ProMED Media Myth On H7N8 In Dubois County Indiana

[niman]

ProMED has published a commentary, Avian influenza (08): USA (IN) poultry, HPAI revised to LPAI H7N8, claiming that "What is interesting is that USDA announced these cases as highly pathogenic and now seems to be recanting".

 

This mis-information is unfortunate.  The USDA data suggests that low path was widespread in turkey farms in northern Dubois county.  This low path  H7N8 infection went undetected until the virus evolved to high path on the index farm, leading to a drop in water consumption and excessive deaths.  Subsequent testing in the 10 km exclusion zone identified low path H7N8 in adjacent farms.

USDA announced the HPAI on the index farm followed by the detection of H7 on nearby farms, followed by characterization of these subsequent H7 confirmations as LPAI.

ProMED should issue a retraction of the comments and then find commentators with a basic knowledge of avian influenza evolution in poultry farms.

http://promedmail.org/direct.php?id=20160118.3944747

Edited January 18, 2016 by niman

[niman]

Published Date: 2016-01-18 00:28:50
Subject: PRO/AH/EDR> Avian influenza (08): USA (IN) poultry, HPAI revised to LPAI H7N8, update 
Archive Number: 20160118.3944747

AVIAN INFLUENZA (08): USA (INDIANA) POULTRY, HPAI REVISED TO LPAI H7N8, UPDATE
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A ProMED-mail post
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International Society for Infectious Diseases
http://www.isid.org

Date: Sun 17 Jan 2015
Source: USDA [edited]
https://www.aphis.usda.gov/wps/portal/aphis/home/!ut/p/a1/04_Sj9CPykssy0xPLMnMz0vMAfGjzOK9_D2MDJ0MjDz9vT3NDDz9woIMnDxcDA2CjYEKIoEKDHAARwNC-sP1o8BKnN0dPUzMfYB6TCyMDDxdgPLmlr4GBp5mUAV4rCjIjTDIdFRUBADp5_lR/?1dmy&urile=wcm%3Apath%3A%2Faphis_content_library%2Fsa_newsroom%2Fsa_news%2Fsa_by_date%2Fnewsroom-2016%2Fnewsroom-january-2016%2Fct_hpai_indiana_low_path


Update on H7 Avian Influenza Cases in Indiana, Additional Flocks Now Confirmed as Low Pathogenic / Cases Found Through Surveillance Testing in Initial Control Area
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Andrea McNally (202)799-7033
[email protected]
Lyndsay Cole (970)494-7410
[email protected]

The United States Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed the pathogenicity of eight of the nine H7N8 avian influenza detections announced on January 16. The turkey flocks have been confirmed as low pathogenic avian influenza, with additional testing ongoing for the ninth flock.

These January 16 detections were identified as part of surveillance testing in the control area surrounding the initial highly pathogenic H7N8 avian influenza (HPAI) case in that state, identified on January 15.

The pathogenicity of a virus refers to its ability to produce disease. Birds with low pathogenic avian influenza (LPAI) often show no signs of infection or only have minor symptoms. HPAI viruses spread quickly and cause high mortality in domestic poultry. H7 LPAI viruses have been known to mutate into HPAI viruses in the past.

"It appears that there was a low pathogenic virus circulating in the poultry population in this area, and that virus likely mutated into a highly pathogenic virus in one flock," said Dr. John Clifford, USDA Chief Veterinarian. "Through cooperative industry, state and federal efforts, we were able to quickly identify and isolate the highly pathogenic case, and depopulate that flock. Together, we are also working to stop further spread of the LPAI virus, and will continue aggressive testing on additional premises within the expanded control area to ensure any additional cases of either HPAI or LPAI are identified and controlled quickly."

APHIS continues to work closely with the Indiana State Board of Animal Health and the affected poultry industry on a joint incident response. State officials quarantined the additional affected premises and depopulation of birds has already begun. Depopulation prevents the spread of the disease. Birds from the flock will not enter the food system.

No human infections associated with avian influenza A viruses of this particular subtype (i.e., H7N8) have ever been reported. As a reminder, the proper handling and cooking of poultry and eggs to an internal temperature of 165 ˚F kills bacteria and viruses, including HPAI.

As part of existing avian influenza response plans, Federal and State partners continue to work on additional surveillance and testing in the nearby area. No new presumptive cases have been identified since January 16.

The rapid testing and response in this incident is the result of months of planning with local, state, federal and industry partners to ensure the most efficient and effective coordination. Since the previous HPAI detections in 2015, APHIS and its state and industry partners have learned valuable lessons to help implement stronger preparedness and response capabilities. In September, APHIS published a HPAI Preparedness and Response Plan that captures the results of this planning effort, organizing information on preparatory activities, policy decisions and updated strategy documents.

The United States has the strongest AI surveillance program in the world, and USDA is working with its partners to actively look for the disease in commercial poultry operations, live bird markets and in migratory wild bird populations.
Anyone involved with poultry production, from the small backyard to the large commercial producer, should review their biosecurity activities to assure the health of their birds. To facilitate such a review, a biosecurity self-assessment and educational materials can be found at http://www.uspoultry.org/animal_husbandry/intro.cfm

In addition to practicing good biosecurity, all bird owners should prevent contact between their birds and wild birds and report sick birds or unusual bird deaths to State/Federal officials, either through their state veterinarian or through USDA's toll-free number at 1-866-536-7593. Additional information on biosecurity for backyard flocks can be found at http://healthybirds.aphis.usda.gov.
Additional background

Avian influenza (AI) is caused by an influenza type A virus which can infect poultry (such as chickens, turkeys, pheasants, quail, domestic ducks, geese and guinea fowl) and is carried by free flying waterfowl such as ducks, geese and shorebirds. AI viruses are classified by a combination of two groups of proteins: hemagglutinin or "H" proteins, of which there are 16 (H1-H16), and neuraminidase or "N" proteins, of which there are 9 (N1-N9). Many different combinations of "H" and "N" proteins are possible. Each combination is considered a different subtype, and can be further broken down into different strains. AI viruses are further classified by their pathogenicity (low or high)-- the ability of a particular virus strain to produce disease in domestic chickens.
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Communicated by:
ProMED-mail 
<[email protected]>

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[2]
Date: Sun 17 Jan 2015
Source: Indiana State Board of Animal Health [edited]
http://www.in.gov/boah/2390.htm

Indiana Clarifies Avian Flu 
Findings in Nine Flocks
Laboratory Results Confirmed Overnight
FOR IMMEDIATE RELEASE
INDIANAPOLIS --Laboratory testing of samples from 8 of 9 Southern Indiana turkey flocks was completed overnight by the U.S. Department of Agriculture (USDA) National Veterinary Services Laboratory in Ames, Iowa. While all 9 were announced as H7 influenza-positive yesterday, the specific strain was yet to be determined. The Indiana State Board of Animal Health (BOAH) has been informed 8 are low-pathogenic H7N8. Testing continues on the remaining sample. 

Avian influenza does not present a food safety risk; poultry and eggs are safe to eat. The Centers for Disease Control and Prevention (CDC) considers the risk of illness to humans to be very low.

Indiana State Veterinarian Bret D. Marsh, DVM calls this good news, and evidence that Indiana's aggressive surveillance and response efforts in Dubois County are working.

"The low-path H7N8 virus was identified during testing in the 10-km zone around the initial flu-positive flock," Dr. Marsh said. "Because flu viruses are constantly mutating, we want to catch any case as early as possible after infection. We know this virus strain can intensify, so finding these cases as low-path strains shows we are keeping pace with the spread of this disease in the area."

In addition to the HxNx naming scheme for specific strains, AI viruses are further classified by their pathogenicity--the ability of a particular virus strain to produce disease in domestic chickens. Highly pathogenic avian influenza (HPAI) virus strains are extremely infectious, often fatal to domestic poultry, and can spread rapidly from flock to flock. Low pathogenicity avian influenza (LPAI) virus strains occur naturally in wild migratory waterfowl and shorebirds without causing illness. LPAI viruses have the potential to mutate into HPAI.

"This finding does not alter the aggressive control strategy BOAH has set forth," added Dr. Marsh. "Nor does it change our resolve to eliminate this virus wherever we find it."

Priority response by the state of Indiana and USDA continues on all the infected farms. Turkeys are being humanely euthanized on infected sites within 24 hours of diagnosis. Depopulation eliminates the source of infection to prevent the disease from spreading. Disposal of the turkeys, primarily via indoor composting, will be followed by thorough cleaning and disinfection of all barns.

Aggressive testing of other poultry farms in the area continues. During the last 24 hours, commercial farms have yielded 100 negative flu tests, beyond the nine new positives. In addition, state and federal teams have visited 503 residences in the area to identify any small flocks for testing. Tests are pending on 17 small flocks. Residential visits will continue in the 10-km area.
About Indiana Poultry:

Dubois County is Indiana's largest turkey-producing county, growing 1.4 million birds annually. The state ranks fourth in the nation in turkey production. As a major supplier of eggs, ducks and chickens, too, Indiana's poultry industry generates $2.4 billion and employs 14,000 Hoosiers.

UPDATES and INFORMATION:
Situation updates and status reports about ongoing avian influenza response activities, along with critical disease-related information, will be posted online at: www.in.gov/boah/2390.htm . Users may subscribe to email updates on a link at that page.

--
Communicated by:
ProMED-mail 
<[email protected]>

[This strain, H7N8 is not the same strain that was so prevalent last year, which was H7N2. 

What is interesting is that USDA announced these cases as highly pathogenic and now seems to be recanting. It is of course good news but this seems a bit unusual.

These viruses are capable of mutating, especially from low pathogenicity to high pathogenicity. So these premises are likely to be watched and tested very carefully. - Mod.TG

A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/promed/p/217.]

 

See Also

Avian influenza (07): USA (IN) poultry, HPAI H7N8 20160117.3943565
2015
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Avian influenza (102): USA, HPAI H5N2, poultry, turkey 20150501.3332390
Avian influenza (101): USA (KY) H5N2, goose, duck 20150429.3331768
Avian influenza (99): Canada (ON) HPAI H5N2, turkey 20150429.3329590
Avian influenza (97): Canada (ON) poultry; HPAI H5N2 20150424.3319119
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Avian influenza (73): Canada (ON) HPAI H5N2, poultry, OIE 20150410.3288088
Avian influenza (71): Canada (ON) HPAI, H5N2, turkey 20150409.3285805
Avian influenza (63): USA (WY) HPAI H5N2, goose 20150331.3267533
Avian influenza (59): USA (MN): turkey, H5N2 20150329.3264089
Avian influenza (54): USA (CA) poultry, LPAI H7N3, OIE 20150319.3241143
Avian influenza (50): USA (AR) turkey, H5N2 20150313.3227033
Avian influenza (49): USA (MO) turkey, H5N2 20150312.3223765
Avian influenza (39): USA (OR) backyard flock 20150215.3167658
Avian influenza (38): USA (ID) 20150213.3161063
Avian influenza (34): USA (WA) hobby birds 20150204.3141350
Avian influenza (29): USA (WA) game birds 20150130.3132628
Avian influenza (17): USA (WA) wild duck, HPAI H5N1, OIE 20150122.3109001
Avian influenza (16): USA (WA, ID) HPAI H5N2, H5N8 20150121.3107002
Avian influenza (09): USA (UT) H5N8, wild duck 20150115.3094193
Avian influenza (08): USA (CA) HPAI H5N8, wild bird 20150115.3093306
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