L15 - EAE and Corynebacterium

What pathogen causes Enzootic Abortion of Ewes (EAE)?

Chlamydia abortus

What species does Chlamydia abortus target?

Sheep, cattle, pig, goats

What type of of bacteria is Chlamydia abortus?

• Spherical

• Unable to synthesize own ATP → Energy Parasite

• Intracellular Parasite

• Cell walls lack peptidoglygan → have LPS instead

What types of disease does Chlamydia abortus cause?

Respiratory, Enteric and Reproductive

How is Chlamydia abortus transmitted?

• Fecal-oral

• Placentas and uterine discharge

• Ingestion

When does Chlamydia abortus typically cause abortion in ewes?

Early pregnancy

Late pregnancy will usually not abort, but potential to abort in next pregnancy

When do most EAE outbreaks occur?

The breeding season after introduction of infection to the flock (typically due to replacement ewes being affected)

EAE Pathogenesis

• First signs @ 90 days gestation

• Chlamydia abortus targets trophoblast layer of placenta → inflammation → thrombotic vasculitis and tissue necrosis

• Abortion results from reduced fetal-materal exchange → lack of placental endocrine fxn and immune protection from dam

Symptoms of EAE

• Abortion during late pregnancy

• Birth of premature, weak lambs

• Necrosis of cotyledons

• Edema of adjacent intercotyledonary tissue

• Dirty pink uterine exudate

Do sheeps affected with Chlamydia abortus have decreased fertility?

No, only attacks placenta

How is EAE diagnosed?

• Aborted lambs

• Evidence of necrotic placentitis

• Elevated EBs in placental smears

• MZN Staining → can be confused with Coxiella burnetti

How is EAE treated?

• Antibiotics → doesn’t eliminate infection, ewes can still shed at parturition

• Long-acting oxytetracycline

How is EAE controlled?

• Isolate aborted ewes for 2-3 weeks

• Clean birthing areas

• Long-acting oxytetracycline to ewes who haven’t lambed yet

• Live attenuated vaccine → prior to breeding

• Inactivated vaccine → pregnant animals

Is Chlamydia abortus zoonotic?

Yes, pregnant women should avoid contact with ewes during lambing season

What kind of bacteria is Corynebacterium spp?

• Gram +

• Cocci, club or rods (pleomorphic) → “Chinese Characters”

• Non-spore forming

• Non-motile

• Facultative anaerobe

What test results will Corynebacterium spp have?

• Catalase +

• Oxidase +

• Urease + (pathogenic members) → except C. bovis

What do the types of Corynebacterium renale cause?

C. renale (Type 1) → cattle, sheep, goats → cystitis, pyelonephritis, enzootic balanoposthitis

C. pilosum (Type 2) → cattle → cystitis, pyelonephritis

C. cystitidis (Type 3) → cattle → severe cystitis, rarely pyelonephritis

What characterizes the lesions of Corynebacterium spp?

Suppuration → make pus

How do blood agar plates compare between C. pseudotuberculosis vs. C. renale?

Why is there more pleomorphism and cocci forms of Corynebacterium spp in older cultures?

Lack of nutrients → slower metablism and shrinkage of rods

What is pyelonephritis?

Infection of kidneys

What causes the most severe form of cytitis in bovines?

C. cystitidis

What forms of Corynebacterium renale cause cystitis?

Any

What are contributing factors to C. cystitidis presence?

• Stress of parturition

• High-protein diet → increases pH of urine → ideal for colonization

Which kidney is a result of chronice vs. acute pyelonephritis from C. cystitidis?

Left → acute

right → chronic pyelonephritis

Signs of bovine pyelonephritis

• First sign: bloody urine

• Kicking at abdomen

• Dysuria and arched back

• Long-standing cases → renal damage

How is bovine pyelonephritis diagnosed?

• Thickened ureters and enlarged kidney on rectal palpation

• RBCs and protein in urine

• C. renale in urinary deposits

Review

Top: C. pilosum (type 2) → dark yellow

Left: C. cystitidis (type 3) → white

Right: C. renale (type 1) → dull yellow

Tween 80 Medium

Top → C. cystidis → hydrolysis with Tween 80

C. renale and C. pilosum are negative

How is bovine pyelonephritis treated?

Antibiotic therapy

Penicillin → excreted in urine so very effective

What is Pizzle Rot also known as?

Ulcerative (enzootic) balanoposthitis

What species does Ulcerative balanoposthitis target?

Sheep, goats, cattle (esp. castrated males)

What pathogen causes Ulcerative balanoposthitis?

Corynebacterium renale

Pathogenesis of Ulcerative balanoposthitis

• High protein intake → increase in urinary UREA

• C. renale hydrolysis of urea → produces lots of ammonia

• Ammonia irritates penis

What population is Ulcerative balanoposthitis more common in?

Castrated males

Symptoms of Ulcerative balanoposthitis

• Swelling of prepuce

• Difficulty urinating

• Ulceration around preputial orifice → brown crust

• If untreated, orifice can occlude

How is Ulcerative balanoposthitis treated and controlled?

• Stop high-protein diet

• Separate affected animals

• Look at prepuce and make sure not obstructed → clip and clean fur

• Tx: Penicillin and Cephalosporins

• Testosterone Tx Q3 months