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Zoonotic Influenza & Highly Pathogenic Avian Influenza (HPAI) in Poultry Photo: Tim Uyeki, CDC.

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Presentation on theme: "Zoonotic Influenza & Highly Pathogenic Avian Influenza (HPAI) in Poultry Photo: Tim Uyeki, CDC."— Presentation transcript:

1 Zoonotic Influenza & Highly Pathogenic Avian Influenza (HPAI) in Poultry Photo: Tim Uyeki, CDC

2 Learning Objectives Describe inter-species transmission of avian influenza virus Describe characteristics of HPAI vs. LPAI List avian influenza control measures in poultry populations Describe measures to mitigate risk for poultry and outbreak response workers

3 3 Categories of Influenza in Humans Seasonal (Human) Avian (Zoonotic) Pandemic

4 Pandemic Potential Antigenic drift and shift  Annual epidemics  Large changes- rare sporadic pandemics HA PB1 PB2 PA NP NA MA NS M2 HemagglutininNeuraminidase M1 Matrix An influenza virus does not have to be HPAI to have pandemic potential.

5 Many Species Affected by Influenza A Genetic Reservoirs Intermixing H1, H3 H1, H2, H3 H3, H7 Commercial, LBMs Others H1-12 H14-15 H1-2, 4-7, H9-13, H10 H1, H3, H4, H7, H13 Other Aquatic Birds? H5N1

6 Two Groups of Influenza in Poultry Low pathogenic AI (LPAI)  Most common influenza virus infection in birds  Mild clinical and inapparent infections  Any subtype (H1 to H16) Highly pathogenic AI (HPAI)  Causes severe illness in poultry and often death  Some H5 or H7 virus strains  LPAI H5 or H7 can mutate into HPAI H5 or H7 subtypes Most AI viruses are not a public health problem

7 Avian Influenza in Other Species Domestic and wild birds Ducks, geese, sparrows, poultry, pets May be asymptomatic & infect other birds Mammals Humans, cats, dogs, pigs, horses, marine mammals, ferrets, minks, stone marten Infection via exposure to infected birds

8 Avian Influenza in Cats and Dogs Domestic cats, tigers, leopards, dogs H5N1 from ingesting infected poultry For HPAI H5N1 areas, FAO recommends:  Keep cats from infected birds  Keep cats indoors on commercial poultry operations  Monitor cats for infection  Advises AGAINST killing cats to control virus Role in spreading H5N1 is unknown

9 Highly Pathogenic Avian H5 and H7 Subtypes Can Cause Human Infection Transmission  Contact with infected sick or dead birds  Contact with contaminated poultry or bird products  Rare human-to-human transmission (HPAI H5N1) Human disease  Usually due to infection with HPAI Severity varies by virus strain  LPAI infections documented Usually mild symptoms Examples: H7 and H9 viruses

10 LPAI Strains Can Mutate into HPAI Wild birds introduce LPAI to domestic flocks  LPAI can rapidly evolve into HPAI  HPAI causes poultry epizootics Mutations observed with some H5 and H7 subtypes  Most H5 and H7 are LPAI, do not mutate  Need rapid detection and aggressive intervention  Can lead to pandemics  May take years to clear from a geographic area

11 Poultry Outbreaks: Notifiable Avian Influenza (NAI) “Avian influenza in its notifiable form (NAI) is defined as an infection in POULTRY caused by any influenza A virus of the H5 or H7 subtypes or by any AI virus with an intravenous pathogenicity index (IVPI) greater than 1.2 (or as an alternative at least 75% mortality) as described below. NAI viruses can be divided into highly pathogenic notifiable avian influenza (HPNAI) and low pathogenicity notifiable avian influenza (LPNAI)” World Animal Health Organization

12 LPAI Infection in Birds Natural hosts: waterfowl, gulls, shorebirds  Usually exhibit no signs of illness LPAI in non-reservoir species  Domesticated unvaccinated fowl easily infected  No outward disease or only mild infection  Non-specific signs (respiratory, ruffled feathers, reduced egg production)  Easy to miss!  Resembles other diseases  Anticipated in some regions

13 HPAI Infection in Birds Natural host: wild birds and waterfowl  Usually asymptomatic  Severe, fatal disease in some wild bird species Domestic ducks  Can be infected but appear healthy  In contact with humans and domestic poultry  Transmit virus via feces and respiratory secretions

14 HPAI Symptoms in Poultry HPAI lethal in poultry Facial edema; swollen & cyanotic combs, wattles; drastic decline in egg production Internal hemorrhaging in 48 hours Mortality nears 100% Difficult to miss - severe disease and sudden onset

15 Transmission Between Birds Viral shedding – main transmission routes  Feces (most common in poultry)  Respiratory secretions Contact between infected & healthy birds Indirect contact  Contamination  Unwashed egg shells  Airborne transmission  Improper carcass disposal

16 Geographic Spread of Virus Movement of birds  Migratory and free-ranging birds  Legal poultry trade  Illegal poultry trade Movement of equipment  Vehicles, tractors, buckets Movement of people  Hands, hair, clothing, shoes Investigators must practice biosecurity!

17 Is LPAI or HPAI more common among poultry? Answer: LPAI Review Question #1

18 Why is HPAI infection among poultry important to public health? Answer: HPAI has been transmitted to humans and has the greatest know potential to develop into a pandemic Review Question #2

19 Avian Influenza on Poultry Farms Prevention and Control

20 Increased disease surveillance in high risk areas Increased biosecurity on poultry farms Control of movement of birds and fomites Rapid, humane destruction of infected and at-risk birds and proper disposal of carcasses Vaccination of at-risk poultry in some circumstances Timely updating of vaccines for poultry to keep up with antigenic changes of circulating strains

21 AI Surveillance Tools: Active Surveillance Test at poultry slaughter/processing sites  Trachael or cloacal swabs  Serum, eggs Test birds at live bird markets Test exhibition, pet and fighting birds Import and export testing Door-to-door interviews with poultry owners

22 AI Surveillance Tools: Passive Surveillance Increase sick and dead bird investigations Investigate poultry clinical case reports Investigate flocks with production drops Investigate flocks with respiratory disease

23 Diagnosis of Avian Influenza in Poultry Detection Antibody, antigen, virus or RNA Rapid tests Screen for infection of flock

24 Biosecurity Via Bioexclusion Keep poultry indoors Prevent new bird contact Clean/disinfect between flocks Control traffic onto farm

25 FAO Sector Systems For analytical purposes four main production systems (sectors) have been characterized by FAO and OIE: Sector 1: Industrial Integrated System Sector 2: Commercial Production System Sector 3: Small-Scale Commercial Production System Sector 4: The Village or Backyard System

26 Biosecurity: Sectors 1 & 2 Large Commercial Poultry Operations High level bio- security Birds/products marketed commercially

27 Biosecurity: Sector 3 Small Commercial Poultry Operations Birds/products may enter live bird markets Birds/products marketed commercially and/or distributed locally Low to minimal or moderate biosecurity

28 Biosecurity: Sector 4 Backyard Poultry Birds/products consumed locally Minimal-to- nonexistent biosecurity

29 Biocontainment on Infected Farms Depopulate Movement control  On and off farm Test birds Close and disinfect bird markets and swap meets

30 Destruction and Disposal of Birds in Affected Area Humanely kill birds within 24 hours of diagnosis  Carbon dioxide, dislocate neck, other methods  Keep accurate records  Dispose per EPA guidelines Communication and security Clean & disinfect 21 day hiatus after inspection Enhanced active/passive surveillance

31 Compensation Reimbursement for loss of birds Encourages  Voluntary reporting of sick/dead birds  ‘Stamping Out’ efforts Payment  Monetary  In-kind payment (restocking, supplies)

32 Vaccination for Poultry with Inactivated Whole Avian Influenza Virus Advantages  Can be effective against circulating H5 subtype  Reduces viral shedding Disadvantages  Possible subclinical infection Vaccinated poultry can still shed virus  Administered by injection  May limit exportation  Involves veterinary authorities Recombinant vaccines under development

33 Seasonal Influenza Vaccine for Humans Exposed to H5N1 Vaccinate poultry workers and health workers, but keep in mind: In tropics and subtropics, human influenza epidemic all year  Timing and vaccine composition challenging Vaccine does not protect against H5N1, but against reassortment At least two week delay for protection

34 Occupational Exposure to Sick Poultry HPAI & LPAI viruses can spread to humans Rare, but preventive measures critical  Biosafety measures  Personal protective equipment Surveillance of exposed workers Annual seasonal influenza vaccination Co-infection with avian and human influenza A viruses could lead to reassortment

35 Personal Protective Equipment (PPE) Impermeable gloves Goggles Respirators  Fit testing Protective clothing Boots or protective foot covers Biosafety and biocontainment Photo: Tim Uyeki, CDC

36 Public Health and Animal Health Integration Communicate and share data between animal and human surveillance networks improves the ability to:  Characterize risk  Prevent disease spread  Enhance control efforts Joint participation  AI surveillance, response and control group  Development of guidelines and action plans Cross-notification of results  Establish official channels of communication

37 Why has seasonal influenza vaccination been recommended in poultry workers responding to H5N1 outbreaks in poultry? Answer: Vaccination of poultry workers with seasonal influenza vaccine may minimize the risk of co-infection and genetic reassortment of human and avian influenza viruses in humans. Review Question #3

38 What are the benefits and drawbacks of vaccines in the prevention and control of HPAI in poultry? Answer: They can limit spread of infection, but may also prevent the implementation of control measures when needed. Review Question #4

39 Limiting the Spread of Avian Influenza A (H5N1)

40 Limit animal infections Improve farm biosecurity Cull sick/exposed animals Disinfect premises Vaccinate poultry Limit human infections Use PPE around sick animals and humans Antiviral prophylaxis in at-risk individuals Isolate and treat human cases Educate the public Develop preparedness and response plans Prevention of H5N1

41 Public Health Response to AI H5N1 in Birds Identify infection source  Eliminate risky exposures  Involve veterinary collaboration Identify contacts of human and animal cases  Actively monitor temperature & illness for 7-10 days  If ill, refer to physician  Do not test for H5N1 unless ill Give antiviral prophylaxis if indicated

42 Antiviral Chemoprophylaxis for Human H5N1 Infections CDC recommendations:  Pre-exposure for persons involved in killing or disposing of infected poultry  Post-exposure for persons in close contact to infected birds within the previous 10 days WHO. Rapid advance guidelines for pharmacological management of H5N

43 Antiviral Chemoprophylaxis for H5N1: WHO Recommendations Who is at low risk? Those who:  Cull non-infected or likely non-infected animals  Handle sick animals while using appropriate PPE  Decontaminate environments while using appropriate PPE Antiviral chemoprophylaxis is generally not recommended for low-risk persons

44 Antiviral Chemoprophylaxis for H5N1: WHO Recommendations, continued Who is at moderate risk? Those who:  Handle sick animals or decontaminate without appropriate PPE  Are unprotected & have exposure to infected birds or to birds implicated in human cases Chemoprophylaxis for a week after last exposure WHO recommends oseltamivir for chemoprophylaxis of high-risk groups

45 Antivirals Not Used in Animals Human use only Use in poultry threatens effectiveness for treatment of human AI: “WHO, FAO and OIE urge Member States not to use antiviral drugs in animals in order to preserve the efficacy of these drugs for the treatment of influenza infections in humans.” (November 2005)

46 Summary Isolate domestic birds from wild birds Practice good biosecurity in all flocks Need adequate surveillance systems Early detection and rapid response Response is a joint effort between both animal and public health authorities

47 Resources Animal Health World Organization for Animal Health: UN Food and Agriculture Organization: USDA Avian Influenza website _INFLUENZA&navtype=SU _INFLUENZA&navtype=SU Human Health World Health Organization: US Centers for Disease Control:

48 Glossary for Lectora pathogenicity highly-pathogenic avian influenza (HPAI) versus low- pathogenic avian influenza (LPAI) zoonotic mutagenic epizootic OIE Depopulation notifiable avian influenza IVPI

49 Glossary, continued HPNAI LPNAI viral shedding fomites biosecurity PPE recombinant vaccines


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