Ovine abortion

Question 1

When is foetal loss defined as abortion in the sheep?

Answer 1

140-150 days (147d)

Question 2

What level of abortion should be the threshold of concern?

Answer 2

> 2%

Question 3

What is the most common cause of abortion in sheep?

Answer 3

Chlamidophila abortus (enzootic abortion)

Question 4

What clinical signs are indicative of C. abortus?

Answer 4

Abortion after 90 days. Vaginal discharge. Weak lambs. Placentitis (intercotyledonary thickening). Lambs organ inflammation. Sheep are rarely ill.

Question 5

Describe the phases of life of C. abortus.

Answer 5

Extracellular infective - avoids the immune response and becomes intracellular (vacuole)
Intracellular reproductive - able to reproduce by binary fission and parasitically feed off the cell.

Question 6

Describe the morphology of C. abortus.

Answer 6

Gram negative cocci

Question 7

How is C. abortus spread?

Answer 7

Oral transmission. Aborting ewes - heavily contaminated discharges. Carrier ewes - shedding at lambing (+ oestrus)

Question 8

What occurs in the sheep when C. abortus infects sheep which are:

1. pre 90d gestation
2. post 90d gestation
3. Post lambing
4. Once aborted

Answer 8

1. CA remains extracellularly until 90d
2. Abortion
3. Harbours CA in repro tract until next lambing
4. Generally immune

Question 9

How does placentitis during C. abortus infection cause lamb death?

Answer 9

Inflammation of the placenta affects nutrient transportation and hormone productio therefore causing lamb death or damage.

Question 10

How can C. abortus be diagnosed?

Answer 10

PM lesions - leathery, intercotyledonary thickening. SUBMIT TO APHA
ZN staining
PCR/ serology

Question 11

How can C. abortus be controlled?

Answer 11

Isolate and burn ALL contaminated material. Remember it is a zoonotic risk.
Treat all ewes prelambing with 20mg/kg Oxytet and repeat in a fortnight. Vaccinate 4 weeks prior to tupping (Enzovax). Ensure biosecurity (don’t buy in.

Question 12

Name the health scheme associated with C. abortus.

Answer 12

EAE accredited ewes from SRUC health schemes.

Question 13

Enzovax

Answer 13

Live attenuated vaccine.
Strong and durable immunity
4 weeks prior to tupping

Question 14

Describe the effects of Toxoplasmosis in early, mid and late pregnancy in the sheep.

Answer 14

Early - 8-10% foetal resorption
Mid - Abortion, weak lambs, mummified foetus
Late - abortion, week, immunity

Question 15

Definitive T. gondii host?

Answer 15

Cat

Question 16

True or false. T. gondii oocysts are very resistent to environmental pressures. How long can they survive in the environment?

Answer 16

True, more than 500 days. They are a significant cause of infection.

Question 17

How can T. gondii infection be diagnosed in sheep?

Answer 17

Submit: foetus, placenta and blood sample.
Gross: Strawberry lesions on the placenta
PCR/ serology/ iFAT

Question 18

How can T. gondii be controlled in sheep?

Answer 18

Biosecurity - sheep, cats and vermin.

Vaccination - Toxovax.

Question 19

Toxovax

Answer 19

Live attenuated.

Give 3 weeks prior to tupping

Question 20

Which groups of people are most at risk from T. gondii infection?

Answer 20

Immunosupressed and pregnant.

Question 21

Which Salmonella spp. is associated with ovine abortion?

Answer 21

Salmonella abortus ovis

Question 22

Describe the morphology of S. abortus ovis.

Answer 22

Gram negative rods (as for all salmonella!)

Question 23

Clinical signs of S. abortus ovis.

Answer 23

Abortion in the last 1/3 of pregnancy.
Metritis following abortion.
Systemic disease.

Question 24

What treatment plan should be instigated during S. abortud ovis infection?

Answer 24

Whole group plus individual Oxytet.
Plus non-steroidals for individuals
Ensure a closed flock, mix brought in sheep after lambing.

Question 25

Which Campy species is associated with ovine abortion?

Answer 25

Campylobacter fetus fetus

Question 26

Clinical signs associated with C. abortus abortus.

Answer 26

Abortion in the last 6 weeks of pregnancy. | Metritis

Question 27

How many weeks post infection does abortion occur in a C fetus fetus infection?

Answer 27

1-4 weeks

Question 28

Name some sources of C. fetus fetus

Answer 28

Carrier sheep Contaminated feed and water Aborted material Birds

Question 29

Describe the diagnosis and control of C. fetus fetus.

Answer 29

Dx - smear and culture placenta, fetal stomach and liver | Control - isolate aborting ewes and dispose of material, broad spec ABs

Question 30

True or False. C. fetus fetus is zoonotic.

Answer 30

True

Question 31

Border disease is caused by what?

Answer 31

Pestivirus similar to BVD/CSF

Question 32

Clinical signs assocaited with Border Disease.

Answer 32

Barren ewes Placentitis (10-30d post infection) - reabsorbed, weak, mummified Hairy shaker lambs

Question 33

Hairy shaker lambs.

Answer 33

CNS - cerebella hypoplasia Skin - hairy Skeleton - long limbs

Question 34

How does border disease affect ewes at: | 1. first stage of pregnancy, 2. day 60-85, 3. Post day 85

Answer 34

1. 50% reabsorption, still births 2. Abortion, hairy shakers, PIs produced 3. Normal and Ab positive (immune) in ewe and lamb & Immunity

Question 35

How old should PIs be when they are first tested for their persistent infection with border disease?

Answer 35

3 months - tested for virus antigen

Question 36

Name an Orthobunyavirus associated with ovine abortion and describe its route of transmission.

Answer 36

Schmallenberg virus. Transmitted by midges.

Question 37

What clinical signs are associated with Schmallenberg virus?

Answer 37

Cattle - mild, diarrhoea, fever, quick recovery. Sheep - lamb birth defects, increased barren/return to service

Question 38

Describe the congenital abnormalities associated with schmallenberg virus.

Answer 38

``` Bent limbs fixed joints twisted neck/ spine domed head brachygnathia inferior blindness fitting inability to suckle ```

Question 39

``` Poorly preserved (>pH) silage is associated with which pathogen which can cause abortion in sheep? How can it be treated? ```

Answer 39

``` Listeria monocytogenes (abortion, septicaemia and encephalitis. Antibiotics - OT or penicillin ```

Question 40

Which TBD is associated with ovine abortion?

Answer 40

Anaplasma phagocytophilia. | Remember to treat with ectoparasiticides - pyrethroids