seeing,” she said, “but we have to think about other things such as stray voltage.”
In Canada, she noted a unique situation with infectious bronchitis that had some of the earmarks of the Delmarva strain of bronchitis. “They had a history of flocks being stalled in production, so as they’re coming up into production, all of a sudden they stopped. Economically, they could not keep those flocks. Once the birds are affected, they will never lay eggs.” Last year in Pennsylvania six flocks displayed what was called false layer syndrome.
“These are birds that are supposed to be in production but, in fact, they’re not,” she said. Bird producers are encouraged to take questionable fowl to the UPenn diagnostic lab, and it was there that an incidental finding appeared during a necropsy submitted for another reason. “Our history was similar except our production had stalled 80 – 85 percent.”
That affected percentage was difficult to assess during mere walkthroughs or flock observation. There were some that were mildly affected; it looked like they had water belly. “Those birds were standing like penguins,” she said. “We believe that it is probably similar to Canada,” she said. “That we do have the Delmarva strain, but we can’t prove it.” And so people have started to use a vaccine that affords a cross-protection to the Delmarva strain because there is not a vaccine specifically for that strain.
With laryngotracheitis, Davison said farmers should be aware that it does show up sporadically. Though there hasn’t been an outbreak, there has been one recent case. Wanting her audience to remember what the disease looks like, she showed a slide featuring a chicken with closed eyes “because they have conjunctivitis.” With that is also breathing difficulty. “When we open them up, lesions are in the trachea. The birds die quickly.” Another slide showed a reddening of the trachea with “some caseous material” resembling grated or cottage cheese. “I want to show you this picture,” she said, “because this year and a couple years ago, this was the characteristic of the caseous material. It looks like Eggo. It’s what we saw with this recent case.” Referencing yet another slide — which she described as ‘classical’ — it shows “where the virus got into the lining of the trachea and multiplied causing the lining of the trachea to peel off.” It is what vets have been seeing in recent years.
Davison then turned to something she hasn’t seen in nearly three decades, blackhead. Called histomoniasis, this is usually a turkey disease, ptotozoal in nature. The case she is talking about centered on birds from a chicken farm. Peafowl, grouse and quail are also susceptible. “The birds will be very depressed, evidence diarrhea, and can have very high mortality. Mortality in the flock we were dealing with was .59 percent…certainly not as high as some of these turkey flocks can get with this disease.”
They started seeing worms in the cecum over a year ago. Transmission of the disease is direct, via cecal worms and earthworms. There is no treatment for the birds if they are raised for human consumption. Prevention measures should include routine control of cecal worms; pasture rotation; and chickens and turkeys should be separated.