162. Swine dysentery, intestinal spirochaetosis of swine and birds.

Question 1

Swine dysentery Occurence and aetiology?

Answer 1

Swine dysentery

Occurrence: worldwide, widespread - great economic impact

Aetiology:

• B. hyodysenteriae,(Brachyspira)
• B. innocens,
• B. pilosicoli,
• B. intermedia

Question 2

Epidemiology?

Answer 2

Epidemiology

• Infected pigs shed: widespread infection
• Transmission with faeces
• Swine, birds, rodents
• Indirect Course of the disease is influenced by:
• Virulence and bacterium load
• Resistance of the host
• Management, nutrition (mycotoxin, hygiene, change of diet),
• stress, transport
• predisposing effects:
• Large scale farms predispose
• Immunity will be slowly developed
• Animals remain carriers after healing

Question 3

Pathogenesis?

Answer 3

Pathogenesis

• PO Infection
• Mucous membrane of the large intestine (no adherence)
• Damage of the epithelium (haemolysin, endotoxin),
• Increased mucous production by goblet cells
• Inflammation
• Necrosis of the surface of the epithelium
• Dilatation of the blood vessels, permeability is increased - flow of serum and blood into the gut
• lumen
• Decreased absorption
• Diarrhoea
• Str. germinativum intact: regeneration (damage only in upper layer!)
• Antibodies (blood, local): type specific

Question 4

Clinical signs of swine dysentery?

Answer 4

Clinical signs

• Incubation: 10-14 days, Clinical signs above 6-8 weeks
• Diarrhoea (watery faeces, later blood, mucous, fibrin, debris)
• Fever, decreased appetite, thirst
• Dehydration
• Weight loss - Death or healing

Question 5

Pathology of swine dystentery?

Answer 5

Pathology

• Stomach: is full, hyperaemic, mucous layer
• Large intestine
• Mucous membrane swollen, reddish
• Necrosis of the mucous membrane
• Reddish gut content

Question 6

Diagnosis and differential diagnosis?

Answer 6

Diagnosis

• Epidemiology ʹ clinical signs ʹ pathology
• Detection of agent: microscopy, IF, PCR, bacterium culture on blood agar, add spectinomycin (prevents over bacteria growing)
• (movement of axial filaments with stain)
• Detection of antibodies: agglutination, iIF, ELISA; herd diagnosis (indirect immunofluo)

ͻ Differential diagnosis:

1. swine intestinal spirochaetosis,
2. proliferative enteritis,
3. swine typhoid,
4. paratyphoid,
5. coli
6. diarrhoea,
7. TGE

Question 7

Treatment and prevention of swine dysentery?

Answer 7

Treatment

• Antibacterial treatment: lincomycin, tylosine, tylvalosine, tiamulin
• EU not licenced: carbadox, virginiamycin, dimetridasole
• Method of treatment: individual treatment, herd treatment (water, feed)
• Antibiotic susceptibility is changing ʹ check resistance!
• Reduction of ration to a 1/3 and with ad lib water
• Elimination of predisposing factors, hygiene
• Carriers remain ʹ but not clinical signs

Prevention

• Prevention of introduction
• Closed herds
• Introduction of animals only after quarantine (antibiotic treatment!)
• Hygienic rules, disinfection, control dung
• Infected herd:
• Reduction of overcrowding and mixing
• Improving hygiene, preventive antibiotic treatment (stricter regulations reg ATB from 2022)
• No vaccines

Question 8

Eradiation of swine dysentery?

Answer 8

Eradication

• 1) SPF herds: strict technical and personal conditions
• 2) Herd replacement
• 3) Eradication by using antibiotics
• Antibiotic treatment of pregnant sows and piglets (1st day) in the farrowing unit
• Isolation of piglets after weaning
• Prevention of reinfection (dung, rodents)

Question 9

Intestinal spirochaetosis of swine Aetiology, epidemiology and pathogenesis?

Answer 9

Intestinal spirochaetosis of swine

Aetiology:

• B. pilosicoli - major genetic differences within the species

Epidemiology

• Host range: Su, Ho, Apes, Eq, Dog, Birds
• Milder disease
• Growers, adults (younger pigs compared to dysentery)
• Infection from faeces
• Viable in faeces for 4-7 months ʹ not zoonotic just same source

Pathogenesis:

• Infection Po -> large intestine -> Inflammation

Question 10

Clinical signs, pathology diagnosis treatment prevent of intestinal spirochaetosis of swine?

Answer 10

Clinical signs

• Watery faeces, mucous, gray (mortar like)
• No blood in the faeces, weight loss

Pathology

Lesions in the large intestine

Local inflammation of the mucous membrane

Diagnosis, treatment, prevent: like SU dysentery

Question 11

Avian intestinal spirochaetosis Occurence aetiology epidemiology?

Answer 11

Avian intestinal spirochaetosis

Occurrence: common - geese, ducks, hens, turkey

Aetiology:

• B. alvinipulli, B. pilosicoli, B. hyodysenteriae, B. intermedia,
• virulence variants
• mixed infections can happen

Epidemiology

• Infection from faeces
• Predisposing factors
• Not infectious: management, nutrition, hygiene, overcrowding; laying
• Infectious: bacterial and viral infections

Question 12

Pathogenesis, clinical signs pathology diagnosis epidemiology treatment of avian intestinal spirochaetosis?

Answer 12

Pathogenesis: ​

• PO infection->large intestine-> inflammation

Clinical signs:

• diarrhoea (blood), arthritis, drop in egg production

Pathology:

• fibrinous, necrotic inflammation (caecum & the LI); nephropathy

Diagnosis

• Epidemiology ʹ clinical signs ʹ pathology
• Bacteriological examination: detection, culture (strict anaerobic)

Treatment, prevention:

• general epi measures, antibiotics (macrolide, tiamulin, lincomycin)