FIV

FIV, or feline immunodeficiency virus, is a retrovirus belonging to the lentivirus genus that establishes a lifelong infection in domestic and wild felids, progressively undermining the immune system's capacity to defend the body against pathogens, neoplasms, and other threats. The virus was first characterized by researchers at the University of California, Davis in 1986 after investigation of a cattery where multiple animals exhibited signs of chronic wasting and immune compromise. Since its discovery, FIV has been identified in domestic cat populations across every inhabited continent, with seroprevalence figures typically falling between one and fourteen percent depending heavily on the population surveyed, the geographic region, and the prevalence of risk factors such as outdoor roaming, intact reproductive status, and fighting behavior among the cats tested.

The biological kinship between FIV and human immunodeficiency virus has made the feline virus an important subject of comparative virology and a naturally occurring model for understanding lentiviral pathogenesis and immune evasion strategies. Both viruses are enveloped RNA viruses that carry the enzyme reverse transcriptase, enabling them to convert their RNA genome into proviral DNA that integrates permanently into host chromosomal DNA within infected cells. This integration establishes a reservoir of latently infected cells that harbor the viral genome in a form inaccessible to immune clearance, rendering the infection permanent with currently available medical interventions. Despite the mechanistic similarities, FIV is exclusively a feline pathogen with no capacity to infect humans, canines, or other non-felid species, and it is readily destroyed outside the host by desiccation, ultraviolet radiation, and routine disinfectants including dilute bleach solutions.

The clinical trajectory of FIV infection is defined by its protracted and variable course, spanning months to many years between initial viral acquisition and the eventual emergence of clinical immunodeficiency. Following a brief acute phase with transient mild illness, the virus enters a prolonged latent period during which the infected cat remains clinically well while the virus replicates at low levels within lymphoid tissues and gradually erodes the CD4-positive T lymphocyte population. This extended asymptomatic interval, which can last five years, ten years, or longer in many cats, means that the majority of FIV-positive cats spend most or all of their lives without showing any outward signs of disease. The eventual development of symptomatic immunodeficiency is not inevitable within a normal feline lifespan, and many FIV-positive cats die of causes entirely unrelated to their retroviral status.

Misconceptions surrounding FIV have historically contributed to the unnecessary euthanasia of infected cats in shelter environments and to the reluctance of potential adopters to take FIV-positive cats into their homes. The outdated belief that FIV represents an immediate death sentence has been replaced by a growing body of evidence demonstrating that well-managed FIV-positive cats can enjoy years of normal-quality life and that the risk of casual household transmission to uninfected housemates is negligible in the absence of aggressive fighting. Progressive shelter policies now support the adoption of FIV-positive cats into informed homes, and advocacy organizations have worked to educate the public about the manageable nature of this chronic infection.

Bite wounds sustained during aggressive fighting between cats constitute the overwhelmingly dominant natural transmission pathway for FIV, a relationship that shapes every aspect of the virus's epidemiology and determines which cats face the greatest risk of infection. FIV is present at high titers in the saliva of infected cats, and the deep puncture wounds produced by feline canine teeth during combat serve as highly efficient conduits for depositing virus-laden saliva beneath the recipient's skin and into the subcutaneous tissues, muscle, and bloodstream. The mechanics of this transmission route explain the striking epidemiological skew toward intact male cats, which engage in territorial and mating-related combat at far higher rates than neutered males or females of any reproductive status. Studies across multiple geographic regions consistently report male-to-female infection ratios of approximately two-to-one to as high as five-to-one.

Casual social contact between cats living in the same household does not represent a meaningful route of FIV transmission, a finding with profound practical implications for the management of FIV-positive cats in domestic settings. Controlled longitudinal studies in which FIV-positive cats were housed with FIV-negative cats in stable, non-aggressive social groups have demonstrated negligible seroconversion rates among the initially negative cats over observation periods extending to several years. Activities including mutual grooming, sharing food and water dishes, using the same litter boxes, sleeping in close physical contact, and playing together do not facilitate viral transfer at rates sufficient to sustain transmission. This evidence provides the scientific foundation for current recommendations allowing FIV-positive cats to be housed with FIV-negative cats in appropriately managed households where inter-cat aggression is absent.

Maternal transmission from an FIV-infected queen to her offspring represents a secondary natural transmission pathway that operates through transplacental viral transfer during gestation, contact with virus in vaginal secretions during birth, or ingestion of virus-containing milk during nursing. The efficiency of vertical transmission is variable and influenced significantly by the mother's viral load, the stage of her infection at the time of pregnancy, and whether acute viremia is occurring during gestation or lactation. Published estimates of vertical transmission rates span a wide range from under five percent to as high as seventy percent, reflecting the heterogeneity of these maternal factors across different study populations. Kittens born to FIV-positive mothers acquire passive maternal antibodies through colostrum that can produce positive results on antibody-based screening tests for up to six months after birth, necessitating delayed retesting or PCR-based approaches to determine the true infection status of these kittens.

Iatrogenic transmission through blood transfusion, contaminated surgical instruments, or shared needles is theoretically possible but effectively prevented by standard veterinary practices including donor screening, aseptic surgical technique, and use of disposable equipment. All feline blood donors should undergo FIV testing before any donation to eliminate this preventable transmission route. Experimental evidence suggests that sexual transmission through virus-containing semen may occur, though its significance under natural mating conditions remains uncertain. Transmission through arthropod vectors such as fleas has been investigated but not convincingly demonstrated as an epidemiologically important pathway. The environmental fragility of FIV, which survives only briefly outside the feline host, further limits transmission to situations involving direct inoculation of body fluids.

The population-level epidemiology of FIV reflects the dominance of bite-wound transmission and identifies specific risk demographics with elevated infection prevalence. Free-roaming intact males in areas with high population density and intense territorial competition carry the highest risk, with prevalence rates in some surveyed feral male populations exceeding twenty percent. Strictly indoor cats in stable households face virtually no risk of acquisition. Geographic prevalence varies with cultural practices around cat ownership, neutering rates, and the proportion of the cat population that roams freely. Concentrated populations in shelters, particularly those accepting feral or stray intakes, show elevated prevalence, making intake screening an important component of shelter disease management.

The natural history of FIV infection proceeds through a series of clinically and immunologically distinct phases that collectively span years to over a decade in many infected cats. The acute phase commences within approximately one to three weeks of viral inoculation and is driven by a burst of uncontrolled viral replication as the virus disseminates from the site of entry through the bloodstream and lymphatic system to seed lymphoid tissues throughout the body. During this initial viremia, viral loads in peripheral blood reach their zenith and the virus colonizes regional lymph nodes, the spleen, thymus, bone marrow, and mucosal-associated lymphoid tissue. The clinical expression of acute infection is generally mild and frequently overlooked by owners, consisting of transient low-grade fever, mild malaise, decreased appetite, and modest generalized lymph node enlargement lasting one to several weeks before resolving spontaneously.

The subclinical carrier phase that follows the resolution of acute viremia represents the numerically dominant period of FIV infection, commonly extending five to ten years and occasionally exceeding twelve years or more. Throughout this prolonged interval, the cat exhibits no externally visible signs of disease and maintains normal eating habits, activity levels, grooming behavior, body weight, and social interactions. Beneath this outward normalcy, however, the virus persists in a state of low-level chronic replication within CD4-positive T lymphocytes, macrophages, and dendritic cells in lymphoid tissues. Each round of viral replication destroys a cohort of infected cells, producing a gradual but relentless attrition of the CD4-positive T cell population that is the functional backbone of cell-mediated adaptive immunity. The pace of this decline is influenced by viral strain virulence, the genetic background and innate immune competence of the host, nutritional status, stress levels, and the presence of concurrent infections that activate the immune system and inadvertently stimulate viral replication.

Progressive deterioration of cell-mediated immunity eventually crosses a functional threshold beyond which the cat can no longer mount effective responses against organisms that a healthy immune system would readily suppress. This transition marks the onset of the symptomatic immunodeficiency phase, during which clinical disease emerges in the form of chronic, recurrent, or treatment-resistant infections, unexplained weight loss, persistent lymphadenopathy, and declining vitality. Laboratory evaluation at this stage typically reveals lymphopenia with a disproportionate reduction in CD4-positive cells, a declining CD4-to-CD8 ratio that may invert, neutropenia in some cats, non-regenerative anemia, and hyperglobulinemia from polyclonal B cell stimulation. The duration of the symptomatic phase is highly variable among individuals and may span months to several years, with periods of relative stability punctuated by episodes of opportunistic disease.

The terminal immunodeficiency stage corresponds to the feline equivalent of AIDS and is characterized by profound, irreversible immune collapse that leaves the cat defenseless against an expanding spectrum of pathogens. Severe opportunistic infections involving multiple organ systems develop concurrently or in rapid succession, and established infections become refractory to antimicrobial therapy that would be effective in immunocompetent patients. Wasting syndrome with progressive muscle loss and subcutaneous fat depletion advances despite nutritional support. Neoplastic conditions, particularly lymphoma and certain carcinomas, arise at elevated frequency as immune surveillance against malignant transformation fails. Central nervous system involvement, whether from direct viral neuropathogenesis or secondary opportunistic infections of neural tissue, may produce behavioral changes, cognitive decline, seizure activity, or progressive neurological deficits. When the cumulative burden of disease renders quality of life unacceptable despite maximal supportive care, humane euthanasia becomes the appropriate and compassionate intervention.

The clinical manifestations attributed to FIV are predominantly the consequences of immune depletion rather than direct viral cytopathic effects, meaning that the spectrum of disease observed in symptomatic FIV-positive cats essentially reflects the diversity of opportunistic and secondary infections that exploit the weakened immune defenses. Severe chronic gingivostomatitis ranks among the most prevalent and clinically significant conditions in FIV-associated disease, producing agonizing inflammation of the gingiva, buccal mucosa, palatal arches, and pharyngeal tissues. Affected cats experience such intense oral pain that they approach food with obvious hunger but then recoil, drop partially chewed food, drool copiously, paw at their mouths, and eventually cease eating altogether. Weight loss follows rapidly, creating a cycle of deteriorating nutrition that further compromises immune function. The pathogenesis involves an aberrant inflammatory response to oral bacterial biofilms and feline calicivirus in the context of dysfunctional T cell regulation.

Chronic and recurrent upper respiratory disease is frequently encountered in FIV-positive cats as the mucosal immune defenses of the nasal passages, sinuses, and airways become progressively compromised. Persistent nasal discharge ranging from serous to mucopurulent, chronic sneezing, conjunctivitis with ocular discharge, and audible congestion develop and prove resistant to standard antimicrobial regimens that would resolve identical infections in immunocompetent cats. Bacterial culture of nasal discharge may reveal polymicrobial infections with opportunistic organisms including Pasteurella, Bordetella, and Mycoplasma species alongside persistent viral shedding of herpesvirus or calicivirus. Lower respiratory involvement including pneumonia can develop in severely immunocompromised cats and may be caused by bacterial, fungal, or protozoal organisms that rarely affect cats with intact immune systems.

Dermatological problems occur with increased frequency and severity in FIV-positive cats, manifesting as chronic bacterial pyoderma, recalcitrant dermatophyte infections, demodicosis that resists conventional treatment, non-healing wounds and abscesses, and chronic otitis. The skin serves as a critical component of innate immunity, and the loss of effective immune surveillance within cutaneous tissues allows commensal and environmental organisms to establish persistent infections. Systemic mycotic infections, particularly cryptococcosis, deserve special attention because of their predilection for immunocompromised cats and their capacity to produce devastating disease involving the nasal cavity, subcutaneous tissues, eyes, and central nervous system. Skin masses should be evaluated with cytology or biopsy, as cutaneous lymphoma and mast cell tumors occur at elevated rates in FIV-positive cats.

Gastrointestinal manifestations in FIV-associated disease include chronic diarrhea from opportunistic enteric infections with organisms such as Cryptosporidium, Giardia, and Salmonella, as well as inflammatory bowel disease driven by immune dysregulation within the gut-associated lymphoid tissue. Malabsorption and chronic nutrient loss compound the wasting effects of reduced appetite, chronic infection, and the elevated metabolic demands of persistent immune activation. Hepatobiliary disease including lymphocytic cholangitis and hepatic lymphoma has been documented at increased prevalence. Ocular disease including anterior uveitis, which may present as a change in iris color, cloudiness within the anterior chamber, excessive tearing, or photophobia, develops in some FIV-positive cats and may result from immune complex deposition within ocular tissues or from direct viral effects.

Neurological disease attributable to FIV can result from the virus's intrinsic neurotropism or from secondary infections of the central nervous system. FIV crosses the blood-brain barrier during acute infection and establishes productive infection within microglia, astrocytes, and perivascular macrophages, producing a spectrum of neurobehavioral abnormalities including personality changes, inappropriate elimination, disrupted sleep-wake cycles, compulsive behaviors, decreased responsiveness, and apparent cognitive decline. Opportunistic central nervous system infections, most notably toxoplasmosis and cryptococcal meningoencephalitis, produce more acute and severe neurological signs including seizures, ataxia, vestibular dysfunction, circling, head tilt, nystagmus, and progressive paresis. Peripheral neuropathies affecting cranial and spinal nerves have also been reported.

The standard diagnostic approach for FIV employs a sequential two-step strategy in which a highly sensitive screening test is followed by a highly specific confirmatory test for any positive result, a protocol designed to maximize the accuracy of the final diagnosis by leveraging the complementary strengths of different assay methodologies. Point-of-care screening tests used in clinical practice are typically enzyme-linked immunosorbent assay or immunochromatographic lateral flow devices that detect anti-FIV antibodies in whole blood, serum, or plasma samples. These screening assays achieve sensitivity values generally exceeding ninety-five percent, meaning they correctly identify the vast majority of truly infected cats. However, their specificity is somewhat lower, and false-positive results do occur, particularly when the test is applied to low-prevalence populations where the prior probability of any individual cat being infected is small.

Confirmatory testing for cats that yield positive results on initial screening is essential to exclude false-positive diagnoses before delivering a definitive result that will influence the cat's management, housing, and adoption prospects. Western blot immunoassay and polymerase chain reaction testing for proviral DNA serve as the principal confirmatory modalities. Western blot analysis separates FIV proteins by molecular weight on an electrophoretic membrane and probes them with the cat's serum, producing a banding pattern that can distinguish true infection-generated antibodies from the nonspecific cross-reactive antibodies that cause false positives on screening assays. PCR directly detects viral genetic material integrated into host cell DNA, providing confirmation independent of antibody status and thus capable of identifying infected cats during the pre-seroconversion window period and resolving ambiguous serological results.

Interpretation of FIV test results demands awareness of several biological and technical factors that can produce misleading outcomes. The post-exposure seroconversion window typically spans two to four weeks but may extend to eight weeks or occasionally longer, during which a recently infected cat will test antibody-negative on screening despite harboring the virus. Cats with documented bite-wound exposure should therefore be tested at the time of the incident to establish a baseline and retested at least sixty days later to allow seroconversion. Kittens born to FIV-positive queens passively acquire maternal anti-FIV antibodies through colostral ingestion, and these maternally derived antibodies can produce positive screening results for up to approximately six months of age without indicating true infection. Any kitten under six months testing positive should be retested after that age, or proviral PCR should be performed to determine actual infection status.

The clinical scenarios that warrant FIV testing encompass both routine screening situations and targeted diagnostic evaluations. Every cat should undergo FIV testing upon initial acquisition, whether adopted from a shelter, purchased from a breeder, or taken in as a stray. Cats presenting after bite wounds or fights with cats of unknown status should follow the baseline-and-retest protocol. All potential feline blood donors require confirmed negative status before any donation. Cats with clinical presentations suggestive of immunodeficiency-associated disease, including chronic recurrent infections, severe gingivostomatitis, unexplained weight loss, persistent lymphadenopathy, chronic non-responsive skin infections, or unusual neoplasms, should be tested if their retroviral status is unknown or was last assessed long ago.

Supplemental diagnostic assessment beyond the FIV test itself is necessary in all confirmed FIV-positive cats to characterize baseline health status, quantify the degree of existing immune compromise, identify concurrent conditions that could accelerate disease progression, and establish reference values for longitudinal monitoring. A complete blood count with differential provides critical information about lymphocyte numbers, neutrophil adequacy, and red blood cell parameters. Serum biochemistry evaluates hepatic and renal function and detects metabolic abnormalities. Urinalysis with culture screens for proteinuria and subclinical urinary tract infection. Testing for feline leukemia virus should always accompany FIV evaluation, as dual retroviral infection carries a substantially grimmer prognosis than either infection alone. Baseline thoracic and abdominal imaging screens for lymphoma, organomegaly, and other structural abnormalities.

Management of the FIV-positive cat revolves around a comprehensive strategy aimed at preserving remaining immune function, preventing exposure to additional pathogens, detecting and treating secondary infections promptly, and maintaining overall physical and psychological wellbeing through attentive daily care. No curative antiviral therapy exists for FIV, and the treatment landscape focuses entirely on optimizing the cat's ability to coexist with the virus for as long as possible while maintaining acceptable quality of life. This supportive philosophy parallels the management approach for HIV-positive individuals in the era before effective antiretroviral therapy became available, and it can be remarkably successful, with many FIV-positive cats living well into their senior years under appropriate care.

Prompt and aggressive treatment of secondary infections is the single most impactful clinical intervention for extending the comfortable lifespan of FIV-positive cats. Because the immunocompromised cat mounts weaker and slower immune responses to infection, antimicrobial therapy must be initiated earlier, dosed appropriately, selected based on culture and sensitivity data whenever feasible, and continued for longer durations than would be standard for immunocompetent patients. Empirical antibiotic selection risks inadequacy against the more resistant organisms that preferentially colonize immunocompromised hosts, making diagnostic sampling and culture a particularly worthwhile investment in this population. Fungal infections require prolonged systemic therapy with agents such as itraconazole or fluconazole, guided by serial monitoring of antigen titers or culture results to confirm microbiological cure rather than relying on clinical improvement alone.

Oral disease management is frequently the most challenging and impactful aspect of clinical care for symptomatic FIV-positive cats. Full-mouth or subtotal extraction of premolar and molar teeth, while an aggressive surgical intervention, achieves meaningful clinical improvement in the majority of cats with chronic faucitis and caudal stomatitis by eliminating the plaque-associated bacterial antigen load that drives the dysregulated mucosal immune response. Cats that respond incompletely to dental surgery may require ongoing medical management with immunomodulatory agents including cyclosporine, anti-inflammatory therapy with corticosteroids used cautiously given the existing immunodeficiency, and analgesic support with buprenorphine or gabapentin to maintain appetite and comfort. Interferon omega, where available, has shown benefit in some cases of refractory FIV-associated stomatitis.

Nutritional management, environmental optimization, and stress minimization form the essential non-pharmacological pillars of FIV-positive cat care. A nutritionally complete and balanced commercial diet providing high-quality animal protein supports lean body mass and immune function, while raw or undercooked animal products must be strictly excluded from the diet of immunocompromised cats due to the elevated risk posed by foodborne bacterial and parasitic pathogens. Body weight should be tracked regularly to detect early trends toward the cachexia that heralds disease progression. The living environment should provide security, predictability, vertical territory, and opportunity for mental stimulation while minimizing crowding, competition, and social stress that elevate cortisol levels and accelerate immune decline. Indoor confinement serves the dual purpose of shielding the FIV-positive cat from environmental pathogens and preventing virus transmission to other cats.

Vaccination protocols for FIV-positive cats are modified to account for their immunocompromised status while still providing whatever protection can be generated against common feline pathogens. Core vaccines including feline panleukopenia, herpesvirus, and calicivirus are recommended using inactivated or recombinant formulations rather than modified-live products, which carry theoretical risk of causing vaccine-associated disease in immunodeficient individuals. Rabies vaccination is administered as legally required. The diminished immune responsiveness of FIV-positive cats may result in lower antibody titers and shorter duration of immunity following vaccination, but the consensus position is that partial protection is preferable to leaving the already immunocompromised patient entirely unprotected against vaccine-preventable diseases.

The prognosis for an FIV-positive cat has improved markedly over the decades since the virus was first characterized, driven by advancing veterinary knowledge, more nuanced approaches to management, and a cultural shift away from reflexive euthanasia toward proactive chronic disease care. Contemporary longitudinal studies report median survival times from diagnosis of approximately five to eight years, with significant individual variation reflecting differences in viral strain, host genetics, stage at diagnosis, quality of care, and the burden of concurrent disease. Critically, many cats diagnosed incidentally or during routine screening while clinically asymptomatic enjoy survival times approaching or equaling the lifespan of uninfected cats of similar age, particularly when maintained with consistent veterinary oversight and indoor housing that minimizes exposure to secondary pathogens.

Quality of life during the asymptomatic carrier phase, which constitutes the majority of the infected cat's lifetime, is functionally identical to that of an uninfected cat. Asymptomatic FIV-positive cats eat with normal appetite, maintain healthy body condition, engage in play and exploration, groom themselves appropriately, interact socially with household members both feline and human, and display the full repertoire of normal feline behaviors. Owners who receive an FIV-positive diagnosis for their cat should be counseled that their cat is not imminently dying, is not suffering from its infection, and will likely continue to live a comfortable and enjoyable life for years. This reassurance is therapeutically important because owner perception of the diagnosis heavily influences willingness to invest in ongoing care and the quality of attention the cat receives.

The decision to adopt or retain an FIV-positive cat involves balancing the anticipated commitment of more frequent veterinary monitoring, the potential for increased treatment costs as the disease eventually progresses, and the modest adjustments to household management against the very real reward of providing a home to a cat that is often overlooked in adoption settings. FIV-positive cats can safely share a household with FIV-negative cats when social dynamics are stable and non-aggressive, as the negligible risk of casual contact transmission has been well established by research. The primary management requirements include maintaining strictly indoor housing, providing six-monthly veterinary examinations with baseline laboratory work, ensuring prompt evaluation of any new clinical signs, feeding a high-quality commercially prepared diet, and avoiding unnecessary immunosuppressive medications.

Long-term veterinary monitoring follows a structured protocol that serves to detect early evidence of immune decline, identify secondary conditions at their most treatable stage, and track trends in key health parameters over time. Wellness examinations every six months, rather than the annual standard for healthy cats, provide twice-yearly opportunities for physical assessment, weight trending, oral examination, and palpation for lymphadenopathy or organomegaly. Laboratory panels including complete blood count, serum biochemistry, and urinalysis performed at least annually track lymphocyte counts, organ function, and urinary tract health. Concurrent feline leukemia virus testing should be performed periodically in cats with ongoing risk of exposure. Owners serve as the primary daily monitors and should report any changes in appetite, weight, coat quality, activity level, litter box habits, or behavior promptly, as these subjective observations often provide the earliest indication that the disease may be progressing.

Preventing FIV acquisition targets the dominant bite-wound transmission pathway through management strategies that reduce fighting between cats. Neutering male cats substantially diminishes territorial aggression and roaming behavior, directly lowering the frequency of the inter-male combat that drives viral spread. Large-scale trap-neuter-return programs that achieve high sterilization coverage in free-roaming cat colonies reduce the population-level prevalence of fighting and consequently decrease the rate of new FIV infections within managed colonies. Confining cats exclusively indoors eliminates the primary risk scenario for viral acquisition by removing contact with potentially infected outdoor cats. Enclosed outdoor spaces such as catios, screened porches, and supervised harness walks provide environmental enrichment without the risk of aggressive encounters with unfamiliar cats.

No FIV vaccine is currently commercially available following the discontinuation of the only previously marketed product, a killed adjuvanted vaccine that was available in the United States from 2002 until its manufacturer ceased production. The vaccine generated considerable controversy because it induced antibodies in vaccinated cats that were indistinguishable from natural infection-generated antibodies on standard point-of-care screening tests, producing diagnostic interference that complicated FIV screening in shelters, veterinary clinics, and research settings. The inability to differentiate vaccinated cats from infected cats on routine testing was considered a significant enough liability to constrain the vaccine's adoption, and no replacement product has yet reached the market despite ongoing research into alternative vaccine platforms.

Screening and management of FIV-positive cats within institutional settings including shelters, rescues, and catteries represent important population-level prevention strategies. Routine FIV testing at shelter intake identifies infected animals and informs placement, housing, and management decisions. Current shelter medicine guidelines increasingly support the adoption of FIV-positive cats into appropriate homes rather than defaulting to euthanasia, recognizing the prolonged period of good health most infected cats enjoy. In breeding programs, exclusion of FIV-positive animals eliminates the risk of vertical transmission to offspring. Community cat programs balance the impracticality of removing all FIV-positive cats from managed colonies against the reduced transmission pressure achieved through universal neutering.

Immediate veterinary consultation is essential when an FIV-positive cat develops any new health concern or when a previously stable FIV-positive cat exhibits deterioration in condition, as early intervention consistently produces better outcomes in the immunocompromised patient. Signs demanding prompt attention include the onset of oral pain manifesting as reluctance to eat, drooling, or facial pawing; respiratory symptoms including nasal discharge, sneezing, coughing, or labored breathing that persist beyond a day or two; skin wounds or lesions that fail to heal, expand, or recur after treatment; unintended weight loss exceeding five percent of body weight; chronic or recurring diarrhea; the appearance of any new mass, lump, or lymph node enlargement; fever; and any neurological change including altered behavior, balance disturbance, seizures, or vision impairment.

All cats of unknown retroviral status should undergo FIV testing before introduction into new households, following any bite-wound incident with a cat of unknown status, and as part of the diagnostic evaluation for chronic, recurrent, or unusually severe infections. Owners should understand clearly that FIV is a feline-only virus with absolutely no risk of transmission to humans, dogs, or other non-feline household animals. A positive FIV result is not a reason for panic or for euthanasia; it is the beginning of a manageable chronic condition that, with informed care, allows most cats to continue living comfortably for years. The veterinary team serves as the owner's partner in navigating this diagnosis, providing education, monitoring, and treatment that together enable the best possible outcome for the FIV-positive cat.