Abortions may be idiopathic or the result of metabolic or hormonal abnormalities, nutritional deficiencies, trauma, toxicities, or infectious processes. Investigation of the cause of ovine abortions has previously relied on a combination of histopathological examination of fetal tissues and placenta, along with bacterial culture of fetal stomach contents or tissue in combination with serological tests. PCR techniques are recommended to assist with the diagnosis of abortion.
Use of PCR technology increases the ability to search for pathogens implicated in ovine abortion but is an adjunct to other conventional laboratory tests, rather than replacing them. A full ovine abortion diagnostic workup can involve a combination of microbiology, histopathology and now PCR testing to increase the chances of confirming the cause of the abortion. Appropriate sample collection is integral in helping determine the cause.
Samples to collect:
We recommend collecting the following samples when investigating sheep abortions:
- Fetal stomach contents or lung.
- Fetal blood or fluids (pleural or peritoneal).
- Fixed tissues (placenta, liver, lung, kidney, spleen, brain, heart)
Recommended laboratory testing:
Using the testing recommended below our success rate in diagnosing sheep abortions is approximately 80-90%. See abortion submission form for full testing available. Recommended testing includes:
- Microbiology – abortion culture panel or selected tests.
- Serology for toxoplasma antibody.
- PCR testing on fetal stomach contents
- Histopathology on all tissues, including placenta.
- The abortion panel includes culture for Campylobacter, Salmonella and aerobic bacteria (including Listeria sp.).
- Toxoplasma abortion in vaccinated ewes occasionally seen
- Placenta can be cultured if fetal tissues are not available, but contamination is a significant problem, e.g. if Campylobacter jejuni is cultured from fetal stomach contents it is likely to be significant, whereas its presence in the placenta could easily be due to faecal contamination.
- Histology can sometimes be useful in sheep abortions but does not often give you a specific answer when the other testing is negative, e.g. it may reveal a bacterial placentitis (an indication that you might want to sample further abortions from the property to try and determine the bacterium involved), and it will sometimes detect lesions of Toxoplasma infection in the cotyledon when the fetal heart blood is negative.
- If taking samples for histology sample liver, lung, heart, spleen, brain and placenta (cotyledon and intercotyledonary placenta).
- Each year we see a few outbreaks of abortion where the fetal liver lesions look like Campylobacter sp. infection but it is not, and these have been shown to be due to Helicobacter sp. This bacterium is very difficult to culture, but we now have a PCR test for this.
- If you suspect Hairy Shaker Disease take a heart blood sample and submit for PCR testing.
Consult our Veterinary Handbook for further information or just give us a call.