Feline immunodeficiency virus (FIV) infection in domestic pet cats in Australia and New Zealand: Guidelines for diagnosis, prevention and management.

Despite the passage of over 30 years since its discovery, the importance of feline immunodeficiency virus (FIV) on the health and longevity of infected domestic cats is hotly debated amongst feline experts. Notwithstanding the absence of good quality information, Australian and New Zealand (NZ) veterinarians should aim to minimise the exposure of cats to FIV. The most reliable way to achieve this goal is to recommend that all pet cats are kept exclusively indoors, or with secure outdoor access (e.g., cat enclosures, secure gardens), with FIV testing of any in-contact cats. All animal holding facilities should aim to individually house adult cats to limit the spread of FIV infection in groups of animals that are stressed and do not have established social hierarchies. Point-of-care (PoC) FIV antibody tests are available in Australia and NZ that can distinguish FIV-infected and uninfected FIV-vaccinated cats (Witness™ and Anigen Rapid™). Although testing of whole blood, serum or plasma remains the gold standard for FIV diagnosis, PoC testing using saliva may offer a welfare-friendly alternative in the future. PCR testing to detect FIV infection is not recommended as a screening procedure since a negative PCR result does not rule out FIV infection and is only recommended in specific scenarios. Australia and NZ are two of three countries where a dual subtype FIV vaccine (Fel-O-Vax® FIV) is available and offers a further avenue for disease prevention. Since FIV vaccination only has a reported field effectiveness of 56% in Australia, and possibly lower in NZ, FIV-vaccinated cats should undergo annual FIV testing prior to annual FIV re-vaccination using a suitable PoC kit to check infection has not occurred in the preceding year. With FIV-infected cats, clinicians should strive to be even more thorough than usual at detecting early signs of disease. The most effective way to enhance the quality of life and life expectancy of FIV-infected cats is to optimise basic husbandry and to treat any concurrent conditions early in the disease course. Currently, no available drugs are registered for the treatment of FIV infection. Critically, the euthanasia of healthy FIV-infected cats, and sick FIV-infected cats without appropriate clinical investigations, should not occur.

Detection of Brucella spp. during a serosurvey of pig-hunting and regional pet dogs in eastern Australia.

Brucellosis is a zoonotic disease with worldwide distribution. Brucella suis serotype 1 is thought to be maintained in the Australian feral pig population, with disease prevalence higher in Queensland (Qld) than New South Wales (NSW). Pig hunting is a popular recreational activity in rural Qld and NSW, with feral pigs in these states thought to carry B. suis. Brucellosis associated with B. suis has been diagnosed in dogs engaged in pig hunting in some of these areas. A total of 431 dogs from northern Qld and north-west NSW were recruited. Two distinct cohorts of clinically healthy dogs were tested - (1) 96 dogs from central, north and far north Queensland actively engaged in pig-hunting and (2) 335 dogs from rural and remote north-west NSW that were primarily companion (non-pig hunting) animals. Serum samples were tested for antibodies to Brucella spp. using the Rose Bengal test (RBT) test followed by complement fixation testing (CFT) for RBT-positive samples. A subset of samples was retested using RBT and CFT. Seven dogs were considered seropositive for B. suis from Qld and remote NSW, including 4/96 (4.2%; 95% CI 3.5% to 4.3%) from the pig-hunting cohort and 3/335 (0.9%) from the regional pet dog cohort. The use of RBT and CFT in dogs to detect anti-Brucella antibodies requires validation. Veterinarians treating pig-hunting dogs and physicians treating pig hunters in central, north and far north Qld need to be aware of the zoonotic risk posed by B. suis to these groups.

Seroprevalence of Coxiella burnetii in pig-hunting dogs from north Queensland, Australia.

The causative agent of Q fever, Coxiella burnetii, is endemic to Queensland and is one of the most important notifiable zoonotic diseases in Australia. The reservoir species for C. burnetii are classically ruminants, including sheep, cattle and goats. There is increasing evidence of C. burnetii exposure in dogs across eastern and central Australia. The present study aimed to determine if pig-hunting dogs above the Tropic of Capricorn in Queensland had similar rates of C. burnetii exposure to previous serosurveys of companion dogs in rural north-west New South Wales. A total of 104 pig-hunting dogs had serum IgG antibody titres to phase I and phase 2 C. burnetii determined using an indirect immunofluorescence assay test. Almost one in five dogs (18.3%; 19/104; 95% confidence interval 9.6%-35.5%) were seropositive to C. burnetii, with neutered dogs more likely to test positive compared to entire dogs (P = 0.0497). Seropositivity of the sampled pig-hunting dogs was one of the highest recorded in Australia. Thirty-nine owners of the pig-hunting dogs completed a survey, revealing 12.8% (5/39) had been vaccinated against Q fever and 90% (35/39) were aware that both feral pigs and dogs could potentially be sources of C. burnetii. Our findings indicate that pig hunters should be aware of the risk of exposure to Q fever during hunts and the sentinel role their dogs may play in C. burnetii exposure.

Diagnosing feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) infection: an update for clinicians.

With the commercial release in Australia in 2004 of a vaccine against feline immunodeficiency virus (FIV; Fel-O-Vax FIV®), the landscape for FIV diagnostics shifted substantially. Point-of-care (PoC) antibody detection kits, which had been the mainstay for diagnosing FIV infection since the early 1990s, were no longer considered accurate to use in FIV-vaccinated cats, because of the production of vaccine-induced antibodies that were considered indistinguishable from those produced in natural FIV infections. Consequently, attention shifted to alternative diagnostic methods such as nucleic acid detection. However, over the past 5 years we have published a series of studies emphasising that FIV PoC test kits vary in their methodology, resulting in differing accuracy in FIV-vaccinated cats. Importantly, we demonstrated that two commercially available FIV antibody test kits (Witness™ and Anigen Rapid™) were able to accurately distinguish between FIV-vaccinated and FIV-infected cats, concluding that testing with either kit offers an alternative to PCR testing. This review summarises pertinent findings from our work published in a variety of peer-reviewed research journals to inform veterinarians (particularly veterinarians in Australia, New Zealand and Japan, where the FIV vaccine is currently commercially available) about how the approach to the diagnosis of FIV infection has shifted. Included in this review is our work investigating the performance of three commercially available FIV PoC test kits in FIV-vaccinated cats and our recommendations for the diagnosis of FIV infection; the effect of primary FIV vaccination (three FIV vaccines, 4 weeks apart) on PoC test kit performance; our recommendations regarding annual testing of FIV-vaccinated cats to detect 'vaccine breakthroughs'; and the potential off-label use of saliva for the diagnosis of FIV infection using some FIV PoC test kits. We also investigated the accuracy of the same three brands of test kits for feline leukaemia virus (FeLV) diagnosis, using both blood and saliva as diagnostic specimens. Based on these results, we discuss our recommendations for confirmatory testing when veterinarians are presented with a positive FeLV PoC test kit result. Finally, we conclude with our results from the largest and most recent FIV and FeLV seroprevalence study conducted in Australia to date.

The protective rate of the feline immunodeficiency virus vaccine: An Australian field study.

A case-control field study was undertaken to determine the level of protection conferred to client-owned cats in Australia against feline immunodeficiency virus (FIV) using a commercial vaccine. 440 cats with outdoor access from five Australian states/territories underwent testing, comprising 139 potential cases (complete course of primary FIV vaccinations and annual boosters for three or more years), and 301 potential controls (age, sex and postcode matched FIV-unvaccinated cats). FIV status was determined using a combination of antibody testing (using point-of-care test kits) and nucleic acid amplification, as well as virus isolation in cases where results were discordant and in all suspected FIV-vaccinated/FIV-infected cats ('vaccine breakthroughs'). Stringent inclusion criteria were applied to both 'cases' and 'controls'; 89 FIV-vaccinated cats and 212 FIV-unvaccinated cats ultimately satisfied the inclusion criteria. Five vaccine breakthroughs (5/89; 6%), and 25 FIV-infected controls (25/212; 12%) were identified, giving a vaccine protective rate of 56% (95% CI -20 to 84). The difference in FIV prevalence rates between the two groups was not significant (P=0.14). Findings from this study raise doubt concerning the efficacy of Fel-O-Vax FIV® under field conditions. Screening for FIV infection may be prudent before annual FIV re-vaccination and for sick FIV-vaccinated cats. Owners should not rely on vaccination alone to protect cats against the risk of acquiring FIV infection; other measures such as cat curfews, the use of 'modular pet parks' or keeping cats exclusively indoors, are recommended.