Sheep abortion

List the zoonotic infectious causes of abortion in sheep

Chlamydia abortus (most common)

Toxoplasma gondii (2nd most common)

Campylobacter (3rd most common)

Listeria

Salmonella

List the non-infectious causes of abortion in sheep

Poor nutrition/BCS

Pregnancy toxaemia

Rough handling

Transport

Vaccinaton/foot trimming

Dog worry

Fluke/worms

When should abortion be investigated in a flock of sheep?

If abortion rates fall above 2%

What are important samples to take when investigating abortion in sheep

Placenta including cotyledons

Stomach content (or liver/lung)

Spleen/thymus

What is the likely causative agent of this abortion? Describe the pathology and pathophysiology.

Chlamydia abortus

Marked placentitis

• inflamed cotyledons and intercotyledonary areas

• thick fibrinopurulent or necrotic exudate (looks like custard)

Bacteria causes gradual reduction of nutrient/excretory exchange in foetus

Describe the patterns of abortion with enzootic abortion of ewes

(Chlamydia abortus)

Infection can be acquired previous season then abort next season

Infection can occur same season but takes 6 weeks to incubate

Diagnosis and treatment of Chlamydia abortus

MZN of placenta (or poorer sensitivity with stomach content)

Dam serology tests flock exposure

Treat abortion storms with long acting tetracycline

What is the likely causative agent of this abortion and describe the pathology.

Toxoplasma gondii

Spreads in cat faeces - 10 oocysts is an infective dose

Inflamed cotyledons with white miliary necrotic foci

Foetal pathology is non-specific, abortion can happen at any stage. Can be mummified or normal.

Causes poor scanning percentages

How is Toxoplasma gondii diagnosed?

PCR of cotyledons

Histopathology of brain

Dam serology to assess flock exposure

What is the likely cause of this abortion and describe the pathology.

Schmallenberg virus

transmitted by midges Culicoides, that peak in the late summer and early autumn

periodical re-emergence of disease

• arthrogryposis

• torticollis

• scoliosis

• brachygnathia inferior

• hydranencephaly

• cerebral hypoplasia/cerebellar aplasia

• micromyelia

How is Schmallenberg diagnosed?

Fresh brain or brainstem PCR

What is the likely cause of this abortion and describe the patholoy

Campylobacter (fetus fetus is most common)

Transmitted in faeces and vaginal fluids, and can be spread by wild birds and rodents

Associated with ground feeding and poor trough hygiene

Lambs have multifocal necrotizing hepatitis forming target-like lesions

Placenta has pale/small necrotic cotyledons

How is Campylobacter diagnosed?

Bacteriology of stomach content (or liver/lung if absent)

• takes 4 days for initial bacterial identification