Detection of Chlamydia abortus in aborted chorioallantoises of horses from Western Canada.

The study titled “Detection of Chlamydia abortus in aborted chorioallantoises of horses from Western Canada” presents research on the prevalence of chlamydia in aborted horse pregnancies in Western Canada. The findings emphasize the need for improved biosecurity protocols to prevent zoonotic transfer of the pathogen.

Objective of the study

The study’s primary objective was to shed light on the prevalence of chlamydia, specifically Chlamydia abortus, in aborted horse pregnancies in Western Canada. The endeavor comes in light of similar research in Australia and the lack of comprehensive studies on this subject in North America.

• This research was prompted by a need to better understand the prevalence of the chlamydia pathogen in equine populations, following a zoonotic transfer event of Chlamydia abortus from aborted equine tissues in Australia.
• It aimed to provide insights that could be beneficial in the establishment of efficient biosecurity protocols to prevent the zoonotic transfer of this pathogen.

Methodology

To conduct this research, scientists used 99 formalin-fixed, paraffin-embedded placental samples originating from equine abortions in Western Canada between 2009 and 2020. These samples underwent standard Chlamydia-specific 16S rRNA conventional PCR testing.

• These samples were chosen to give a wide-ranging view of the prevalence of the pathogen within the equine population over a substantial timespan.
• The use of the 16S rRNA conventional PCR testing is characteristic for its specificity to chlamydial DNA, and thus provides reliable results on the presence of the pathogen.

Findings

Out of the 99 placental samples, 26 tested positive for chlamydial DNA. Further DNA sequencing identified 22 out of these 26 cases as Chlamydia abortus.

• Out of the positive cases, most (17 out of 26) originally didn’t have a final diagnosis noted on their pathology reports.
• 21 of the 22 Chlamydia abortus-positive samples were confirmed as positive through chlamydial immunohistochemistry, further solidifying the results.

Implications

The study concluded a high prevalence of Chlamydia abortus in equine abortions, an outcome contrasting to similar studies conducted in Europe. These findings indicate the need for more robust biosecurity measures in equine foaling, abortion, and stillbirth management to prevent the zoonotic transfer of this pathogen.