Temporary importation of Babesia and Ehrlichia seropositive horses into Australia.

This research primarily discusses the issues surrounding the importation of horses that are seropositive for Babesia and Ehrlichia into Australia, focusing specifically on ready and potential sources of infection, such as ticks and other wildlife, at the Eastern Creek Quarantine Station (ECQS). It suggests a need to revisit the protocols for prevention measures, particularly for treating animals with acaricides, and calls for further investigation into ehrlichial diseases.

Wildlife and Parasites at Eastern Creek Quarantine Station (ECQS)

• The paper points out existing misinformation regarding the presence of hares at ECQS. It highlights that hares have been a constant at the station and could serve as a blood source for ticks introduced into the country by quarantined animals.
• Furthermore, the research underscores the existence of other local wildlife like rodents, native marsupials, feral cats, and wild ducks, as well as hematophagous insects, all of which can potentially act as reservoirs and transmission vectors for ehrlichial diseases in various mammals, including horses.

The Issue with Imported Ticks

• Among the findings, it is revealed that Rhipicephalus sanguineus ticks found on quarantined dogs, tested and treated for Ehrlichia canis pre-importation, were actually introduced into Australia on dogs hailing from a country where E canis is prevalent.
• The research suggests that this incident indicates a need for the Australian Quarantine and Inspection Service (AQIS) to reevaluate its protocols for acaricide treatment of imported animals, especially if the containment conditions at ECQS don’t improve.

Introduction and Spread of Ehrlichial Diseases

• The study brings up the fact that no prerequisites for horses to be tested for ehrlichial diseases prior to importation into Australia have existed in the past.
• However, as of 1995, horses imported from countries such as the USA, the EU, Singapore, and Hong Kong have been required to undergo a 21-day pre-export acaricide treatment, with exceptions being made for horses from New Zealand.
• The AQIS does not consider New Zealand as a source of vectors for horse ehrlichial diseases.

Diagnosis and Detection of Ehrlichial Diseases

• The research discusses the limitations of the current serological tests for detecting Ehrlichia risticii infections, highlighting the absence in Australia of a particular test, known as western immunoblot testing, that differentiates between ehrlichial antigens.
• The paper further notes the lack of polymerase chain reaction (PCR) testing in Australia for ehrlichial diseases, despite their emerging significance and despite PCR being the gold standard for detecting active infections.
• The absence of any reported examinations of Australian ticks for ehrlichial DNA is also pointed out.

Implications and Recommendations

• The paper emphasises that vectors for Ehrlichia canis have gone undetected in the past, suggesting that current quarantine methods may not be sufficient.
• Based on this and other reported findings, the lack of a requirement for tests for serological disease in horses entering Australia is questioned, pushing for a reconsideration of policies in light of past security lapses and emerging knowledge about ehrlichiae life cycles.