Occupational Health Aspects of Avian Flu

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Occupational Health Aspects of Avian Flu

• Avian flu as an occupational exposure

John Halpin M.D. University of Illinois/Chicago
School of Public Health Chief Resident Department
of Occupational Medicine
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Influenza pandemics are rare but recurring
events. They have typically occurred every 10-50
years throughout recorded history.

• WHO Press Kit document

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20th Century Flu Pandemics
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"It is only a matter of time before an avian flu
virus -- most likely H5N1 -- acquires the ability
to be transmitted from human to human, sparking
the outbreak of human pandemic influenza"
November 7, 2005

• Dr. Lee Jong-Wook
• WHO Director-General

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How lethal will Pandemic be?
Stats 20 to 50 million killed worldwide
Almost 1 billion infected worldwide
(50 of population) Fatality Rate of 2-5
"Because the 1918 pandemic was the most
devastating infectious disease outbreak ever
recorded, WHO does not feel it is appropriate to
project future pandemic numbers based on such an
exceptional event." WHO Press kit document
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Perspective Yearly Flu stats

• Infects 10 to 20 percent of world population per
  year
• 5 million hospitalizations per year
• 500,000 fatalities worldwide each year

These are average yearly numbers, thus an
epidemic would be significantly higher
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Epidemic vs Pandemic

• Avian flu has currently been an epidemic in
  birds, and an outbreak in humans
• A pandemic does not necessarily imply higher
  numbers killed than with an epidemic
• Fundamental difference is the amount of natural
  immunity that humans have to the virus strain

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Three Requirements of Pandemic

• New virus emerges from animal reservoir, for
  which no human immunity exists, and gains ability
  to infect humans
• Virus gains ability to replicate in Humans
  efficiently enough to cause significant
  morbidity/mortality
• Virus gains ability to spread efficiently from
  Human to Human

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How might a Pandemic strain occur?
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Most likely pandemic candidate H5N1

• There are many other avian flu viruses (15)
• Most low pathogenicity, but a few are HPAI
• Since 1959, viruses of the H5, H7, and H9
  subtypes have crossed the species barrier to
  infect humans on 10 occasions
• H5N1 unique for its extremely high pathogenicity
  to poultry, causing concern for its potential in
  humans
• But it could end up being another strain

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Type (A) H5N1

• Hemagglutinin and Neuraminidase surface proteins
  (H5N1)

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Human Cases of H5N1
As of October 24, 2005
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Pandemic Flu

• Pandemic by definition will involve the
  infection of millions of people, most in a
  non-occupational setting

So then why would it be important to look at
Avian flu as an Occupational exposure??
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SARS

• SARS taught us the importance of viewing newly
  emerging infectious diseases as an occupational
  exposure
• SARS stats
• 33 of initial cases were food handlers
• Greater than 20 of all cases were HCWs
• In Canada and Singapore, 40 of cases were HCWs

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Lessons Learned

• Certain occupations are uniquely positioned to be
  in contact with animal reservoirs of disease
• Despite existing precautions, HCW's as an
  occupation are at high risk of infection from
  newly emerging infectious diseases.

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But who will HCWs likely be treating first?

• Which Occupations are at highest initial risk of
  Avian flu exposure/infection?

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Small Scale Poultry Farmers
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Avian flu transmission to Humans

• Birds shed H5N1 virus into their respiratory and
  gastric secretions, their feathers, their
  droppings, and into substance of muscle
• Highest risk is from direct contact with infected
  live poultry, or with contaminated surfaces in
  vicinity of poultry
• Most human cases to date have been among rural
  poultry farmers, and their families.

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Larger Scale Poultry Farmers
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Bird Cullers
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Veterinarians
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Bird Handlers at Markets
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Food Handlers
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Other High Risk Occupations

• Medical Care Support Staff
• Nurses, Paramedics, Respiratory Therapists
• Lab workers
• Tranport personnel
• Medical Waste disposal personnel
• Laboratory Workers involved with Avian flu
  vaccine production
• Airline Flight Crews

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Are Poultry Workers concerned?

• Monday, October 10, 2005N.C. poultry workers in
  dark about possible bird fluAssociated
  PressCHARLOTTE, N.C. - North Carolina poultry
  workers say they've been left in the dark as the
  world faces the looming threat of a potentially
  deadly bird flu hopscotching around the globe.
  ...

"The lack of a campaign to inform poultry workers
indicate they are seen as "expendable workforce"
because they're poor, largely Hispanic and
undocumented, said Baldemar Velasquez, president
of the Farm Labor Organizing Committee."
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IUF Concern
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IUF Concern

• Finally, the most significant silence in the
  H5N1 crisis concerns agricultural and processing
  workers. This is a silence reinforced by the WHO
  Recommendations which state that No case has
  yet been detected among workers in the commercial
  poultry sector. As a result of this claim, no
  measures are proposed to national governments to
  protect agricultural workers or poultry
  processing workers.

IUF Website
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Plea from IUF

• The IUF has therefore called on the WHO to
  recognize the specific occupational hazards faced
  by agricultural workers and to incorporate
  appropriate measures into their guidelines and
  action plans. The IUF has called on the WHO,
  FAO, OIE, and ILO to jointly develop an action
  plan that addresses the multiple economic,
  social, and health impacts of the H5N1 crisis on
  agricultural workers and their communities.

Posted to IUF website on 28-Oct-2005
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How can these Occupations protect themselves?

• Specific measures, such as PPE and anti-virals
  are important
• Protection plans should be developed using
  broader Occupational Health concepts
• Another SARS Lesson Learned
• Use of Occupational Hygienists in Singapore
  hospitals dramatically reduced infection in HCWs

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Occupational Health Prevention Paradigm

• Engineering Controls
• Vaccine Human and Pandemic flu
• Anti-Viral Medications
• Isolation Rooms for infected birds, humans
• Administrative Controls
• Sheltering Birds from contact with Wild birds
• Individual Worker Controls
• Personal Hygiene/Food Safety
• PPE
• Always considered last by principles of Occ.
  paradigm

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Bio-Engineering Controls

• Vaccines
• Seasonal human flu vaccine
• Pandemic flu vaccine
• Anti-viral Medications
• Tamiflu and Relenza
• Can be used for
• Prophylaxis Pre and Post exposure
• Treatment of active infection

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Tamiflu Dosing

• Current dosages based on Human flu infection
  (CDC)
• Canadians (CFIA) came up with pre-exposure
  prophylaxis guidelines in relation to H7 outbreak
  in poultry in February, 2004
• Current Dosing recommendations
• Pre-exposure 75 mg qD for up to 6 weeks, with
  two week break (CFIA)
• Post-exposure 75 mg qD for five days (CDC)
• Treatment(Human Flu) 75 mg BID for five days
  (CDC)

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Administrative Controls

• reducing the number of people exposed to the
  hazard
• decreasing the time that people are exposed to
  the hazard
• isolating the hazard
• introducing equipment to control the hazard
• Maintenance of protective equipment or clothing
• introducing better working practices and systems

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Personal Hygeine/Food Safety

• Principle tools used to combat all infectious
  diseases
• Proper Hand Washing
• Keeping sanitary and unsanitary products
  separated
• Clean and disinfect surfaces that are
  contaminated
• Particularly important on small scale poultry
  farms, where process from live bird to food on
  table occurs locally
• INFOSAN has addressed these issues specifically

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INFOSAN

• International Food Safety Authorities Network
• Though risk varies between developed and
  under-developed countries, INFOSAN stresses a
  unified, consistent message
• Bottom Line Handling of infected birds, either
  live, slaughtered, or packaged is hazardous if
  protective guidelines unheeded.

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Food Safety Guidelines

• Conventional cooking (temperatures at or above
  70C in all parts of a food item) will inactivate
  the H5N1 virus. Properly cooked poultry meat is
  therefore safe to consume.
• The H5N1 virus, if present in poultry meat, is
  not killed by refrigeration or freezing.
• Home slaughtering and preparation of sick or dead
  poultry for food is hazardous this practice must
  be stopped.

INFOSAN Information Note No. 7/2005
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Food Safety Guidelines

• Eggs can contain H5N1 virus both on the outside
  (shell) and the inside (whites and yolk). Eggs
  from areas with H5N1 outbreaks in poultry should
  not be consumed raw or partially cooked (runny
  yolk) uncooked eggs should not be used in foods
  that will not be cooked, baked or heat-treated in
  other ways.
• There is no epidemiological evidence to indicate
  that people have been infected with the H5N1
  virus following consumption of properly cooked
  poultry or eggs.
• The greatest risk of exposure to the virus is
  through the handling and slaughter of live
  infected poultry. Good hygiene practices are
  essential during slaughter and post- slaughter
  handling to prevent exposure via raw poultry meat
  or cross contamination from poultry to other
  foods, food preparation surfaces or equipment

INFOSAN Information Note No. 7/2005
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Personal Protective Equipment
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Current WHO guidance

• "N95 respirator masks are preferred. Standard
  well-fitted masks should be used if N95
  respirators are not available"
• Mask highefficiency masks should be used where
  possible, with surgical masks as a second
  alternative"

SEARO Prevention and Control of Influenza due
to Avian Influenza Virus A (H5N1)
Influenza A (H5N1) WHO Interim Infection Control
Guidelines for Health Care Facilities
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3 Routes of Flu Transmission

• Direct Contact
• Droplet
• Aerosol (Droplet Nuclei)

Surgical masks, by virtue of both their
filtration capabilities and inability to effect a
seal to the wearers face, are ineffective in
protecting the wearer from inhalation of such
aerosols. IOHA Position Paper
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WHO technical guidance

• "Transmission of human influenza is by droplets
  and fine droplet nuclei (airborne). Transmission
  by direct and indirect contact is also
  recognized. However, during the 1997 influenza A
  (H5N1) outbreak in humans in Hong Kong (China),
  droplet and contact precautions successfully
  prevented nosocomial spread of the disease. So
  far there is no evidence to suggest airborne
  transmission of the disease in the current
  outbreaks in Thailand and Viet Nam. Nevertheless,
  because of the high mortality of the disease and
  the possibility of the virus mutating to cause
  efficient human-to-human transmission, WHO is
  currently recommending the use of high-efficiency
  masks in addition to droplet and contact
  precautions. "

Influenza A (H5N1) WHO Interim Infection Control
Guidelines for Health Care Facilities March, 2004
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Bottom Line

• Surgical Masks are more appropriate for patients
  suspected of Avian flu infection
• Respiratory Particulate Devices (RPD) are
  recommended for worker protection

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These are the General Principles..

• How are they applied to each high risk Occupation?

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Must Consider many things

• Language and Education level
• How simple must the message be?
• Cultural issues
• Can culture accept the changes necessary?
• Ex Changing social fabric of living closely
  with flock
• Economic impacts
• Losing whole livelihood to Culling entire flock
• Compensation?
• Costs of implementation
• Availability of protective items
• Vaccine
• Medications
• Protective Gear (N95 vs surgical masks)

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WHO General Recommendations for all high risk
Occupations

• High Risk Workers should have priority to receive
  seasonal vaccination to Human Flu
• Personal Protective Equipment is recommended for
  all High Risk Occupations
• Poultry Workers, Bird Cullers, Veterinarians,
  Health Care Workers
• Prophylactic Medications can be used by high risk
  occupations
• Canada states up to 6 weeks, with 2 week break
  (75 mg BID)
• High Risk Workers should be monitored for flu
  symptoms
• Suspected Cases should be
• Isolated, Tested by WHO laboratories for virus
  strain, and Epidemiological information gathered

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Specific guidelines being developed for

• Small Scale Poultry Farmers and Food Handlers
• Large Scale Poultry Farmers
• Large Scale Food Handlers
• Health Care Facilities/Workers
• Bird Culling Workers
• Veterinarians
• Field Biologists
• Laboratory Workers involved with H5N1 and H7N7
  avian flu strains
• Airline Flight Crews
• Workers travelling to High Risk locations

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Making use of current guidelines from

• WHO
• WPRO
• SEARO
• FAO
• OIE
• European Agency for Safety and Health

• NIOSH
• OSHA
• CDC
• US National Wildlife Health Center

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Collaboration with

• HQ
• Occupational Health
• Corvalan, Carlos Coordinator OEH
• Eijkmans, Gerry Focal Point, Occupational
  Health
• Food Safety, Zoonoses and Foodborne Diseases
• Schlundt, Jorgen - Director
• Ben Embarek, Peter Karim Scientist
• Fontannaz, Francois - Scientist
• Infection Control in Healthcare Settings
• Pessoa-Da-Silva, Carmem - Medical Officer
• Personal Protective Equipment issues
• Thomson, Dr. Gail - Medical Officer
• WPRO
• Ogawa, Dr Hisashi - Regional Adviser
• Dziekan, Dr. Gerard Infection Control
• Hazzard, Tony - Scientist
• Horby, Dr Peter William Vietnam
• SEARO
• Caussy, Dr Deoraj - Scientist / Environmental
  Epidemiologist

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"Indonesia now has nine confirmed cases, and
health officials fear that a nurse involved in
the care of the latest casualty may have caught
it too. (Not confirmed as H5N1)"
BBC, 11/5/2005

• Is this the first HCW infected by Avian flu, and
  by Human to Human Transmission??

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Questions?