Brachyspira and Lawsonia

Question 1

Lawsonia intracellularis characteristics

Answer 1

-biocontainment level 2
-obligate intracellular parasite
-cant be grown outside of cell culture

Question 2

Brachyspira spp characteristics

Answer 2

-biocontainment level 2
-aerotolerant anaerobe
-do not typically form colonies
-hard to grow

*Treponema spp closely related and similar growth requirements

Question 3

Host/habitat of Lawsonia intracellularis

Answer 3

-obligate intracellular
-lives in enterocytes of hosts

Question 4

Host/habitat of Brachyspira spp

Answer 4

-found in GI tract

-domestic and wild birds, pigs, people, rodents, dogs

Question 5

Virulence factors of Lawsonia intracellularis

Answer 5

-type 3 secretion systems
-very little known

Question 6

Brachyspira spp virulence factors

Answer 6

Speculation on virulence factors, but poorly defined

1. Flagella- motility
2. chemotaxis- attracted to mucous
3. Hemolysins?

Question 7

Taxonomy differentiation

Answer 7

Use PCR and DNA sequencing to differentiate species

Question 8

Lawsonia intracellularis

Answer 8

-cause of proliferative enteritis (ileitis)= corrugation of mucosa**
-in pigs and horses
*unknown if pig and horse strains are same

Question 9

Multiple forms of Lawsonia intracellularis disease

Answer 9

1. intestinal adenomatosis- hyperplasia of crypt epithelium
2. Necrotic enteritis= chronic disease with mucosal necrosis
3. Regional ileitis= chronic disease with thickening of muscularis layer of ileum
4. Proliferative hemorrhagic enteropathy
   **can resemble swine dysentery

Question 10

Lawsonia intracellularis in horses

Answer 10

-increasing recognition in horses causing proliferative enteropathy
>granulomatous and proliferative enteritis

-common in weanling foals (4-6mths)

-clinical signs: weight loss, diarrhea, colitis

-transmitted by fecal oral route

Question 11

Lawsonia intracellularis in hamsters

Answer 11

-Causes Wet tail
-clinical signs: diarrhea, dehydration, anorexia, death
-can cause outbreaks in large colonies (likely pet stores)
-affects weanlings (3-8wks)
-treat with antimicrobials and aggressive rehydration
-isolate affected animals

Question 12

Swine dysentery cause

Answer 12

-caused by B. hyodysenteriae (classic cause) and B. hampsonii (new emerging, very common in W. Canada)

-common in 90s, re-emerging since late 2000s

-common in older pigs (grower, finishers)

Question 13

Severity of Swine dysentery for B. hyodysenteriae and B. hampsonii

Answer 13

B. hampsonii: less severe

B. hyodysenteriae: more sever

Question 14

Clinical signs of Swine Dysentery

Answer 14

**incubation period 3-7 days

-#1 sign=diarrhea (mild-watery-muco-hemorrhagic)
-inappetence
-pyrexia
-mortality in peracutely affected animals

Question 15

Control of swine dysentery

Answer 15

-unclear where it comes from (carriers or wildlife??)
-antimicrobials used in affected herds
-no vaccines

Question 16

Spirochetal colitis

Answer 16

-caused by B. pilosicoli

-Finisher pigs: wet cement feces without blood
Younger: severe diarrhea (watery or mucoid)

-less severe than swine dysentery

-disease self limiting
-linked with poor feed efficiency

Question 17

Control measures for spirochetal colitis

Answer 17

-antimicrobials
-no vaccine
-good practice management (all in all out, control other disease)

Question 18

Brachyspira spp in birds

Answer 18

Affected by a variety of species:

1. B. alvinipulli
2. B. pilosicoli
3. B. hyodysenteriae

Question 19

B. alvinipulli in poultry

Answer 19

associated with wet feces= diarrhea, green-yellow frothy cecal fluid

Question 20

B. pilosicoli in poultry

Answer 20

colonization of cecum associated with mucosal thickening

Question 21

B. hyodysenteriae in poultry

Answer 21

severe, necrotizing typhlitis in juvenile rheas (related to ostriches and emus)

Question 22

Brachyspira spp in humans

Answer 22

Intestinal spirochetosis (from B. pilosicoli and B. aalborgi)

-common in developing countries; in developed in children, HIV patients, MSM

-infrequently recognized because signs are with GI tract (chronic diarrhea, +/- blood, cramping, colitis)

Question 23

Digital dermatis

Answer 23

-caused by Treponema spp

-likely polymicrobial infection of bovine foot= proliferative or erosive lesions

-may be linked with management problem

Question 24

Digital dermatitis treatment and control

Answer 24

Management
-avoid cattle standing in wet material
-prevent maceration of skin which facilitated infection

Treatment:
-topical washing for early lesions
-topical antibiotics if more severe (Oxytetracycline or lincomycin/spectinomycin)

Question 25

Sample collection

Answer 25

1. Lawsonia intracellulitis
   -feces, rectal swabs
   -illeal tissue at necropsy
2. Brachyspira spp
   -rectal swabs
   -colonic or cecal tissues collected at necropsy
3. Treponema spp
   -swabs
   -tissue microscopy

**No freezing samples- key to growing Brachyspira

Question 26

Lab ID of Lawsonia

Answer 26

-histological examination (silver stains)
-PCR of feces or ileal/colonic tissues

Question 27

Lab ID of Brachyspira spp

Answer 27

-microscopy of fecal smears
-culture (need multiple cultures)
-PCR based assays
-sequencing is gold standard for species level ID
-histological exam of cecal/colonic tissues

Question 28

Lab ID of Treponema spp

Answer 28

-microscopy

Question 29

Zoonoses

Answer 29

-poorly understood

-origin of human infections not systemically studied

-transmission between animals likely
**role of wildlife/animals in agriculture settings (rats, mice, wild birds)
eg. Snow Geese- Nunavut and US midwest, possible contact with pigs

Question 30

Treatment for Lawsonia

Answer 30

-susceptibility testing impossible (obligate intracellular parasite)

-INEFFECTIVE: penicillins, bacitracin, aminoglycosides, virginiamycin, ionophores

Question 31

Treatment of Brachyspira

Answer 31

-Pigs= treatment relies on pleuromutilins and macrolides use
*trying to develop susceptibility testing= agar dilution (small amounts of antibiotics on each part of plate) but not available

-Lack standard methods