abortion

Question 1

when are PME submissions highest?

Answer 1

February to March (spring)

Question 2

what are the causes of ovine abortion?

Answer 2

24% Enzootic abortion of ewes (EAE).
24% campylobacter fetus fetus
21% toxoplasmosis
13% other ( borders etc)
8% mixed infections
5% salmonella Dublin
5% listeria monocytogeres

so 45% is due to enzootic abortion and toxoplasmosis

Question 3

what are the infectious causes of abortion?

Answer 3

Enzootic abortion of ewes (chlamydia abortus)
toxoplasmosis
salmonellosis
campylobacterosis
listeriosis
borer disease

Question 4

what are the non-infectious causes of abortion?

Answer 4

counts towards around 2% of total abortions
pregnancy toxaemia
rough handling
transport
stress

Question 5

how to calculate the lambing percentage?

Answer 5

(Number of lambs born/Number of ewes put to the tup) x 100

Question 6

how to calculate the rearing percentage?

Answer 6

(Numbers of lambs reared/ Number of ewes put to the tup) x 100
tup means ram mating with the ewe

Question 7

what can cause a reduced lambing percentage?

Answer 7

abortion/ stillborn
insufficient ewe nutrition (no flushing)
severe weather/ stress
concurrent diseases ( e.g. fluke around tupping)

Question 8

what action should be taken during high abortion levels

Answer 8

• assume the abortion is due to infectious reasons
• isolate and mark aborted ewes immediately
  -do not foster lambs to aborted ewes
  -removed and destroy aborted material
  -ask a vet for advice/ sample for investigation
  -blood sample barren ewes when greater abortions that expected

Question 9

what causes enzootic abortion (EAE)?

Answer 9

Chlamydophila abortus
enzootic means peculiar to or constantly present in a location

Question 10

what is the epidemiology of Enzootic abortion?

Answer 10

usually brought in with replacement
intracellular bacteria - preference for placenta leading to placentitis
transmitted via ingestion
transmission through new lambs, afterbirth and vaginal discharge on surfaces
pregnant ewes may abort soon after infection
empty infected ewes - latency - asymptomatic until pregnancy ( can be years later)

Question 11

what are the signs of enzootic abortion (EAE)?

Answer 11

abortion occurs in the last trimester, especially finally 2-3 weeks
ewes usually not ill otherwise
stillborn lambs or live premature lambs may also be seen
a thickened and inflamed placenta

Question 12

what is the diagnosis of Enzootic abortion (EAE)

Answer 12

history and appearance of the placenta
microscopy of stained impression smear
NB there is no rise in serum titre until 2-3 weeks after the abortion, so there is no tests for latent infections, but useful retrospectively

Question 13

what are the preventative measures of Enzootic abortion (EAE)?

Answer 13

immediate action:
all aborted ewes should be isolated for over 6 weeks
all aborted materials removed
cull aborted ewes
disinfection the pens
do not foster lambs onto aborted ewes

Question 14

how to prevent enzootic abortion if there are multiple cases, up to 30% being affected?

Answer 14

long action oxytetracyclines can be used to suppress an outbreak from 90 days of gestation
This may need to be repeated at 14-day intervals
following an abortion, a ewe may have normal lambings from then on out, however, is still a carrier and will give it to the lambs and is infectious to other ewes

Question 15

what is the typical picture of enzootic abortion (EAE)

Answer 15

year 1- clean flock no history of EAE
buys infected replacement ewes

Year 2- some replacement females abort
infection spreads

Year 3 - abortion storm with over 30% of ewes aborting

year 4 - subsequent years, 5-10% of ewes will abort
mostly younger ewes will be affected

Question 16

what are the preventative measures for EAE?

Answer 16

enzovax which is a live vaccine immunisation which protects the ewes

Question 17

what is another cause for infectious ovine abortion?

Answer 17

Toxoplasmosis

Question 18

what is toxoplasmosis caused by?

Answer 18

Toxoplasma gondii
a well-adapted protozoa parasite, meaning it rarely causes significant disease in an infected definitive host.

Question 19

what is the intermediate host of toxoplasma gondii?

Answer 19

almost any warm-blooded animal ( but do not shed oocysts)

Question 20

what is the definitive host of toxoplasma gondii?

Answer 20

Felidae family (domestic cat) needed to complete lifecycle.

Question 21

is the disease zoonotic?

Answer 21

Yes. but humans usually get infected by meat and the surrounding environment.
they get mild flu symptoms unless they are pregnant (which can cause abortion, stillbirths or birth defects) or immunosuppressed (have encephalitis)

Question 22

how does the definitive host cause abortions in sheep?

Answer 22

Farm cat faeces in the hay can infect the sheep, causing abortion

Question 23

what is the source of infection of toxoplasmosis?

Answer 23

oocysts in the cat faeces
contamination in barns, feeds, bedding etc
one cat faeces dropping can infect 100 ewes
can survive in the environment for over a year
aborted tissue may be infectious for people who handle it.

Question 24

what are the signs of toxoplasmosis?

Answer 24

losses during and after pregnancy
barrenness
reabsorption
mummified ( dried) foetuses
abortions
stillbirths
weak lambs
leathery or white placenta
ewe is not usually ill
lesions- white, chalky foci of necrosis and calcification of up to 2mm diameter
lesions give a strawberry appearance

Question 25

what is the diagnosis of toxoplasmosis?

Answer 25

foetal antibodies ( from foetal fluid) by indirect fluorescent antibody test (IFAT) for more than 35 days post-injection the high antibody titre in dam is not diagnostic, but low levels rule out abortion due to toxoplasmosis

Question 26

what immediate action can be taken for toxoplasmosis?

Answer 26

no precautions specific to toxoplasmosis but be aware of mixed causes in a flock and treat them as EAE in feed, coccidiostat can help but it is expensive (antiprotozoal agent which prevents reproduction of the protozoa)

Question 27

how to control toxoplasmosis?

Answer 27

infection of ewes at any time will lead to lifetime long immunity vaccination of the whole flock initially or the younger half? vaccinate the replacement as they enter the flock in the following years medicate feeds keep only adult neutered cats

Question 28

other causes of infectious ovine abortion?

Answer 28

campylobacter

Question 29

what are the causes of campylobacter?

Answer 29

2 causative agents: 1) campylobacter jejuni- primarily an enteric bacteria (zoonotic) 2) C. fetus fetus purchased disease

Question 30

what are the signs of campylobacter?

Answer 30

abortion in the last 2 weeks stillbirths premature lambs the ewe may not be ill or may have a fever ewe can have diarrhoea, depression, discharge before abortion

Question 31

how is campylobacter transmitted?

Answer 31

faeco-oral route ( from carrier sheep, but birds also implicated)

Question 32

what else can campylobacter present?

Answer 32

it can present lesions: placentitis with cotyledon necrosis and intercotyledonary oedema (swelling) in C.fetus fetus, may have an oedematous foetus

Question 33

how to diagnose campylobacter

Answer 33

get a culture of foetal stomach content

Question 34

what are the actions taken in the event of an outbreak of campylobacter?

Answer 34

isolate- aborting ewe is a rich source of bacteria foetus, placenta and discharge are heavily contaminated others may then produce stillborn or weak live lambs ewes solidly immune and will not abort again apply the same principles of EAE (but antibiotics will not help)

Question 35

what are some other causes of abortion in sheep?

Answer 35

listeriosis

Question 36

what causes listeriosis?

Answer 36

it is caused by listeria monocytogenes or L. ivanovii ubiquitous (presenting) found in soil poor silage is a major source of infection well fermented silage does not allow multiplication poor silage which has not fermented as well, less acidic

Question 37

what are the signs of listeria?

Answer 37

abortion encephalitis in sheep (circling disease) typhlitis (inflammation of cecum) sepsis in lambs

Question 38

what happens during listeriosis abortions?

Answer 38

abortions occur a few weeks after infection ( may be only sign) may have some sheep with nervous signs dead or weak lambs sheep-to-sheep transmission probably has low significance.

Question 39

what actions are taken to deal with listeriosis?

Answer 39

treat it as if it is EAE examine the silage will be reflecting on the silage 3 weeks ago culling affected ewes is pointless

Question 40

another cause for abortion in sheep?

Answer 40

salmonellosis

Question 41

what causes salmonellosis?

Answer 41

various strains are implicated by: Salmonella Montevideo S. Dublin – usually source is cattle S. Typhimurium S. abortus ovis (rarely seen)

Question 42

what are the signs of salmonellosis?

Answer 42

death diarrhoea malaise pyrexia congested mucus membranes metritis after abortion (inflammation of the uterus)

Question 43

what are the treatments for salmonellosis?

Answer 43

delivery of autolytic/ emphysematous lambs death may still occur a week later due to uterine devitalisation antibiotics NSAIDs (non-steroid anti-inflammatory drugs) oral fluids aborted sheep isolated for at least 6 weeks

Question 44

what are the infectious causes of bovine abortion?

Answer 44

BVD IBR Neosporosis salmonellosis campylobacter mycotic disease leptospirosis listeria brucellosis (notifiable)