Infectious Repro Disease

Question 1

What is the abortion agent and route of infection for

Enzootic Abortion of Ewes?

Answer 1

Chlamydia abortus

A ewe shedding at the previous lambing time

Question 2

What is the abortion agent and route of infection for

Toxoplasmosis?

Answer 2

Toxoplasma gondii

Cat faeces from a young or immunocom-promised cat

Question 3

What is the abortion agent and route of infection for

Campylobacteriosis?

Answer 3

Campylobacter fetus fetus & Campylobacter jejuni

Carrier ewe, mechanical transmission by birds, vermin

Question 4

What is the abortion agent and route of infection for
Salmonellosis?

Answer 4

Various Salmonellas – esp

S. Abortus, S. Montevideo, S. Dublin

Carrier sheep, Wild birds,

Question 5

What is the abortion agent and route of infection for
Border disease?

Answer 5

Border Disease Virus - Persistently infected lamb (or possibly calf as ~20% BDV cases are actually cattle BVD)

Question 6

What are the Clinical signs and pathology of EAE?

Answer 6

Aborted foetuses in the last 2 weeks of gestation. Intercotyledonary thickening & brownish exudate.

Question 7

How can you diagnose EAE?

Answer 7

Modified Ziehl-Nielson stain on placenta shows red-stained elementary bodies.

Serology on blood from ewe

Question 8

How can we Prevent and control EAE?

Answer 8

Care with replacement ewes!

Vaccination – pref 3 weeks before tupping before exposure.

In an outbreak – isolate the ewe & remove debris etc. Give dead vaccine to other pregnant ewes in the face of the outbreak if poss or live vaccine at least 3 weeks before next tupping.

Oxytet antibiotic possible in face of outbreak but not as routine

Question 9

What are the Clinical signs and pathology of toxoplasma?

Answer 9

Resorption of foetuses, empty ewes, mummified & aborted foetuses. Weak lambs born.

White dots on cotyledons

Question 10

How can you diagnose toxo? (2)

Answer 10

IFAT on fetal thoracic & abdominal fluid.

Serology on blood from ewe

Question 11

How can you prevent and control toxo?

Answer 11

Vaccination of replacement ewes.

Decoquinate by mouth not practical

Question 12

What are the Clinical signs and pathology of campylobacter?

Answer 12

Abortion in last 6 weeks of pregnancy, weakly lambs.

May get grey areas of necrosis on foetal livers

Question 13

How can you diagnose campylobacter?

Answer 13

Gram smear of placenta & foetal stomach contents – curved G-ve rods

Question 14

How can you prevent and control campylobacter?

Answer 14

Isolate aborted ewes & remove all contaminated bedding etc.

Good immunity develops but expect further outbreaks after 4 years

Vaccine (Campyvax) can be imported from NZ under a special import licence

Question 15

What are the Clinical signs and pathology of salmonella?

Answer 15

Varied – often metritis & scour in ewes, aborted & weakly live lambs

Question 16

How can we diagnose salmonella?

Answer 16

Gram smear of placenta & foetal stomach contents – short G-ve rods

Culture on MacConkey’s agar

Question 17

How can you prevent and conctrol salmonella?

Answer 17

Cattle vaccines may be used under the cascade.

Isolate aborted ewes & strict hygiene.

Antibiosis in the face of outbreak

Question 18

What are the Clinical signs and pathology of border dx?

Answer 18

Resorption, mummification, abortion, stillbirths, hairy shaker lambs

Question 19

How can you diagnose border dx?

Answer 19

PCR or virus isolation from foetal spleen. Blood from lamb (pre-colostrum)

Serology on ewe blood

Question 20

How can you prevent and control border dx?

Answer 20

Avoid mixing pregnant ewes & lamb replacement females separately.

Once BDV is in a flock, only control is mixing of non-pregnant ewes with PI lambs to ensure sero-conversion before pregnancy.

BVD vaccine not shown to be effective in sheep