Jacqueline M. Norris

Treatment of feline herpesvirus-1 associated disease in cats with famciclovir and related drugs

Background Feline herpesvirus 1 (FHV-1) is a common cause of ocular and upper respiratory disease in cats and kittens, and a potential cause of eosinophilic dermatitis. Hypothesis The systemic anti-herpes drug, famciclovir (Famvir; Novartis), would be effective in the clinical management of disease attributable to FHV-1, including conjunctivitis, keratitis, corneal sequestra, rhinosinusitis and FHV-1 associated dermatitis. Clinical outcome Oral famciclovir was used to treat signs considered referable to FHV-1 in 10 cats: four had primary ocular disease, two had rhinosinusitis and four had FHV-1 associated dermatitis. Patients treated in Australia (five cats) and Europe (one cat) were given 62.5 mg of famciclovir once or twice daily. Four cats treated in the USA were given 125 mg three times daily. Famciclovir was uniformly well tolerated and, in all cases, had a positive impact on the patients condition. The apparent improvement in lesions was superior to what had been achieved previously using other therapeutic strategies. One cat with severe destructive rhinosinusitis was significantly improved by a 4-month course of famciclovir in combination with antibacterials. Corneal sequestra detached in two out of three cats treated; cats with ocular signs were qualitatively more comfortable, with reduced clinical signs and an improved appearance of the eyes. Critically, oral famciclovir therapy was considered more convenient than topical ocular therapy. All four cats with FHV-1 associated dermatitis improved substantially, although relapse occurred subsequently in three patients. A further cat with presumptive FHV-1 associated dermatitis responded to topical aciclovir cream before famciclovir could be sourced. Conclusions Famciclovir appears to be a promising systemic drug for treating diseases associated with FHV-1 infection. More rigorous clinical trials are required to optimise the dosing regimen for safe and effective specific anti-herpes treatment in feline clinical medicine.

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.

Demographics and husbandry of pet cats living in Sydney, Australia: results of cross-sectional survey of pet ownership

Our aim was to collect baseline data on the age, gender, breed, reproductive status and husbandry (housing, diet, vaccination, veterinary attention) of pet cats living in Sydney. Accordingly, a cross-sectional survey of 2768 households was conducted using a postal questionnaire. The 2006 Sydney residential phone book was used as the sampling frame. Non-responders were re-mailed the questionnaire on two further occasions, 2 and 4 weeks after the first posting. Completed questionnaires were received from 884 households. No pets were kept by 387 (43.8%) respondents. Dogs and cats were owned by 295 (33.4%) and 198 (22.5%) of households, respectively, with 7.8% of households having both cat(s) and dog(s). Fish and birds were the next most popular pets. Of the 198 cat-owning households, 54.0% kept only cat(s), while 46.5% kept cats with other pets. The distribution of cat ownership across Sydney was non-uniform. Each cat-owning household kept 1.3 cats on average, with the majority keeping one (75.8% households) or two (18.7%). For the 260 cats, the mean age was 7.1 years, the median 6 years, with a range of 3 months to 22 years. There were significantly more female (143; 55%) than male cats (117; 45%). Only seven cats (2.7%) were sexually entire, and these were all ≤6 years. Crossbred cats outnumbered pedigree cats by a ratio of 3.3:1. The Burmese was the most common breed, followed by the Persian. The median age of pedigree cats (5.5 years) was significantly lower than for domestic crossbred cats (7.0 years). Most cats were housed both indoors and outdoors (72.6%), with 19.7% being restricted to indoors and/or ‘pet park enclosures’. Pedigree cats were significantly more likely than crossbreds to be housed indoors. Most owners fed their cats a combination of commercial dry and canned food (38.1%), although fresh meat was popular also and either fed alone (1.6%) or in combination with dry food (14.4%), tinned food (1.6%) or canned and dry food (25.8%). A diet consisting of dry food alone was fed to cats in 13.4% of households. Ninety percent of cats had been vaccinated at least once, while 72.2% received a vaccination in the last 3 years. Older cats were less likely to have been vaccinated recently than younger cats. Only 5.8% of cats had never visited a veterinarian. For the 243 cats that had received veterinary attention, the average number of years since the last visit was 1.5.

Clinicopathological findings associated with feline infectious peritonitis in Sydney, Australia : 42 cases (1990-2002)

Objectives To review the clinicopathological findings in naturally‐occurring, histopathologically confirmed cases of feline infectious peritonitis in client‐owned cats in Sydney, Australia, with the purpose of identifying factors assisting in the diagnosis of this complex disease syndrome and to characterise the disease as it occurs in this region. Design Retrospective clinical study: the clinical records of all cats with histopathologically confirmed feline infectious peritonitis at the University Veterinary Centre Sydney and a private cat hospital in Sydney between 1990 and 2002 were reviewed for signalment, history, physical findings, diagnostic test results and the distribution of histological lesions throughout the body at necropsy. Results Forty‐two cats met the inclusion criteria. Significant features of this study that unique to the contemporary literature are i) the over‐representation of certain breeds (Burmese, Australian Mist, British Shorthaired, and Cornish Rex) and the under‐representation of other breeds (Domestic Shorthaired, Persian); ii) the overrepresentation of males; iii) the tendency for effusive disease in Australian Mist cats and non‐effusive disease in Burmese; iv) the even age distribution of disease seen in cats older than 2 years‐of‐age; and v) the presence of fulminant immune‐mediated haemolytic anaemia in two cats in this study. Conclusion The study highlights the diverse range of clinical manifestations and the complexities experienced by clinicians in diagnosing this fatal disease. Some aspects of the epidemiology and clinical manifestations of feline infectious peritonitis appear different to the disease encountered in Europe and North America, most notably the over‐representation of specific breeds and the presence of immune‐mediated haemolytic anaemia.

Associations amongst three feline Porphyromonas species from the gingival margin of cats during periodontal health and disease.

Digoxigenin labelled whole chromosomal DNA probes directed against three feline members of the genus Porphyromonas (P. gingivalis VPB 3492, P. circumdentaria NCTC 12469T and P. salivosa VPB 3313) were used to identify and quantify organisms in samples taken from the gingival margins of 40 domestic cats with different grades of periodontal disease. At the right upper canine tooth, the grade of periodontal disease ranged from 0 to 5 and the cfu of facultative/obligate anaerobes ranged from 5.5 x 10(4) to 2.0 x 10(6)). In 38 of the 40 cats, at least one of the three Porphyromonas species was isolated and regression analysis showed that the cfu of total Porphyromonas sp. was a highly significant indicator of the grade of periodontal disease (p < 0.001, R2 0.510). Feline P. gingivalis was isolated from 37 of the 40 cats and regression analysis showed that it was a highly significant predictor of the grade of periodontal disease (p < 0.001, R2 0.561). The cfu of P. salivosa was a significant predictor of the grade of periodontal disease (p < 0.001, R2 0.286) and regression analysis showed that there was a significant positive relationship between cfu of P. circumdentaria and grade of periodontal disease (p = 0.018, R2 0.116). The periodontal grades at the right upper third premolar tooth ranged from 0 to 6. The cfu of facultative/obligate anaerobes isolated ranged from 1.2 x 10(5) to 7.9 x 10(6), and regression analysis showed that cfu was a significant predictor of periodontal grade (p < 0.001, R2 0.378). The cfu of total Porphyromonas species ranged from 1.2 x 10(4) to 1.7 x 10(6) and regression analysis of the cfu against the grade of periodontal disease showed a highly significant association (p < 0.001, R2 0.633). The cfu of P. gingivalis ranged from 0 to 1.1 x 10(6) and regression analysis of the cfu of P. gingivalis against the grade of periodontal disease showed a highly significant association (p < 0.001, R2 0.439). The cfu of P. salivosa was a significant predictor of the grade of periodontal disease (p < 0.001, R2 0.479) and the same association was found between cfu of P. circumdentaria and grade of periodontal disease (p = 0.002, R2 0.204). This study has established Porphyromonas as anumerically significant and highly prevalent genus in feline periodontal disease.

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.

Observed occurrence of Tritrichomonas foetus and other enteric parasites in Australian cattery and shelter cats

Cattery-housed pedigree cats, located mostly within the USA, have the highest reported prevalence of Tritrichomonas foetus (T foetus) to date. This prospective, multi-institutional, cross sectional study examines the occurrence of T foetus and other enteric parasites in cattery-housed and shelter cats within Australia, where T foetus has only recently been identified. Faecal specimens were collected from 134 cats, including 82 cattery-housed pedigree cats and 52 shelter cats. Faecal examinations performed for most cats included concentration techniques, Snap Giardia test, culture in InPouch medium, and polymerase chain reaction (PCR) amplification of T foetus ribosomal ribonucleic acid (rRNA) genes using species-specific primers. Observed occurrence of T foetus, Giardia species, Isospora species and Toxascaris leonina for cattery-housed cats (and catteries) were 0%, 7.4 (13.8)%, 10.9 (22.6)% and 1.6 (3.2)%, respectively. Observed occurrence of T foetus, Giardia species, Isospora species and hookworms for shelter cats were 0%, 11.5%, 9.8% and 4.9%, respectively. These results suggest the prevalence of T foetus in cattery-housed cats is currently much lower in Australia than in the USA, while Isospora and Giardia species infections are common.

Bacteriological warfare amongst cats: what have we learned about cat bite infections?

Cat bite infections are one of the most common infectious diseases presenting to veterinary practices and to emergency rooms at human hospitals. This review describes the disease in humans and cats, the origin of organisms involved in cat bite abscesses and the importance of selected organisms such as members of the genus Porphyromonas in the disease. It also discusses future directions, the importance of identifying significant organisms and why an understanding of antimicrobial susceptibility patterns is of consequence to the outcome of the disease in humans and cats.

Seroprevalence study of feline coronavirus in owned and feral cats in Sydney, Australia.

Objectives To establish the seroprevalence of Feline Coronavirus (FCoV) infection in two defined groups of cats in Sydney: owned and feral cats; ii) to identify factors associated with an increased risk of infection with FCoV; and iii) to establish the seroprevalence and FCoV antibody titres of owned cats with immunohistochemically confirmed feline infectious peritonitis (FIP). Design Prospective multi‐institutional cross sectional study. Procedure Serum samples from owned cats presented to three inner city veterinary clinics in Sydney and feral cats from a colony in South Western Sydney over an 11‐month period were tested for FCoV antibodies using the Immunocomb test kit. The relationship between serological score and six major factors (breed, age, gender, number of cats per household, living environment and health status) in the owned cat sample population was analysed and compared to cats with FIP. Results The seroprevalence of FCoV infection in the sample population of owned and feral cats was 34% and 0%, respectively. The median Immunocomb scores of DSH, Persian, Siamese and Devon Rex cats were significantly lower than that of Burmese, BSH, Abyssinian, Birman, Ragdoll and Russian Blue. The median Immunocomb score of pedigree cats less than 2 years‐of‐age was significantly higher than for pedigree cats greater than 2 years‐of‐age. This distinction was not evident in DSH cats in these age groups. The number of cats per household at the time of blood collection had a strong positive association with Immunocomb score. The median Immunocomb score of cats with immunohistochemically confirmed FIP was significantly higher than cats in the sample population of owned cats but there was sufficient overlap between these two groups to make definitive diagnosis of FIP by serology impossible. Conclusion This represents the first seroprevalence study of FCoV in Australia. The major determinants of antibody score of owned cats identified in this study were breed, age and the number of cats per household. The significant relationship between the breed of the cat and the FCoV antibody titre further supports the notion, proposed previously by the authors, that breed related differences exist in the immunological response to FCoV infection.

Prolonged resilience of Tritrichomonas foetus in cat faeces at ambient temperature.

We have investigated the diagnostic utility of culture methods for Tritrichomonas foetus from cat faeces and the influence of faecal storage on the sensitivity of two different culture systems, InPouch TF-Feline (Bio-Med Diagnostics) and Modified Diamonds Medium. Normally formed cat faeces were spiked using a 10-fold serial dilution of 2 x 10(2) to 2 x 10(5)T. foetus per gram of faeces prior to storage at either room temperature or under refrigeration. At different time points a 20mg sample of spiked faeces was inoculated into each of the culture systems which were evaluated daily for up to 7 days and on day 11. Successfully cultured T. foetus 24h following faecal spiking and storage at room temperature demonstrates that the environmental resilience of the organism is greater than previously anticipated. At a conservative detection limit of 2 x 10(3) organisms per gram of faeces the accumulative sensitivity of each culture method was found to be 83% and 100% for the InPouch TF-Feline and Modified Diamonds Medium respectively over a 6h period. This research demonstrates that voided faeces kept at room temperature for up to 6h represent suitable material for diagnostic investigation. The resilience of T. foetus suggests that transmission is not limited to close contact between cats.