Feline calicivirus (FCV) is a highly contagious virus that is one of the major causes of upper respiratory infections (URIs) or cat flu in cats.

This virus is ubiquitous and causes disease in cats all over the world. 

Feline calicivirus (FCV) is a small virus that mainly causes acute upper respiratory infections (URIs) in cats, although it has been associated with some other diseases also (see below). The virus is readily transmitted between cats through:

• Direct contact – through contact with saliva, ocular or nasal secretions
• Inhalation of sneeze droplets
• Sharing or food bowls and litter trays
• A contaminated environment (including bedding and grooming aids) – FCV can potentially survive up to a month in the environment, although probably often does not survive more than 7-14 days.

A characteristic of FCV is that the virus mutates readily during replication and this means that many different strains of the virus exist in nature, some of which are more pathogenic than others (ie, are a cause of more severe disease).

• Acute upper respiratory infection – Acute URI is the most common manifestation of FCV infection. Typical signs include sneezing, nasal discharge, ocular discharge, conjunctivitis, ulceration of the tongue, lethargy, inappetence and fever. Signs may last from a few days to a few weeks and vary in severity. In young kittens the virus may also cause pneumonia.
• Gingivitis and stomatitis – chronic gingivitis is a common disease in cats, although the underlying cause(s) are not fully understood. However, FCV can be isolated from virtually all cats with this condition, and it is thought that persistence of FCV infection in these cats is part of the cause of the gingivitis. This is not a simple disease though, as other cats exposed to the virus from a cat with chronic gingivitis will usually only develop upper respiratory signs. Other factors therefore seem to predispose individual cats to developing gingivitis in response to persistent FCV infection.
• Limping syndrome – occasionally, in young cats in particular, infection with FCV may also cause joint inflammation (arthritis). This is a transient problem, usually only lasting a few days, but the kitten or cat may be extremely uncomfortable with painful joints during this time. Often, but not always, there will be signs of URI at the same time. (See: Limping syndrome and feline calicivirus)
• Virulent systemic FCV infection – vsFCV – on rare occasions, outbreaks of disease have been reported with very much more pathogenic strains of FCV termed vsFCV. These are associated with mutations of the virus that allow infection to be established within different organs and in the cells that line blood vessels. This can result in severe disease including pneumonia, hepatitis (liver inflammation), pancreatitis, skin swelling and ulceration, and bleeding from the nose and intestine. Fortunately these outbreaks are very rare, but up to 50% or more of affected cats may die

In most cases, a specific diagnosis of FCV infection will not be required. The presence of typical signs of URI is enough for a presumptive diagnosis of FCV (and/or feline herpesvirus – FHV) infection. If a specific diagnosis is required, ocular or oral swabs can be submitted to a veterinary laboratory where the virus can be grown in culture or, more commonly, detected by PCR (a molecular technique for detecting the genetic material of the virus).

FCV infections are frequently complicated by secondary bacterial infections, so supportive treatment with antibiotics is usually required. Good nursing care is critical and cats may need to be hospitalised for intravenous fluid therapy and nutritional support in severe cases. Steam inhalation or nebulisation may help in cases of severe nasal congestion and as the cat will not be able to smell food well, using tinned or sachet foods that are gently warmed will help.

In colonies of cats, any cat showing clinical signs should be isolated if at all possible, and strict hygiene should be ensured with disinfection, and use of separate feeding bowls, litter trays, implements etc, careful washing of hands, use of separate (or disposable) apron etc.

Vaccination for FCV is important for all cats. Two or three injections are recommended in kittens, starting at around 8 weeks of age. Cats should receive a booster at a year of age, and after that should receive further booster vaccines every 1-3 years.

Vaccination does not necessarily prevent infection with FCV but will greatly reduce the severity of clinical disease. Additionally, as there are many different strains of the virus, it is difficult to design a vaccine that will protect against all of them. Some newer vaccines incorporate more than one strain of FCV to provide a broader range of protection.

Feline calicivirus (FCV) is one of the major causes of feline infectious upper respiratory tract disease (cat flu).

Classical cat ‘flu’ follows a short incubation period of 3–5 days and consists predominantly of upper respiratory tract disease (sneezing, rhinitis, nasal discharge, conjunctivitis, ocular discharge and oral ulceration). These signs may be accompanied by pyrexia (raised temperature) and occasionally other manifestations, such as coughing and pneumonia.

From an early stage, transient lameness has also been observed as a clinical feature in some cats infected with FCV and it now seems clear that this is, in fact, a relatively common clinical manifestation of FCV infection. The transient lameness associated with FCV has acquired the name ‘limping syndrome’.

FCV was confirmed as a cause of lameness during early observations that showed kittens infected with FCV from other cats with limping syndrome developed pyrexia, depression and inappetence within 2-3 days. Within hours of developing pyrexia, the kittens also developed generalised or localised stiffness, manifesting as shifting lameness in some, and an almost complete reluctance to move in others. None of the cats developed sneezing or ocular discharge, but about one third developed oral ulcers (one of the classic signs of FCV upper respiratory infection). Clinical signs were reported to resolve within 48 to 72 hours with no residual effects. The joints were painful on touch/manipulation, and generalised hyperaesthesia (pain or hypersensitivity to touch) was present.

Further studies of FCV infection showed that FCV viral proteins could be identified in the synovial membrane (the membrane surrounding the joint space) in several cats either vaccinated with a live FCV vaccines and/or infected with FCV. Evidence suggests that the viral proteins are present in association with antibodies, and thus may be present as ‘immune complexes’ (a combination of the viral protein and a specific antibody produced against it) which can provoke an inflammatory response. In some cases, the entire FCV virus can be isolated from joints of cats exposed to FCV showing signs of disease including lameness, with evidence that the virus was provoking an acute inflammatory reaction.

It is therefore evident that after natural exposure to FCV, systemic infection arises which can, at least in some circumstances, involve localisation of the virus to joint tissues where it may cause an inflammatory reaction, possibly through local replication there or possibly through stimulation of immune-mediated inflammation. This is a form of viral-induced polyarthritis (joint inflammation affecting more than one joint).

It seems that certain strains of FCV have a greater propensity to cause lameness than others.

Limping syndrome associated with FCV infection is most commonly seen in kittens, and may occur after their first vaccination. Some vaccines may be more likely than others to induce limping syndrome but as manufacturers change and refine their vaccines this appears to be less common now. Additionally, even when occurring after vaccination, some cases of limping syndrome may still be associated with acquired FCV infection rather than the vaccine itself.

In summary, FCV clearly has the ability to cause a transient polyarthritis (inflammation affecting more than one joint) in cats, and most commonly in young kittens. This is a fairly common manifestation of FCV infection and may occasionally also be associated with FCV vaccination (especially live vaccines).

The severity varies widely from inapparent inflammation and mild limping, through to severe polyarthritis where the cats are reluctant to move, inappetent and the joints appear painful when touched.

Affected cats spontaneously recover, but if clinical signs are severe, anti-inflammatory medication may be required and your kitten or cat should be checked by your vet. Although FCV is obviously a common cause of limping syndrome in young cats, there are numerous other potential causes of lameness, and if clinical signs are severe, or persist for longer than a few days, veterinary attention should always be sought.

https://icatcare.org/advice/feline-calicivirus-fcv-infection/

What is Ringworm ?

Ringworm or dermatophytosis is an infection caused by a particular type of fungus that has the ability to grow on the skin and use the superficial layers of the skin, hair or nails as a source of nutrition. Collectively the fungi able to do this are termed ‘dermatophytes’.

Although ringworm is a common term used to describe dermatophyte infections, this has nothing to do with worms.

There are approximately 40 different species of dermatophyte fungi, each tending to cause infection in a particular host animal. In the cat, the vast majority of cases of dermatophytosis are caused by infection with Microsporum canis (M canis). This organism can also cause infection in many other species, including dogs and humans.

How do cats become infected with ringworm (M canis)?

Dermatophytosis is a contagious infection. During infection, thousands or millions of microscopic spores are produced around infected hairs and these are the main source of infection for other animals. Infected hairs and spores are shed into the cat’s environment so other cats may become infected either by direct contact with an infected animal or by exposure to a contaminated environment or object such as grooming tools, clippers or bedding. Spores in the environment can remain infectious for up to two years and are difficult to kill.

Spores will adhere to the skin and this can be the start of a new infection. Although intact skin is quite resistant to infection, any abrasion or damage to the skin will allow infection to develop more readily. Infection is more common in young cats (less than one year old), and in longhaired cats. Younger cats may have poorer natural skin defences and a less well developed immune response and it is possible that long-haired cats groom less efficiently so trapping of spores may be easier and removing of them more difficult.

The appearance of dermatophyte infections in cats is very variable. Some cats have severe skin disease, while other cats have only very minor lesions or no obvious lesions at all and may look completely normal.

Typical skin lesions are discrete, roughly circular areas of hair loss, particularly on the head, ears or legs. The hairs surrounding affected areas may be broken. The affected skin is often scaly and may look inflamed. However, ringworm can look very similar to many other feline skin diseases, including some of the clinical manifestations of flea allergy dermatitis, and may present as symmetrical alopecia or even feline acne. Some loss of hair is usually involved, but the amount of inflammation, scaling and itchiness is variable. 

The clinical signs may suggest the possibility of dermatophytosis, but further investigations are needed to confirm the diagnosis and to rule out other diseases. Three diagnostic tests are commonly used:

• Examination under ultraviolet (Wood’s lamp) illumination: A Wood’s lamp emits ultraviolet light of a particular wavelength. During infection with M canis a product is produced within infected hairs that causes them to fluoresce an apple-green colour under Wood’s lamp illumination. This can be a quick and easy test to see if M canis infection is likely, however:
  • Only around 50% of cases of M canis infection show fluorescence
  • Other dermatophyte infections do not result in fluorescence
  • Some medications or contaminants on the skin and hair can also cause fluorescence
  • For these reasons, other tests are also needed to make the diagnosis
• Microscopic examination of suspected hairs: examination of hairs and skin scrapings under a microscope, collected from an area of skin suspected to be infected by the dermatophyte, can be very valuable. Fungal elements can often be seen along with spores surrounding infected hairs, but accurate results require experience and this is often best done at a laboratory.
• Fungal culture: culture of hairs in the laboratory using a special fungal culture medium is the most reliable way of diagnosing infection. In addition, this test enables the species of dermatophyte to be identified. One disadvantage is that it can take up to three weeks to get a result from fungal culture.

If one cat in a household is diagnosed as having ringworm then all the other animals will need to be examined, even if they seem to be completely unaffected. In most cases all cats in a household will be culture-positive and require treatment. Please note that the absence of dermatophytes on microscopic examination of a skin biopsy does not rule out dermatophytosis.

Treatment is always advised because although most cases eventually resolve, infected cats are a risk to other cats and also to humans – M canis is an important zoonotic disease as it can be quite easily spread from cats to humans. In addition to treating the dermatophyte infection with anti-fungal drugs, any predisposing causes (such as other skin conditions) should also be managed.

Treatment can be either systemic (anti-fungal tablets or liquids given by mouth) or topical (applied to the skin). In most cases, it is best to use a combination of both systemic and topical therapy as this has the best effect. Topical treatment alone is rarely very effective, and should only be used in very young kittens if there is concern over using systemic drugs. In all other cases, systemic treatment is more important than topical treatment, although the latter can still be very helpful.

Several anti-fungal drugs are available that are usually very effective against dermatophytes although some may be better than others. Systemic therapy usually has to be given for a minimum of 6 weeks. Example include:

• Itraconzole – commonly used and one of the most effective drugs for dermatophytosis in cats
• Griseofulvin – this is an old drug that used to be commonly used – it remains effective, but itraconazole is an easier and more effective treatment
• Other drugs – others such as terbinafine and fluconazole have also been used successfully to treat dermatophytoisis in cats but may not be as effective as itraconazole in most cases

Topical therapy can play a very important role in reducing environmental contamination and helping to speed resolution of disease. A variety of preparations are available:

• Anti-fungal creams (e.g., miconazole cream) – these can sometimes be helpful for small localised areas of infection, but as cats readily lick off creams, these have limited application in cats.
• Anti-fungal shampoo – for example shampoos containing miconazole and chlorhexidine. These can be used twice weekly on cats and have been found to be very effective in helping treat infections
• Anti-fungal dips – for example lime-sulphur dips or enilconazole dips. These too can be used on a regular basis and are helpful in treating infections

Careful clipping of the hair around infected areas will also be of benefit in helping to make treatment more effective and in reducing environmental contamination with spores.

Helping to prevent infection of other animals and humans by decontaminating the environment is important. This is much easier if infected cats can be restricted to one easily cleaned room. All areas of the house to which infected animals have had access will require decontamination, but efforts can then be concentrated on the room in which the cat(s) are confined.

Any objects such as collars, baskets, bedding, toys and grooming tools should also be regarded as contaminated and either disinfected or disposed of. Cardboard boxes can be used as temporary disposable beds and these should be disposed of at least once a week.

Decontamination is achieved by a combination of two approaches:

• Physically removing the infected hairs from the environment – this is best achieved by thorough vacuum cleaning of contaminated rooms or areas on a daily basis. All areas should be cleaned as thoroughly as possible and ideally vacuum bags should be burned as this will destroy the spores. Under suitable circumstances a blow-lamp can be used to burn hairs off wire runs and cages.
• Chemical disinfection – many disinfectants have poor efficacy against dermatophyte spores, but hypochlorite or gluteraldehyde solutions are likely to be effective. Some others are also effective, but always check with your vet that what you are intending to use is effective and safe to use around cats.

Where dermatophyte infections occur in multicat households, it is probably best and easiest to assume that all the cats are infected and treat them all appropriately. If cats are not already infected, the treatment they are receiving will help prevent infection developing and it is usually an easier way to ensure the infection is eliminated as quickly as possible.

Prevention of infection is a particular concern among cat breeders, and while it is impossible to ever completely prevent the risk, certain precautions may be warranted. In this situation, if a new cat is to be introduced into a household, it is possible to isolate the new cat and perform a fungal culture from a coat brushing (taking a brushing from all over the cat’s hair coat). If the culture result is negative this is the best assurance that it is safe to introduce the new cat.