Transmission Of Infectious Agents Causing Abortion

Question 1

What is an abortion?

Answer 1

premature expulsion from the uterus of non-viable products of conception

Question 2

Premature birth meaning

Answer 2

premature expulsion from the uterus of viable products of conception.

Question 3

Still birth meaning

Answer 3

delivery of a fully formed dead neonate.

Question 4

What is embryonic or foetal death

Answer 4

reabsorption, mummification, maceration

Question 5

Why is abortion important?

Answer 5

1. Health and welfare of dam
2. Economics;
   • Lost calves/lambs
   • Getting the animal pregnant again
   • Keeping the animal while getting pregnant
   • Direct treatment, replacement and investigation costs
3. Legal; “an abortion or calving which takes place less than 271 days after service/insemination, or 265 days after implantation or transfer of an embryo, whether the calf is born dead or alive”
4. Zoonotic;
   Some abortion pathogens are zoonotic: Protect yourself
   Obligation to protect others against

Question 6

Describe the steps leading to and after abortion of animal

Answer 6

• Communicate zoonotic risk
• Immediate isolation of the dam
• Disposal (removal vs submission) of aborted
material and infected bedding
• Permanent identification of the dam
• Vaccination
• Whole flock antibiotic treatment: NOT acceptable as control measure

Question 7

What are the individual costs of an abortion of;
-dairy cow
-beef cow
-sheep

Answer 7

-630 pounds
-800
-85

Question 8

After an abortion what are you required to send to laboratory?

Answer 8

– Dead foetus(es): foetal stomach content, foetal fluid, liver, lung
and heart
– Placenta: including cotyledon and surrounding membrane (vaginal swab)
– Dam blood samples

Question 9

What are the 2 main causes of abortion?

Answer 9

Infectious agents
Non infectious

Question 10

What are the 2 main mechanisms of infectious abortion

Answer 10

Direct- infectious agents cause disruption of placental supply (placentitis)- pathogen directly causes abortion

Indirect- inability to carry foetus to term (due to reasons like maternal endotoxaemia, foetal hypoxia)- pathogen causes systemic disease

Question 11

What is the mechanism for non infectious abortion

Answer 11

Indirect

Question 12

What are ways of preventing abortions?

Answer 12

Biosecurity (prevent the entrance);
-Closed vs open herd/flock
-Quarantine (returning stock)
-Neighbouring farms/fences
-Stray animals/vermins
-Health schemes (accredited)

Vaccination;
– Cattle: Salmonella, Leptospirosis, IBR, BVDV – Sheep: Toxoplasma, EAE, SBV

Question 13

How do we contain an abortion outbreak?

Answer 13

Biocontainment (prevent the spreading):
-Disinfection
Isolate the animal
-Breeding
-Treatment vs cull

Avoid future losses: cull, vaccination, (antibiotics?)

Question 14

Are there any clinics signs other than abortion itself?

Answer 14

Often no

Question 15

Name some of the main causes of ruminant abortion
-bovine

Answer 15

-Bacillus licheniformis
*Neospora caninum
-Salmonella species
-Truperella pyogenes
-Listeria monocytogenes
-Campylobacter fetus
fetus
• Bovine Viral Diarrhoea
• Bovine herpes virus type I
-Leptospira hardjo
• Aspergillus species
-Brucella abortus

( - = bacteria
• = virus
* = Protozoa)

Question 16

Name some of the main causes of abortion
-in ovine

Answer 16

-Chlamydia abortus (EAE)
*Toxoplasma gondii
-Campylobacter species
-Salmonellaspecies
-Listeriaspecies
• Border disease virus (BDV)
• Schmallenburg virus (SBV)
-Coxiella burnetii
-Anaplasma phagocytophilum
-Brucella species
• Bluetongue virus

Question 17

Name the most common infectious disease causing abortion in;
-beef (33%)
-dairy (30%)
-sheep (2)

Answer 17

1.Bacillus licheniformis
2. Neospora caninum
3. Chalmydia abortus (EAE) & Toxoplasma gondii

Question 18

Main zoonotic infectious causes of ruminant abortion

Answer 18

-brucellosis (undulant fever)
-chlamydiosis (EAE)
-Q fever