Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses with global impact on the health of domestic cats. The two viruses differ in their potential to cause disease. FeLV is more pathogenic, and was long considered to be responsible for more clinical syndromes than any other agent in cats. FeLV can cause tumors (mainly lymphoma), bone marrow suppression syndromes (mainly anemia), and lead to secondary infectious diseases caused by suppressive effects of the virus on bone marrow and the immune system. Today, FeLV is less commonly diagnosed than in the previous 20 years; prevalence has been decreasing in most countries. However, FeLV importance may be underestimated as it has been shown that regressively infected cats (that are negative in routinely used FeLV tests) also can develop clinical signs. FIV can cause an acquired immunodeficiency syndrome that increases the risk of opportunistic infections, neurological diseases, and tumors. In most naturally infected cats, however, FIV itself does not cause severe clinical signs, and FIV-infected cats may live many years without any health problems. This article provides a review of clinical syndromes in progressively and regressively FeLV-infected cats as well as in FIV-infected cats.

Clinical Aspects of Feline Retroviruses: A Review

1. Behaviour counseling and the veterinary practitioner 2. Puppy and kitten development 3. Prevention: the best medicine 4. Behaviour counseling and behavior diagnostics 5. Treatment: behavior modification techniques 6. Phamacologic intervention in behavioural therapy 7. Complementary and alternative therapy for behavior problems 8. Feeding and diet related problems 9. Pain assessment, pain management, sedation and anesthesia 10. Stereotypic and compulsive disorders 11. Fears and phobias 12. The effects of aging on behavior in senior pets 13. Unruly behaviors, training and management - dogs 14. Unruly behaviors, training and management - cats 15. Canine destructive behaviors 16. Feline destructive behaviors 17. Canine house-soiling 18. Feline house-soiling 19. Canine aggression 20. Feline aggression 21. The European approach to behavior counseling Appendix A (tables listing where figures appear in text) Appendix B (manufacturers and resource list) Appendix C (handouts and forms) Appendix D (dosage table)

Handbook of behavior problems of the dog and cat

Clinical aspects of feline immunodeficiency and feline leukemia virus infection.

Background and goals Cats have become the most popular pet in the United States, yet statistics about veterinary care for cats remain troubling. 1 Although most owners consider their cats to be family members, cats are substantially underserved, compared with dogs. In 2006, owners took their dogs to veterinarians more than twice as often as cats, averaging 2.3 times/year, compared with 1.1 times/year for cats, and significantly more dogs (58%) than cats (28%) were seen by a veterinarian one or more times/year. 2 Cat owners often express a belief that cats ‘do not need medical care’. Two reasons for this misconception are that signs of illness are often difficult to detect, and cats are perceived to be self-sufficient. 2 One role of the veterinarian is to develop a partnership with cat owners that will pave the way for a lifelong health care plan. These guidelines aim to outline an evidence-based life stage wellness program to aid the veterinary medical team in delivering the best comprehensive care for cats. Specific goals are to provide: Life stage classification Distinct life stages (age groups) in cats are not well defined, in part because individual animals and body systems age at different rates, a process that is influenced by many factors. These guidelines follow one convenient classification (see box below). These age designations help to focus attention on the physical and behavioral changes that occur at different stages (eg, congenital defects in kittens, obesity prevention in the junior cat). It must be recognized, however, that any age groupings are inevitably arbitrary demarcations along a spectrum, and not absolutes. Evidence-based health care Supporting references for specific recommendations are supplied where possible, and any previously published guidelines on particular topics are referred to where relevant. Readers should note, however, that the guidelines panel was hampered in its efforts by the relative paucity of disease incidence data by age group that is available, and there is an urgent need for research to guide the future of evidence-based feline health care. 3

/pdf/aafp-aaha-feline-life-stage-guidelines-51xzx5432n.pdf

AAFP-AAHA: feline life stage guidelines.

1Although most owners consider their cats to be family members, cats are substantially underserved, compared with dogs. In 2006, owners took their dogs to veterinarians more than twice as often as cats, averaging 2.3 times/year, compared with 1.1 times/year for cats, and significantly more dogs (58%) than cats (28%) were seen by a veterinarian one or more times/year. 2 Cat owners often express a belief that cats ‘do not need medical care’. Two reasons for this misconception are that signs of illness are often difficult to detect, and cats are perceived to be self-sufficient. 2 One role of the veterinarian is to develop a partnership with cat owners that will pave the way for a lifelong health care plan. These guidelines aim to outline an evidence-based life stage wellness program to aid the veterinary medical team in delivering the best comprehensive care for cats. Specific goals are to provide: ✜ Recommendations for optimal health care for cats throughout the different life stages. ✜ Practical suggestions and tools to facilitate improved veterinary visits and to enhance the client–veterinarian clinical encounter. ✜ A foundation from which to access sources of additional information. Life stage classification Distinct life stages (age groups) in cats are not well defined, in part because individual animals and body systems age at different rates, a process that is influenced by many factors. These guidelines follow one convenient classification (see box below). These age designations help to focus attention on the physical and behavioral changes that occur at different stages (eg, congenital defects in kittens, obesity prevention in the junior cat). It must be recognized, however, that any age groupings are inevitably arbitrary demarcations along a spectrum, and not absolutes. Evidence-based health care Supporting references for specific recommendations are supplied where possible, and any previously published guidelines on particular topics are referred to where relevant. Readers should note, however, that the guidelines panel was hampered in its efforts by the relative paucity of disease incidence data by age group that is available, and there is an urgent need for research to guide the future of evidence-based feline health care. 3

https://novacatclinic.com/wp-content/uploads/2014/07/Journal-of-Feline-Medicine-and-Surgery-2010-Vogt-43-54.pdf

AAFP-AAHA: Feline Life Stage Guidelines

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are among the most common infectious diseases of cats. Although vaccines are available for both viruses, identification and segregation of infected cats form the cornerstone for preventing new infections. Guidelines in this report have been developed for diagnosis, prevention, treatment, and management of FeLV and FIV infections. All cats should be tested for FeLV and FIV infections at appropriate intervals based on individual risk assessments. This includes testing at the time of acquisition, following exposure to an infected cat or a cat of unknown infection status, prior to vaccination against FeLV or FIV, prior to entering group housing, and when cats become sick. No test is 100% accurate at all times under all conditions; results should be interpreted along with the patient's health and risk factors. Retroviral tests can diagnose only infection, not clinical disease, and cats infected with FeLV or FIV may live for many years. A decision for euthanasia should never be based solely on whether or not the cat is infected. Vaccination against FeLV is highly recommended in kittens. In adult cats, antiretroviral vaccines are considered non-core and should be administered only if a risk assessment indicates they are appropriate. Few large controlled studies have been performed using antiviral or immunomodulating drugs for the treatment of naturally infected cats. More research is needed to identify best practices to improve long-term outcomes following retroviral infections in cats.

/pdf/2008-american-association-of-feline-practitioners-feline-3607wdge6n.pdf

2008 American Association of Feline Practitioners' feline retrovirus management guidelines

Feline infectious peritonitis (FIP) is one of the most important infectious diseases and causes of death in cats; young cats less than 2 years of age are especially vulnerable. FIP is caused by a feline coronavirus (FCoV). It has been estimated that around 0.3% to 1.4% of feline deaths at veterinary institutions are caused by FIP.This document has been developed by a Task Force of experts in feline clinical medicine as the 2022 AAFP/EveryCat Feline Infectious Peritonitis Diagnosis Guidelines to provide veterinarians with essential information to aid their ability to recognize cats presenting with FIP.Nearly every small animal veterinary practitioner will see cases. FIP can be challenging to diagnose owing to the lack of pathognomonic clinical signs or laboratory changes, especially when no effusion is present. A good understanding of each diagnostic test's sensitivity, specificity, predictive value, likelihood ratio and diagnostic accuracy is important when building a case for FIP. Before proceeding with any diagnostic test or commercial laboratory profile, the clinician should be able to answer the questions of 'why this test?' and 'what do the results mean?' Ultimately, the approach to diagnosing FIP must be tailored to the specific presentation of the individual cat.Given that the disease is fatal when untreated, the ability to obtain a correct diagnosis is critical. The clinician must consider the individual patient's history, signalment and comprehensive physical examination findings when selecting diagnostic tests and sample types in order to build the index of suspicion 'brick by brick'. Research has demonstrated efficacy of new antivirals in FIP treatment, but these products are not legally available in many countries at this time. The Task Force encourages veterinarians to review the literature and stay informed on clinical trials and new drug approvals. 

2022 AAFP/EveryCat Feline Infectious Peritonitis Diagnosis Guidelines

Clinical importance: Feline infectious peritonitis (FIP) is one of the most important infectious diseases and causes of death in cats; young cats less than 2 years of age are especially vulnerable. FIP is caused by a feline coronavirus (FCoV). It has been estimated that around 0.3% to 1.4% of feline deaths at veterinary institutions are caused by FIP. Scope: This document has been developed by a Task Force of experts in feline clinical medicine as the 2022 AAFP/EveryCat Feline Infectious Peritonitis Diagnosis Guidelines to provide veterinarians with essential information to aid their ability to recognize cats presenting with FIP. Testing and interpretation: Nearly every small animal veterinary practitioner will see cases. FIP can be challenging to diagnose owing to the lack of pathognomonic clinical signs or laboratory changes, especially when no effusion is present. A good understanding of each diagnostic test’s sensitivity, specificity, predictive value, likelihood ratio and diagnostic accuracy is important when building a case for FIP. Before proceeding with any diagnostic test or commercial laboratory profile, the clinician should be able to answer the questions of ‘why this test?’ and ‘what do the results mean?’ Ultimately, the approach to diagnosing FIP must be tailored to the specific presentation of the individual cat. Relevance: Given that the disease is fatal when untreated, the ability to obtain a correct diagnosis is critical. The clinician must consider the individual patient’s history, signalment and comprehensive physical examination findings when selecting diagnostic tests and sample types in order to build the index of suspicion ‘brick by brick’. Research has demonstrated efficacy of new antivirals in FIP treatment, but these products are not legally available in many countries at this time. The Task Force encourages veterinarians to review the literature and stay informed on clinical trials and new drug approvals.

AAFP Position Statement

DOI: 10.1177/1098612X221118746 © The Author(s) 2022 Most veterinarians recognize the cat that presents with thoracic or abdominal effusion as possibly having feline infectious peritonitis (FIP). However, what about those cats only presenting with uveitis, seizures or with non-specific signs? The diagnosis of FIP in these cases becomes a lot more complicated and can be frustrating. The image on the right highlights how the presumptive diagnosis of FIP is made ‘brick by brick’, with each additional brick increasing the index of suspicion for the disease. Typically, there is not one single laboratory test or clinical sign that definitively diagnoses the disease. For most cases, the minimum database consists of serum biochemistry, a complete blood count and urinalysis, along with feline retrovirus testing. However, these test results may or may not be helpful in the case of FIP. One of the factors that makes FIP unique is that running analyses on blood samples is unhelpful in most instances since the virus is typically present only in low amounts in the blood, and is often not detectable. This characteristic requires the clinician to ‘think outside the box’: what diagnostic plan will have the greatest potential for providing enough individual bricks to point toward FIP as the underlying cause for the presenting clinical picture? Deciding which samples, such as effusion, tissue (eg, obtained via fine-needle aspiration or Tru-cut biopsy), cerebrospinal fluid, aqueous humour or serum, should be obtained and analyzed will depend upon the clinical signs present and the overall diagnostic accuracy of the test. Further, the various diagnostic tests offered by reference laboratories can differ in that one PCR assay may not be the same as another performed at a different laboratory. While PCR assays ultimately identify very small amounts of the FIP-associated virus, each assay is designed to identify a certain mutation. If that specific mutation is not present in that particular FIP-associated virus, the test is falsely negative. This is a challenge when dealing with a virus that is prone to mutations every time it replicates. Our knowledge of the virus is continuing to evolve through ongoing research. But, a further complication in understanding FIP is that while we know feline coronavirus mutates, this does not necessarily mean the mutated virus will cause FIP. Other factors are instrumental – notably the mutated virus changes cellular tropism and is able to efficiently replicate, multiplying in monocytes and macrophages, allowing for rapid systemic spread throughout the body. This is followed by activation of FIP-associated feline coronavirus-infected monocytes/ macrophages, leading to pronounced cytokine production and immune system activation. The resulting viral load may still, however, be undetectable using current assays. Invaluable guidance for clinicians when dealing with the varied clinical presentations of FIP and idiosyncrasies of the available diagnostic tests is provided in the 2022 AAFP/EveryCat Feline Infectious Peritonitis Diagnosis Guidelines, which appear on pages 905–933 of this issue. Compiled by a Task Force of experts, they contain a range of graphics and complementary resources, as outlined in the box below. While the gold standard of a single diagnostic test remains elusive, these guidelines offer the best means currently available for diagnosing FIP in your patients.

Vicki Thayer

Papers

2008 American Association of Feline Practitioners' feline retrovirus management guidelines

2022 AAFP/EveryCat Feline Infectious Peritonitis Diagnosis Guidelines

2022 AAFP/EveryCat Feline Infectious Peritonitis Diagnosis Guidelines

AAFP Position Statement

Rising to the challenge of FIP diagnosis