FeLV and FIV in Cats: Two Different Viruses, One Rapid Test, and What a Positive Result Is Actually Worth

Signs of Feline leukaemia virus and feline immunodeficiency virus infection

The 11 signs to watch for are listed below. Any one of them is a reason to consult your nearby vet; none of them is a diagnosis.

• Weight loss over months, with a coat that stops looking cared for
• Sore, red or bleeding gums, drooling, or dropping food while eating
• Infections that keep returning in the skin, ears, eyes, gums or bladder
• A fever that comes and goes and does not settle on antibiotics
• Pale gums, weakness or breathlessness from anaemia
• Swollen lymph nodes felt as lumps under the jaw or in front of the shoulders
• Eating less, or a kitten that stops growing while its littermates grow
• Diarrhoea that keeps returning, or vomiting with no other explanation
• A bite wound or abscess from a cat fight, which is how this virus moves
• Cloudy or inflamed eyes, or a change in the shape of one pupil
• Disorientation, behaviour change or seizures with no other diagnosis

Breeds on this site that document this condition

No cat breed on this site has a published within-breed denominator for either virus, and the reason is that neither is a breed disease. Risk tracks lifestyle, not pedigree. Among 415 client-owned cats in Hong Kong, 11 of 185 mixed-breed cats were seropositive for feline immunodeficiency virus against 2 of 230 purebred cats, p equal to 0.004, and that gap describes who goes outside and fights rather than who has papers. Pooled across 113 studies worldwide, the single factor that raised seropositivity most was outdoor access, at a prevalence ratio of 4.38 with a 95 percent confidence interval of 2.26 to 8.47, ahead of adult age at 2.83 and male sex at 2.53. A Europe PMC title and abstract search pairing both viruses with breed, purebred, pedigree, Siamese, Persian and domestic shorthair returned 151 records on 27 September 2026 and not one of them carried a within-breed prevalence figure, while the Labrador and hip dysplasia control through the identical route returned 110 on-topic papers. So this page publishes no breed cards rather than dress a lifestyle risk up as ancestry. If you want the documented health picture for the cats most often kept in Indian homes, it is on the Persian, Siamese and Bombay pages.

FeLV and FIV are two different diseases, and the difference changes what you do

FeLV and FIV are two different diseases that spread by different routes, damage a cat in different ways and carry very different prognoses, and almost the only thing they share is the plastic cassette they are tested on. Feline leukaemia virus is a gammaretrovirus that a cat sheds in saliva, and it moves through ordinary friendly contact. Feline immunodeficiency virus is a lentivirus, related in structure to human immunodeficiency virus but infecting only cats, and it moves mainly through fight wounds. Reading one result as though it were the other is the commonest and most expensive mistake made with this test.

Feline leukaemia virus is a social disease. A persistently infected cat sheds infectious virus in saliva and also in faeces, urine and milk, so any close contact between cats can pass it on, including mutual grooming and sharing a feeding dish or a litter tray, as well as bite wounds, and an infected queen can pass it to her kittens before birth or while nursing. The virus does not survive long outside a cat's body, so this is about cats in contact with cats, not about contaminated surfaces.

Feline immunodeficiency virus is an aggression disease. The primary route is a bite wound from an infected cat, and casual non-aggressive contact such as sharing water bowls or mutual grooming does not appear to be an efficient way of spreading it; sexual contact is not a significant route either. That single difference in transmission is why the same household advice cannot be given for both viruses, and it is why an entire male cat with outdoor access is the classic case.

Neither virus infects people. Feline immunodeficiency virus causes a feline disease similar to acquired immune deficiency syndrome in humans, but it is a highly species-specific virus that infects only felines and there is currently no evidence that it can infect or cause disease in humans. That answer matters in Indian households where a positive result is sometimes read as a reason to remove the cat from a home with children.

How common each virus is, and why that decides your test result

The two viruses run at similar low single-figure rates in owned cats and diverge sharply once you look at sick or free-roaming animals. In a cross-sectional study of 62,301 cats tested at 1,396 veterinary clinics and 127 animal shelters across the United States and Canada, seroprevalence was 3.1 percent for feline leukaemia virus antigen and 3.6 percent for feline immunodeficiency virus antibody. Among 17,041 unhealthy cats in that dataset, 2,368 (13.9 percent) were seropositive for one or both viruses, against 1,621 of 45,260 healthy cats (3.6 percent). Cornell puts feline leukaemia virus at 2 to 3 percent of all cats in the United States and Canada and up to 30 percent in cats that are ill or otherwise at high risk, and feline immunodeficiency virus at roughly 2.5 to 5 percent of healthy North American cats and 15 percent or more in cats that are sick or at high risk.

A German study of 17,462 client-owned cats found feline immunodeficiency virus in 3.2 percent and feline leukaemia virus in 3.6 percent, with the feline immunodeficiency virus rate stable over ten years while the feline leukaemia virus rate fell from 6 percent to 1 percent across the same decade, which is what a working vaccination and testing programme looks like in a national dataset. Median age was 6 years in the feline immunodeficiency virus cats and 3 years in the feline leukaemia virus cats, a gap that tells you something about each disease before any survival curve is drawn.

The nearest large study to India geographically tells the same story with sharper edges. Of 713 cats sampled in Hong Kong, feline immunodeficiency virus seroprevalence was 46 of 298 community cats (15.4 percent) against 13 of 415 client-owned cats (3.1 percent), a difference significant at p below 0.001, while feline leukaemia virus was effectively absent, with a single regressive infection in 415 client-owned cats (0.2 percent, 95 percent confidence interval 0.0 to 1.3) and no markers of infection at all in 298 community cats. A five-fold gap between free-roaming and owned cats in the same city is the pattern an Indian dataset would most likely reproduce, and nobody has collected one.

Globally, a systematic review and meta-analysis that screened 873 studies and included 113 of them put pooled feline immunodeficiency virus seropositivity at 9.43 percent with a 95 percent confidence interval of 8.24 to 10.78, the highest continental estimate being Asia at 14.34 percent (10.92 to 18.61) and the lowest North America at 5.93 percent (4.33 to 8.07). A separate meta-analysis of infection rates from 47 published articles found the highest percentages of feline leukaemia virus or feline immunodeficiency virus infected cats in areas of lower gross domestic product at purchasing power parity, at p at or below 0.001. Both findings point the same way for India, and neither is an Indian measurement.

After a cat meets feline leukaemia virus, one of three things happens

After exposure to feline leukaemia virus a cat ends up with an abortive, a regressive or a progressive infection, and which of the three it is decides almost everything about its future. This three-way framing replaced the older language of regressor cats, latent infection and persistent viraemia once molecular methods made the differences visible, and it is the single most important thing about this virus that the first page of Google India does not mention at all.

Abortive infection means the cat met the virus and cleared it. Test results for culturable virus, antigen, viral RNA and proviral DNA are all negative, and the only trace is an antibody response. Such a cat will never test positive on any routine test and neither the owner nor the veterinarian may ever know it was exposed.

Regressive infection means the immune response contained the virus without eliminating it. Viral shedding stops once the first antigenaemic phase is over, but proviral DNA stays detectable in blood by PCR and the virus is integrated into the cat's genome, so it is unlikely to be completely cleared over time. Regressively infected cats do not shed infectious virus and are at low risk of feline leukaemia virus associated disease, but their provirus is infectious through a blood transfusion and reactivation can occur many years later, particularly if the cat becomes immunosuppressed.

Progressive infection means the cat did not contain the virus. Infection is not held back, the bone marrow becomes infected, the cat sheds virus and remains infectious to other cats, and neutralising antibodies are usually undetectable. Cats with progressive infection have a shorter survival time than cats with regressive infection and typically die of feline leukaemia virus associated disease within several years.

The order in which the tests turn positive matters for anyone deciding when to retest. Viral RNA is usually detectable in plasma by real-time reverse-transcriptase PCR within 1 week of exposure, proviral DNA by PCR within 2 weeks, and finally p27 antigen, which usually appears by 30 days but can take longer in some cats. Cats with regressive infection pass through the same early phases with similar viral loads, and only later does their load fall away to undetectable, which is precisely why a single test on a single day cannot classify a cat.

Read that table by population rather than by percentage. In 440 healthy Australian pet cats, 370 (84 percent) showed no sign of ever having met the virus and only 2 had a progressive infection. In the two Sydney rescue facilities, where infected cats were housed with uninfected ones and healthy cats were not separated from sick ones, 31 of 89 cats (35 percent) were unexposed and 19 (21 percent) were progressively infected. The same virus, the same country, the same year, and a forty-fold difference in progressive infection driven by housing. In southern Germany, four tests run on each of 495 cats found 9 progressive (1.8 percent) and 6 regressive (1.2 percent) infections, and the authors concluded both outcomes are now rare there.

Why the rapid test cannot tell you which of the three a cat has

A point-of-care kit that tries to classify the three outcomes has been tested in the field and it failed. A combined antigen and antibody kit sold in Europe was run on 200 Australian and 170 German cats and scored against PCR, neutralising antibody and laboratory ELISA results. In the first cohort it correctly identified 109 of 122 unexposed cats (89 percent) and 21 of 23 progressive infections (91 percent), but none of 23 regressive infections and none of 32 abortive infections. In the second cohort it got 148 of 158 unexposed (94 percent) and 4 of 4 progressive, but 0 of 2 regressive and 1 of 6 abortive (17 percent). The authors concluded the kit was unable to determine the different outcomes in the field and needs improvement before it is used on field samples.

Classifying a cat therefore still means a laboratory. An antigen-positive, PCR-positive cat can transition to a regressive pattern, usually within 16 weeks of infection, so the useful question after a first positive is not which of the three labels applies today but which one applies after the cat has been retested.

What feline immunodeficiency virus does to a cat, and over what timescale

Feline immunodeficiency virus works slowly, through three phases, and most of what an owner eventually sees comes from other infections rather than from the virus itself. The acute phase is easy to miss, the asymptomatic phase can last years, and the progressive phase is where the immune system stops handling everyday organisms. A cat can sit in the middle phase looking completely healthy for most of its life.

The clinical picture is a list of other diseases. As the virus spreads through the immune system, cats enter a progressively immunocompromised state during which secondary infections take hold, and the signs that bring a cat to a clinic are usually those infections rather than the retrovirus. Chronic gum and mouth inflammation is the most characteristic of them, and feline immunodeficiency virus infection sometimes leads to gingivitis, painful inflammation of the gums.

The association with oral disease is measurable. Of 1,611 cats with oral disease in the United States and Canada dataset, 157 (9.7 percent) were seropositive for feline immunodeficiency virus and 76 (4.7 percent) for feline leukaemia virus, against overall rates of 3.6 and 3.1 percent. In a twenty-year cohort of 132 sanctuary cats in the United Kingdom, oral disease was significantly linked to feline immunodeficiency virus at p equal to 0.004. If your cat has gums that will not settle, the retrovirus test is a reasonable part of the work-up rather than an afterthought. The mouth itself is covered on the periodontal disease in dogs and cats and tooth resorption in cats pages.

The bite-wound signature is even clearer. Of 1,983 cats presenting with abscesses or bite wounds, 247 (12.5 percent) were seropositive for feline immunodeficiency virus and 110 (5.5 percent) for feline leukaemia virus. A cat that has come home from a fight is the single most useful moment to test, and the correct timing is not the day of the fight, because antibody takes time to appear.

The lymphoma link, and what it looks like after vaccination

Cancer is where feline leukaemia virus does its worst work, and the relationship is not symmetrical between the two viruses. In the United Kingdom sanctuary cohort, neoplasia, and lymphoma in particular at 76.9 percent, was strongly associated with feline leukaemia virus at p below 0.001. The proportions of feline lymphoma attributable to the virus have fallen a long way since vaccination began, and the oncology side of that story, including what a feline lymphoma caseload looks like now, is set out on the lymphoma in dogs and cats page, which deliberately left the retroviral picture to this one. The two pages agree on the direction and on the boundary. A cat diagnosed with lymphoma should be tested for both viruses, because the result changes the household advice even where it does not change the treatment protocol.

Feline immunodeficiency virus is also associated with lymphoid malignancy, but at nothing like the same weight. In the same sanctuary cohort, the effect of feline immunodeficiency virus on longevity was real but far smaller than the effect of feline leukaemia virus, at p equal to 0.037 against p below 0.001. Multiple studies show that cats infected with feline immunodeficiency virus have low levels of morbidity and mortality with appropriate husbandry and disease management.

There is no licensed antiretroviral treatment for the virus itself. Treatment is limited and mostly uses drugs developed for human immunodeficiency virus; zidovudine can help cats with severe stomatitis or neurological disease but has not been shown to prolong survival and can have serious side effects. No drug is registered anywhere for the treatment of feline immunodeficiency virus infection, and the most effective way to extend a positive cat's life is to optimise basic husbandry and to find and treat concurrent conditions early. A 2025 review from an Indian-affiliated group surveys the antiretroviral and immunomodulator work in progress and the repeated failures of vaccine development, and concludes that prevention and management remain the practical tools.

How the test works, and what a single positive result is actually worth

To read a feline retrovirus test correctly, start from what each half of it detects. The feline leukaemia virus half looks for free p27 antigen in blood, which is a piece of the virus itself, so a positive means virus is present now. The feline immunodeficiency virus half looks for antibody, which is the cat's response, and a response can come from infection, from its mother's milk or from a vaccine. Those are two different kinds of evidence on one cassette, and they fail in different ways.

The antigen side has one large advantage. Feline leukaemia virus antigen testing is not confounded by maternally acquired immunity or by feline leukaemia virus vaccination, and most cats test positive within 30 days of exposure, although antigenaemia takes longer in some. It also has a clear limitation: antigen tests should not be run on tears or saliva, because sensitivity is low, and in one study saliva detected only 54 percent of infected cats.

The antibody side is the one that catches people out. Most cats produce antibody within 60 days of infection, so a cat tested too soon after a fight can be genuinely infected and genuinely test negative. At the other end, some cats entering the terminal phase test antibody negative because high viral loads sequester antibody in immune complexes, and a European study found an increasing number of cats testing negative on point-of-care kits but positive on Western blot between 1998 and 2019, which the authors read as imported viral variants reducing the diagnostic efficiency of those kits.

Why most positives in a low-prevalence population are wrong

This is the arithmetic that decides whether a healthy cat lives. Four combination kits were compared blind against reference standards on a sample set of 146 feline leukaemia virus positive, 154 negative, 94 feline immunodeficiency virus positive and 97 negative samples, none of them from vaccinated cats. Sensitivity and specificity for feline leukaemia virus were 100 and 100 percent for SNAP, 89.0 and 95.5 percent for WITNESS, 91.8 and 95.5 percent for Anigen, and 85.6 and 85.7 percent for VetScan; for feline immunodeficiency virus they were 97.9 and 99.0, 94.7 and 100, 96.8 and 99.0, and 91.5 and 99.0 percent. Those look like excellent numbers. They are, and they are still not enough.

The reason is that a test's positive predictive value depends on how common the disease is in the population being tested, not on how good the test is. The same study calculated predictive values across prevalences from 1 to 50 percent, and the conclusion published in the abstract is blunt: in typical cat populations with seroprevalence of 1 to 5 percent, a majority of positive results reported by most point-of-care test devices would be false-positives, which could result in unnecessary segregation or even euthanasia.

A 6 percent positive predictive value means that if that kit reports feline leukaemia virus antigen in a healthy pet cat from a population where roughly one cat in a hundred is infected, the result is wrong about nineteen times out of twenty. The negative predictive value of all four kits stayed high and declined only slightly even at 25 percent prevalence or greater, which is the other half of the point: a negative result on a healthy low-risk cat is trustworthy, and a positive result on the same cat is not.

This is not a theoretical artefact. In Hong Kong, point-of-care antigen testing of 415 client-owned cats produced five presumed false positives against one genuine infection, and that single genuine infection turned out to be regressive, detected by PCR rather than by antigen. The authors state the consequence directly, that feline leukaemia virus infection is rare in Hong Kong, which negatively affects the positive predictive value of diagnostic tests, and that confirmation of a positive result using PCR is essential.

The retest intervals, and why they are 30 days and 60 days

To use the retest intervals correctly, count from the last possible exposure rather than from the day you brought the cat home. Negative results are generally reliable when a highly sensitive kit is used on an apparently healthy cat with a low-risk lifestyle, with one exception, which is a cat in the early phase of infection before feline leukaemia virus antigenaemia has developed, under 30 days, or before feline immunodeficiency virus antibodies have developed, under 60 days. When antibody testing is negative but recent infection cannot be ruled out, testing should be repeated no earlier than 60 days after the last potential exposure.

A positive needs the opposite treatment, which is immediate confirmation rather than a wait. Because the consequences of a positive screening test are significant for the cat's future, additional testing is recommended, especially in low-risk and asymptomatic cats, and it can be done at once with a referral-laboratory microwell p27 ELISA, a PCR for provirus, or a point-of-care antigen test of a different brand. For feline immunodeficiency virus, confirmatory testing is recommended for all positive results, because a diagnosis may lead to management changes or to euthanasia in a shelter setting.

1. Test at the right moment. Test a cat when you acquire it, after any exposure to a cat of unknown status, before a first feline leukaemia virus vaccination, and whenever it falls ill.
2. Treat a positive as a screen, not a verdict. Confirm it the same week with a different method, a laboratory p27 ELISA or a proviral PCR for feline leukaemia virus, a second validated kit or a PCR or Western blot for feline immunodeficiency virus.
3. Retest a negative after 60 days when exposure inside the window cannot be ruled out, counting from the last possible exposure and not from the test.
4. Retest a positive kitten rather than acting on it, because antibody from its mother can make it positive to the age of 6 months.
5. Ask which kit was used if the cat is vaccinated against feline immunodeficiency virus, because two kits can separate vaccine antibody from infection and one widely used kit cannot.
6. Keep a discordant cat separate until the picture resolves, because cats with discordant results should be considered potential sources of infection for other cats until their status is clarified.

Kittens, and the vaccine that breaks the antibody test

A positive antibody test in a kitten usually means the kitten drank antibody, not that it caught a virus. Antibodies pass to kittens nursing on an infected or a vaccinated queen, which can produce a positive point-of-care antibody result up to the age of 6 months, and under natural circumstances kittens born to an otherwise healthy chronically infected queen rarely acquire the infection before or after birth. Most kittens that test antibody positive initially test negative once maternal antibody has waned, and kittens still testing positive after 6 months of age are likely to be truly infected. A positive kitten can be retested immediately with a reliable PCR assay rather than waiting.

The real-world evidence for this is direct. At a rescue shelter that took in five feline immunodeficiency virus positive queens with 19 nursing kittens between them, all 19 kittens tested negative after weaning, which the author read as vertical transmission not having occurred.

The vaccine problem is separate and it is geographic. Fel-O-Vax FIV was used in Canada, the United States, Australia, New Zealand and Japan, and it complicated antibody-based diagnosis because vaccinated cats produce antibodies that some commercially available tests cannot distinguish from those induced by natural infection; those antibodies can persist more than 7 years in some cats, and the product was discontinued in Canada and the United States in 2015. Australia and New Zealand are two of the three countries where the dual subtype vaccine is still available. India is not one of them, which removes this particular trap from an Indian clinic, but not from an imported cat.

Where the vaccine is in use, the kit matters. In a mixed population of 119 vaccinated and 239 unvaccinated Australian cats, two lateral flow kits, WITNESS and Anigen Rapid, had 100 percent sensitivity and 98 and 100 percent specificity respectively and could establish true infection status irrespective of vaccination history, while the SNAP combo could not tell whether detected antibody came from vaccination, natural infection or both. That is a striking reversal of the feline leukaemia virus ranking in the same pair of kits, and it is the clearest argument on this page for asking your veterinarian which cassette they are about to open.

Your cat has tested positive. What that does and does not mean

A positive result on an in-clinic kit means your cat needs a second test, not a decision. Both the American Association of Feline Practitioners and the Association of Shelter Veterinarians say a retrovirus infection is not on its own a reason to put a cat down, and the guidelines add that owners should be made aware of the potential for false-positive results and that the clinician should offer additional testing whenever possible and feasible.

That warning is not abstract. Of 17 Australian shelters that answered a questionnaire, 4 said they euthanised all cats positive for feline immunodeficiency virus regardless of health status. Put that next to the predictive value table above and the scale of the problem becomes clear: in a low-prevalence population, a policy of killing every cassette positive kills mostly uninfected cats.

A confirmed positive for feline immunodeficiency virus changes three things and nothing else. The cat should live indoors, both to protect it from other infections and to stop it biting other cats; it needs closer monitoring than an uninfected cat, because early detection of concurrent disease is what preserves its life expectancy; and any new cat entering the household needs its own status known. It does not need an antiviral, because none is registered, and it does not need to be rehomed away from children, because the virus does not infect people.

A confirmed positive for feline leukaemia virus changes more, because this cat can infect others. A progressively infected cat sheds virus and should not share bowls, trays or grooming with uninfected cats. A regressively infected cat does not shed, but it must never be a blood donor, because proviral DNA is infectious by transfusion and can cause viraemia and disease in the recipient. That distinction is only visible with PCR, which is the practical argument for paying for the confirmatory test rather than acting on the cassette.

One more thing changes after any confirmed positive, and it is the household rather than the cat. If one cat in a multi-cat household is found to be infected, the remaining cats should be tested. Whether they then need separating is the next question, and the answer is different for the two viruses.

Can a cat with feline immunodeficiency virus live with cats that are negative

Yes, in a stable household where the cats do not fight, and the evidence for that has moved from theory to direct observation. Cats in households with stable social structures where housemates do not fight are at negligible risk of acquiring the infection. The same is not true of feline leukaemia virus, and conflating the two is how households get bad advice.

The study that settled the feline immunodeficiency virus question followed real households rather than laboratory cats. At one rescue shelter, initial testing of 138 cohabiting cats found 130 negative and 8 positive, six neutered males and two spayed females. A second test in 45 of the negative and 5 of the positive cats, at a median of 28 months after the first and a range running from 1 month to 8.8 years, showed results unchanged. A third test in four of the original negative cats and one remaining positive cat, at a median of 38 months, was also unchanged. Years of cohabitation with naturally infected cats, and no transmission.

The guidelines carry one contrary observation and they name it. One study did report a high rate of transmission within a household without observed fighting, but that household also included cats co-infected with feline leukaemia virus. That is the honest state of the evidence: one outlier with a confounder, against a prospective series covering nearly nine years.

The practical rule follows from the transmission route rather than from the test result. Whether to advise separating infected from uninfected cats depends on whether there is a history of inter-cat aggression and wounding within the indoor social group, and even where the status of every cat in a multi-cat household is not known, transmission is relatively uncommon in stable, established groups kept indoors. Owners should also be told that cats which cannot live peacefully together are more likely to fight, and that no new cat should be introduced into such a household.

Group housing is where feline leukaemia virus does damage, and the Sydney rescue data in the outcomes table is what that looks like. In shelters that group-house cats, feline leukaemia virus testing is essential for identifying uninfected cats to place in the group, and vaccination of group-housed cats is recommended in long-stay shelters and sanctuaries but not in short-stay ones. For individually housed cats in less well-resourced shelters, testing and vaccination are not necessary because the risk of transmission is low, and adopters should instead be advised to discuss testing with their own veterinarian.

1. Test the new cat before it meets the resident cat, not after, and count 60 days from its last possible exposure before you trust a negative.
2. Isolate the new arrival until a second negative result 60 days later, particularly if it comes from a group with unknown status.
3. Test the resident cats too if one cat in the house is found positive.
4. Separate for feline leukaemia virus, assess for feline immunodeficiency virus. Separation for the second virus turns on whether these particular cats wound each other.
5. Fix the fighting rather than the test result. Neutering, more litter trays, more feeding stations and more vertical space reduce the bite wounds that move this virus.

How long positive cats live, with the denominators and the disagreement

Cats with feline immunodeficiency virus commonly reach something close to a normal lifespan, cats with progressive feline leukaemia virus infection usually do not, and the published studies still disagree about how large the first penalty is. While there is no cure for feline immunodeficiency virus, recent studies suggest that infected cats commonly live average life spans as long as they are not also infected with feline leukaemia virus. This page publishes the studies that disagree rather than picking one.

The two viruses do not sit on the same scale, and the New Zealand pair of numbers shows it most starkly. In a first-opinion caseload of 572 cats tested between 2010 and 2016, median survival after a positive test was 10 days for feline leukaemia virus and 650 days for feline immunodeficiency virus. Read that with the caveat the authors give, which is that testing and vaccination in New Zealand appear targeted at high-risk animals and may bias prevalence estimates; a cat tested in first opinion practice is usually a cat that is already unwell, so 10 days is the survival of cats tested because they were dying, not the survival of every infected cat.

On feline immunodeficiency virus the disagreement is genuine and it is worth seeing. A retrospective case-control study of 520 client-owned cats found multiple haematological and biochemical abnormalities common in old, sick cats regardless of status, and concluded that a negative effect of the virus on survival was not apparent, so the presence of those abnormalities should not be assumed to indicate clinical progression. A German survival subset likewise found no significant difference. Against that, the twenty-year United Kingdom sanctuary cohort did find a reduction, significant at p equal to 0.037, and framed it as infected cats being less likely to live to extremely old age rather than as a shortened life, and the large matched comparison reported to the retrovirus symposium and quoted by the AAFP guidelines put the gap at about 1.1 years on a median of 6.0.

Three things reconcile most of that. The first is the population: a referral centre, a first-opinion practice, a sanctuary that also houses cats with behavioural problems and a matched national dataset are not sampling the same cats. The second is euthanasia near diagnosis, which the AAFP guidelines flag directly, noting a high rate of euthanasia in the first year after diagnosis for both viruses, likely driven either by the disease that prompted the visit or by the killing of healthy infected cats for infection control. The third is housing, and it has been shown inside a single study: infected cats in a high-stress, large multi-cat household died of diseases consistent with severe immunodeficiency, most commonly lymphoma, while infected cats in small low-stress groups mostly stayed healthy for the 22 months of observation.

The conclusion the guidelines draw from all of it is the one to take home. These studies demonstrate that retrovirus-infected cats, and especially cats infected with feline immunodeficiency virus, may experience normal longevity with appropriate husbandry and disease management. The variable you control is not the virus. It is the household.

One caveat belongs on the largest of those numbers. The comparison of more than 1,000 positive cats with more than 8,000 controls comes from a 2006 conference abstract presented at the 8th International Feline Retrovirus Research Symposium, cited in the AAFP guidelines rather than published as a full paper, so it carries less weight than the peer-reviewed cohorts around it even though it has by far the largest denominator.

How to stop a cat catching either virus

To stop a cat catching either virus, remove the exposure first and treat vaccination as the second line, because neither vaccine is good enough to replace keeping a cat out of fights and away from unknown cats. Avoiding exposure is the best way to prevent feline leukaemia virus infection, and the vaccine sits on top of that rather than instead of it.

Neutering does most of the work on feline immunodeficiency virus, because it removes the behaviour that spreads it. Being a sexually intact male was a risk factor for seropositivity for both viruses in the 62,301-cat dataset, alongside adult age, outdoor access and clinical disease, and the cat sterilisation guide for India sets out what the procedure costs and when to book it. Keeping a cat indoors or in secure outdoor access removes the rest, which is the first recommendation in the Australian and New Zealand guidelines. The indoor cat safety guide covers how to do that in an Indian flat without making the cat miserable.

The feline leukaemia virus vaccine, and the test that must come first

The 2024 World Small Animal Veterinary Association guidelines moved this vaccine up a category. In parts of the world where feline leukaemia virus related diseases are endemic, the vaccine should be considered core for young cats under 1 year of age and for adult cats with outdoor access or living with cats that have outdoor access. The schedule is two doses, the first as early as 8 weeks of age and the second 3 to 4 weeks later, a booster one year after the last dose of the initial series, and after that annual revaccination for cats at continuing high risk or every 2 or 3 years according to the product leaflet for low-risk cats.

One instruction in that guideline is non-negotiable and is routinely skipped. Only cats that are negative for feline leukaemia virus should be vaccinated, and testing should be performed prior to vaccine administration. The reason is given plainly in the shelter section, quoting the AAFP guidelines: if a vaccinated cat's status is unknown and the cat is later found to be infected, vaccine efficacy would be questioned and vaccine failure suspected. A vaccine given to an already-infected cat protects nothing and confuses everything afterwards. The cat vaccination schedule for India sets out what Indian clinics actually stock against this schedule.

The feline immunodeficiency virus vaccine, and why it is not the answer

The one commercially available feline immunodeficiency virus vaccine is a killed, adjuvanted, dual subtype product given as three doses, the first as early as 8 weeks of age and two more at intervals of 2 to 3 weeks. Its measured field performance is the problem. In the only published field study, a case-control design in 440 Australian cats with outdoor access, 5 of 89 vaccinated cats (6 percent) and 25 of 212 unvaccinated controls (12 percent) were infected, giving a protective rate of 56 percent with a 95 percent confidence interval of minus 20 to 84, and the difference between the groups was not statistically significant at p equal to 0.14. A confidence interval that includes zero protection is not a foundation for a household plan, and the authors concluded that owners should not rely on vaccination alone.

The vaccine also carries a diagnostic cost. Vaccination against feline immunodeficiency virus is not recommended in shelters, because transmission among co-housed cats that do not fight appears to be uncommon, the level of vaccine-induced immunity is variable, and vaccine-induced positive antibody results complicate any future determination of a vaccinated cat's true status. Where the vaccine is used, annual testing before annual revaccination is advised, so that infection acquired during the preceding year is not vaccinated over.

• Neuter, because intact males fight and fighting is how feline immunodeficiency virus moves.
• Keep cats in, or give them secure outdoor access rather than free roaming.
• Test every new cat before it meets a resident cat, and again 60 days later.
• Test before the first feline leukaemia virus vaccine, every time, without exception.
• Screen blood donors for both viruses and for provirus by PCR, because a regressively infected donor can transmit infection even with a negative antigen test.
• Do not test as a substitute for managing the household. A test result changes what you know; the litter trays, the feeding stations and the front door change what happens.

FeLV and FIV in India: what is known, what a test costs, and what is missing

For India the honest answer is that nobody has measured it. There is no published seroprevalence survey of either virus in Indian domestic cats, free-roaming, shelter or owned, and this page records the search that establishes that rather than asserting it. That is not the same as saying Indian cats are unaffected, and it is not the same as saying Indian veterinary science ignores cats.

Here is the search, with its control. On 27 September 2026, a Europe PMC title and abstract search for feline leukaemia virus or feline immunodeficiency virus against India returned 5 records. Opening each one: three are substring artefacts, including an ethnomedicinal survey from Chhattisgarh and a 1980 paper on Escherichia coli plasmids; one is a 1995 case report of cryptococcosis in a cat, from Barcelona, not India; and one is a genuine Indian study, of lions. An affiliation search returned 14 records, of which the only feline retrovirus work by an Indian-affiliated group is a 2025 narrative review rather than a survey Akhtar N, Mishra R, Tripathi S. Through the identical route on the same day, canine parvovirus against Indian author affiliation returned 80 records, and the Labrador and hip dysplasia syntax control returned 110. The instrument finds Indian veterinary virology when Indian veterinary virology exists.

The one real Indian felid serosurvey is about lions and it found nothing. Fifty-six captive Asiatic lions, including 17 Afro-Asian hybrids, from six captive centres in western India were sampled between December 1998 and March 1999 and tested with commercial ELISA kits. There were no detectable levels of feline immunodeficiency virus antibody and no feline leukaemia virus antigen in any of them, while in the same samples 49 of 56 (87.5 percent) were positive for canine distemper virus and all 56 (100 percent) for feline parvovirus antibody. The authors treated the absence as a risk in itself, recommending screening of in-contact animals, since a naive population is a vulnerable one. That is a 27-year-old result about a captive wild felid in Gujarat, and it says nothing about a house cat in Chennai in 2026.

Indian feline virology is otherwise busy, which is what makes the retroviral gap specific rather than general. Indian groups have published the first molecular detection of feline coronavirus from India, out of Madras Veterinary College at Tamil Nadu Veterinary and Animal Sciences University in Chennai, along with the complete genome of feline panleukopenia virus, feline panleukopenia detection from Mizoram, feline and canine parvovirus circulation in Gujarat and Cytauxzoon infection in domestic cats in Bihar, all within the last few years. Panleukopenia and the coronaviruses have Indian pages here already, at feline panleukopenia and FIP in cats. The retroviruses do not, because the data does not exist to write one from.

What a test costs in India, and where the search sends you instead

Testing is purchasable in India but it is not standardised and it is not priced by any public institution. A distributor in Bhopal advertises the PetX JCA104D combo rapid test at Rs 5,500 a box, in stock, with the price stated as excluding all taxes. That figure passes the conversion check, coming to about 65 United States dollars at 84.38 to the dollar and about 74 at 74 to the dollar, neither of which is a round dollar list price, so it reads as a genuine Indian quotation rather than a converted foreign one.

The government rate cards are the interesting part, because of what they leave out. Bihar Animal Sciences University publishes a bedside and pen-side diagnostic list of exactly five tests at its Bihar Veterinary College hospital: feline infectious peritonitis antigen at Rs 300, feline panleukopenia antigen at Rs 300, a canine parvovirus and distemper combo antigen at Rs 500, a four-way tick-borne combo at Rs 800 and a Theileria antibody rapid test kit at Rs 500. Neither feline retrovirus appears anywhere on that list, or anywhere in the rest of the fee schedule. A government veterinary hospital that runs a bedside kit for feline coronavirus and a bedside kit for feline panleukopenia does not run one for feline leukaemia virus. ICAR-IVRI at Izatnagar prices a lateral flow test for infectious diseases at Rs 500 for pets and names no disease at all, so an owner reading that rate card cannot tell whether a retrovirus combo is included.

The search results are worse than the rate cards. The Google India results page for the query an Indian owner would actually type, captured on 27 September 2026, returned about 6,770 results and an organic top ten containing a Justdial listing for cat vaccination centres in Noida, a Facebook thread from a Saudi expatriate cat group, an Etsy shopping page for feline assistant merchandise, a 2013 paper on feline leukaemia virus phylogenetics, a ResearchGate figure, an American humane society advertising a 20 dollar test in Georgia, a Korean diagnostic development paper and a United States kitten first-year guide. Not one Indian veterinary page carrying a rupee price. The only rupee figures on the page came from an advertisement and from the AI Mode reply, which in the saved bytes said a combo test typically costs between Rs 1,200 and Rs 3,500 at an Indian clinic or lab. An AI answer rewrites itself between calls, so that number is reported here as what the saved capture contained on that date and not as a surveyed Indian price.

What the Indian results page actually said, city by city

Every rupee figure an Indian owner meets on that query comes from an AI answer or an advertisement, and the saved capture shows where each one came from. The AI Mode reply opened by stating that in India a combo test typically costs between Rs 1,200 and Rs 3,500 at a veterinary clinic or lab, then broke that down, saying that dedicated pet diagnostic labs such as VetScan Delhi generally charge around Rs 1,500 for a combo test and that individual rapid tests at local or at-home pet care services can start around Rs 1,200. Its supporting results named an at-home feline leukaemia virus test in Hyderabad, printed on the results page as ₹1,200.00, a veterinary laboratory in Delhi, and a Facebook thread in the Mumbai Cat Club asking what feline infectious peritonitis, feline leukaemia virus and parvovirus tests cost in Mumbai, whose own snippet on that results page says the cost of those tests in Mumbai is not uniform. The Hyderabad product page that snippet pointed at returned 404 on this attempt, so the figure could not be confirmed at source. None of these is a surveyed Indian price, and a Google AI answer rewrites itself between calls, so they are recorded here as what the saved bytes contained on 27 September 2026 and nothing more.

The People also ask box on that query asked exactly one question, and it was not about cats. It asked how much a viral marker kit costs, which in Indian search means the human panel for human immunodeficiency virus, hepatitis B surface antigen and anti-hepatitis C, and Google answered it with prices from three human pathology chains, quoting a rapid card method at around Rs 700 to Rs 1,150 at Redcliffe Labs or Pathkind Labs and a laboratory method through Tata 1mg at Rs 1,287 to Rs 1,709 depending on the city, with about Rs 1,709 given for Bangalore. A cat owner in Bengaluru who reads that number and books that test has bought a human hepatitis and HIV screen. The only Indian-domain page in the top ten for the bare query is a Purina India article dated 26 May 2025 in which the word India appears once, inside its own title.

What Indian paperwork already assumes about these viruses

Indian insurance wording is ahead of the Indian market, in a way that could cost an owner a claim. Exclusion 35 of the Go Digit pet insurance customer information sheet refuses treatment for any illness for which vaccination is available and recommended by the veterinarian but rejected by the owner, and the cat list it prints names feline herpesvirus 1, feline calicivirus, feline panleukopenia, rabies, feline leukaemia, feline infectious peritonitis and feline immunodeficiency virus. The qualifier that vaccination must be available does the protective work here, because no feline leukaemia virus or feline immunodeficiency virus vaccine is sold in India, but the list is worth reading before a claim rather than after it. The pet insurance guide sets out how the other Indian wordings handle the same clause.

The vaccination position leaves India in a gap. The World Small Animal Veterinary Association makes the feline leukaemia virus vaccine core for cats under a year old in regions where the virus is prevalent or remains of concern, and non-core elsewhere, and it also notes that there are regions where infection is rare and the disease is diagnosed only in imported cats. India cannot be placed in either bracket, because no one has measured which it is. Meanwhile the three cat vaccines on sale in India are all trivalent, so the question is academic until a product arrives. Retroviral testing sits in the same grey zone on the routine-care side, where the adult cat care guide records it as a lifestyle call rather than a fixed item.