Table 1 Group details

1

381

Dogs (multiple breeds) residing in the Northern Beaches local government area of Sydney, New South Wales (NSW) specifically within postcodes 2101–2108 and 2084 (Fig. 1). This densely populated area of NSW is highly enzootic for the Australian paralysis tick (Ixodes holocyclus). Numerous cases of tick paralysis in domestic animals are treated by veterinarians in this area each year and the emergency departments of three local hospitals (Mona Vale, Manly and Hornsby) collectively treated 1,131 tick bite presentations in humans between July 2014 and August 2016 (Dr Ben Taylor, Mona Vale Hospital, 2016 pers. com.). Dogs were recruited by advertisement through local veterinary hospitals and at the Pittwater (now Northern Beaches) Council’s annual event ‘Dog Day by the Bay’ (in 2012 and 2013) at the Rowland Reserve, Bayview. Dogs in this group represented a cohort considered highly likely to be exposed to I. holocyclus and therefore act as potential sentinels for human infections.

2

60

Dogs (multiple breeds) owned by and living with people with a variety of symptoms (e.g. headaches, joint and muscle pain, fatigue, sleeplessness, rash, memory loss, etc.) consistent with a ‘Lyme disease-like syndrome’, who had received a diagnosis of a tick-associated illness by a medical practitioner. Owners enrolled their dogs following advertisements by patient advocacy groups and by word of mouth. Dogs assigned to this group were located throughout Australia, but mostly in coastal NSW and Western Australia. Dogs in this group were chosen because of their close association with humans who had received a diagnosis and may, therefore, provide selective evidence for a sentinel status.

3

84

Dogs (foxhounds) resident at Northern Serums Pty Ltd, Lismore NSW, an APVMA-approved manufacturer of paralysis tick antiserum. Most (n = 79) of these dogs were bred within the facility, with five adult dogs sourced originally from elsewhere, i.e. Brisbane (n = 1) and Melbourne (n = 4). At this facility, approximately 400 unfed (questing) female I. holocyclus ticks collected from multiple locations in coastal NSW (Lismore North, Casino, Tabulam South, Macksville) and Queensland (Maleny, Atherton and Bauple Mountain) are attached to each dog annually and allowed to feed and engorge before removal. Blood is drawn regularly from these dogs for the manufacture of hyperimmune serum which is supplied commercially to veterinarians for the treatment of tick paralysis in domestic animals. Dogs in this group were chosen to specifically test the hypothesis that dogs bitten by I. holocyclus are sentinels for certain infections transmitted by this tick species.

4

30

Dogs (camp dogs; dingo crosses and other breeds) residing at two indigenous communities located on the Dampier Peninsula, north of Broome in the tropical Kimberley region of Western Australia. These dogs were sampled as part of routine health assessments and to determine the internal and external parasite load. In this area, there is a high prevalence of the brown dog tick (Rhipicephalus sanguineus) and minimal ectoparasite control. These dogs served as a control group since I. holocyclus does not occur in this location.

Total

555