Avian Influenza: Outbreak in Spring 2015 and Preparing for Fall James A. Roth, DVM, PhD Center for Food Security and Public Health College of Veterinary Medicine Iowa State University
Topics for Today • Understanding key properties of influenza viruses • How did the H5N2 virus get to Iowa? • Characteristics of and response to the current outbreak • Preparedness for a potential return of the virus during the next flu season
High Path Avian Influenza Outbreak
Canine Influenza Outbreak
Understanding Key Properties of Influenza Viruses
Influenza A Virus • Enveloped RNA virus: 8 segments, H and N are coded for by different segments • 16 hemagglutinins • Important for attachment to host cell • 9 neuraminidase • Important for virus release from host cell
Influenza Antigenic Drift • Point mutations in H and/or N • H and N remain the same numbers but they are different than the original • May result in decreased immunity, antibody does not bind as well • Antigenic drift is the cause of seasonal epidemics http://www.youtube.com/watch?v=ug-M1nIhfIA
Influenza Antigenic Shift • Emergence of a new subtype (change in H and/or N type) • Example: H3N2 to H5N1 • No immunity, therefore causes pandemics • Mechanisms • Direct transmission animal to human • Genetic reassortment in a population • Re-emergence of virus in a species http://www.youtube.com/watch?v=DdFCx8jbesQ
Influenza A Reservoir • Wild waterfowl and migrating birds are reservoir • All avian influenza viruses are type A • All H and N types - low pathogenicity in waterfowl
Interspecies Transmission H4N5, H13N9 H3N2 H3N2 H1N1 H3N8 H1N2 All H3N2 H1N1 H5N1 * H7N9 * H5N1* H5N1 H7N9, Ferrets H5N2, etc * Rare occurrences
Zoonotic Influenza Avian influenza in humans: sporadic infections, some fatal • H5N1, H7N9, H7N7 – Not in this hemisphere • Swine influenza in humans • CDC reported 31 cases from 2005-2011 • Prior to 2005: 1 case every 1-2 years • H3N2 306 cases mostly in visitors to fairs, 2012 • Ferrets • Can be infected by humans and vice versa • Equine • No reports of clinical cases caused by natural exposure • Canine • No reports of clinical cases caused by natural exposure • Center for Food Security and Public Health, Iowa State University CVM, 2011
Risk Factors for Influenza Disease
Risk Factors for Influenza Disease
High Pathogenicity vs Low Pathogenicity Avian Influenza • LPAI- asymptomatic to mild infection • HPAI – can have 100% morbidity and mortality, many body systems affected
High Pathogenicity vs Low Pathogenicity Avian Influenza • HPAI: • An H5 or H7 with specific genetics and/or high lethality • Any non H5 or H7 with high lethality • LPAI: • Any H type including H5 or H7 • No or mild clinical signs • Infection localized
How did the H5N2 avian influenza virus get to Iowa?
H5N1 Avian Influenza • 2004/5 – H5N1 emerged in Asia, killed millions of poultry and is zoonotic • Concern that H5N1 would spread through migrating waterfowl from flyways in Europe/Asia to the Western hemisphere • Extensive surveillance programs established in U.S. • No detections of this strain of H5N1 in Western hemisphere • New strains of H5 avian influenza detected in Canada and US fall 2014 − Not zoonotic
H5 HPAI reports from East Asia September 2014 through April 8, 2015 (OIE) W W P P P P P P P W P W P P W W W P P P P Eastern Asia Reports of H5 HPAI subsided in the region during summer 2014. Then in September, outbreaks of H5N1, H5N2, H5N6, H5N8 HPAI occurred in China. Original H5N8 outbreak occurred January- April, 2014, most intensely in S. Korea and Japan. After 5 months with no reported cases, H5N8 was detected again, 24 September, in S. Korean commercial poultry. It was detected again in Japan in November. H5N2, H5N3, H5N8 outbreaks occurred in Taiwan in early 2015. H5N1 in wild birds H5N2 in wild birds H5N3 in wild birds H5N6 in wild birds H5N8 in wild birds W W W W W H5N2 in poultry H5N8 in poultry P H5N1 in poultry P P H5N3 in poultry P H5N6 in poultry P
H5 HPAI reports from North America November 2014 through April 8, 2015 (OIE) W W P W P W P P P P W P W W W P P P P W W P P P P P P P P W P W North America P P W W W P P H5N2 first isolated 30 November 2014 from P P P commercial poultry in British Columbia; outbreak continues into 2015. Eastern Asia H5N8 first isolated 10 December 2014 from Reports of H5 HPAI subsided in the region captive wild birds in Washington; later Western Europe during summer 2014. Then in September, isolated from backyard poultry in Oregon. outbreaks of H5N1, H5N2, H5N6, H5N8 Similarly, H5N2 identified in US wild birds H5N8 first isolated 4 November HPAI occurred in China. and backyard poultry. 2014 from commercial poultry in Germany; also isolated in November Original H5N8 outbreak occurred January- H5N1 first isolated 29 December 2014 from from a wild duck. April, 2014, most intensely in S. Korea and wild duck in Washington. Japan. After 5 months with no reported By mid-December, H5N8 was cases, H5N8 was detected again, 24 H5N8 isolated 19 January 2015 from isolated from commercial poultry in September, in S. Korean commercial poultry. commercial turkey farm in California. The Netherlands, United Kingdom, It was detected again in Japan in November. and Italy. H5N2 detected in poultry in South Dakota, H5N2, H5N3, H5N8 outbreaks occurred in Minnesota, Missouri, Arkansas, and Kansas Taiwan in early 2015. in March 2015 and Ontario, Canada in April 2015. H5N1 in wild birds H5N2 in wild birds H5N3 in wild birds H5N6 in wild birds H5N8 in wild birds W W W W W H5N2 in poultry H5N8 in poultry P H5N1 in poultry P P H5N3 in poultry P H5N6 in poultry P
H5 HPAI reports from North America November 2014 through April 8, 2015 (OIE) East Atlantic flyway W W P W P W P P P P W P W W W P P P P W W P P P P P P P P W P W P P W W W P P Migratory aquatic birds – also the likely mode for P P P H5N8 HPAI virus spread to North America Eurasian (EA) H5N8 was likely carried to Alaska by infected birds migrating on the East Asia / Australia flyway. Within 3 months, HPAI viruses were detected in the Pacific Americas flyway and the Mississippi/Central Americas flyway. EA H5N8 underwent gene reassortment with low pathogenicity avian influenza (LPAI) strains endemic to North American wild birds. This means a bird was co-infected at some point with the H5N8 and an American (AM) LPAI strain, enabling the 8 gene segments to be mixed and matched in new combinations. EA/AM H5N1 and EA/AM H5N2 isolates in the western and central US were reassortants that contained genes of North American and Eurasian origin. H5N1 in wild birds H5N2 in wild birds H5N3 in wild birds H5N6 in wild birds H5N8 in wild birds W W W W W H5N2 in poultry H5N8 in poultry P H5N1 in poultry P P H5N3 in poultry P H5N6 in poultry P
Characteristics of the current HPAI outbreak
Figure 1. All HPAI Detections As Of May 13, 2015 PM (as reported on www.aphis.usda.gov) *one or more detections may have occurred in county
Figure 7. Premises Detected for ALL STATES Including WILD BIRD detections from 12/8/2015 to 7/2/2015 By WEEK Wild Bird Detections in the Pacific Flyway Wild Bird Detections First Detection in a First Detection in in the Central/ Commercial Flock in 38 Commercial Iowa 40 Mississippi Flyways 37 California Flock 35 30 First Detection in 30 Commercial 26 Minnesota Flock 24 23 25 Wild Bird (Pacific) 19 18 20 Commercial (Pacific) 15 Captive Wild (Pacific) 15 12 12 11 Backyard (Pacific) 8 10 7 6 1 Wild Bird (Central/Miss) 5 5 4 3 3 3 2 5 1 1 2 2 Commercial (Central/Miss) 1 1 Backyard (Central/Miss) 0 Earliest available date indicating clinical signs is used for figure. For most premises, this is the date of clinical signs, a suspect status, or a presumptive positive status. Some premises may only have a confirmed positive status date. 320 detections (4 captive wild bird; 21 backyard flocks; 211 commercial flocks; 84 wild birds). o Only full weeks (7 days) are pictured; in addition to the dates pictured, there have been no detections after 6/28/2015. o All captive bird, backyard flock, and commercial flock data are from EMRS. o Wild bird dates are based on date of collection, from USDA/USGS/National Flyway Council data. o This represents 80% of the captive bird detections, 100% of all other detections. o Figures may change slightly as data is added to EMRS (e.g., date of clinical signs). 2 5
Iowa Poultry Production In March 2015: • Iowa had 59.5 million egg layer chickens in 3,821 laying facilities (1 st in US egg production) • 16.5 billion eggs produced annually (17% of national production) • Raise over 11 million turkeys (9th in US turkey production) on about 200 farm sites
Highly Pathogenic H5N2 Avian Influenza in Iowa April 13 to June 16, 2015 Total Poultry 31,502,052 Affected (6/8/2015) 77 infected sites Layers 24,725,086 − 6 “Backyard” sites Pullets 5,624,336 − 71 Commercial sites Turkeys 1,128,729 Hatchery 18,791 Backyard Flocks 5,110 http://www.iowaagriculture.gov/AvianInfluenza.asp
Preparedness for Avian Influenza Secure Egg Supply Plan Biosecurity Vaccination??
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