Dirofilarioses in cats: European guidelines from the ABCD on prevention and management

OVERVIEW

Dirofilaria immitis and Dirofilaria repens are the most important filarial worms, causing heartworm disease and subcutaneous dirofilariosis, respectively. D repens is currently considered an emerging zoonotic agent in Europe.

LIFE CYCLE AND INFECTION

Filarial worms infect mainly dogs, but also cats, ferrets, wild carnivores and humans. The life cycle involves an intermediate mosquito host. Compared with dogs, cats are imperfect hosts for dirofilarial worms. After inoculation, only a low number of L3 larvae develop to the adult stage in a small percentage of cats. Heartworm disease in cats may be associated with severe pulmonary thromboembolism and an eosinophilic inflammatory response in the lungs, potentially leading to sudden death. Otherwise self-cure occurs in most cases after 18-48 months. Subcutaneous dirofilariosis may present as subcutaneous nodules or dermatitis.

DIAGNOSIS AND TREATMENT

Diagnosis in cats is more difficult compared with dogs and needs a multistep approach (antigen and antibody tests, as well as diagnostic imaging). Cats with acute heartworm disease require stabilisation within an intensive care unit. Cats with respiratory signs or suggestive radiographic changes should receive prednisolone and follow-up with a similar multistep approach. Adulticidal therapy is not safe in cats.

PREVENTION

In endemic areas cats should receive year-round chemoprophylaxis from 2 months of age.

Pan-European Study on the Prevalence of the Feline Leukaemia Virus Infection - Reported by the European Advisory Board on Cat Diseases (ABCD Europe)

Feline leukaemia virus (FeLV) is a retrovirus associated with fatal disease in progressively infected cats. While testing/removal and vaccination led to a decreased prevalence of FeLV, recently, this decrease has reportedly stagnated in some countries. This study aimed to prospectively determine the prevalence of FeLV viraemia in cats taken to veterinary facilities in 32 European countries. FeLV viral RNA was semiquantitatively detected in saliva, using RT-qPCR as a measure of viraemia. Risk and protective factors were assessed using an online questionnaire to report geographic, demographic, husbandry, FeLV vaccination, and clinical data. The overall prevalence of FeLV viraemia in cats visiting a veterinary facility, of which 10.4% were shelter and rescue cats, was 2.3% (141/6005; 95% CI: 2.0%–2.8%) with the highest prevalences in Portugal, Hungary, and Italy/Malta (5.7%–8.8%). Using multivariate analysis, seven risk factors (Southern Europe, male intact, 1–6 years of age, indoor and outdoor or outdoor-only living, living in a group of ≥5 cats, illness), and three protective factors (Northern Europe, Western Europe, pedigree cats) were identified. Using classification and regression tree (CART) analysis, the origin of cats in Europe, pedigree, and access to outdoors were important predictors of FeLV status. FeLV-infected sick cats shed more viral RNA than FeLV-infected healthy cats, and they suffered more frequently from anaemia, anorexia, and gingivitis/stomatitis than uninfected sick cats. Most cats had never been FeLV-vaccinated; vaccination rates were indirectly associated with the gross domestic product (GDP) per capita. In conclusion, we identified countries where FeLV was undetectable, demonstrating that the infection can be eradicated and highlighting those regions where awareness and prevention should be increased.

Effect of cat litters on feline coronavirus infection of cell culture and cats

Objectives

Feline infectious peritonitis (FIP) is caused by infection with feline coronavirus (FCoV). FCoV is incredibly contagious and transmission is via the faecal–oral route. FCoV infection, and therefore FIP, is most common in breeder and rescue catteries, where many cats are kept indoors, using litter trays. Whether it is possible to break the cycle of FCoV infection and reinfection using cat litters has never been investigated. The aim of the study was to examine the effect of cat litters on FCoV infectivity and virus load in multi-cat households, and transmission frequency.

Methods

Fifteen cat litters were mixed and incubated with FCoV, centrifuged and the supernatants tested in vitro for the ability to prevent virus infection of cell culture. To test applicability of in vitro results to real life, virus load was measured in two households in a double crossover study of four Fuller’s earth-based cat litters by testing rectal swabs using FCoV reverse transcriptase quantitative PCR.

Results

Four litters abrogated FCoV infection of cell culture, nine reduced it to a greater or lesser extent and two had no effect. One brand had different virus inhibitory properties depending on where it was manufactured. Fuller’s earth-based litters performed best, presumably by adsorbing virus. In the field study, there appeared to be less virus shedding on one Fuller’s earth-based cat litter.

Conclusions and relevance

The in vitro study successfully identified cat litters that inactivate FCoV; such litters exist so do not need to be developed. Fuller’s earth-based litters best prevented infection of cell culture, but did not completely abrogate FCoV transmission in two multi-cat households. A dust-free clumping Fuller’s earth litter appeared to fare best, but virus shedding also varied on the control litters, complicating interpretation. Sawdust-based cat litters are not useful in FCoV-endemic households because they track badly and have a poor effect on virus infection.

Evaluating the cost of iatrogenic urethral catheterisation injuries

INTRODUCTION

Technique is vital to prevent urethral trauma during urethral catheterisation (UC). Education programmes are helpful but are not compulsory and safe UC remains operator dependent. Traumatic UC is associated with increased morbidity, length of stay, resource utilisation and surgical intervention.

AIM

To determine the cost of iatrogenic urethral injuries managed in a tertiary referral centre over a 6-month period.

METHODS

A 6-month prospective study monitored iatrogenic urethral injuries secondary to traumatic UC. Included were referrals from district hospitals and inpatient consultations relating to urethral injury caused by traumatic UC. The added cost of management was estimated.

RESULTS

Thirteen iatrogenic urethral injuries were recorded in 6 months. Management included open surgery for a ruptured bladder (n = 1), flexible cystourethroscopy (n = 10), suprapubic catherisation (n = 4), 3-way catheterisation (n = 4) and catheter re-insertion under direct vision (n = 6). The cost of acute management of these injuries was approximately €50,000 including theatre costs, ambulance transfer, hospital stay, procedural and equipment costs and short-term follow-up care.

CONCLUSION

Iatrogenic injuries during UC represent a significant cost burden to the healthcare system. Training programmes should be compulsory for all healthcare professionals routinely involved in catheterisation procedures.

Feline injection-site sarcoma

Overview:

In cats, the most serious of adverse effects following vaccination is the occurrence of invasive sarcomas (mostly fibrosarcomas): so-called ‘feline injection-site sarcomas’ (FISSs). These develop at sites of previous vaccination or injection. They have characteristics that are distinct from those of fibrosarcomas in other areas and behave more aggressively. The rate of metastasis ranges from 10–28%.

Pathogenesis:

The pathogenesis of these sarcomas is not yet definitively explained. However, chronic inflammatory reactions are considered the trigger for subsequent malignant transformation. Injections of long-acting drugs (such as glucocorticoids, and others) have been associated with sarcoma formation. Adjuvanted vaccines induce intense local inflammation and seem therefore to be particularly linked to the development of FISS. The risk is lower for modified-live and recombinant vaccines, but no vaccine is risk-free.

Treatment and prevention:

Aggressive, radical excision is required to avoid tumour recurrence. The prognosis improves if additional radiotherapy and/or immunotherapy (such as recombinant feline IL-2) are used. For prevention, administration of any irritating substance should be avoided. Vaccination should be performed as often as necessary, but as infrequently as possible. Non-adjuvanted, modified-live or recombinant vaccines should be selected in preference to adjuvanted vaccines. Injections should be given at sites at which surgery would likely lead to a complete cure; the interscapular region should generally be avoided. Post-vaccination monitoring should be performed.

Matrix vaccination guidelines: ABCD recommendations for indoor/ outdoor cats, rescue shelter cats and breeding catteries

OVERVIEW

This article presents, in a user-friendly, tabluated form, the ABCD's current vaccination recommendations for four broad categories of cats: outdoor cats (ie, those with access outdoors that come into contact with other cats outdoors); indoor cats (ie, those with no contact with other cats from outdoors); rescue shelter cats; and cats in breeding catteries. Note that it is not always possible to make a clear distinction between these various categories and the definition in any individual case is left up to the veterinary surgeon conducting the vaccination interview.

Pasteurella multocida infection in cats: ABCD guidelines on prevention and management

OVERVIEW

Pasteurella species are part of the normal oral flora of cats. They are also a common cause of infection in this species and an important zoonotic agent. INFECTION IN CATS: Pasteurella species are commonly isolated from subcutaneous abscesses and pyothorax in cats. They may also cause secondary lower respiratory tract infection and have been associated with spinal empyema and meningoencephalomyelitis. INFECTION IN HUMANS: Disease in humans mainly occurs after a cat bite or scratch, but may also be transmitted via respiratory secretions from cats in close contact with a person. Signs of local infection after a cat bite appear in a few hours (3-6 h). Severe disease and a fatal outcome mostly occur in immunocompromised people, but have also been reported in immunocompetent healthy individuals. Cat ownership by immunocompromised people may carry a risk.

Leishmaniosis in cats: ABCD guidelines on prevention and management

OVERVIEW

Leishmania infection is less known in cats than in dogs and humans; felids were traditionally considered a resistant species, and canids as the main reservoir. Only sporadic cases of feline disease have been reported worldwide, mainly caused by L infantum. Epidemiological investigations have confirmed, however, that feline infections are not rare and that disease occurrence might be underestimated in endemic areas.

INFECTION

Cats are infected by the same Leishmania species that infect dogs and humans in tropical and subtropical areas worldwide. Sand fly vectors take blood meals from cats and are competent vectors for L infantum, as shown experimentally.

DISEASE SIGNS

Skin lesions (ulcerative, crusty, nodular or scaly dermatitis) are the most frequent clinical manifestations and sometimes the only findings on physical examination. Lymph node enlargement, weight loss, ocular involvement (nodular blepharitis, uveitis, panophthalmitis), decreased appetite, chronic gingivostomatitis and lethargy are the most frequent non-cutaneous findings, alone or in combination.

DIAGNOSIS

Direct confirmation can be obtained by cytology, histology, isolation or polymerase chain reaction (PCR) on samples of skin, lymph nodes, blood or any affected tissue. Serology using a validated immunofluorescence test, ELISA, direct agglutination or Western blot has been used to assess infection frequencies.

DISEASE MANAGEMENT

Little information is available about treatment with follow-up reports. Long-term administration of allopurinol (10-20 mg/kg q12h or q24h) is usually clinical effective. Vaccines are licensed for dogs only.

Sporotrichosis in cats: ABCD guidelines on prevention and management

OVERVIEW

Sporotrichosis is an important subcutaneous fungal infection of humans and animals in some endemic tropical and subtropical areas. Among domestic species, cats are the most frequently infected.

INFECTION

The primary mode of transmission is traumatic inoculation of fungal conidia from plants and soil. Contact with infected cats is the major mode of transmission to humans, especially in endemic areas like Brazil, where a large epidemic has occurred in the past decade.

DISEASE SIGNS

Most cases in cats are cutaneous, presenting as multiple ulcerated nodules and draining tracts in the skin. Lymphadenopathy, respiratory signs and systemic dissemination may also occur.

DIAGNOSIS

Diagnosis is based on fungal detection by cytology and/or histology, and confirmation by culture.

TREATMENT

Treatment consists of at least 2 months' systemic antifungal therapy, with itraconazole as the first-choice agent. The prognosis is favourable provided there is good owner compliance and adverse drug effects do not occur.

PREVENTION

Contact with infected cats carries a high zoonotic risk. Cat owners travelling to endemic areas should be warned and advised to keep their cats indoors to prevent infection. Professionals must wear gloves when handling cats with skin nodules and ulcers and dealing with diagnostic samples.

ABCD: Update of the 2009 guidelines on prevention and management of feline infectious diseases

OVERVIEW

In this article, the ABCD guidelines published in the JFMS Special Issue of July 2009 (Volume 11, Issue 7, pages 527-620) are updated by including previously unavailable and novel information. For a better picture, the reader is advised to consult that issue before focusing on the novel features.

Leptospira species infection in cats: ABCD guidelines on prevention and management

OVERVIEW

Leptospirosis is a bacterial disease affecting a variety of domestic and wild animals as well as humans worldwide. Leptospirosis has been reported in over 150 mammalian species. It is considered an emerging infectious disease in humans and in dogs. Subclinically infected wild and domestic animals serve as reservoir hosts and are a potential source of infection for incidental hosts and humans.

INFECTION

Reports of leptospirosis in cats are rare, but the importance of cats shedding Leptospira species and serving as a source of infection has recently gained attention. Leptospira species antibodies are commonly present in the feline population, and Leptospira species shedding of cats with outdoor exposure has been demonstrated. Cats mostly become infected through transmission from hunting rodents.

SIGNIFICANCE

The role of healthy carrier cats as a source of contamination, as well as the role of leptospires as a pathogen in cats, are likely underestimated.

Capnocytophaga canimorsus infection in cats: ABCD guidelines on prevention and management

OVERVIEW

Capnocytophaga canimorsus and Capnocytophaga cynodegmi are part of the normal bacterial flora of the oral cavity of dogs and cats. C canimorsus is more pathogenic and causes more severe infections in humans.

INFECTION

Disease is less frequently seen after a cat bite, scratch or close contact than after dog contacts. Serious disease has been reported in people, especially associated with immunocompromise and alcoholism. Disease in cats is not well documented; two cases of respiratory infection have been associated with the presence of these bacteria.

DIAGNOSIS

Diagnosis is based on culture in specific media, but these are slow growing bacteria; polymerase chain reaction and sequencing may aid in diagnosis and species identification.

TREATMENT

Penicillin or beta-lactams are the treatment options of choice. ZOONOTIC POTENTIAL: Based on incidence surveys, the zoonotic potential is low. The risk may be higher for immunocompromised persons, where dog and cat ownership must be discussed.

Aujeszky's disease/pseudorabies in cats: ABCD guidelines on prevention and management

OVERVIEW

Although pseudorabies in swine - Aujeszky's disease - has been eradicated from many pork-producing countries, the virus may still lurk in other vertebrate species and cause feline cases. Infection occurs through the ingestion of uncooked meat and organ material and presents as an acute encephalitis with a short incubation period and a rapidly fatal outcome. The ABCD considers this reason enough to include a review of this, now very rare, condition in this Special Issue.

Babesiosis in cats: ABCD guidelines on prevention and management

OVERVIEW

Babesiosis is a tick-borne protozoan disease caused by parasites of the genus Babesia that belong to the Piroplasmida. The disease is named after the Romanian bacteriologist Victor Babeş. Babesiosis is also known as piroplasmosis (from Latin pirum, meaning 'pear', and plasma, 'image, formation').

INFECTION

Babesiosis affects domestic and wild animals and humans worldwide. While the disease is recognised in dogs around the world, it is found only rarely in cats. HUMAN DISEASE: Babesia species are common blood parasites of mammals. Human babesiosis is uncommon, but more cases in people have been reported recently, most likely because of rising awareness.

Cryptococcosis in cats: ABCD guidelines on prevention and management

OVERVIEW

Cryptococcosis is worldwide the most common systemic fungal disease in cats; it is caused by the Cryptococcus neoformans- Cryptococcus gattii species complex, which includes eight genotypes and some subtypes (strains) with varying geographical distribution, pathogenicity and antimicrobial susceptibility. Cats acquire the infection from a contaminated environment. The prognosis is favourable in most cases, provided a diagnosis is obtained sufficiently early and prolonged treatment is maintained.

INFECTION

Basidiospores are the infectious propagules of Cryptococcus species as they penetrate the respiratory system and induce primary infection. Asymptomatic colonisation of the respiratory tract is more common than clinical disease. Avian guanos, particularly pigeon droppings, offer favourable conditions for the reproduction of C neoformans. Both Cryptococcus species are associated with decaying vegetation.

DISEASE SIGNS

Cryptococcosis caused by C neoformans or C gattii is indistinguishable clinically. The disease can present in nasal, central nervous system (which can derive from the nasal form or occur independently), cutaneous and systemic forms.

DIAGNOSIS

An easy and reliable test for cryptococcosis diagnosis is antigen detection in body fluids. Only isolation and polymerase chain reaction allow identification of the species genotype.

DISEASE MANAGEMENT

Amphotericin B, ketoconazole, fluconazole and itraconazole have all been used to treat cats. Surgical excision of any nodules in the skin, nasal or oral mucosa assists recovery. Continued treatment is recommended until the antigen test is negative.

PREVENTION

Efficient preventive measures have not been demonstrated. Vaccines are not available.

Cowpox Virus Infection in Cats

Overview:

The misnomer ‘cowpox’ has historical roots: cats rather acquire the virus from small rodents. It has a wide host spectrum (including man) and causes skin lesions, predominantly on the head and paws. Progressive proliferative ulcerations in kittens and immunosuppressed cats may take a fatal course. Cat owners should be informed about the zoonotic risk.

Bartonella Species Infection in Cats

Overview:

Over 22 Bartonella species have been described in mammals, and Bartonella henselae is most common worldwide. Cats are the main reservoir for this bacterium. B henselae is the causative agent of cat scratch disease in man, a self-limiting regional lymphadenopathy, but also of other potentially fatal disorders in immunocompromised people.

Infection:

B henselae is naturally transmitted among cats by the flea Ctenocephalides felis felis, or by flea faeces. A cat scratch is the common mode of transmission of the organism to other animals, including humans. Blood transfusion also represents a risk.

Disease signs:

Most cats naturally infected by B henselae do not show clinical signs but cardiac (endocarditis, myocarditis) or ocular (uveitis) signs may be found in sporadic cases. B vinsonii subspecies berkhoffii infection has reportedly caused lameness in a cat affected by recurrent osteomyelitis and polyarthritis.

Diagnosis:

Isolation of the bacterium is the gold standard, but because of the high prevalence of infection in healthy cats in endemic areas, a positive culture (or polymerase chain reaction) is not confirmatory. Other compatible diagnoses must be ruled out and response to therapy gives a definitive diagnosis. Serology (IFAT or ELISA) is more useful for exclusion of the infection because of the low positive predictive value (39–46%) compared with the good negative predictive value (87–97%). Laboratory testing is required for blood donors.

Disease management:

Treatment is recommended in the rare cases where Bartonella actually causes disease.

Prevention of infectious diseases in cat shelters

Overview:

Recommendations are given in relation to infectious diseases in rescue shelters. The ABCD recognises that there is a wide variation in the design and management of shelters, and that these largely reflect local pressures. These guidelines are written with this diverse audience in mind; they point to the ideal, and also provide for some level of compromise where this ideal cannot immediately be attained. In addition consideration should be given to general requirements in order to optimise overall health and wellbeing of cats within the shelter.

Housing:

Compartmentalisation of the shelter into at least three individual sections (quarantine area for incoming cats, isolation facilities for sick or potentially infectious cats, and accommodation for clinically healthy, retrovirus-negative cats) can facilitate containment of a disease outbreak, should it occur.

Standard of care:

Incoming cats should receive a full health check by a veterinary surgeon, should be dewormed and tested for retrovirus infections (feline leukaemia virus [FeLV] and/or feline immunodeficiency virus [FIV]) in regions with high prevalence and in shelters that allow contact between cats. Cats which are not rehomed should receive a regular veterinary check-up at intervals recommended by their veterinarian.

Vaccination:

Each cat should be vaccinated as soon as possible against feline panleukopenia virus (FPV), feline herpesvirus (FHV-1) and feline calicivirus (FCV) infections.

Hygiene:

Adequate hygiene conditions should ensure that contact between shedders of infectious agents and susceptible animals is reduced as efficiently as possible by movement control, hygiene procedures of care workers, barrier nursing, cleaning and disinfection.

Stress reduction:

Stress reduction is important for overall health and for minimising the risk of recrudescence and exacerbation of infectious diseases. In general, a special effort should be made to rehome cats as soon as possible.

Giardiasis in cats

Overview:

Giardia is a protozoan parasite that infects the small intestine of cats and can cause diarrhoea. The biotypes that affect cats do not appear to infect humans. Infection is most common in young cats, particularly from multicat backgrounds.

Disease signs:

Infected cats that develop clinical signs show small intestinal diarrhoea and there may be associated weight loss.

Diagnosis:

Diagnosis of infection is usually based on an in-practice ELISA for faecal antigen or zinc sulphate flotation of several pooled faecal samples. Polymerase chain reaction (PCR) tests are available but not used so widely. Infection can be detected in clinically healthy cats so interpretation of a positive result in cats with diarrhoea requires care.

Treatment:

Fenbendazole or metronidazole are regarded as the treatments of choice. Secondary gut changes may be slow to resolve and so diarrhoea may continue for some time after infection has been eliminated.

Rare systemic mycoses in cats: blastomycosis, histoplasmosis and coccidioidomycosis

Overview:

Rare fungal infections, including those hitherto not reported in Europe, may occur sporadically in non-endemic areas, or imported cases may be seen.

Infections:

Blastomycosis is mainly seen in North America; no cases have been reported in Europe. Histoplasmosis, which is endemic in the eastern US, Central and South America, has been diagnosed in Japan and Europe. Coccidioidomycosis is endemic in the southwestern US, Central and South America; only one imported case has been reported in Europe. The primary mode of transmission is inhalation of conidia or spores from the environment.

Disease signs:

Most feline cases present with a combination of clinical signs (mainly respiratory, along with skin, eye, central nervous system and bone). Lymphadenopathy and systemic signs may be present.

Diagnosis:

Diagnosis is based on fungal detection by cytology and/or histology. Commercial laboratories do not routinely perform fungal culture. Diagnosis of coccidioidomycosis, which is more difficult, may be supported by antibody detection.

Treatment:

Treatment consists of prolonged systemic antifungal therapy, with itraconazole as the first-choice agent for histoplasmosis and blastomycosis. The prognosis is good if owner compliance is adequate and adverse drug effects do not occur.

Prevention:

Cat owners travelling to endemic areas should be warned about these diseases. There is no zoonotic risk.

Rare opportunistic mycoses in cats: phaeohyphomycosis and hyalohyphomycosis

Overview:

Phaeohyphomycoses and hyalohyphomycoses are rare opportunistic infections acquired from the environment. More cases have been reported in recent years in humans and cats.

Disease signs:

Single or multiple nodules or ulcerated plaques (which may be pigmented) in the skin are the typical lesions. In some cases the infection disseminates or involves the central nervous system (CNS).

Diagnosis:

Diagnosis is based on fungal detection by cytology and/or histology. Culture provides definitive diagnosis and species identification.

Treatment:

Treatment involves surgical excision in cases of localised skin disease followed by systemic antifungal therapy, with itraconazole as the agent of first choice. Relapses after treatment are common. Itraconazole and other systemic antifungal agents have been used to treat systemic or neurological cases, but the response is unpredictable. The prognosis is guarded to poor in cats with multiple lesions and systemic or neurological involvement.

Zoonotic risk:

There is no zoonotic risk associated with contact with infected cats.

Feline Viral Papillomatosis

Overview:

Papillomaviruses are epitheliotropic and cause cutaneous lesions in man and several animal species, including cats.

Infection:

Cats most likely become infected through lesions or abrasions of the skin. Species-specific viruses have been detected but human and bovine related sequences have also been found, suggesting cross-species transmission.

Clinical signs:

In cats, papillomaviruses are associated with four different skin lesions: hyperkeratotic plaques, which can progress into Bowenoid in situ carcinomas (BISCs) and further to invasive squamous cell carcinomas (ISCCs); cutaneous fibropapillomas or feline sarcoids; and cutaneous papillomas. However, papillomaviruses have also been found in normal skin.

Diagnosis:

Papillomavirus-induced skin lesions can be diagnosed by demonstration of papillomavirus antigen in biopsies of skin lesions, or detection of papillomavirus-like particles by electron microscopy and papillomavirus DNA by polymerase chain reaction (PCR).

Treatment:

Spontaneous regression might be expected. In cases of ISCC, complete excision should be considered if possible.

Francisella Tularensis Infection in Cats

Overview:

Disease in cats after infection with the zoonotic bacterium Francisella tularensis has been reported only from North America; rodents and lagomorphs are the more susceptible hosts. Tularaemia is transmitted by ticks, but also acquired by direct contact, bite, scratch, ingestion or inhalation. Clinical signs range from mild chronic localised infections to fatal acute disease; antibiotic therapy is efficient. Acquiring the infection from cats is a risk for owners of outdoor cats, veterinarians and technicians.

Dermatophytosis in Cats

Overview:

Dermatophytosis, usually caused by Microsporum canis, is the most common fungal infection in cats worldwide, and one of the most important infectious skin diseases in this species. Many adult cats are asymptomatic carriers. Severe clinical signs are seen mostly in kittens or immunosuppressed adults. Poor hygiene is a predisposing factor, and the disease may be endemic in shelters or catteries. Humans may be easily infected and develop a similar skin disease.

Infection:

Infectious arthrospores produced by dermatophytes may survive in the environment for about a year. They are transmitted through contact with sick cats or healthy carriers, but also on dust particles, brushes, clothes and other fomites.

Disease signs:

Circular alopecia, desquamation and sometimes an erythematous margin around central healing (‘ringworm’) are typical. In many cats this is a self-limiting disease with hair loss and scaling only. In immunosuppressed animals, the outcome may be a multifocal or generalised skin disease.

Diagnosis:

Wood’s lamp examination and microscopic detection of arthrospores on hairs are simple methods to confirm M canis infection, but their sensitivity is relatively low. The gold standard for detection is culture on Sabouraud agar of hairs and scales collected from new lesions.

Disease management:

In shelters and catteries eradication is difficult. Essential is a combination of systemic and topical treatments, maintained for several weeks. For systemic therapy itraconazole is the drug of choice, terbinafine an alternative. Recommended topical treatment is repeated body rinse with an enilconazole solution or miconazole with or without chlorhexidine. In catteries/shelters medication must be accompanied by intensive decontamination of the environment.

Vaccination:

Few efficacy studies on anti- M canis vaccines (prophylactic or therapeutic) for cats have been published, and a safe and efficient vaccine is not available.

Aspergillosis in Cats

Overview:

Aspergillosis is a sporadic mycosis that occurs worldwide in mammals and birds and leads to a usually chronic, and only rarely acute, disease that mainly affects the nasal cavity and sinuses.

Infection:

Aspergillus species infections are commonly associated with predisposing local or systemic factors. Local disease can spread and involve the central nervous system or the lungs. Some Aspergillus species can also disseminate, causing systemic infections. In contrast to dogs, in which (nasal) aspergillosis is relatively common, aspergillosis is rare in cats, but considered an emerging infection.

Clinical signs:

There are two clinical forms of aspergillosis in cats, the sinonasal form (characterised by signs of chronic nasal infection) and the newly emerging, more invasive sino-orbital form (characterised by signs of orbital and surrounding tissue invasion). Sino-orbital involvement has been described now in approximately half of the reported cases.

Disease management:

Treatment should consist of local and systemic antifungal therapy.

Yersinia Pestis Infection in Cats

Overview:

Plague, the medieval ‘Black Death’, is caused by a Gram-negative coccobacillus, Yersinia pestis, which also infects cats. As in people, it is transmitted from rodents through flea bites; it occurs in Asia, Africa and the Americas in flea-infested regions, all year round, and where rodent reservoirs are abundant. A poor prognosis is associated with high fever, and the pulmonary and septicaemic forms. Antibiotic therapy, flea control and avoidance of rodent contacts have made this infection manageable.

Tritrichomoniasis in Cats

Overview:

Tritrichomonas foetus is a protozoan organism that is specific to cats and can cause large bowel diarrhoea. It is distinct from other Tritrichomonas species and not considered to be zoonotic. Infection is most common in young cats from multicat households, particularly pedigree breeding catteries.

Disease signs:

Affected cats show frequent fetid diarrhoea, often with mucus, fresh blood and straining, but generally remain bright and do not lose weight.

Diagnosis:

Diagnosis of infection is usually based on direct microscopic examination of freshly voided faeces. Polymerase chain reaction (PCR) testing is more sensitive but may detect infections unrelated to diarrhoea and, therefore, requires care in interpretation.

Treatment:

The treatment of choice is ronidazole, which should be used with care as it is an unlicensed drug for cats with a narrow safety margin. Clinical signs are generally self-limiting in untreated cases, but may take months to resolve.

Coxiellosis/Q Fever in Cats

Overview:

Q fever is a zoonotic disease caused by Coxiella burnetii. Farm animals and pets are the main reservoirs of infection.

Infection:

Cats become infected by ingestion or inhalation of organisms from contaminated carcases of farm animals, or tick bites. Infection is common, as shown by several serological studies.

Clinical signs:

Experimentally, fever, anorexia and lethargy have been noted. In the field, infection usually remains subclinical. Abortion might occur. C burnetii has been isolated from the placenta of aborting cats, but also from cats experiencing normal parturition.

Diagnosis:

Infection with C burnetii can be diagnosed by isolation of the agent or serology.

Prevention:

Most important is the potential zoonotic risk. Cats suspected of having been exposed to C burnetii might shed organisms during parturition. Wearing gloves and a mask when attending parturient or aborting cats can minimise the risk of infection. Tick prevention is recommended.

Mycobacterioses in Cats

Overview:

Mycobacterial infections are important in humans and animals. Cats can be infected by several Mycobacterium species, which may cause different syndromes, mainly tuberculosis, atypical or non-tuberculous mycobacteriosis and leprosy. In recent years, awareness has increased about how to recognise and confirm these infections. More cases are diagnosed today, which probably means that the disease has escaped detection in the past.

Infection:

Most cases in cats are cutaneous, presenting as nodules in the skin and draining tracts, ulceration and local lymphadenopathy; however, systemic dissemination may also occur.

Diagnosis:

Definitive diagnosis is difficult when the bacterium cannot be detected by histology or culture. However, species confirmation is essential for treatment and prognosis, so material for culture and polymerase chain reaction should be submitted in every suspected case.

Treatment:

Treatment is challenging. A combination of two or three antibiotics is needed, and treatment must be continued for some months, which makes owner compliance especially difficult in cats.

Zoonotic risk:

There is a zoonotic risk associated with some mycobacterial species. Concerns should be communicated in every case of an immunocompromised owner in contact with an infected cat.

Chlamydophila felis infection. ABCD guidelines on prevention and management

OVERVIEW

Chlamydophila felis is a Gram-negative bacterium and its primary target is the conjunctiva. The bacterium does not survive outside the host.

INFECTION

Transmission requires close contact between cats; ocular secretions are probably the most important body fluid for infection. Most cases occur in cats under 1 year of age. Chlamydophila felis is the infectious organism most frequently associated with conjunctivitis.

DISEASE SIGNS

Unilateral ocular disease generally progresses to become bilateral. There can be intense conjunctivitis with extreme hyperaemia of the nictitating membrane, blepharospasm and ocular discomfort. Transient fever, inappetence and weight loss may occur shortly after infection, although most cats remain well and continue to eat.

DIAGNOSIS

PCR techniques are now preferred for diagnosing C felis infection. Ocular swabs are generally used. In unvaccinated cats, antibody detection can be used to indicate infection.

DISEASE MANAGEMENT

Tetracyclines are generally regarded as the antibiotics of choice. Doxycycline has the advantage of requiring only single daily administration and is given at a dose of 10 mg/kg orally. Vaccination should be considered if there is a history of confirmed chlamydial disease in a shelter. Single housing and routine hygiene measures should suffice to avoid cross-infection. Cats maintained together for longer terms should be vaccinated regularly. In breeding catteries where C felis infection is endemic, the first step should be to treat all cats with doxycycline for at least 4 weeks. Once clinical signs have been controlled, the cats should be vaccinated.

VACCINATION RECOMMENDATIONS

Vaccination should be considered for cats at risk of exposure to infection. Vaccination generally begins at 8-10 weeks of age, with a second injection 3-4 weeks later. Annual boosters are recommended for cats at continued risk of exposure.

Feline infectious peritonitis. ABCD guidelines on prevention and management

OVERVIEW

Feline coronavirus infection is ubiquitous in domestic cats, and is particularly common where conditions are crowded. While most FCoV-infected cats are healthy or display only a mild enteritis, some go on to develop feline infectious peritonitis, a disease that is especially common in young cats and multi-cat environments. Up to 12% of FCoV-infected cats may succumb to FIP, with stress predisposing to the development of disease.

DISEASE SIGNS

The 'wet' or effusive form, characterised by polyserositis (abdominal and/or thoracic effusion) and vasculitis, and the 'dry' or non-effusive form (pyogranulomatous lesions in organs) reflect clinical extremes of a continuum. The clinical picture of FIP is highly variable, depending on the distribution of the vasculitis and pyogranulomatous lesions. Fever refractory to antibiotics, lethargy, anorexia and weight loss are common non-specific signs. Ascites is the most obvious manifestation of the effusive form.

DIAGNOSIS

The aetiological diagnosis of FIP ante-mortem may be difficult, if not impossible. The background of the cat, its history, the clinical signs, laboratory changes, antibody titres and effusion analysis should all be used to help in decision-making about further diagnostic procedures. At the time of writing, there is no non-invasive confirmatory test available for cats without effusion.

DISEASE MANAGEMENT

In most cases FIP is fatal. Supportive treatment is aimed at suppressing the inflammatory and detrimental immune response. However, there are no controlled studies to prove any beneficial effect of corticosteroids.

VACCINATION RECOMMENDATIONS

At present, only one (intranasal) FIP vaccine is available, which is considered as being non-core. Kittens may profit from vaccination when they have not been exposed to FCoV (eg, in an early-weaning programme), particularly if they enter a FCoV-endemic environment.

Feline herpesvirus infection. ABCD guidelines on prevention and management

Overview

Feline viral rhinotracheitis, caused by feline herpesvirus (FHV), is an upper respiratory tract disease that is often associated with feline calicivirus and bacteria. In most cats, FHV remains latent after recovery, and they become lifelong virus carriers. Stress or corticosteroid treatment may lead to virus reactivation and shedding in oronasal and conjunctival secretions.

Infection

Sick cats shed FHV in oral, nasal and conjunctival secretions; shedding may last for 3 weeks. Infection requires direct contact with a shedding cat.

Disease signs

Feline herpesvirus infections cause acute rhinitis and conjunctivitis, usually accompanied by fever, depression and anorexia. Affected cats may also develop typical ulcerative, dendritic keratitis.

Diagnosis

Samples consist of conjunctival, corneal or oropharyngeal swabs, corneal scrapings or biopsies. It is not recommended that cats recently vaccinated with a modified-live virus vaccine are sampled. Positive PCR results should be interpreted with caution, as they may be produced by low-level shedding or viral latency.

Disease management

‘Tender loving care’ from the owner, supportive therapy and good nursing are essential. Anorexic cats should be fed blended, highly palatable food – warmed up if required. Mucolytic drugs (eg, bromhexine) or nebulisation with saline may offer relief. Broad-spectrum antibiotics should be given to prevent secondary bacterial infections. Topical antiviral drugs may be used for the treatment of acute FHV ocular disease. The virus is labile and susceptible to most disinfectants, antiseptics and detergents.

Vaccination recommendations

Two injections, at 9 and 12 weeks of age, are recommended, with a first booster 1 year later. Boosters should be given annually to at-risk cats. For cats in low-risk situations (eg, indoor-only cats), 3-yearly intervals suffice. Cats that have recovered from FHV-associated disease are usually not protected for life against further disease episodes; vaccination of recovered cats is therefore recommended.

H5N1 avian influenza in cats. ABCD guidelines on prevention and management

OVERVIEW

Avian influenza is a disease of birds, caused by a type A influenza virus. The subtype H5N1 avian influenza occurs primarily in birds and infection varies from mild disease with little or no mortality to a highly fatal, rapidly spreading epidemic (highly pathogenic avian influenza). It is extremely rare for cats to be infected and there are only very few confirmed reports of the disease in cats in Europe.

INFECTION

Cats can be infected via the respiratory and oral routes (eg, by eating infected birds). The key precondition for infection is that the cat lives in an area where H5N1 virus infection has been confirmed in birds. Additionally, the cat should have had outdoor access to an environment where waterfowl is present, or contact with poultry or uncooked poultry meat, or close contact with an H5N1-infected, sick cat during the first week of infection. CLINICAL SUSPICION: Clinical signs in cats may include fever, lethargy, dyspnoea, conjunctivitis and rapid death. Neurological signs (circling, ataxia) have also been recorded.

DIAGNOSIS

The veterinary authorities should be notified. Oropharyngeal, nasal and/or rectal swabs or faecal samples of suspected cases should be submitted for PCR and/or virus isolation. Post-mortem samples of lung and mediastinal lymph nodes should be obtained. Particular care should be taken when handling the cat and/or samples.

DISEASE MANAGEMENT

The virus is sensitive to all standard medical disinfectants. Cats with suspected H5N1 infection should be kept in strict isolation. Owners should be advised to confine the cat to a separate room prior to bringing it to the veterinary clinic. VACCINATION AND DISEASE PREVENTION: No H5N1 vaccines are commercially available for cats. In the event of confirmed cases of H5N1 avian influenza in birds in the area, owners should keep their cats indoors until further information is available, and follow official regulations.

Feline leukaemia. ABCD guidelines on prevention and management

OVERVIEW

Feline leukaemia virus (FeLV) is a retrovirus that may induce depression of the immune system, anaemia and/or lymphoma. Over the past 25 years, the prevalence of FeLV infection has decreased considerably, thanks both to reliable tests for the identification of viraemic carriers and to effective vaccines.

INFECTION

Transmission between cats occurs mainly through friendly contacts, but also through biting. In large groups of non-vaccinated cats, around 30-40% will develop persistent viraemia, 30-40% show transient viraemia and 20-30% seroconvert. Young kittens are especially susceptible to FeLV infection.

DISEASE SIGNS

The most common signs of persistent FeLV viraemia are immune suppression, anaemia and lymphoma. Less common signs are immune-mediated disease, chronic enteritis, reproductive disorders and peripheral neuropathies. Most persistently viraemic cats die within 2-3 years.

DIAGNOSIS

In low-prevalence areas there may be a risk of false-positive results; a doubtful positive test result in a healthy cat should therefore be confirmed, preferably by PCR for provirus. Asymptomatic FeLV-positive cats should be retested.

DISEASE MANAGEMENT

Supportive therapy and good nursing care are required. Secondary infections should be treated promptly. Cats infected with FeLV should remain indoors. Vaccination against common pathogens should be maintained. Inactivated vaccines are recommended. The virus does not survive for long outside the host.

VACCINATION RECOMMENDATIONS

All cats with an uncertain FeLV status should be tested prior to vaccination. All healthy cats at potential risk of exposure should be vaccinated against FeLV. Kittens should be vaccinated at 8-9 weeks of age, with a second vaccination at 12 weeks, followed by a booster 1 year later. The ABCD suggests that, in cats older than 3-4 years of age, a booster every 2-3 years suffices, in view of the significantly lower susceptibility of older cats.

Bordetella bronchiseptica infection in cats. ABCD guidelines on prevention and management

OVERVIEW

Bordetella bronchiseptica is a Gram-negative bacterium that colonises the respiratory tract of mammals and is considered to be a primary pathogen of domestic cats. It is sensible to consider B bronchiseptica as a rare cause of zoonotic infections. The bacterium is susceptible to common disinfectants.

INFECTION

The bacterium is shed in oral and nasal secretions of infected cats. Dogs with respiratory disease are an infection risk for cats. The microorganism colonises the ciliated epithelium of the respiratory tract of the host, establishing chronic infections.

DISEASE SIGNS

A wide range of respiratory signs has been associated with B bronchiseptica infection, from a mild illness with fever, coughing, sneezing, ocular discharge and lymphadenopathy to severe pneumonia with dyspnoea, cyanosis and death.

DIAGNOSIS

Bacterial culture and PCR lack sensitivity. Samples for isolation can be obtained from the oropharynx (swabs) or via transtracheal wash/ bronchoalveolar lavage.

DISEASE MANAGEMENT

Antibacterial therapy is indicated, even if the signs are mild. Where sensitivity data are unavailable, tetracyclines are recommended. Doxycycline is the antimicrobial of choice. Cats with severe B bronchiseptica infection require supportive therapy and intensive nursing care.

VACCINATION RECOMMENDATIONS

In some European countries an intranasal modified-live virus vaccine is available. The modified-live product is licensed for use as a single vaccination with annual boosters. Cats should not be routinely vaccinated against B bronchiseptica (non-core), since the infection generally causes only a mild disease.

Feline immunodeficiency. ABCD guidelines on prevention and management

Overview

Feline immunodeficiency virus (FIV) is a retrovirus closely related to human immunodeficiency virus. Most felids are susceptible to FIV, but humans are not. Feline immunodeficiency virus is endemic in domestic cat populations worldwide. The virus loses infectivity quickly outside the host and is susceptible to all disinfectants.

Infection

Feline immunodeficiency virus is transmitted via bites. The risk of transmission is low in households with socially well-adapted cats. Transmission from mother to kittens may occur, especially if the queen is undergoing an acute infection. Cats with FIV are persistently infected in spite of their ability to mount antibody and cell-mediated immune responses.

Disease signs

Infected cats generally remain free of clinical signs for several years, and some cats never develop disease, depending on the infecting isolate. Most clinical signs are the consequence of immunodeficiency and secondary infection. Typical manifestations are chronic gingivostomatitis, chronic rhinitis, lymphadenopathy, weight loss and immune-mediated glomerulonephritis.

Diagnosis

Positive in-practice ELISA results obtained in a low-prevalence or low-risk population should always be confirmed by a laboratory. Western blot is the ‘gold standard’ laboratory test for FIV serology. PCR-based assays vary in performance.

Disease management

Cats should never be euthanased solely on the basis of an FIV-positive test result. Cats infected with FIV may live as long as uninfected cats, with appropriate management. Asymptomatic FIV-infected cats should be neutered to avoid fighting and virus transmission. Infected cats should receive regular veterinary health checks. They can be housed in the same ward as other patients, but should be kept in individual cages.

Vaccination recommendations

At present, there is no FIV vaccine commercially available in Europe. Potential benefits and risks of vaccinating FIV-infected cats should be assessed on an individual cat basis. Needles and surgical instruments used on FIV-positive cats may transmit the virus to other cats, so strict hygiene is essential.

Feline Rabies: ABCD Guidelines on Prevention and Management

Overview Rabies virus belongs to the genus Lyssavirus, together with European bat lyssaviruses 1 and 2. In clinical practice, rabies virus is easily inactivated by detergent-based disinfectants.

Infection Rabid animals are the only source of infection. Virus is shed in the saliva some days before the onset of clinical signs and transmitted through a bite or a scratch to the skin or mucous membranes. The average incubation period in cats is 2 months, but may vary from 2 weeks to several months, or even years.

Disease signs Any unexplained aggressive behaviour or sudden behavioural change in cats must be considered suspicious. Two disease manifestations have been identified in cats: the furious and the dumb form. Death occurs after a clinical course of 1–10 days.

Diagnosis A definitive rabies diagnosis is obtained by post-mortem laboratory investigation. However, serological tests are used for post-vaccinal control, especially in the context of international movements.

Disease management Post-exposure vaccination of cats depends on the national public health regulations, and is forbidden in many countries.

Feline Calicivirus Infection: ABCD Guidelines on Prevention and Management

Overview Feline calicivirus (FCV) is a highly variable virus. More severe, systemic forms of FCV infection have been observed recently.

Infection Sick, acutely infected or carrier cats shed FCV in oronasal and conjunctival secretions. Infection occurs mainly through direct contact.

Disease signs The main clinical signs are oral ulcers, upper respiratory signs and a high fever. Feline calicivirus may be isolated from nearly all cats with chronic stomatitis or gingivitis. Cats with ‘virulent systemic FCV disease’ variably show pyrexia, cutaneous oedema, ulcerative lesions on the head and limbs, and jaundice. Mortality is high and the disease is more severe in adult cats.

Diagnosis Diagnosis of FCV can be achieved by virus isolation or reverse-transcriptase PCR. Viral RNA can be detected in conjunctival and oral swabs, blood, skin scrapings or lung tissue using PCR. Positive PCR results should be interpreted with caution, as these may be a consequence of low-level shedding by persistently infected carriers. The diagnosis of virulent systemic FCV disease relies on clinical signs and isolation of the same strain from the blood of several diseased cats.

Disease management Supportive therapy (including fluid therapy) and good nursing care are essential. Anorexic cats should be fed highly palatable, blended or warmed food. Mucolytic drugs (eg, bromhexine) or nebulisation with saline may offer relief. Broad-spectrum antibiotics may be administered to prevent secondary bacterial infections. Feline calicivirus can persist in the environment for about 1 month and is resistant to many common disinfectants.

Feline panleukopenia. ABCD guidelines on prevention and management

OVERVIEW

Feline panleukopenia virus (FPV) infects all felids as well as raccoons, mink and foxes. This pathogen may survive in the environment for several months and is highly resistant to some disinfectants.

INFECTION

Transmission occurs via the faecal-oral route. Indirect contact is the most common route of infection, and FPV may be carried by fomites (shoes, clothing), which means indoor cats are also at risk. Intrauterine virus transmission and infection of neonates can occur.

DISEASE SIGNS

Cats of all ages may be affected by FPV, but kittens are most susceptible. Mortality rates are high - over 90% in kittens. Signs of disease include diarrhoea, lymphopenia and neutropenia, followed by thrombocytopenia and anaemia, immunosuppression (transient in adult cats), cerebellar ataxia (in kittens only) and abortion.

DIAGNOSIS

Feline panleukopenia virus antigen is detected in faeces using commercially available test kits. Specialised laboratories carry out PCR testing on whole blood or faeces. Serological tests are not recommended, as they do not distinguish between infection and vaccination.

DISEASE MANAGEMENT

Supportive therapy and good nursing significantly decrease mortality rates. In cases of enteritis, parenteral administration of a broad-spectrum antibiotic is recommended. Disinfectants containing sodium hypochlorite (bleach), peracetic acid, formaldehyde or sodium hydroxide are effective.

VACCINATION RECOMMENDATIONS

All cats - including indoor cats - should be vaccinated. Two injections, at 8-9 weeks of age and 3-4 weeks later, are recommended, and a first booster 1 year later. A third vaccination at 16-20 weeks of age is recommended for kittens from environments with a high infection pressure (cat shelters) or from queens with high vaccine-induced antibody levels (breeding catteries). Subsequent booster vaccinations should be administered at intervals of 3 years or more. Modified-live virus vaccines should not be used in pregnant queens or in kittens less than 4 weeks of age.

Ability of antibodies to two new caliciviral vaccine strains to neutralise feline calicivirus isolates from the UK

This study examined a panel of 110 UK field isolates of feline calicivirus (FCV) for susceptibility to cross-neutralisation by a panel of eight antisera raised in cats infected with FCV strains F9, 255, FCVG1 and FCV431. The pairs of antisera raised against F9 or 255, neutralised 20 and 21 per cent or 37 and 56 per cent of field strains of virus respectively. In contrast, the pairs of antisera raised against the newer vaccine strains FCVG1 or FCV431 neutralised 29 and 70 per cent or 67 and 87 per cent of field strains respectively. Antisera raised against the two newer strains, namely FCVG1 and FCV431, neutralised a greater proportion of field strains of calicivirus than antisera raised against the older FCV vaccine strains F9 and 255.

Altered tryptophan metabolism in FIV-positive cats

BACKGROUND

Feline immunodeficiency virus (FIV) is analogous to human immunodeficiency virus, the causative agent of human acquired immunodeficiency syndrome (AIDS). In AIDS patients, a progressive reduction in serum tryptophan concentration occurs because of activation of an inducible tryptophan degradation pathway mediated by elevated lamda-interferon production.

HYPOTHESIS

Cats infected with FIV have increased tryptophan catabolism evidenced by reduced circulating concentrations of tryptophan and increased concentrations of the tryptophan catabolite kynurenine.

ANIMALS

Convenience sample of 235 cats submitted for diagnostic FIV serology (115 FIV-negative and 120 FIV-positive cats).

METHODS

Retrospective, cross-sectional study. Serum was assayed for tryptophan and kynurenine using a high performance liquid chromatography assay with fluorescence and ultraviolet detection, respectively.

RESULTS

Tryptophan and kynurenine concentrations were log-normally distributed. Geometric mean concentrations were: tryptophan: FIV-positive 30.6 microM (95% CI: 26.8 34.8 microM), FIV-negative 48.9 [microM (95% CI: 43.6-54.9 microM) (P < .001); kynurenine: FIV-positive 22.7 microM (95% CI: 25.5-10.9 microM), FIV-negative 9.9 microM (95% CI: 20.3-9.03 microM) (P < .001). The ratio of kynurenine to tryptophan was: FIV-positive 4.93 (95% CI: 5.62-4.32), FIV-negative 1.34 (95% CI: 1.53 1.17) (P < .0001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Serum tryptophan concentration was significantly lower and serum kynurenine concentration was significantly higher in FIV-positive cats. The kynurenine: tryptophan ratio was >3-fold higher in FIV-positive animals, indicating increased tryptophan catabolism in this group. Dietary or pharmacologic intervention to support serum tryptophan concentrations has been shown to be clinically useful in humans with AIDS and might be applicable to cats with FIV infection.

Highly pathogenic avian influenza H5N1 virus in cats and other carnivores

The Asian lineage highly pathogenic avian influenza (HPAI) H5N1 virus is a known pathogen of birds. Only recently, the virus has been reported to cause sporadic fatal disease in carnivores, and its zoonotic potential has been dominating the popular media. Attention to felids was drawn by two outbreaks with high mortality in tigers, leopards and other exotic felids in Thailand. Subsequently, domestic cats were found naturally infected and experimentally susceptible to H5N1 virus. A high susceptibility of the dog to H3N8 equine influenza A virus had been reported earlier, and recently also HPAI H5N1 virus has been identified as a canine pathogen. The ferret, hamster and mouse are suitable as experimental animals; importantly, these species are also kept as pets. Experimental intratracheal and oral infection of cats with an HPAI H5N1 virus isolate from a human case resulted in lethal disease; furthermore, cats have been infected by the feeding of infected chickens. Spread of the infection from experimentally infected to in-contact cats has been reported. The epidemiological role of the cat and other pet animal species in transmitting HPAI H5N1 virus to humans needs continuous consideration and attention.