Lecture 8. • Pullorum disease, fowl typhoid • Paratyphoid • Arizonosis • Colibacillosis • Fowl cholera Flashcards
Pullorum disease, fowl typhoid
• Causative agent
Salmonella Pullorum, S. Gallinarum ▪ Salmonella enterica serovariants ▪ Gram-negative, non-motile rod ▪ susceptibility: chicken (can affect more species, eg. turkey) ▪ Not zoonotic
Pullorum disease, fowl typhoid • Resistence, spread
▪ Medium resistant, high temperature is enough to
eliminate (above 70°C)
▪ Survives months in frozen food products
▪ Common disinfectants are efficient
▪ Spread mostly via feces, fluids, can survive in
water, feed
▪ Most important route: germinative route
▪ Can be transmitted horizontally
▪ Carriers
Salmonella Pullorum, S.
Gallinarum
▪ Salmonella enterica serovariants
• Diseases
• 2-3 week old animals - septicemia ▪ peracute form ✓minimal gross lesions ▪ acute form ✓enlarged and congested liver, spleen, kidney ✓necrotic foci in liver ✓spleen can be mottled white ✓perihepatitis, pericarditis ✓necrotic foci (big) in myocardium ✓caseous content in cecum ▪ mortality can reach 100% • in adult -multiple degenerative follicles -caseous exudate in oviduct -fibrinous perihepatitis, peritonitis
Salmonella Pullorum, S.
Gallinarum
▪ Salmonella enterica serovariants
• Diagnosis & Control
▪ flock history ▪ clinical appearance (age group) ▪ pathology ▪ microbiology (cultivation) ✓culture on plain or bloody agar ▪ serology ✓agglutination test ✓ELISA
• Control ▪ eradication ✓screening for carriers ✓establishing Salmonella-free hatcheries, flocks (disinfection of egg shells) ✓obtaining eggs/chicks and poults from S.-free sources ✓basic hygiene ✓personnel ✓regular screening ▪ vaccination ✓if no eradication measures can be taken ▪ treatment…
Paratyphoid
• Causative agent
other Salmonella spp. ▪Most frequently S. Typhimurium, S. Enteritidis ▪Gram-negative, motile rod (flagella) ▪Susceptibility: numerous cold- and warm-blooded animals are carriers, potencial sources ▪Human risk, food safety ▪ZOONOSIS
Paratyphoid• Resistence, spread
▪ Sensitive, high temperature eliminates (above 70°C) ▪ Survives months in frozen food products ▪ Persist in environment ▪ Shed via feces, persist in water, feed ▪ Poultry food products! ▪ Most important: per oral infection ▪ Transmitted via germinative route also ▪ Carriers
Paratyphoid • diseases
• 1 week old animal - septicemia ▪ acute form ✓coagulated yolk sac content ✓enlarged liver, spleen ✓miliary necrotic foci in liver and spleen ✓fibrinous perihepatitis, pericarditis ✓caseous exudate in cecum ▪ lower mortality rate ▪ chronic form - intestinal colonization, carrier status, intermittent shedding in adults -caseous exudate in oviduct -fibrinous perihepatitis, peritonitis
Paratyphoid • diagnosis & control
▪ flock history ▪ clinical appearance (age group) ▪ pathology ▪ culturing ✓plain or bloody agar ▪ serology ✓agglutination test ✓ELISA ▪ numerous rules on regular screening requirements
Control ▪eradication ✓screening for carriers ✓Salmonella-free hatchery (disinfection of egg shells – migration through pores) ✓obtaining eggs/chicks and poults from S.-free sources ✓hygiene ✓personnel ✓regular screening ▪vaccination – in some countries ▪treatment…
Arizonosis
• Causative agent
Salmonella enterica subsp. arizonae ▪Susceptibility: turkey (chicken, duck, wild birds) ▪Gram-negative, motile rod (flagella) ▪Distributed worldwide ▪Eradicated from commercial turkeys
Arizonosis • Resistence, spread
▪ Almost like paratyphoid
▪ High morbidity and mortality among turkey poults
(1-5 week, 10-50% mortality)
▪ Intestinal colonization, carrier status –
intermittant shedding
▪ Colonization in laying hens (ovary, oviduct)
▪ Contamination of egg shell
▪ Important to screen breeder flocks, eliminate
carriers
▪ Bacterin vaccin can be used
Colibacillosis• Causative agent
Escherichia coli (APEC)
▪Gram-negative bacillus
▪ Susceptibility: every poultry species
▪ Facutative pathogenic, accompanies other infections
▪Usually not zoonotic
▪Grows anywhere, frequent in environment
▪O-, K-, H- and F-antigens (classification –
serogroup, serotype)
• Immune response directed mostly against O-antigen
• Diseases: diarrhea, septicemia, localized lesions
• Cytotoxins: enterotoxins (ST and LT), verotoxins, cytotoxic necrotizing factor (CNF)
▪ enterotoxin – diarrhea
▪ verotoxin – vessel wall lesions
▪ cytotoxic necrotizing factor – hemorrhages, necrosis
• Endotoxins - septicemia
Colibacillosis • Resistence, spread
▪ Not too sensitive, high temperature eliminates (above
60°C)
▪ Difficult to eliminate from environment (persistent
shedding with feces)
▪ Common inhabitant of guts
▪ Can enter the egg on its’ pores (fecal contamination)
▪ Disease (virulent strain): pass through the mucosa or
enters directly from environment (wounds) – acute
inflammatory response
▪ Predesposing factor (wounds, immunosuppression,
primery infections, high E. coli load)
Colibacillosis • Clinical signs
▪Vary greatly (including morbidity and mortality rates)
▪ Younger birds more often affected
▪Highly virulent strain: sudden death without severe lesions
▪Mild virulence/efficient immunity/localized disease form can remain unnoticed
▪ Layers: salpingitis, peritonitis, sporadic death
▪ septicemia: lethargy, inappetence (dehydration)
• Diseases
▪ localized
✓omphalitis (+ yolk sac infection) – 0-1. week
-egg shell contamination, hatchery (or in ovo in case of oophoritis, salpingitis)
✓coliform cellulitis
• serosanguineous/fibrinous exudate on abdomen, thigh
• locus minoris resistentiae!
✓swollen head syndrome
• acute-subacute, rare form
• periorbital cellulitis
• usually secondary after viral respiratory disease
✓diarrhea
• primary E. coli enteritis rare (<=>mammals)
• attaching and effacing E. coli (AEEC), ETEC, EHEC, EPEC and EIEC in this group
✓venereal colibacillosis
• in turkey breeder hens after first insemination – vaginitis
✓coliform salpingitis/peritonitis
• drop in egg production
• ascending infection or due to egg binding, cloacal prolapse, etc
▪ Systemic forms
✓colisepticemia
• acute, subacute–polyserositis
• chronic – granulomatous inflammation
• bursal atrophy can occur
• enlarged and congested spleen
• origin can be: respiratory-origin (most frequent – airsacculitis), enteric-origin (mainly in turkeys following hemorrhagic enteritis)
• neonatal septicemia: 1-2 days after hatching (splenomegaly, edema of serous membranes, congested lungs)
• meningitis, encephalitis (CNS form)
• in layers (chicken, turkey): acute colibacillosis (onset of egg production, not as often)
• ducks: pericarditis, perihepatitis, airsacculatis
• surviving septicemia: chronic lesions (osteomyelitis, arthritis, tenosynovitis, spondylitis)
• coligranuloma (Hjarre’s disease)
Fowl cholera
• Causative agent
Pasteurella multocida ▪Gram-negative ▪Susceptibility: all poultry species ▪Water fowl and turkey are most susceptible ▪Younger birds are more or less resistent (under 16 weeks of age) ▪Mostly horizontal transmission (carriers, wild birds, rodents, personnel…)
Fowl cholera • Clinical signs
▪ through respiratory tract (can infect via other
mucosas), sometimes through wounds
✓gets into lungs, then bacteremia/septicemia
✓acute form: sudden death, mortality increases rapidly
(hepato- and splenomegaly, hemorrhages under serosal
linings, mucous membranes)
✓prolonged infection: anorexia, thick nasal discharge,
cyanosis, diarrhea
✓chronic form (low virulent strain or survival of acute
disease): arthritis, abscess formation (cranium, comb,
wattle, airways, oviduct)
• Control ▪avoid introduction of pathogen to the flock (epidemiologic measures!) ▪vaccination ✓inactivated bacterin ✓live attenuated
