Topic 124 - Fowl cholera (RED)

Question 1

What is fowl cholera?

Answer 1

a contagious bacterial disease of birds caused by Pasteurella multocida, can be both chronic or acute

Question 2

Occurrence of fowl cholera

Answer 2

Worldwide, BUT more common in warmer climate
Europe = seen during the summer and early autumn

Question 3

Which type of farming is fowl cholera most commonly seen?

Answer 3

Backyard farms and outdoor keeping

Question 4

Causative agent of fowl cholera:

Answer 4

P. multocida A

Question 5

Virulence variants of fowl cholera:

Answer 5

High = acute fowl cholera
Low = Chronic fowl cholera, causing asymptomatic infection

Question 6

Susceptible hosts of fowl cholera:

Answer 6

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

Question 7

How is the resistance of fowl cholera?

Answer 7

Low, BUT survives in water for weeks

Question 8

How is virulent strain of fowl cholera infected?

Answer 8

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

Question 9

How is less virulent strain of fowl cholera infected?

Answer 9

The bacteria can already be present in the flock

The infection happens through discharges of carrier animals, tools and water

NO GERMINATIVE INFECTION

Question 10

Predisposing factors of fowl cholera

Answer 10

Mainly environmental factors, which is why fowl cholera is a primary pasteurellosis = no previous infection needed

Question 11

Morbidity and mortality of fowl cholera:

Answer 11

HIGH morbidity
HIGH mortality

There is an exponential mortality, the death curve is very steep

Question 12

Age susceptible for fowl cholera:

Answer 12

Growers and adults, above 6-8 weeks of age - NEVER in day old birds

Question 13

Route of infection in case of fowl cholera:

Answer 13

Airborne
Oral
(Wound and conjunctiva can also)

Question 14

Pathogenesis of fowl cholera:

Answer 14

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

Question 15

Name 3 factors which fowl cholera is influenced by, as to how serious it becomes:

Answer 15

1. Virulence
2. Resistance
3. Predisposing factors

Question 16

Incubation time for fowl cholera:

Answer 16

1-5 days

Question 17

What are the clinical forms in case of fowl cholera:

Answer 17

Peracute
Acute ⭢ Most severe
Chronic

Question 18

Clinical signs in peracute form of fowl cholera

Answer 18

No clinical signs
Might see some ataxia and they often die

Question 19

Clinical signs in acute form of fowl cholera

Answer 19

Fever
Anorexia
Depression
Green-yellowish diarrhoea
Nasal discharge
Sneezing
CNS signs
Cyanosis

Question 20

Clinical signs in chronic form of fowl cholera

Answer 20

Weight loss
Arthritis
Movement disorders

Question 21

PM lesions in case of fowl cholera:

Answer 21

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

Question 22

Diagnosis of fowl cholera:

Answer 22

Staining and microscopic examination
Bacterium isolation
PCR, used to examine the carriage of salmonella

Question 23

Treatmepnt of fowl cholera

Answer 23

1. AB, but time is crucial - Immediate AB treatment is necessary and its given oral
2. Elimination of the predisposing factors

Question 24

How to prevent fowl cholera

Answer 24

1. Prevention of predisposing factors
2. Vaccine

Question 25

Type of vaccines used for fowl cholera

Answer 25

Inactivated vaccines and attenuated vaccines

Europe = only inactivated, attenuated is not allowed