Dermatophytosis is a medical term for a fungal infection that most
commonly affects the hair, nails (claws) and skin of felines. The most common
parasite for this infection is known as ‘microsporum
canis’, trichiphyton mentagrophytes and microsporum gypseum (this is what
is commonly known as ringworm). This fungal infection is more common in cats,
and other mammals, but more likely affect long haired breeds than short haired.
Ringworm (microsporum gypseum) is
diagnosed largely in populations with kittens than those with older cats.
Many different species of fungi
found around the globe have the potential – or already do – to cause ringworm,
however most cases in felines are caused by the fungi microsporum canis, microsporum gypseum or of trichophyton (a
specific genus of fungi) species. Spores can be found on infected animals or
around the area of living quarters of infected animals, and any spores that are
shed from infected animals can live for up to 24 months. The optimal
environment for these spores are humid, and warm. It is because of this that
they can inhabit anywhere; i.e. bedding, furniture, walls, or any fomite.
Felines are known to be
asymptomatic carriers of the fungal infection and can harbour or shed the
organism without showing any clinical signs, it is known that chronic carriers
of this fungal infection can be routinely cultured to determine if they carry
the fungal infection.
Like most fungi, ringworm can be
transmitted by direct contact with the fungal spores; these fungal spores can
be found almost anywhere (as mentioned previously). Because the spores can
survive for a long period of time, it is common for felines to contract
ringworm from anywhere else that other felines (or even dogs) have been. Fortunately,
adult felines usually have a resistance to the fungus and never develop any
visible clinical signs. But any felines under a year old and senior,
free-roaming cats, and those that are malnourished, under stress or have any
immunosuppressant diseases such as parasites or viral infections may also have
an increased risk of developing symptoms and contracting the fungal infection.
It is also thought that genetic factors can play a role, as Persian felines
appear more susceptible to ringworm than other breeds.
Felines with ringworm may present
with different symptoms, such as skin lesions (which can appear in different
shapes and sizes depending on where they occur and how long they have been
present) – one of the most classic symptoms is a small round lesion that is
devoid of any hair (even in long-haired felines). It is common for skin lesions
to have ‘scaly’ skin around the centre, and small pustules are often found in
the lesion. Like most skin lesions, it will start as a small spot and continue
to grow. The lesion may or not be irritated or itchy, it entirely depends on
what type it falls under. Skin Lesions are commonly found on the ears, tail and
head. It is also common, if the infection occurs over the entire body, that it
creates a generalised scaly or greasy skin condition – it is also common for
felines to suffer hair loss if affected with this fungal virus. Alopecia is
also known as the first clinical sign, and can also cause hairballs or
scratching at the ears. In some cases of this fungal infection, ringworm can
cause the claws to grow malformed.
Like most fungal infections, it
cannot be diagnosed by observing the lesion, as several tests are normally
carried out to properly diagnose. A common method for treatment is by a
specialised black light called a ‘Wood’s lamp’. Several species of the ringworm
fungus will glow a fluorescent colour when exposed to a Wood’s lamp. The most
reliable way to identify a ringworm infection is by collecting scales and crust
from the skin and coat and performing a fungal culture. It’s common for the
Veterinarian will use a toothbrush to collect this sample of hair and scales,
and to do this in-house; meaning that results are much more rapid than if sent
to a laboratory to be cultured.
As mentioned before, lesions are
common as a clinical sign of fungal infections, but can be treated. In healthy
shorthaired felines, with minimal lesions, they can be treated with a topical
cream that contains and antifungal such as miconazole, or thiabendazole. To
further treat any underlying conditions, a good diet and good hygiene is key.
If the condition if more severe,
then a combination of topical and oral treatment can be used. If the feline is
longhaired then the veterinarian may advise to clip all the fur to achieve any
ringworm treatment, this ensures that the topical treatment reaches the skin
properly and diffuses into the dermis. It’s also important to note that any
equipment used to clip any fur must be properly sterilised before being used on
any other animal as they would then pose a risk of infection. Again, if the
case is more severe, then a recommended topical treatment; is a lime sulphur
dip. These do pose a bad odour and could even turn the coat a yellowish colour,
but they are extremely effective and should be used if recommended.
Alternatives to this include miconazole shampoos and rinses.
If your feline has severe lesions
of the skin, oral anti-fungal agents are recommended. Especially where the
feline is longhaired and in cases where the claws are infected also. These can
also be recommended if the patient does not respond to any topical treatment
within two to four weeks.
Bacterial disease in dogs – Nocardiosis
Nocardiosis is an infectious disease that affects different body
systems, including the respiratory, nervous system and musculoskeletal in Canines.
This highly infectious bacterium is found in soil and can enter the dog’s body
through any open wounds or through the respiratory tract when it inhales. The
most common strain of this bacterium is Nocardia
asteroides. Though this is rare, dogs are also susceptible to proactinomyces spp. It is also important
to note that any dogs suffering from an immunosuppressant disease, their
likelihood of contracting Nocardiosis increases.
Nocardia is a pleomorphic (can
alter their size), facultative (able to live under different environmental
conditions), intracellular bacterium, and non-spore forming. When a Gram smear
is performed, it appears as cocci or coccobacilli forms with long branching
filaments – it also tends to fragment into rods and cocci.
The symptoms of Nocardiosis spp are hugely dependant on
the site of the initial infection. For example, if the bacterium infects the
plural body cavity (this includes the lungs and all surrounding mucous
membranes) then the symptoms can include pyrexia, dyspnoea and emaciation. If
the infection is located on the skin, then different symptoms will be present,
e.g. chronic non-healing wounds and draining lymph nodes. If the initial
infection is not localised in one specific area of the canine, then the
symptoms could include: weight loss, lethargy, and pyrexia.
Diagnosis of this bacterial
infection is based on the epidemiologic findings, the clinical signs and a
microbiologic examination. The Veterinarian will most likely take samples from
the tracheobronchial fluid or the abdomen to identify the site of the
infection. Other diagnostic procedures can be carried out, e.g. x-rays, and
urine analysis. There are usually one or more diagnostic procedures carried out
to rule out other potential causes (this could include tumours or even fungal
The treatment for Nocardiosis is
dependent upon the initial site of the infection (where the bacterium has infected)
and the symptoms that coincide. If infection occurs in the pleural cavity, then
it is most likely that the canine will be hospitalised to prevent any further
dehydration caused by the infection. It is also likely that drainage of any
fluid will occur (this may be performed on a regular occurrence on direction of
a Veterinarian). Alongside other forms of treatment, a long-term antibiotic
therapy is imperative to fight off the infection. But like all infections,
tender, loving care is also key in ensuring a full recovery from the infection!
Because of the nature of Nocardiosis,
and its frequency to affect the musculoskeletal and central nervous system
(CNS); it is imperative that the dog is closely monitored for up to a year after
therapy. The signs to look out for are as followed: anorexia, pyrexia,
seizures, dyspnoea. Any of these clinical signs could indicate reinfection.
Prevention of this infectious disease is difficult, but can be managed. General
cleanliness and frequent disinfection of any wounds your dog may harbour is a key
way to help prevent this infection, especially if your dog is
Viral diseases in rabbits – Rabbit haemorrhagic disease (RHD)
Rabbit Viral Haemorrhagic disease (VHD or RHD) is a highly
infectious disease that is caused by the calicivirus, and only affects lagomorphs
of the Oryctolagus cuniculus species i.e. domesticated European rabbits. The calicivirus
in rabbits is known to shut down major organs, such as the liver and gut, but is
also known to cause haemorrhages or bleeding.
Rabbit Viral Haemorrhagic disease,
is a very swift killer. Some rabbits infected with this disease may pass
without showing any clinical signs at all. But it has been reported that some
bleed around the mouth, nose and rectal passage. The reason that this disease
is such a swift killer, is because the incubation period of the disease from
the date of contracting the virus is minimal – with most rabbits dying within
48 hours from initial exposure. The mortality rate, according to rabbit.org, is
between 50 and 100%, with the latter of the two being the closest figure. The
rabbit calicivirus is a hard one to beat (according to peteducation, the virus
was able to kill over ten million rabbits within eight weeks), as it can remain
viable in the environment for 105 days at 20°C – 68F – and for even longer at
3.8°C (39F). This strong virus, can even withstand freezing. VHD has no known
cure in the UK, but a vaccine is available (and strongly advised of) to all Lagomorphs
by administration from a Veterinarian.
Treatment of VHD is almost non-existent due to the quick mortality
of rabbits infected with the calicivirus, as mentioned previously, it is
important that rabbits are vaccinated annually, as the vaccination only
provides cover of a year. The clinical signs that may be present (if
applicable) can include: anorexia, lethargy, dyspnoea, pyrexia, spasms and
sudden death. A Veterinarian may offer Intravenous fluid therapy (IVFT) as an
option to help with the clinical signs, but in cases where VHD is present, then
it is normally kinder for euthanasia to take place. If a case of VHD is suspected
i.e. if large numbers of populations of rabbits are dying, then it should be
reported to a veterinarian, whom will then be able to advise on proper handling
of an infectious rabbit.
Transmission of VHD in rabbits can
normally occur by direct contact with an infected rabbit or any fomites that
may harbour the virus. Other ways of infection are: oral, conjunctival pathways
and intranasally; it is also possible that the urine and faeces of an infected rabbit
may shed the virus. This virus is also known to be airborne, and can travel by the
wind. Though the virus cannot reproduce in other mammals, predators such a fox,
some birds and ferrets can excrete the virus through their faeces after
injected an infected rabbit. Flies, mosquitoes and rabbit fleas also have the potential
to harbour and spread the disease throughout the lagomorph population.
Diagnoses of VHD can be indicated in
an infected rabbit usually by post-mortem, as the clinical signs of VHD can be like
myxomatosis, pasteurellosis and E. coli. Lagomorphs that pass from VHD are
normally in a good outward state, however post-mortems usually reveal necrosis
of the liver & splenomegaly. The liver of a rabbit that has died from VHD
usually shows it as being friable and swollen, the spleen being dark/black in
colour. It is also possible that haemorrhages be seen in other organs and tissues.
Enteritis of the small intestine and swollen meninges may also occur.
Another method of diagnosis includes
laboratory tests, such as revere transcription polymerase chain reaction (RT-PCR)
which is a method used in molecular biology to detect the RNA expression of a virus,
negative staining and western blotting (used to detect different proteins
within a tissue).