2015 MPF Convention Regional Disease Update-South and West John G. Brown, DVM, MAM Zoetis, Inc. John.brown@zoetis.com 706-206-8028 I was asked to give an update on the disease situation in the southern and western regions of the United States. I will begin my presentation by addressing the elephant in the room initially and then move on to diseases that the rank and file members are more likely to run across. Avian Influenza: As you have no doubt heard, there have been numerous HPAI virus isolations on the west coast since late last year along the Pacific Flyway in both wild birds and a few commercial and backyard flock. Below is an update as of the most recent information I have available. I will present the information in chart form after some initial comments. The initial diagnosis was in western Canada in British Columbia s Fraser Valley on December 2. Two commercial farms were diagnosed and by December 13 th, 9 farms were diagnosed and 240,000 birds had been destroyed. I know my initial thought at the time was here we go again. The Fraiser Valley is a very concentrated area of mixed poultry production with many producers with multiple species on the same farm. Back several years ago the area basically depopulated most commercial operations in the area due to HPAI and my fear was this was going to be a repeat of the same situation due to the difficulty in keep the virus isolated in such a densely poultry populated area. However, the lessons learned from the previous break were extremely useful and the area has been free of diagnoses since December 13, 2014. Below is a summary of the cases seen in the United States since December 8, 2014.
Wild Bird Cases Date Location Species Virus Dec. 8, 2014 Whatcom, WA Mallards and Northern Pintails H5N2 EA/AM Dec. 16, 2014 Whatcom, WA American Wigeon H5N8 EA Dec. 20, 2014 Lane, Or Mallard H5N2 EA/AM Dec. 23, 2014 Whatcom and Clark, WA Northern Pintails and Mallard H5N2 EA/AM Dec. 24, 2014 Columbia, OR Mallard H5N2 EA/AM Dec. 28, 2014 Butte, CA Gadwall H5N8 EA Dec. 29, 2014 Whatcom, WA American Green Winged Teal H5N1 EA/AM Dec. 29, 2014 Whatcom, WA Coopers Hawk H5N2 EA/AM Dec. 29, 2014 Gray's Harbor, WA Peregrine Falcon H5N8 EA Dec. 30, 2014 Clark, WA American Wigeon H5N8 EA Dec. 31, 2014 Butte, CA American Wigeon H5N8 EA Jan. 1, 2015 Whatcom, WA Mallard H5N2 EA/AM Jan. 2, 2015 Davis, UT American Wigeon H5N8 EA Jan. 3, 2015 Morrow, OR Wood Duck H5N2 EA/AM source : USDA-USGS Feb 13, 2015 Backyard and Commercial Flocks Date Location Species Virus Dec. 19, 2014 OR Backyard (Mixed Flock) H5N8 EA Jan. 3, 2015 WA Backyard (Mixed Flock) H5N2 EA/AM Jan. 9, 2015 WA Backyard (Mixed Flock) H5N2 EA/AM Jan. 16, 2015 WA Backyard (Mixed Flock) H5N2 EA/AM Jan. 16, 2015 ID Backyard (Mixed Flock) H5N2 EA/AM Jan. 23, 2015 CA Commercial (Turkey) H5N8 EA Jan. 29, 2015 WA Backyard (Pheasants) H5N2 EA/AM Feb. 2, 2015 WA Backyard (Mixed Flock) H5N2 EA/AM Feb.3, 2015 WA Backyard (Chickens) H5N2 EA/AM Feb. 12, 2015 CA Commercial (Chickens) H5N8 EA source : USDA-USGS Feb 13, 2015 Note: EA indicates an H5 AI virus of Eurasian origin which is highly pathogenic to poultry and has been circulating in the flyways for some time. The EA/AM type is a reassortment of the Eurasian virus and a North American AI virus. The commercial turkey flock that was diagnosed was located in Stanisluas County California and was found in one house of a nine house farm. There was high mortality in the one house and birds were submitted to the lab and the farm was immediately quarantined by the company. As of the last report,
4500 turkeys died, 1200 were destroyed and 145,000 were described as susceptible. Monitoring is continuing but no more positives have been seen. In February, In Kings County CA, a farm with Commercial broilers and ducks was diagnosed with HPAI and apparently destroyed but I have no further information on that outbreak. To summarize the recent spate of AI isolations and diagnoses, the monitoring and vigilance has paid off and there has not been the rapid spread commercially as in some situations in the past. It is however, very apparent that the AI virus is still a constant threat as it continues to circulate in the wild bird populations and the viral reassortment can create more or less pathogenic viruses at any time. In the rest of the country people generally think they are safe as this virus is in the Pacific Flyway so not need to worry. Not the case!! All those birds migratory patterns join in the northern parts of Canada, Asia, etc. To think that those birds do not intermingle with birds that might migrate via different flyways is an erroneous assumption. Producers should be aware of the potential for wild migratory birds to be shedding AI viruses and therefore should keep up strict biosecurity practices to prevent the introduction of AI onto their farms. Remember there are three things necessary for disease to occur, presence of the pathogen, susceptible population of birds, and a suitable environment for both to survive. You can prevent the introduction of the pathogen with strict biosecurity program. I see lots of very good written biosecurity plans but very few are followed each and every time a flock is visited. Make a plan and follow that plan each and every day! Now on to other diseases that are present in the regions I am supposed to be talking about. Coccidiosis The industry moved birds off the floor years ago and into cages to prevent coccidiosis as well as other diseases. This seemed to work very well until several years ago when Coccidiosis seemed to become more and more of a problem in cage and cage-free operations. Why is this? I am not certain but I think a lot has to do with changes in the way we manage our pullets, different equipment being used, genetic changes to the breeds, etc. In a survey that Dr. Gingerich does annually among veterinarians that work with layer chickens, Coccidia was one of the top concerns and diseases diagnosed. I am seeing more and more coccidia in the lay house at around peak production with high mortality due to Necrotic Enteritis. Pullets also in some areas appear to be having coccidia problems as well. We will discuss some of my thoughts and potential responses different producers are using to correct the problem. FDN
I am sure that Dr. Gingerich has covered this issue very well so I will not spend too much time on FDN other than to say that it is present in most regions of the country in layers. I have not seen it personally in pullets but I believe some veterinarians have diagnosed the problem in pullets as well. Calcium Depletion Calcium depletion is a very common diagnosis in layer at various times during production. Some flock will see Calcium depletion or soft bones at around peak production and some flocks will exhibit this issue later in lay. To some extent I think a small amount of Calcium depletion is normal in a high producing flock struggling to consume sufficient nutrients to compensate for the output of the shell. We certainly have seen a tremendous improvement in egg numbers and peak performance of all breeds over the recent years and it is hard to imagine a small bird producing that many eggs without some loss of Calcium from the skeletal system. Many veterinarians have their own Calcium depletion treatment regime that makes nutritionists cringe. In any event, my treatment regime is as follows: 25# large particle Calcium and 5# dicalcium phosphate per ton of feed top-dressed not reformulated. Feed this diet for 2 weeks. Once that diet is in front of the birds and they are consuming it, I also add Vitamin D3 in the water at 10,000 IU per gallon of drinking water for three day in a row the first week the treatment diet is being used. During the second week the diet is being fed, the Vitamin D3 should be used two day that week but not two day in a row, two days separated by a few days. This program can be repeated as needed but should not be fed continuously. I like to use it as needed or scheduled every 8 weeks. Peripheral Neuropathy/MD PN or peripheral neuropathy looks so much like MD that I am grouping them together. PN occurs in pullets and I have seen it as early as 6 weeks and seen it last until as late as 16-17 weeks of age. The presentation of this condition is that birds are on their sides unable to walk or struggle to walk and appears as leg paralysis seen in pictures of MD in shown in textbooks about diseases of poultry. I believe this PN is much more of a problem that MD currently. Infectious Coryza Infectious Coryza is a bacterial disease that many in the Midwest or Northeast are unfamiliar with as it is typically considered a warm weather disease. It has traditionally been seen in southern California, southern Texas, Florida but not high on a differential diagnosis list in other parts of the country. Back in the 1990 s however, a farm in New England broke with IC and as a result vaccinated and treated their way out of the problem over several years. Recently a farm in the northern part of the western US was diagnosed with the problem.
IC is cause by the bacterium called Haemophilus paragallinarum (recently renamed Avibacterium paragallinarum) and causes sinusitis, feed consumption drop, egg production loss and mortality. It is reported that the exudate from the nostrils smells like sulfur. The literature describes the signs as swollen infraorbital sinus and the results almond shaped eyes, feed sticking to the nostrils, depressed birds, and production drops. Treatment with Aureomycin has been shown to be relatively effective in reducing the clinical and production issues related to the infection. Vaccination with one of several available inactivated IC vaccines is the recommended course once diagnosed. Biosecurity As I mentioned earlier, Biosecurity needs to be a prime focus for the industry. In order for a disease to occur, birds have to be exposed to the disease causing organism. Keeping disease causing organisms out of the chicken house is the purpose of a good biosecurity plan. 1. Limit Visitors to only those necessary 2. If visitors are necessary, they must be required at a minimum to wear coveralls, boots and hair cover. Farm clothes and farm shoes are even better. 3. Vehicles should be clean and the floor boards disinfected between visits 4. 48-72 hour time between farm visits should be enforced. 5. Workers who go outside the US especially to areas with diseases not endemic to the US should be required to take a week away from the farm before returning to work.