Lawsonia

Question 1

Species of animals mainly affected by lawsonia?

Answer 1

Pigs, hamsters, & horses

Question 2

4 forms of proliferative enteropathy in swine

Answer 2

• proliferative hemorrhagic enteropathy (mainly older but naïve animals, finisher and breeder pigs)
• porcine intestinal adenomatosis
• necrotic enteritis
• regional ileitis

Question 3

Can you culture Lawsonia intracellularis? If yes, what media should you use?

Answer 3

No, it cannot be cultured

Question 4

Describe pathogenesis of Lawsonia

Answer 4

1) infects tonsils and LN; primarily in macrophages

2) migrate to GIT; infect enterocytes within crypts

3) continuous cell division w/o differentiation (hyperplasia)

4) crypts elongated & branched

5) increased neutrophils, macrophages, and lymphocytes

6) decreased goblet cells

Question 5

How does proliferative enteropathy present in pigs w/ acute infection?

Answer 5

• intestinal hemorrhage
• sudden death
• pale carcass
• petechial hemorrhage in intestinal mucosa

Question 6

What age of animals does PHE occur in?

Answer 6

• older but naive animals
• finisher and breeder pigs

Question 7

How should you properly sanitize areas contaminated by Lawsonia intracellularis?

Answer 7

Clean area w/ iodophore povidone iodine and quarternary ammonium disinfectants

Question 8

L. intracellularis doesn’t induce disease in germ-free pigs. Which other organisms resemble these characteristics?

Answer 8

Brachyspira hyodysenteriae

Question 9

How do you differentiate disease caused by L. Intracellularis vs B. Hydodysentriae?

Answer 9

• Lawsonia : small intestine affected; (darker blood in feces)
• Brachyspira: large intestine affected; (bright red blood in feces)

Question 10

What can be done to control lawsonia?

Answer 10

• all in/all out
• screen replacement stock (w/ antibody titer)
• modified live Vx (enterisol illeitis)

Question 11

How to treat lawsonia

Answer 11

• chloratetracycline, lincomycin-spectinomycin, tylosin/tiamulin

Question 12

What age group does equine proliferative enteropathy affect and how do you diagnose the disease in horses?

Answer 12

• Weaning foals of 3-6 mos
• abdominal ultrasound of thickened loop of small intestine

Question 13

Treatment for equine proliferative enteropathy

Answer 13

• fluid and electrolyte therapy
• erythromycin, azithromycin, rifampin

Question 14

How is lawsonia primarily spread?

Answer 14

• mechanically: boots
• biologic vectors: mice, birds, insects
• poop from infected pigs
• species to species

Question 15

What do you observe on a histology of lawsonia lesions?

Answer 15

• Proliferative adenomatosis
• mitotic figures
• disappearance of goblet cells

Question 16

How do you describe the gross postmortem examination of Lawsonia?

Answer 16

Thickened loop of small intestines

Question 17

What are symptoms of equine proliferative enteropathy

Answer 17

• dullness, fever, wt loss, colic, diarrhea, hypoproteinemia
• leukocytosis
• mild anemia

Question 18

How does proliferative enteropathy present in pigs w/ chronic infections?

Answer 18

• caused by stress 1-3 wks post-weaning
• lasts 1-3 weeks
• mild enteritis persists at 10-12 weeks

Question 19

How does proliferative enteropathy present in pigs w/ subclinical infection?

Answer 19

Manifests w/ animals showing poor growth

Question 20

How does proliferative enteropathy present in horses?

Answer 20

• 3 to 6 mo weanlings
• stress induced
• dullness, fever, wt loss, colic, diarrhea, hypo-proteinemia
• leukocytosis
• mild anemia