130. Fowl typhoid.

Question 1

Fowl typhoid Occurence and aetiology?

Answer 1

Fowl typhoid / Pullorum disease

• Occurrence

• Formerly very common (50-60’s) - large scale farms
• Rare b/c of eradication programs
• Cases b/c of hobby keepers: Zoo, cage birds,
• (small farms) – smuggling eggs

• Aetiology:

• S. Gallinarum / S. Pullorum (same atgs & clinical signs)
• Susceptibility: hen, (water fowl), other bird species, caged birds

Question 2

Epidemiology of fowl typhoid?

Answer 2

Epidemiology

• Infection (germinative /PO/aerogenic):
• hatchery (aerogenic), stable
• Source of infection
• Faeces
• Hatchery waste, dead eggs
• Contaminated objects
• Infected animals (cage birds)
• Cock semen
• Double peak curve:
• Week 1 (3-5th day): germinative infection
• End of week 2 (12-15th day): horizontal infection from faeces
• The curve is influenced by:
• grade of infection,
• management, treatment
• Mass losses in the first 4 weeks

Question 3

Pathogenesis of fowl typhoid?

Answer 3

Pathogenesis

• Generalisation
• Embryonic infection (germinative):
• Death (bacterium replicates in the egg – can kill the embryo)
• Weak chicken with omphalitis (day old chicken can infect others in the hatching machine)
• Oral or aerogen infection → gut → septicaemia → parenchymal organs: heart, ovary (focal inflammation, necrosis)
• reach the ovary & lay infected eggs
• Long bacterium carriage (lifelong)

Question 4

Clinical signs of fowl typhoid?

Answer 4

Clinical signs

• Eggs: hatching % decr, death incr
• Chicken (day old)
• Weak chicken, omphalitis (naval inflammation, oedema & necrosis)
• Fever, diarrhoea („white diarrhoea” – white layer from uric acid b/c incr. metabolism due to fever)
• Chronic sign: Arthritis (leg, wing)
• Young/adult (few weeks – adult)
• Chronic – not so typical clinical signs
• Rupture of egg follicles → peritonitis
• Diarrhoea, abd pain (follicles of ovarium ruptured)
• Drop in egg production
• Weight loss, anaemia

Question 5

Pathology of fowl typhoid?

Answer 5

Pathology

o Chicken

▪ Unabsorbed yolk

▪ Focal inflammation in the heart muscle,

▪ Enteritis (haemorrhages, fibrin),

▪ Focal inflammation - necrosis: lungs, liver, spleen (typhoma)

o Growers/adult

▪ Focal inflammation - necrosis: lungs, liver, spleen

▪ Heart muscle necrosis,

▪ Enlargement of the lymphoid patches, ulcer

▪ Atrophy of the ovaries

Question 6

Diagnosis of fowl typhoid?

Answer 6

Diagnosis – 2 ways

• Disease (clinical signs)
• Epidemiology – clinical signs – pathology (lesions not enough for diagnosis)
• Laboratory diagnosis: Culture – isolation from parenchymal organs or BM of thigh, PCR
• Infection (free state or not)
• Bacteriological examination: culture, PCR
• Serology (preferred): plate-agglutination, tube agglutination, ELISA

Question 7

Differential diagnosis of fowl typhoid?

Answer 7

Differential diagnosis

• Weak chicken,
• omphalitis
• Paratyphoid, other diseases with fever,
• Coli-septicaemia,
• infectious bursitis,
• coccidiosis,
• lung mycosis,
• fowl cholera,
• campylobacter-hepatitis,
• yersiniosis,
• borreliosis

Question 8

Treatment and Prevention of fowl typhoid?

Answer 8

Treatment

• obligate pathogenic – AB cannot solve the problem
• Antibiotics, sulfonamides: tetracycline, fluoroquinolone (help recovery) → then slaughter
• Bacterium shedding → exclusion from breeding

• Prevention

• Eradication: elimination of shedders (slaughter), disinfection
• Isolated keeping of disease free stocks
• Keeping free state
• Parent flock: Plate-agglutination, tube agglutination (examined twice - slide agglutination
• +ve → examine in tube agglutination to clarify)
• Laying flock: Control of hatchery, dead eggs
• Day old chickens: Pathology, bacteriological examinations (double curve, peak of death in 0- 5 days)
• Check parent flock (),
• laying flock (control eggs – dead eggs)