Ontario Animal Health Network (OAHN)
Poultry Expert Network
Quarterly Producer Report

Poultry Veterinarian Survey Highlights – Q2

Broilers

Early systemic bacterial infections (<14 days) were stable to increased this quarter. Escherichia coli continues to be commonly identified from these cases both in pure cultures and mixed with other bacteria including E. cecorum and occasionally P. aeruginosa.

Late systemic bacterial infections (>14 days) were also stable to increased this quarter with E. coli as the main cause and mixed with Enterococcus cecorum.

Other causes of early mortality were stable and included intestinal intussusceptions in a couple of flocks of 5-day-old chicks and mycotic pneumonia in a flock of 6-day-old chicks.

The number of reovirus-associated lameness cases reported over this last quarter was quite variable and practitioner dependent with the majority reporting stable cases but others reporting decreased or increased numbers of cases. The general consensus was that there was a lower percentage of affected chickens in affected flocks. Summarized reovirus genotyping results for the last two years and the first quarter of 2020 indicate that there has again been a shift in the genetic composition of the variant reovirus strains with a continued decrease in the variant D strains since 2019 and the continued low incidence of some Ontario classic strains and Variant H which began to emerge in 2018.

Escherichia coli and Enterococcus cecorum were identified as the main causes of bacterial lameness this quarter with most practitioners reporting stable to increased prevalence.

The number of cases of nutritional and developmental lameness remained stable this quarter Developmental lameness is often multifactorial including environmental factors.

Both coccidiosis and necrotic enteritis cases were reported as stable to increased by practising veterinarians. The number of cases reported by the AHL were also stable and were predominantly small intestinal coccidiosis with fewer cases of mixed small intestinal and cecal coccidial burdens or only cecal coccidiosis. One case of necrotic enteritis reported by the AHL was associated with small intestinal/cecal coccidiosis.

Inclusion body hepatitis (IBH) cases were variable and reported to be decreased, stable and increased this quarter by the practitioners. Confirmed cases were identified mostly as species E (serotype 8) and those that were genotyped as 100% similar to serotype 8b with one case identified as species D (serotype 1,4).

The number of flocks with infectious bronchitis virus (IBV) were reported as stable to increased this quarter by the poultry practitioners with the variant DMV strain predominating. Clinical presentations included acute mortality just prior to processing and increased incidence of ascites. Barn air quality likely was contributory and the number of cases is expected to dramatically decrease as the weather and air quality improve.

Infectious bursal disease virus (IBDV) infections were stable this quarter.

Most of the practitioners reported stable spiking mortality cases this quarter.

One case of gangrenous dermatitis was reported this quarter.

Submissions to the AHL diagnosed with runting and stunting syndrome caused by astrovirus were stable this quarter.

Reports of proventricular dilation syndrome on farm and as condemnations at processing were decreased this quarter. The AHL continues to have numerous submissions of proventriculi for histologic evaluation. Histologic features most commonly seen are glandular ductal epithelial proliferation and fibrosis with some also having variable degrees of ductal dilation. The trend of reduced glandular inflammation continues with less than 50% of the submissions reporting inflammation which was classified as very mild to mild.

One case of ventriculitis with adenoviral inclusions in the mucosal villi was identified by the lab this quarter and the case was also positive for Inclusion Body Hepatitis (IBH).

One case of salt toxicity resulting in high mortality was reported.

Other causes of condemnation at processing were stable to increased this quarter and included cellulitis and ascites.

Broiler-Breeders

Early systemic bacterial infections (<14 days) with and without associated yolk sacculitis were reported as stable to increased this quarter. Escherichia coli continues to be the most commonly identified bacterial pathogen.

Other causes of early mortality included starve-outs.

Six cases of intestinal intussusception were reported this quarter with 1 at 2 weeks of age, 2 at 6 weeks of age, and one each at 16, 19 and 20 weeks of age. Older birds are affected which differs from what has been reported previously. The reason is still not clear.

Lameness due to bacterial infection was stable to increased this quarter mainly due to Staphylococcus aureus and Enterococcus cecorum. The AHL reported one case of S. aureus associated vertebral osteoarthritis.

One veterinarian reported a case of lameness due to reovirus.

In-lay bacterial septicemia was reported as stable to increased this quarter with E. coli and E. coli mixed with other pathogens including C. perfringens, E. cecorum and G. anatis identified as causes. A couple of cases of septicemia were related to management practices which resulted in overweight males.

IBV infections, causing drops in egg production were stable whereas infections resulting in increased mortality were stable to increased. Both the California and DMV strains were associated with decreased egg production and the DMV strain with mortality.

The number of coccidiosis and necrotic enteritis cases reported by practitioners were stable this quarter. AHL reported three case of necrotic enteritis and one case of E. necatrix coccidiosis that also had necrotic enteritis.

One practitioner noted the substantial decrease in the number of cases of white chick syndrome with only two cases reported by the AHL for the quarter.

The AHL reported on a case of blackhead in 18- week- old pullets which experienced a spike in mortality just prior to being moved. The transfer proceeded with no issues and no further mortality due to blackhead was reported.

Three more cases of cellulitis and myositis secondary to more deeply placed oil adjuvanted vaccines in the neck muscles were reported by the AHL this quarter. When the vaccine is injected deeply into the neck muscle, sometimes granulomas can be visualized around the spinal cord and within the vertebral column on histologic examination highlighting how deep the material can penetrate into the tissues.

The AHL data had a report of low numbers of Capillaria sp. identified on fecal floatation from 35-week-old breeders. Capillaria infection in broiler breeders in Ontario can be found in low levels on individual farms. Clinical signs are rarely identified but infection may reflect the level of biosecurity on the farm. These flocks may also have issues with other disease agents such as IBV.

Layers

The most notable change this quarter was a small (but expected for the time of year) spike in infectious bronchitis cases reported by one veterinarian whereas the majority of veterinarians reported that the number of flocks with a reduction in egg production/egg quality was stable. Similarly, the number of flocks with respiratory signs due to IBV was stable for the majority of practitioners but one veterinarian reported an increase in flocks under their care. Variant DMV strain of IBV infections are
seen but overall the vaccination programs are working well.

One veterinarian reported dual Mycoplasma gallisepticum and Mycoplasma synoviae infections in a flock experiencing
a production drop.

Bacterial peritonitis/salpingitis due to E. coli remained stable for most veterinarians whereas one veterinarian reported seeing fewer cases.

Early systemic bacterial infection (<14 days) was stable.

Both coccidiosis and necrotic enteritis were noted to be stable by practitioners. The AHL noted one case of each both at four weeks of age.

Renal urolithiasis was diagnosed in a 24- week -old laying flock with mortality . This is usually due to either feeding excessive calcium in the pullet barn or with a calcium : phosphorus imbalance when in lay and, in this particular flock, the former was known to have occurred.

Pericardial hemorrhage in layers at 28-29 weeks was diagnosed by one practitioner. This was a short spike in mortality lasting just a couple of days. Histologic examination of some of the affected birds was nondiagnostic. No cause was found. As electrical shock has been known to cause this condition, the electrical trainers were shut off but deaths still occurred. The flock returned to normal health in a couple of days.

Turkeys

Two flocks of young poults 12 and 14 days of age, presenting with increased mortality were diagnosed with turkey viral hepatitis (TVH) based on characteristic histologic liver lesions. In cases of early poult mortality presenting with white liver foci, submission of pancreas in addition to liver for histology is encouraged as pancreatic necrosis is also reported with TVH.

Early systemic bacterial infections <14 days were stable this quarter. E. coli continues to be the most common pathogen. One of these cases also had pneumonia.

Late systemic bacterial infections > 14 days were stable to increased this quarter. E.coli is commonly the sole pathogen but also can be present in mixed bacterial infections with E. cecorum, S.aureus and C.perfringens. E.coli and Salmonella Heidelberg were isolated from 22-day-old turkeys with septicemia. Two of the flocks with septicemia also had pneumonia with E.coli alone and mixed with S. aureus isolated from the lungs.

Necrotic enteritis and coccidiosis cases were reported as stable to increased by practitioners.

Clinical salmonellosis was variably reported as decreased, stable to increased by practitioners. When present, it was typically as a mixed infection with E. coli.

There were no reports of fowl cholera this quarter.

One case of erysipelas was reported.

Reovirus tenosynovitis was reported to be stable to increased this quarter by the practitioners. A surge in reports of aortic rupture occurred during the early part of the quarter and then deeply declined however this could be a temporary reprieve until recently placed flocks reach the critical age of 12-14 weeks. The AHL reported lameness cases including 13 reovirus infections with positive PCR results with two cases also having TD, 3 with aortic rupture, 2 with lymphoplasmacytic epicarditis, 1 with
chondrodystrophy, 1 with S. aureus synovitis and 1 with E. coli tenosynovitis. Genotyping results included 3-Genotype 2 PA strains with 81.9 to 97.8% similarity and one Ontario strain.

Lameness in Ontario turkey flocks can be multifactorial, so, in addition to testing for reovirus, other causes of lameness including Mycoplasma synoviae and Mycoplasma iowae infections, bacterial osteomyelitis, synovitis/tenosynovitis, tibial dyschondroplasia, muscle/tendon rupture from other causes, articular cartilage defects, footpad dermatitis, and dietary deficiencies should be ruled out.

Evaluation of lameness in successive flocks at earlier ages is suggested, for although clinical lameness is more apparent in older turkeys, likely these infections are initiated earlier in the life of the flock and, at that time, infected birds may have a higher reovirus load allowing for a higher probability of detection.

For more information on Turkey Arthritis Reovirus (TARV) and aortic rupture in Ontario turkeys, please see the June issue of the AHL newsletter at https://www.uoguelph.ca/ahl/turkey-arthritis-reovirus-tarv-and-aorticrupture-ontario-turkeys

Rural/Backyard/Non-Quota Flocks

Two cases of infectious laryngotracheitis (ILT) were reported by the AHL just at the end of the quarter with one untypable and one identified as vaccine strain. Since the beginning of May, there have been 4 more premises with ILT.

For further information on ILT and small poultry flocks, go to: https://www.uoguelph.ca/ahl/ahl-labnote-58-infectious-laryngotracheitis-ilt-infections-small-poultry-flocks

Biosecurity should continue to be a focus of conversation with small flock producers. (From: http://www.omafra.gov.on.ca/english/livestock/poultry/facts/12-039.htm)

• Mixing birds of different species and from different sources increases the risk of introducing disease to your flock. It is preferable to keep only birds of similar age and species together (all in/all out).
• If multiple ages and/or species are kept, minimize contact between groups by keeping them in separate locations.
• If new birds are added to your flock, make sure that you get their complete background information, including a history of any diseases and vaccinations. Some vaccines, including some of those used to control infectious laryngotracheitis (ILT), can cause disease in unvaccinated birds. Consult your veterinarian regarding proper vaccination procedures.
• Keep new or returning birds separate (quarantined) for at least 2-4 weeks after returning home, and monitor them for signs of illness. Clean and disinfect cages and equipment used for these birds. Use separate clothing, footwear and equipment for quarantined birds, and handle them last. If the same equipment and clothing must be used, clean and disinfect them before and after handling the birds.
• Avoid sharing equipment and supplies with other bird owners. If this cannot be avoided, clean and disinfect the equipment before and after each use.

Click here to find a veterinarian with a focus on small flock medicine.

Events and News

Poultry Industry Council events: https://www.poultryindustrycouncil.ca/poultryindustry-events/2019-12/

Poultry Health Research Network information, events, and lectures can be accessed on the PHRN website: https://phrn.net/ or on the PHRN YouTube channel: https://www.youtube.com/user/PoultryHRN

Thank You!
We thank the following poultry veterinarians who completed the veterinary survey: Dr. Elizabeth Black, Dr. Peter Gazdzinski, Dr. Shahbaz Haq, Dr. Genevieve Huard, Dr. Mike Joyce, Dr. Anastasia Novy, Dr. Mike Petrik, Dr. Cynthia Philippe, Dr. Joanne Rafuse, Dr. Fernando Salgado-Bierman, Dr. Kathleen Sary, Dr. Ben Schlegel, Dr. Chanelle Taylor, Dr. Lloyd Weber, Dr. Alex Weisz, and Dr. Jessalyn Walkey.