Download Poultry Diseases Transmissible to Man

Poultry Diseases
Transmissible to Man:
Interface of Poultry Health and Public Health
P. A. Dunn
Animal Diagnostic Laboratory, Pennsylvania State University
2012 Northeastern Conference on Avian Diseases,
PA Poultry Sales and Service Meeting
Context: Poultry as a Food Animal
• Starvation is 100% lethal
• Malnutrition is 100% debilitating
– Decreased productivity
– Increased concurrent disease
• Hunger = #1 health problem in
the developing world
– Deaths from lack of food > deaths
from war + malaria + TB + AIDS
– 25,000 deaths per day= 9 million
per year = population of NYC
Context: Poultry as a Food Animal
• POULTRY - THE ULTIMATE FOOD ANIMAL
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Across nations, cultures, religions
“Easy keepers” in subsistence; low inputs; low footprint
High quality protein
Terminal (meat); Non-terminal (egg)
• Socioeconomic, (geopolitical) factors determine
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Food security (stabilizing), food insecurity (unstabilizing)
Availability of animal protein
How people live with / use animals
Perception of risk: benefit
• Risk (zoonosis) = low : Benefits (food source) = high
Zoonosis
• “An infection or infestation shared by man and lower
vertebrate animals”
• People concerned about diseases they might “catch” due to
association with non-human “animals”
• Diseases of Public Health Significance (DPHS)
– Context, perspective is important
• Relatively few poultry zoonoses (dismissive vs non-alarmist, realistic)
– Human to human >>> mammal to human >>> poultry to
human > fish, reptiles, amphibians >>> invertebrates
• But important (alarmist vs practical awareness) – human health is
paramount
– Don’t miss
Very Few Poultry Infectious Diseases
Transmissible to Humans…
• Most not directly transmissible to humans
under normal conditions
• Most successful pathogens are highly adapted
to physiology, anatomy of specific hosts
– Major differences between avian and mammalian
– Cell receptor types, body temperature, etc.
Very Few Poultry Infectious Diseases
Transmissible to Humans…
• Indirectly much more common
– Food-borne: microbes, microbial toxins in / on the product
originating from the bird or carcass, or contaminated from
external source
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Salmonellosis, campylobacteriosis, listeriosis
Many are not causing clinical disease in bird, no lesions at processing
Food prep hygiene; cooking to proper temps.
Inadvertent hand to mouth transfer after handling bird, secretions,
excretions
– Children handling baby chicks
– Hygiene during, after handling of birds
– Insect-vectored from infected bird (usually wild bird) to man:
arbovirus (WNV - transmitted by mosquito)
• Chickens, turkeys relatively resistant to WNV, not important reservoir
But, Important to Recognize…
Stakes are High
• “When you hear hoof beats, don’t look for zebras.”
• “Don’t forget to look for zebras.”
• Investigate the more common conditions, but keep
zoonoses in mind.
• One health concept: veterinarians and physicians,
animal and medical scientists
• Rural vs urban populace, medicine; several generations
“off the farm”; includes patients and doctors
• “My chickens are sick. Are my kids, pets, etc., safe?
Can we eat the eggs, meat?”
Diseases of Poultry, 12th edition
(2008), Y. M Saif, editor-in chief
• 1324 pages; > 9 lbs.
• 6 sections; 33 chapters;
93 subchapters (topics)
• Public health significance– 8/33 chapters; 12/93 subchapters
– Most limited, rare, +/- associated with
compromised immune systems
• Next edition- separate chapter devoted to
DPHS
Diseases of Poultry, 12th ed.
Disease
Newcastle Disease Virus
Human Ailment
Eye Infection
Transmission
Lab accident/ Poultry vaccines
Avian Influenza
Eye, Respiratory, Systemic (HP) Handling infected birds/Aerosols
Arbovirus
Neurologic, systemic
Mosquito bite
Pullorum Disease
Enteritis
Foodborne
Paratyphoid/Salmonella
Gastrointestinal
Foodborne
Campylobacteriosis
Gastrointestinal
Foodborne
Necrotic Enteritis/
C. perfringens Types A & C
Gastrointestinal
Foodborne
Staphylococcosis
Gastrointestinal
Foodborne
Erysipelas
Local (cutaneous) infection
Handling infected birds
Avian Intestinal
Spirochetosis
Gastrointestinal
Unhygienic conditions; contaminated
drinking water
Avian Tuberculosis
Pneumonia
Handling infected birds/Aerosols
Avian Chlamydiosis
Pneumonia, systemic
Handling infected birds/Aerosols
5 Diseases of Poultry
• Avian influenza (orthomyxovirus)- covered by Dr. Perez
– Often on ddx list due to regulatory status; routine diagnostics
• Newcastle disease (paramyxovirus)
– Often on ddx list; routine diagnostics
• Chlamydiosis
– Not often on ddx list for poultry; lesions overlap with other
diseases; often need special diagnostics
• Erysipelas
– Often (?) on ddx list; lesions of acute septicemia- lesions overlap
with other septicemias; routine diagnotics
• Tuberculosis
– Not often on ddx list; lesions should be suggestive; need special
diagnostics to confirm
Avian Influenza
• Avian Influenza, 2008, D.E. Swayne, editor
• 605 pages, 25 chapters: 1 chapter (31 pp)
“Public Health Implications of Avian Influenza
Viruses” by N. J. Cox and T. M. Uyeki
• LPAI- very few cases, very limited illness
(conjunctivitis), most linked to direct contact
with poultry
• HPAI, especially H7N3, H7N7, H5N1- last 15
years; serious illness and deaths
General Approach to Control
Poultry AI Limits Zoonotic
Potential: Several Steps Ahead
• Limiting AIV from adapting from waterfowl,
shorebird strains to gallinaceous strains
– Live Bird Market System control strategies
– Periodic complete sell down, C&D, inspection;
monitoring supply flocks, dealers, haulers; crate
washing…
• Block AIV from entering flocks (biosecurity)
– If AI enters, most likely LPAI, might be H5, H7
Several Steps Ahead…
• Block H5, H7 LPAI from mutating to HPAI by
quick detection, containment, elimination of
infection (depop. or controlled marketing) +/strategic vaccination
• Enhanced biosecurity, comprehensive and
strategic monitoring programs at every step
• As a few HPAI can and do cause serious human
infections, blocking the emergence of these in
poultry is effective public health strategy
Newcastle Disease (APMV-1) in Avian Spp.
• Chickens, turkeys, pigeons, many other species
(cormorants, etc.)
• Lentogenic (non-exotic) in US, Canada
• Mild respiratory signs, secondary E. coli
infections, air sacculitis
• Egg production drops, shell quality problems
• Diagnosed by gross, micro, PCR, VI, serology
• Vaccination widely practiced and highly effective:
modified live, killed, recombinant
Exotic Newcastle Disease (END)
Newcastle Disease (APMV-1) in
Humans
• Risks to people:
– Handling, administering live vaccines
– Performing post mortem exams on actively infected birds
– Working with, isolating, concentrating virus in the lab
• Localized infection- conjunctivitis (“pink eye”); 5- 10 days
duration; resolves completely
• Uncomfortable; cosmetically undesirable
• Topical eye drops or ointments to reduce inflammation,
discomfort, secondary bacterial infections
• Wear gloves, lab goggles/ safety glasses / shields; washing
hands after handling virus or vaccine; avoid touching
hands to eyes; avoid spraying, splashing solutions into
face, eyes.
Conjunctivitis
Avian Chlamydiosis- Chlamydophila
psittaci infection in Avian spp.
• Psittacosis, parrot fever, ornithosis
• Specialized bacterium- obligate, intracellular
• Pet bird species (psittacines = parrot-type)very common- source of most human
infections; also wild bird reservoirs esp.
pigeons (gulls, ducks, herons, egrets)
• Poultry- turkeys; ducks, pheasants (occ.)
chickens (rare)
Chlamydiosis in Turkeys
• Strain differences in C. psittaci
• Mild
– Decreased feed intake; loose, greenish droppings; 1 -4%
mortality
• More virulent
• Clinical signs as above; weight loss; abrupt egg production drop; 1030% mortality
• Lesions:
– Fibrinous exudates over heart +/- air sacs; enlarged
congested spleen, liver (25% air sac condemns in NC turkey flock
associated with chlamydiosis in processing plant workers- 1989)
– Similar to E. coli infections, other bacteremias
Chlamydiosis in Turkeys
• Diagnose by molecular methods (PCR); isolation
(cell cultures, eggs); presumptive Dx by
histopathology, special stains to reveal
elementary bodies, IHC
• Reportable disease
• Treat with chlortetracycline (400 gms CTC/ ton) very
effective at controlling infections; reducing
shed of infective particles before processing
• Grow-out on range – increased risk of exposure
Chlamydiosis Lesions, Organism
Chlamydiosis in Humans
• Flu-like symptoms: fever, chills, headache,
weakness, coughing associated with atypical
pneumonia; +/- joint pain, stomach cramps,
diarrhea
• Incubation period 4- 19 days; mean duration of
illness 9 – 10 days
• Hospitalizations, (deaths) with some frequency
• Tetracycline- class antibiotics
Chlamydiosis in Humans
• Risk to people:
– Workers at turkey processing plant
• Aerosolized infectious particles
• Kill- pick, evisceration most common +/- other areas
including further processing
• Over past 60+ years: TX, MO, NE, OH, MN, NC
– Workers in infected turkey flocks
• Prevent exposure to infected turkeysdiagnose, medicate, controlled processing
Erysipelas in Avian Spp.
• Erysipelothrix rhusiopathiae infection
• Turkeys >>> pheasants, ducks, geese, wild
birds >>> chickens (rare)
• Market turkeys, breeders
• Ranged flocks >>> housed
• Infected soil, enters through breaks in skin;
pecking and fighting; artificial insemination
Erysipelas in Turkeys
• Clinical signs
– Acute: sudden deaths
– Chronic: depression, lameness
• Lesions
– Whole carcass congestion; enlarged, dark liver,
spleen; hemorrhages on heart, other organs;
reddened swollen wounds on head, neck, vent
– Similar to other acute bacteremias
Erysipelas Lesions
Erysipelas in Turkeys
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Diagnosis- routine bacteriologic culture
Treatment- penicillin
Remove sick and dead promptly
Vaccines in at-risk flocks
Beak-trimming, de-snooding, careful AI
technique
• Move from infected range (don’t range)
Erysipelas in Humans
• Risk to people
– Large numbers of ER bacteria in dying birds,
carcasses
– Handling carcasses, performing post mortem
exams
– Turkey handlers, insemination crew
• Usually localized: Erysipeloid = painful, hot
swelling with dark center of skin and
underlying tissue at site of entry
– Resolves completely in a few weeks with
treatment
• Rarely systemic- arthritis; endocarditis,
encephalitis; death
• Penicillin, other antibiotics effective against
Gram positives
• Avoid contact with bare skin (scratches,
etc.); gloves, double sets of gloves
“Tuberculosis”- Avian TB
• Mycobacterium avium sbsp. avium infection
• Different from M. tuberculosis, M. bovis =
common agents of human TB
• No longer present in commercial poultry in
US; sporadic in chickens > 2- 3 years; older
ducks, geese, game birds, pigeons, pet
birds, zoo, aviary spp., wild birds; very rare
in turkeys
Mycobacteriosis in Poultry
• Progressive debilitation, chronic weight loss,
decreased egg production; death
• Granulomatous lesions in liver, spleen, intestine,
bone, lung
– Can look like fungal granuloma, coligranuloma, tumor,
pullorum disease, histomoniasis
• Diagnose by histopathology (acid-fast stain),
special culture (slow), PCR
• No effective treatment; no vaccine
• Control by: modern confinement, all in /all out
management; < 2 -3 years of age.
Granulomatous Lesions in Liver
Gamebird Case
• 2 year old chukar partridge breeders
• Lethargy, weight loss, increased mortality
• Enclosed house, raised wire floors; in use for
“many years”
• Ventilation “not the best”
• Overgrown beaks; unkempt plumage
• Decreased body weight
• Multiple tan/gray masses in lungs +/- serosa of
gizzard, intestines
M. avium in Mammals (Non-primate)
• Swine, rabbits, mink > sheep, llama
• Pets (cat, dog) very resistant
• Reactor cattle to tuberculin test
– React on caudal skin fold test
– Retest by paired cervical method
M. avium in Humans
• First documented case in U.S.- 1930
• Risk to people: Humans relatively resistant
– Increased incidence in immunosuppressed people
• HIV/ AIDS; immunosuppressive chemotherapy; leukemia
• Opportunistic
• Ubiquitous- hard to avoid all contact with the organism
• most human isolates are more closely related to pig isolates
than bird isolates (using molecular methods)
• M. avium serovar 2, the most common chicken serovar, is
rarely isolated from people
• Most infections more likely to be human- to- human
contact than bird- to- human
– Although serovar 1 is common in wild birds and in AIDs patients
Environmental Sources of M. avium
• Aerosolized water
• Piped hot water systems (including household
and hospital water supplies)
• Bathrooms
• House dust
• Soil
• Birds
• Farm animals
• Cigarette components (eg, tobacco, filters, paper)
M. avium in Humans
• Primarily pulmonary infection: cough; fever,
fatigue, weight loss, diarrhea;
disseminated infection to lymph nodes,
bone marrow, tendons, liver, spleen, CNS
• More resistant (than M. tuberculosis, M. bovis) to
commonly used anti tuberculosis drugs
• Combination of 2- 3 antimicrobials for 12
months
Miscellaneous
• Parasites
– Internal parasites very host specific
• Protozoa, helminths
• Most won’t cross into other avian species let
alone into mammals
– External
• Mites, lice, etc.
• Don’t colonize humans; but can board, bite,
irritate temporarily
• Non-infectious- irritants in poultry
house environment
– Allergies-dander, feathers, litter
– Ammonia gas, dust
– Masks, respirators
Cautions, Trends
• Free range systems for poultry (local food, pastured poultry)
– May increase some poultry diseases with zoonotic potentialincreasing public health risk
• Antibiotic – free, organic production
– Ditto as above
• Molecular techniques to detect and identify pathogens
– Very helpful for better, faster detection
– Crucial for modern epidemiology, specific strain identification
– But detection does not equate with productive infection,
presence of disease; results can be misleading
– Context is important; must be medically relevant
Public Health Benefits from Controlling
Poultry Diseases- Direct and Indirect
• Restrictions on poultry workers keeping pet birds
– prevents major risk of chlamydiosis in people
• Keeping “embryo egg” layer flocks healthy
– ensures adequate supply of human flu vaccine
– prevents seasonal flu in people
• Preventing HPAI in poultry
– prevents serious, fatal “bird flu” in people
• Correctly & promptly diagnosing potential zoonoses
– limits risk, exposure; guides proper medical treatment
• Supplying poultry meat and eggs - safe, affordable, high
quality protein
– provides better nutrition for people
Poultry Diseases with Zoonotic
Potential …..
• Remain vigilant to the ones we know.
• Look out for “new” ones.
• When you hear hoof beats,
don’t forget to look for zebras.
• People should not fear association with
poultry as a significant human health risk
under most circumstances.
Newsweek, September 24, 2012
No Chickens?
“When we try to pick out anything by itself, we
find it hitched to everything else in the Universe”
– John Muir