Emergency Animal Disease Surveillance

Online training - Case study 1: Aborting goats

Differential diagnoses

Potential causes of goat abortion

Think about potential causes of goat abortion by completing the exercise below.

Word detection

Based on the lack of other causes and the placental findings, this herd appears to be suffering an infectious abortion event. What are the possible agents involved in caprine or ovine abortion? List as many as you can below.

Agents	Likeness	Comments
Coxiella burnetii	Most likely	A common agent in goats and a common cause of abortion, both in Australia and overseas. Late abortions can occur, with cotyledonary and intercotyledonary necrosis.
Chlamydia species – C. psittaci, or C abortus	Somewhat likely	Chlamydial species are a common cause of abortion in goats. C. abortus is exotic to Australia while C. psittaci is endemic. Abortion can occur at any stage, but most are in the last month, with placentitis evident.
Toxoplasma gondii	Somewhat likely	A common cause of abortion and foetal loss, although less likely based on the distribution of lesions on the placenta.
Campylobacter species	Somewhat likely	Possible but unlikely. Although common in other ruminants, it appears to be rare in goats. But placentitis is a feature.
Leptospira interrogans	Somewhat likely	Abortions can occur at any time, however other clinical signs (e.g. anaemia, icterus, haemoglobinuria) could be expected. Goats are also covered for some serovars of Leptospira by the Leptoshield® vaccine.
Listeria monocytogenes	Somewhat likely	Can cause sporadic abortions, so less likely to be associated with an abortion outbreak. Prior to abortion does may have fever, decreased appetite and reduced milk production.
Fungus (Mucor, Rhizopus etc.)	Somewhat likely	Less likely due to distribution of lesions on placenta.
Akabane virus	Somewhat likely	Arboviruses are present in SE Queensland and can cause abortion. Stillborn or mummified foetuses (arthrogryposis and/or hydranencephaly) are usually found.
Brucella melitensis	Least likely	Although abortion does occur most commonly in the 4th month, the placenta appears grossly normal and the bacteria is exotic to Australia. Other endemic species of Brucella are less likely also.
Caprine Herpesvirus 1 (CpHV 1)	Least likely	Later term abortion, but usually presents with necrotic lesions, not purulent.
Bluetongue	Least likely	Unlikely to cause abortions in goats. Infectious but non-contagious orbivirus transmitted by Culicoides spp., so an event of this scale would be associated with the vector. Often lesions are not seen, as pyrexia leads to abortion.
Border disease virus (BDV)	Least likely	Goats fairly resistant. Usually see foetal anomalies (“hairy shaker” syndrome). Usually have history of this before, or recent introduction of new stock.
Salmonella species	Least likely	Possible, but usually accompanied by other clinical signs. Associated with stress – overcrowding, transportation, poor hygiene.
Mycoplasma species (M. mycoides and M. aglactia)	Least likely	Relatively rare, but can cause late-term abortion
Yersinia pseudotuberculosis	Least likely	Relatively rare, but abortion has been reported in goats