Topic 124 - Fowl cholera (RED) Flashcards
What is fowl cholera?
a contagious bacterial disease of birds caused by Pasteurella multocida, can be both chronic or acute
Occurrence of fowl cholera
Worldwide, BUT more common in warmer climate
Europe = seen during the summer and early autumn
Which type of farming is fowl cholera most commonly seen?
Backyard farms and outdoor keeping
Causative agent of fowl cholera:
P. multocida A
Virulence variants of fowl cholera:
High = acute fowl cholera
Low = Chronic fowl cholera, causing asymptomatic infection
Susceptible hosts of fowl cholera:
Most susceptible are waterfowls, duck and goose but also turkey
Hen - Increases with age
Wild living birds and cage birds show mild clinical signs, but they carry and shed the bacteria ⭢ introducing it to a farm
How is the resistance of fowl cholera?
Low, BUT survives in water for weeks
How is virulent strain of fowl cholera infected?
An introduction to the farm is necessary, the bacteria is not normally present
The infection happens through discharges of carrier animals, tools and water
NO GERMINATIVE INFECTION
How is less virulent strain of fowl cholera infected?
The bacteria can already be present in the flock
The infection happens through discharges of carrier animals, tools and water
NO GERMINATIVE INFECTION
Predisposing factors of fowl cholera
Mainly environmental factors, which is why fowl cholera is a primary pasteurellosis = no previous infection needed
Morbidity and mortality of fowl cholera:
HIGH morbidity
HIGH mortality
There is an exponential mortality, the death curve is very steep
Age susceptible for fowl cholera:
Growers and adults, above 6-8 weeks of age - NEVER in day old birds
Route of infection in case of fowl cholera:
Airborne
Oral
(Wound and conjunctiva can also)
Pathogenesis of fowl cholera:
1. Infection
2. Colonisation of the upper respiratory epithelium of the mucus membrane
3. With predisposing factors: Septicaemia
4. The bacteria reaches the eyes, brain, ear, lungs
5. Eventually leads to death
Name 3 factors which fowl cholera is influenced by, as to how serious it becomes:
- Virulence
- Resistance
- Predisposing factors
Incubation time for fowl cholera:
1-5 days
What are the clinical forms in case of fowl cholera:
Peracute
Acute ⭢ Most severe
Chronic
Clinical signs in peracute form of fowl cholera
No clinical signs
Might see some ataxia and they often die
Clinical signs in acute form of fowl cholera
Fever
Anorexia
Depression
Green-yellowish diarrhoea
Nasal discharge
Sneezing
CNS signs
Cyanosis
Clinical signs in chronic form of fowl cholera
Weight loss
Arthritis
Movement disorders
PM lesions in case of fowl cholera:
ACUTE
1. Haemorrhages, extreme amounts and on large areas
2. Focal inflammation and necrosis in the liver, but also frequently in the spleen and other parenchymal organs
CHRONIC
Arhtritis
Diagnosis of fowl cholera:
Staining and microscopic examination
Bacterium isolation
PCR, used to examine the carriage of salmonella
Treatmepnt of fowl cholera
- AB, but time is crucial - Immediate AB treatment is necessary and its given oral
- Elimination of the predisposing factors
How to prevent fowl cholera
- Prevention of predisposing factors
- Vaccine
Type of vaccines used for fowl cholera
Inactivated vaccines and attenuated vaccines
Europe = only inactivated, attenuated is not allowed
