Cases of Abortion in the Ewe

Question 1

Case presentation:

Mr Mead phoned the practice on 22nd February to report that ‘a few ewes have been slipping their lambs’. He has left a sack of aborted material outside the surgery door.

What information would you want to gather from Mr Mead?

Answer 1

Flock information:

· Number of ewes and flock type

· Due dates

· Housed ewes? When are they moved to housing?

· When are they fed and how much?

· Closed or open flock? Where do replacements come from?

· Have abortions occurs in previous years? If so what caused it?

· What vaccines are used?

· Can we have ultrasound scanning data?

· Have the ewes been transported or handled recently?

Specifics:

· How any and what date of abortions?

· Are ewes systemically ill?

· What age are the ewes that are aborting?

· Are ewes home bred or brought in?

· What did the aborted lambs look like?

· Have the ewes that have aborted been separated?

Question 2

What samples would you take to send to the labs?

Answer 2

· Send the foetus and placenta but sometimes this doesn’t occur. If not:

o Send a section of placenta including one cotyledon and a large area in between cotyledons

o Foetal fluid from thoracic +/- abdomen

o Foetal stomach contents collected sepatically using vacutaner and needle

o Send fresh spleen and liver

Question 3

What tests will the lab do on these samples?

Answer 3

Placenta

· -Modified Ziehl Nielsen stains red for Chlamydophila & Coxiella burnetti

· -Gram smear for Campylobacter (curved G-ve rods)

· -Gram smear for Salmonella (short G-ve rods) or culture on MacConkeys or enrichment media

· -Gram smear or culture for Listeria (G+ bacilli)

· [Immunohistochemistry (IHC) on formalin-fixed paraffin-embedded tissue can demonstrate Chlamydophilia, Toxo, C fetus or C burnetti Ag]

Foetal fluid

· -Indirect fluorescent antibody test (IFAT) for Toxo

· -Microscopic agglutination test for Leptospirosis

Foetal liver or spleen

· -Virus Isolation or PCR for Border Disease

Foetal stomach contents

· -Gram smear or culture for Campylobacter, Salmonella or Listeria

Question 4

What further action do you take?

Answer 4

· More samples to the lab ASAP

o Placenta

o Foetal liver

o Foetal stomach contents

Question 5

What are the implications of these findings?

Answer 5

· Chlamydial abortion, Chlamydophila abortus, enzootic abortion of ewes

· Ewes are aborting because of EAE

Question 6

What would you tell the farmer about EAE?

Answer 6

· Largest incidence of ewe abortion despite a lot of vaccination

· Zoonotic

· Infection occurs orally and doesn’t affect the ewes until next pregnancy

· Check the rams for orchitis but veneral spread is uncommon

Prevention and control:

· Vaccination: three available in the UK

· Treat with whole flock oxytet injections

· EAE testing schemes

Question 7

How can you investigate EAE abortion further?

Answer 7

· EAE testing scheme – all aborted material must be submitted for evaluation and a yearly annual flock test

o No evidence of EAE

§ First year – supervised status.

§ Second year- full accreditation

o Flocks in the scheme get free investigation of aborted material

· Send away further samples as abortions occur (relies on farmer bringing them in and he may not be keen following initial diagnosis).

· Lambing figures – suggest the farmer collects this information – you can use it after lambing to show the extent of the problem.

· Serology of aborted and barren ewes – blood sample 6-8 aborted ewes within the couple of months post-lambing. (Use FLOCKCHECK, a free lab service provided by MSD, if available).

Question 8

What would you tell the farmer about control of Toxoplasma?

Answer 8

· Avoid cats on the farm – past in cat faeces. Prevent access of cats to the ewe feed. If this is not possible do not feed ewes the top hay bales

· Farm cats should be neutered because they roam less

· Sheep and mice and intermediate hosts- have good rodent control

· BEWARE ZOONOTIC

· VACCINE- highly efficacious.

· Serological diagnosis.

· Need dam samples to get positive results not foetal materal therefore when you send foetal material send blood from the dam too.

· Put decoquinate into the feed which can help prevent and control toxoplasma. As concentrates are fed in the last 4-6 weeks it [decoquinate] is less likely to prevent and more likely to treat.

· If you buy hay from another source consider whether they have cats- if they do consider vaccination against toxoplasma.