Infectious diseases in cats

Are infections different in Sphynx cats?

Being hairless does not make Sphynx cats particularly susceptible to every infection. They can develop the same infections as other cats. Age, immunity, vaccination, stress and living conditions have a major influence on how a disease develops.

For this reason, this guide concerns cats as a species. It includes additional points relevant to breeding catteries and homes with several cats, but it is not a list of diseases unique to Sphynx cats.

How infections spread between cats

Cats living together have frequent contact, share rooms and sometimes use the same items. Some infections spread more easily in these conditions. However, this does not mean that every sneeze signals a serious illness or that every positive PCR result requires treatment.

The route of transmission depends on the particular microorganism. FeLV spreads readily through close contact involving saliva, FIV is transmitted mainly through deep bite wounds, and intestinal FCoV spreads by the faecal-oral route. A contaminated environment is also particularly important in panleukopenia. The same risk model cannot be applied to every infection.[1][8]

Appropriate vaccination, sensible quarantine for new animals, reducing stress, a clean environment and prompt action when a cat stops eating, has breathing difficulties or becomes severely weak are all essential.

Understanding test results

Infection means the presence and multiplication of a microorganism within the body.

Disease means impaired health that may result from infection. A cat can be infected without showing visible signs.

Shedding means releasing a microorganism, for example in faeces, saliva or discharge from the eyes and nose.

Colonisation means that microorganisms establish themselves on the body surface or mucous membranes, without necessarily causing disease.

Different tests answer different questions.

An antigen test detects specific components of a microorganism.[1]

An antibody test assesses the immune system’s response.[1]

PCR detects genetic material. For RNA viruses such as FCoV and FCV, a reverse transcription step is used, hence the term RT-PCR. RT-qPCR is a method with real-time measurement that can be used to assess the amount of viral material.[4][10]

Why is a positive or negative result not enough?

A positive PCR result confirms that the target material was detected in the sample. By itself, it does not establish whether the microorganism is alive, whether it is causing the current signs or whether treatment is needed. Depending on the pathogen, it may reflect an active infection, an infection without signs, colonisation or genetic material remaining after an infection. A negative result can be influenced by the sampling site and timing, sample quality, previous treatment and the scope of the test.[10][12]

The diagnostic window is the period after infection during which a particular test may not yet detect it. A newly admitted cat’s result therefore needs to be assessed in relation to the date of its last possible contact with an infected animal. This is not the same as the number of days since arrival at the cattery.[1]

Ct is a parameter in some PCR tests indicating the cycle at which the signal crossed the detection threshold. Under comparable conditions, a lower Ct usually corresponds to a larger amount of target material. However, there is no single Ct threshold that distinguishes the presence of a microorganism without signs from disease in every cat. Results cannot be compared directly across different methods, laboratories and sample types.[10][12]

When interpreting a result, the vet considers the signs, the cat’s examination, sample type, contact history, vaccination and previous treatment together. A modified live vaccine contains an attenuated, or weakened, microorganism. For some infections, its material may be detectable temporarily after vaccination, so the date and product name should be provided. This does not mean that vaccination explains every positive result.[8][9][10]

FeLV, the feline leukaemia virus

Transmission and signs

FeLV, the feline leukaemia virus, is sometimes described as the “cat kissing” disease. This informal expression highlights the importance of close contact in transmission. The virus is shed mainly in saliva and can spread during mutual grooming, through shared bowls and when a mother cares for her kittens. An infected queen can also pass FeLV to her offspring during pregnancy or through her milk.

FeLV does not survive well outside a cat’s body. Drying, cleaning and disinfection quickly inactivate it. Bringing the virus indoors on the soles of shoes is not considered an important route of infection. A bowl used by cats one after another is different, because fresh infected saliva may be a source of the virus. In this respect, FeLV is very different from the environmentally resistant panleukopenia virus.

FeLV can impair immunity, damage bone marrow and increase the risk of certain cancers. The course of infection depends partly on the cat’s immune response. Progressive infection involves persistent viral replication. In regressive infection, the body restricts viral activity, but viral material may remain integrated into the DNA of cells. This is not the same as completely eliminating the infection.[2]

Diagnosis and interpretation

A typical rapid blood screening test detects FeLV p27 antigen. PCR can instead detect provirus, meaning viral material integrated into the DNA of cells. This is why antigen testing and PCR may produce different results, particularly in regressive infection.[1][2]

Following recent exposure, an antigen test may still be negative. Most infected cats develop detectable antigen levels within about 30 days, but some take longer. If suspicion remains, the vet will plan repeat or additional testing. This is an approximate time to detection, not a guarantee that one test can rule out infection.[1]

An unexpected positive result, particularly in a healthy cat with a low risk of infection, needs confirmation. Distinguishing progressive from regressive infection may require monitoring and further tests. A single test should not be the sole basis for irreversible decisions. Neither FeLV vaccination nor maternal antibodies cause a positive result on a standard p27 antigen test.[1][2]

Management and prevention

An infected cat needs individual veterinary care and an assessment of the risk of transmission to other animals. In a breeding cattery, the status of the whole group must be clarified, exposure of uninfected cats reduced, and matings and movements of cats paused until the risk has been assessed. Infected cats are not used for breeding. FeLV vaccination is tailored to age and risk; it does not replace testing and control of contacts.[1][2][20]

FIV, the feline immunodeficiency virus

Transmission and signs

FIV, the feline immunodeficiency virus, can informally be described as the “fighting tomcat” disease. Its main route of transmission is through deep bite wounds during fights. Free-roaming and outdoor unneutered males competing over territory are therefore at particular risk. This is not an official medical term, and females and neutered males can also become infected.

Unlike FeLV, FIV does not spread readily when cats live peacefully together, share a bowl or groom one another. In a stable group without fighting, the risk of transmission is much lower. FIV is a chronic infection, but a cat with a positive result can remain in good health for many years.

When health problems develop, they may include chronic inflammation of the gums and mouth, recurrent infections, weight loss and enlarged lymph nodes. Many problems are caused by secondary diseases associated with impaired immunity. Even in a cat with confirmed FIV, the specific cause of the signs must therefore be identified and treated appropriately. These signs alone do not establish a diagnosis of FIV infection.[3]

Diagnosis and interpretation

Typical FIV screening tests detect antibodies, rather than the p27 antigen tested for in FeLV. Antibodies may not yet be detectable early in infection. If recent exposure cannot be excluded, AAFP guidelines recommend retesting no sooner than 60 days after the last possible contact. The vet may choose an additional method to suit the individual situation.[1][3]

The significance of a positive result also depends on the cat’s risk and history. FIV vaccination has been or is used in some countries and can affect certain antibody tests. An unexpected result should be confirmed using an appropriate method. PCR also has limitations and does not automatically resolve every discrepancy.[1][3]

Management and prevention

Prevention centres on avoiding bite wounds and uncontrolled contacts. A cat with confirmed FIV needs care and prompt investigation of any emerging health problems. In a breeding cattery, this means retiring the cat from breeding, testing the other cats and assessing transmission risk. A positive result alone does not measure the cat’s current wellbeing or automatically imply a short life.[1][3]

Feline coronavirus (FCoV) and FIP

FCoV is a virus, while FIP is a disease that develops in only a small proportion of infected cats. A positive coronavirus test does not automatically mean feline infectious peritonitis.[4]

How does FCoV spread and what signs does it cause?

FCoV spreads mainly by the faecal-oral route. An infected cat sheds the virus in its faeces, and other cats may ingest viral particles while grooming their paws or using shared litter trays. Infection usually causes no signs or only short-lived intestinal signs, particularly in kittens. Detecting FCoV alone is therefore not a reason to diagnose FIP, isolate a cat for life or give antiviral treatment.

Why do some cats develop FIP?

The most widely accepted model is that the virus changes within an individual cat and acquires the ability to replicate efficiently in monocytes and macrophages, allowing severe systemic disease to develop. Researchers are investigating, among other things, changes in the spike protein gene (S), but no single mutation reliably diagnoses FIP or explains every case. The cat’s immune response and probably genetic susceptibility also matter. FIP may therefore occur more often in some related groups, but a pedigree alone cannot predict which cat will become ill. Stress may affect immunity, but it is neither a simple nor a necessary cause of FIP.[4]

Diagnosis: two different questions

Is the cat shedding intestinal FCoV? This is assessed by faecal RT-PCR or RT-qPCR, available individually or as part of an intestinal panel. Viral shedding can vary: one sample may contain a large amount of RNA, the next very little and another an undetectable amount. A single negative result does not establish that a cat is permanently free from infection or will not shed the virus in future. Assessing a group may require repeated samples from individually identified cats.[4]

Does the cat have FIP? Depending on the case, FIP can cause persistent fever, loss of appetite and weight, fluid in the abdomen or chest, eye changes or neurological signs. Diagnosis requires the clinical picture, blood tests, imaging and tests on fluid or tissue to be considered together. A positive faecal PCR for FCoV alone does not diagnose FIP. There is also no universal, simple genetic test that confirms or excludes every form of FIP.[4]

Treatment and infection control within a group

FIP was once considered almost invariably fatal. Today, antiviral medicines, particularly GS-441524, allow many cats to recover. Suspected FIP requires prompt consultation with a vet experienced in diagnosing and managing this disease.[7]

Controlling intestinal FCoV involves litter-tray hygiene, prompt removal of faeces and reducing transmission between groups. Testing helps assess the situation when it forms part of a consistent programme. A single negative result does not justify declaring an entire cattery “coronavirus-free”.[4][6]

Feline panleukopenia

Transmission and signs

Panleukopenia is caused by feline parvovirus (FPV). Young, unvaccinated kittens usually develop the most severe disease. Signs include lethargy, refusal to eat, vomiting and dehydration, sometimes accompanied by diarrhoea.

Panleukopenia in kittens is an emergency. A young cat can become extremely weak and dehydrated within a matter of hours. Diarrhoea may not be present initially, so sudden vomiting and weakness are not reasons to wait for it to appear or to attempt treatment solely at home.

FPV is highly resistant in the environment. It can remain infectious for many months and be carried on objects, clothing or footwear. Indoor cats are therefore also at risk.[8]

Diagnosis and interpretation

A complete blood count is important in the initial assessment. It often shows a marked reduction in white blood cells, particularly neutrophils and lymphocytes. A rapid faecal antigen test is useful, but a negative result does not exclude infection; if suspicion is strong, the vet may request PCR. Positive results may occur for a time after a modified live FPV vaccine, so the date and type of vaccination also need to be considered.[8]

Treatment and prevention

Treatment primarily involves appropriate fluid therapy, controlling vomiting, managing electrolyte disturbances and feeding according to the patient’s condition. The vet may prescribe an antibiotic when there is a risk of bacterial infection or sepsis. Do not independently use outdated protocols that involve starving kittens or unproven serum preparations.

Protection relies mainly on core vaccination tailored to age and risk. An outbreak requires isolation, separate equipment, thorough cleaning and a product with documented efficacy against parvoviruses, used at the correct concentration and for the required contact time. Simply wiping a surface with detergent may not be enough.[8][20]

Consequences of infection during development

Infection in a pregnant queen can cause foetal death, while infection before birth or in the early neonatal period can cause cerebellar hypoplasia in kittens. Affected cats may have permanent problems with movement coordination. This results from damage to the developing nervous system and is not proof that the cat is still shedding the virus.

Feline herpesvirus (FHV-1)

Transmission and signs

Feline herpesvirus type 1 is one of the two main viral causes of cat flu. It mainly causes inflammation of the nose, conjunctiva and cornea. Affected cats may sneeze, have nasal and eye discharge, develop a fever and lose their appetite. A painful eye, marked squinting, sensitivity to light or a cloudy cornea need urgent examination, preferably by a veterinary ophthalmologist. Herpesvirus can cause corneal ulceration and, in kittens, adhesions between the conjunctiva and cornea.

The infection spreads through contact with secretions from the eyes, nose and mouth. After infection, FHV-1 usually remains latent in the body. Stress, other illnesses or treatment that suppresses immunity can reactivate it and trigger renewed shedding, even in a cat that previously appeared healthy. Vaccination reduces disease severity but does not guarantee elimination of infection or carrier status.[9]

Diagnosis and interpretation

For persistent signs or a problem affecting several cats, the vet may request PCR on a swab taken from an appropriate site. A positive FHV-1 result must be assessed alongside the clinical picture, because the test can also detect small amounts of viral material in a cat without active disease. A negative result does not exclude latent infection. Modified live FHV-1 vaccines contain material detectable in the laboratory, but more recent studies suggest that positive swabs after routine vaccination are uncommon. Vaccination should therefore not automatically be used to explain every positive PCR result.[9]

Treatment and prevention

Treatment depends on the cat’s condition. It includes maintaining hydration and food intake, gently clearing discharge and treating eye lesions. When indicated, the vet may prescribe antiviral medicines, including famciclovir. Do not use steroid eye drops without veterinary direction, especially if corneal ulceration has not been excluded. Lysine is not routinely recommended for treating or preventing herpesvirus disease.

Protecting the group involves core vaccination, reducing stress and contact with cats showing signs, and keeping hands and equipment clean. Latent infection can reactivate, so a long period without signs does not mean the virus has been eliminated from the body.[9][20]

Feline calicivirus (FCV)

Transmission and signs

Calicivirus is the other main viral cause of cat flu. Compared with herpesvirus, painful erosions and ulcers on the tongue and oral mucosa are particularly characteristic. A cat may drool, be reluctant to eat, sneeze, have a fever and develop nasal discharge. Some cats show temporary lameness, and infection in kittens can lead to serious pneumonia. No single sign, however, provides a certain diagnosis.

FCV spreads readily through contact with saliva and nasal discharge, and via shared bowls, cages, objects and the hands of people caring for cats. It is a non-enveloped virus and survives better in the environment than FHV-1. Under favourable conditions, it can persist on surfaces for many days or even around a month. Disinfectants should have proven efficacy against FCV and be used according to the manufacturer’s instructions.

The virus has highly diverse strains and can cause illness of varying severity. A particularly severe systemic form, known as VS-FCV or FCV-VSD, occurs rarely. Signs include high fever, swelling of the head and limbs, skin ulcers, jaundice and organ failure. This condition requires urgent hospitalisation and strict isolation measures.

Diagnosis and interpretation

RT-PCR detects FCV RNA and is often included in respiratory disease panels. A positive result confirms viral genetic material in the sample but does not necessarily mean active calicivirus disease. FCV may be detected in an apparently healthy carrier still shedding the virus after an earlier infection. Coinfections, for example with FHV-1 or Chlamydia felis, are also possible, so FCV may not be the main cause of the current signs.

Another situation matters when interpreting results. A cat recently given a vaccine containing live, attenuated FCV may occasionally shed the vaccine strain. PCR can then be positive without indicating natural infection with a field virus. This is sometimes informally called a false positive, although the test may actually have correctly detected vaccine-virus RNA. The laboratory should therefore be given the vaccination date and product name when the test is requested.

In a cat with oral ulcers and respiratory signs, a positive RT-PCR supports the involvement of FCV. RNA quantity and Ct provide supporting information. The principles explained in the testing section apply; these parameters are not independent measures of disease severity.[10]

A negative result does not exclude calicivirus disease. The amount of virus may be small, the sampling site may be less than ideal, and strain diversity can make detection difficult. If the signs are typical, the vet may arrange another test. Standard PCR does not automatically distinguish an ordinary infection from severe systemic disease. When VS-FCV is suspected, the pattern of illness within the group and specialist investigations also matter.[10]

Treatment and prevention

There is no routine, specific antiviral treatment that eliminates FCV. Management includes appropriate nutrition, hydration and pain relief, particularly when oral lesions prevent the cat from eating. Antibiotics are used according to veterinary indications, mainly when a concurrent bacterial infection is suspected or confirmed, rather than solely because PCR is positive. Do not independently administer essential oils or force-feed a cat at risk of aspiration.

FCV vaccination is a core vaccination. It does not provide complete protection against infection, but usually reduces the severity of signs. Recovered cats should also be vaccinated as advised by their vet, because infection does not provide lasting immunity against every strain.[10][20]

Rabies

Transmission and risk

Rabies is a viral disease most commonly transmitted through the bite of an infected mammal. Once clinical signs appear, it is almost invariably fatal and poses a risk to humans. A lower risk in an indoor cat does not make prevention unimportant.

What to do after a suspicious contact

If a cat has had contact with a suspect animal, or a person has been bitten, do not try to decide independently whether the cat is infected. Contact a vet urgently and, if a person has been exposed, a medical doctor as well.

Vaccination and regulations

Vaccination requirements may arise from travel rules and current local regulations, for example in areas at risk of rabies. Check notices from the relevant veterinary authority and agree on prevention with your vet. The safety of a suspicious contact cannot be judged solely by whether the animal looks healthy.[19]

Chlamydia felis and conjunctival infections

Transmission and signs

Chlamydia felis, formerly called Chlamydophila felis, is a bacterium primarily responsible for conjunctivitis. Disease occurs most often in young cats, especially those living in groups. Signs frequently begin in one eye and later affect the other. Redness, swelling of the conjunctiva and discharge develop.

Transmission usually requires close contact, particularly with eye discharge. In a home with several cats, it is therefore important to assess animals that have been in contact with the affected cat as well.[11]

Diagnosis and interpretation

Similar conjunctivitis can result from FHV-1, corneal damage or a noninfectious eye condition. Diagnosis relies on an eye examination and, when indicated, PCR on a properly collected swab. Ordering a broad test panel does not replace choosing the correct sampling site.

Treatment and protecting the group

Confirmed chlamydiosis usually requires a systemic antibiotic, often for several weeks. Randomly chosen eye drops alone are not a substitute for treatment. The vet selects the medicine and duration, because an improvement in the eyes’ appearance does not always mean that infection has ended.[11]

When Chlamydia felis infection persists in a breeding cattery, the vet may recommend treating every cat in the group at the same time. The aim is to reduce reinfection between animals. This differs from an incidental positive M. felis swab in a healthy cat. Management depends on the pathogen identified and the circumstances of the whole group.[11]

Chlamydia felis vaccination is not a core vaccination for every cat. It may be considered for groups at particular risk, based on veterinary advice.[11]

Mycoplasma felis

What is it and how does it spread?

Mycoplasma felis can be detected both in healthy cats and in animals with conjunctival and respiratory disease. Mycoplasmas may colonise mucous membranes without signs, but M. felis should not be regarded solely as a harmless resident bacterium. In the right circumstances, it can be a genuine pathogen.[12]

Mycoplasmas comprise several different species. Those detected in cats include M. felis, M. gatae and M. arginini. If a result is described simply as “mycoplasma”, check the species name and the type of sample tested.

Mycoplasmas mainly colonise the surfaces of mucous membranes. They spread between cats chiefly through close contact, respiratory secretions and mutual grooming. Large groups, frequent introductions of new animals and concurrent viral infections favour transmission. Because mycoplasmas lack a cell wall and do not survive well outside the body, transmission through objects is much less important than direct contact. The transmission principles of the environmentally resistant panleukopenia parvovirus do not apply here.

Signs and clinical significance

M. felis is most commonly associated with conjunctivitis and upper respiratory tract disease. Signs may include redness and swelling of the conjunctiva, tearing, eye discharge, sneezing, nasal discharge and chronic or recurrent signs resembling cat flu. Herpesvirus, calicivirus or other bacteria are often detected at the same time. In this situation, it is not straightforward to determine which microorganism initiated the disease and which is simply present alongside it.

Mycoplasma can also become a secondary pathogen when a previous infection or chronic inflammation has damaged the airways’ natural clearance mechanisms. Its involvement in lower respiratory tract infections, pneumonia, pleuritis, keratitis and arthritis has been reported less often. This does not mean that every sneeze or joint problem is related to mycoplasma. Coughing, rapid breathing or breathing difficulties require prompt investigation, because a nasal swab alone cannot establish the cause of lung disease.

In studies cited by ABCD, M. felis was also detected in 20.4% of healthy cats in Spain, 31% in Switzerland and 18.72% of cats without signs of upper respiratory tract disease in a study from China. These findings concern different populations and do not represent a fixed prevalence applicable to every cattery.[12]

Diagnosis: three examples

The general principles of PCR interpretation described earlier apply. For M. felis, it is particularly important whether the sample comes from a healthy mucous membrane, an inflamed site or the lower airways. There is no universal Ct value that confirms mycoplasma disease.

First example: a healthy cat in a cattery has a positive M. felis PCR, but no sneezing, eye discharge or fever. The result indicates the presence of bacterial material, but does not prove that the cat needs an antibiotic. Observation, assessment of the risk to other animals and discussion of the result with a vet are more important.

Second example: a cat has obvious conjunctivitis, and M. felis is detected in a swab. Its involvement in the disease is more likely, but FHV-1, Chlamydia felis, corneal damage and noninfectious causes should also be considered and excluded as appropriate. Treatment decisions depend on the whole picture, not simply the presence of DNA.

Third example: a cat has severe pneumonia, and M. felis is detected in material collected from the lower airways. This has a different diagnostic significance from a positive throat swab in a healthy animal. It requires assessment alongside imaging, cytology and investigation for other pathogens.

Treatment and prevention

A healthy cat is not automatically treated simply to make the next PCR result negative. Antibiotic treatment may be appropriate when the vet considers M. felis an important cause of conjunctivitis, persistent respiratory signs or lower respiratory tract infection. Doxycycline is often chosen, but the medicine and treatment duration depend on the case.[12]

Mycoplasmas have no cell wall, so penicillins, cephalosporins and other beta-lactam antibiotics do not act directly against them. However, failure to improve with amoxicillin does not prove mycoplasma disease. Recurrence may result from coinfection, renewed exposure or a noninfectious cause of inflammation, rather than necessarily from bacterial resistance.

Doxycycline tablets carry a risk of oesophageal injury. The vet should explain how to administer them and how to follow them with an appropriate amount of water or food. Do not give a cat a dry tablet without following the recommended method for ensuring that it is swallowed safely.

Within a group, important measures include isolating cats with signs, controlling coinfections, quarantining newcomers and limiting contact between groups. There is no widely used vaccine against M. felis. The vet decides whether other cats need treatment after assessing their signs, test results and the situation of the whole group.[12]

If signs recur, investigate whether the underlying problem is FHV-1, chronic damage to the nasal mucosa, lower respiratory tract disease or another cause. The aim is to protect the cats’ health and control infection where it is genuinely responsible for disease.

Bordetella bronchiseptica

Transmission and signs

Bordetella bronchiseptica causes respiratory infections, particularly in large groups of cats. It spreads through nasal and oral secretions, including from an infected dog. It can cause coughing, sneezing, fever and nasal discharge. Young kittens may develop severe pneumonia with breathing difficulties.[21]

Diagnosis and interpretation

Culture or PCR is used for diagnosis. The sample is chosen according to the site of disease; suspected pneumonia may require material from the lower airways. Results are assessed alongside the signs and other investigations.[21]

Treatment and prevention

When the bacterium is responsible for disease, the vet selects an antibiotic, preferably taking the isolated strain’s susceptibility into account. A severely ill kitten may need hospitalisation. Within a group, hygiene and limiting contact with sick cats and dogs are important. Vaccination is not a core measure; it is considered for selected groups at increased risk.[21]

Streptococci

Transmission and signs

Streptococcus canis may be part of the microbiota of feline skin and mucous membranes, but under certain conditions it can cause infections of wounds, the respiratory tract and reproductive organs. In very young or weakened kittens, it can also cause severe systemic disease. A positive culture in a cat without signs therefore does not automatically mean that treatment is necessary.

Streptococcus equi subsp. zooepidemicus is detected less often in cats, but outbreaks of severe respiratory infection have been reported in groups of animals. Sudden weakness, fever, coughing and breathing difficulties require urgent help.[14]

Diagnosis and management

The vet selects material for culture according to the site of disease. If needed, testing includes bacterial identification and an antibiogram, which assesses susceptibility to antibiotics. In severe cases, treatment may begin before all results are available and then be adjusted. An antibiogram alone does not replace assessment of the patient.[14]

Bartonella

Transmission and signs

Bacteria of the genus Bartonella, including Bartonella henselae, can infect cats without causing visible signs for a long time. Fleas play the main role in transmission between cats. Some infections may be associated with fever or other problems, but detecting antibodies or bacterial DNA alone does not establish that Bartonella is causing the current illness.

Diagnosis, management and protecting people

Bartonella henselae also matters for people because it can cause cat scratch disease, particularly after a scratch contaminated with material containing the bacteria. The main preventive measures are effective flea control, promptly washing scratches and avoiding play that leads to bites. There is no justification for routinely giving preventive antibiotics to every healthy cat with a positive result.[15][16]

Dermatophytosis, or ringworm

Transmission and signs

Dermatophytosis, most often caused by Microsporum canis, can cause scaling, crusts, circular skin lesions and, in cats with fur, localised hair loss. Being hairless does not protect a Sphynx from infection. Dermatophytes can spread between cats and to people, including through contaminated objects.[17]

Diagnosis and management

Diagnosis requires tests selected according to the lesions, such as a Wood’s lamp examination, microscopy, culture or PCR. A Wood’s lamp is a supporting tool; a negative examination does not exclude dermatophytosis. Similar lesions may have other causes.[17]

In a breeding cattery, treatment prescribed for affected cats needs to be combined with removal of infectious material from the environment. The plan may include topical and systemic treatment and assessment of the other animals. Do not independently choose a shampoo or antifungal product solely on the basis of the skin’s appearance.[17]

Mycobacterioses, or mycobacterial infections

Transmission and signs

Mycobacterioses are less common infections caused by bacteria of the genus Mycobacterium. They can cause nodules, ulcers and lesions in the tissue beneath the skin, sometimes following an injury. Not every lump, however, has an infectious cause.

Diagnosis and safety

Diagnosis usually involves cytology or biopsy, special stains and sometimes PCR or culture at an appropriate laboratory. Identifying the type of mycobacterium affects further management. Some species pose a risk to people, so sampling and precautions for contact with the cat should be agreed with a vet.[18]

Comparison table

The table brings together the main differences between the infections discussed. The tests listed are examples, and their selection depends on the cat’s condition. I explain their limitations in more detail in the preceding sections.

What to do when a cat shows signs of infection

First assess how urgent the situation is. Breathing difficulties, severe weakness and rapid deterioration require urgent contact with a veterinary clinic. Do not wait for the full set of signs associated with a particular disease to develop.

1. Contact your vet. Explain when the signs began, whether the cat is eating and drinking, whether other animals are ill and whether the cat was recently vaccinated or treated.
2. Limit contact. Where possible, separate the affected cat, provide its own bowls and litter tray, and keep hands and equipment clean. If breathing is difficult, avoid additional stress and do not delay help while arranging isolation.
3. Agree on a testing plan. Have previous results, the names of medicines given and vaccination dates ready. Sample selection should be guided by the signs and suspected infection.
4. Monitor the whole group. Record new signs and contacts between cats. Restrict movements that could spread the infection.

Protecting cats at home and in a breeding cattery

Vaccination. Core protection covers panleukopenia, FHV-1 and FCV. The timing and number of doses depend on age, vaccination history and risk. Vaccination against other infections is considered individually, taking guidelines and applicable regulations into account.[20]

Quarantine for new cats. This should allow time for observation, appropriate testing and assessment of whether tests need to be repeated. Ending quarantine should not depend solely on one negative result from a sample taken immediately after arrival.

Cleaning and disinfection. First remove dirt and organic material, then use a product effective against the particular microorganism. Concentration and contact time matter. A product suitable for one pathogen may not work against FPV, FCV or dermatophyte spores.[8][10][17]

Group management. Reducing stress, overcrowding and unnecessary mixing of cats helps limit the spread of infection. Decisions about isolation, treatment of contacts and return to the group should follow the diagnosis, rather than one rule applied to every positive result.

My approach at Aggio Cat*PL

What about toxoplasmosis, roundworms and other parasites?

Toxoplasmosis is an infection with the protozoan Toxoplasma gondii and can affect both feline and human health. Toxocariasis, in turn, involves the feline roundworm Toxocara cati. These are neither viral nor bacterial diseases. To avoid repeating material already covered, I discuss transmission, faecal testing and prevention in my article “Intestinal parasites and infections in cats”.

For owners, the priorities are regular removal of faeces from the litter tray, hand hygiene and tailoring tests and parasite treatment to the cat’s age and actual risk. A positive Toxoplasma gondii antibody result does not automatically mean that the cat is currently shedding oocysts or is a source of infection for household members.