Risk factors for feline infectious peritonitis in Australian cats.

The objective of this study was to determine whether patient signalment (age, breed, sex and neuter status) is associated with naturally-occurring feline infectious peritonitis (FIP) in cats in Australia. A retrospective comparison of the signalment between cats with confirmed FIP and the general cat population was designed. The patient signalment of 382 FIP confirmed cases were compared with the Companion Animal Register of NSW and the general cat population of Sydney. Younger cats were significantly over-represented among FIP cases. Domestic crossbred, Persian and Himalayan cats were significantly under-represented in the FIP cohort, while several breeds were over-represented, including British Shorthair, Devon Rex and Abyssinian. A significantly higher proportion of male cats had FIP compared with female cats. This study provides further evidence that FIP is a disease primarily of young cats and that significant breed and sex predilections exist in Australia. This opens further avenues to investigate the role of genetic factors in FIP.

Prevalence of feline immunodeficiency virus infection in domesticated and feral cats in eastern Australia.

Serum samples from 340 pet cats presented to three inner city clinics in Sydney Australia, 68 feral cats from two separate colonies in Sydney, and 329 cattery-confined pedigree and domestic cats in eastern Australia, were collected over a 2-year period and tested for antibodies directed against feline immunodeficiency virus (FIV) using immunomigration (Agen FIV Rapid Immunomigration test) and enzyme-linked immunosorbent assay methods (Snap Combo feline leukaemia virus antigen/FIV antibody test kit, IDEXX Laboratories). Western blot analysis was performed on samples in which there was discrepancy between the results. Information regarding breed, age, gender, housing arrangement and health status were recorded for all pet and cattery-confined cats, while the estimated age and current physical condition were recorded for feral cats. The FIV prevalence in the two feral cat populations was 21% and 25%. The majority of FIV-positive cats were male (60-80%). The FIV prevalence in cattery-confined cats was nil. The prevalence of FIV in the pet cat sample population was 8% (27/340) with almost equal prevalence in 'healthy' (13/170) and 'systemically unwell' (14/170) cats. The age of FIV-positive pet cats ranged from 3 to 19 years; all FIV-positive cats were domestic shorthairs with outside access. The median age of FIV-positive pet cats (11 years) was significantly greater than the median age of FIV-negative pet cats (7.5 years: P<0.05). The prevalence of FIV infection in male pet cats (21/172; 12%) was three times that in female pet cats (6/168; 4%; P<0.05). With over 80% of this pet cat population given outside access and continued FIV infection present in the feral population, this study highlights the need to develop rapid, accurate and cost-effective diagnostic methods that are not subject to false positives created by concurrent vaccination against FIV. This is especially important in re-homing stray cats within animal shelters and monitoring the efficacy of the new vaccine, which has not been challenged against Australian strains. The absence of FIV within cattery-confined cats highlights the value in routine screening and indoor lifestyles. This study provides cogent baseline FIV prevalences in three cat subpopulations which can be used for appraising potential disease associations with FIV in Australia.

Disseminated Mycobacterium avium infection in young cats: overrepresentation of Abyssinian cats.

Disseminated Mycobacterium avium-intracellulare complex (MAC) infection was diagnosed in 10 young cats (1-5 years of age) from Australia or North America between 1995 and 2004. A further two cats with disseminated mycobacteriosis (precise agent not identified) were recognised during this period. Of the 12, 10 were Abyssinian cats, one was a Somali cat and one was a domestic shorthair cat. None of the cats tested positive for either FeLV antigen or FIV antibody. The clinical course of these infections was indolent, with cats typically presenting for weight loss, initially in the face of polyphagia, with a chronicity of up to several months. Additional clinical features included lower respiratory tract signs and peripheral lymphadenomegaly. A marked diffuse interstitial pattern was evident in thoracic radiographs, even in cats without overt respiratory involvement. Hair clipped to perform diagnostic procedures tended to regrow slowly, if at all. Diagnosis was generally made by obtaining representative tissue specimens from mesenteric lymph nodes, liver or kidney at laparotomy, or from a popliteal lymph node. The primary antecedent event was most likely colonisation of either the alimentary or respiratory tract, followed by local invasion and eventual lymphatic and haematogenous dissemination. Nine cases were treated using combination therapy with agents effective for MAC infection in human patients. Two cats are still undergoing initial therapy and have responded. Of the remaining seven, all responded during long courses (5-14 months) of clarithromycin combined with either clofazimine or rifampicin, and a fluoroquinolone or doxycycline. Of these, three cats remain well (with durations between 2 months and 2 years following therapy); two developed recurrent disease (at 3 months and 2 years, respectively, following therapy) and have restarted therapy. The remaining two cats improved 1 year and 5 months, respectively, after diagnosis but ultimately succumbed. The two cats in which therapy was restarted have improved dramatically. Certain lines of Abyssinian and Somali cats likely suffer from a familial immunodeficiency that predisposes them to infection with slow-growing mycobacteria such as MAC.

Infections and some other conditions affecting the skin and subcutis of the naso-ocular region of cats--clinical experience 1987-2003.

Infections of the skin or subcutis of the naso-ocular region develop through two mechanisms. Cases with lesions but without concomitant signs of nasal disease probably result from cat scratch injuries. Under certain circumstances, such lacerations result in the introduction of saprophytic microorganisms in such large numbers that host defence mechanisms are overwhelmed. This results in localised, variably invasive, disease in an otherwise immunocompetent host. An unpredictable range of organisms can give rise to such infections including a variety of fungal and bacterial genera. Causal organisms will likely vary from one geography to another as a result of differences in soil type and related environmental factors. Accordingly, procurement of appropriate tissue specimens for culture and susceptibility testing is essential to guide therapy, as these cases require medical and sometimes surgical intervention in order to effect a favourable outcome. In contrast, patients with naso-ocular lesions and concurrent signs of nasal disease have a different pathogenesis. Primary infection of the sinonasal region likely results from the inhalation of infectious propagules, with the infection subsequently penetrating overlying bones to invade the subcutaneous space. These lesions are typically the result of cryptococcosis or aspergillosis and must be distinguished from invasive nasal malignancies. An approach to the investigation and treatment of these patients is presented together with photographs of representative cases.