Mycobacteria infection cats Flashcards
Which mycobacterium can cause disease in cats and dogs?
Tuberculosis
Feline leprosy
Outline tuberculosis
caused by members of the tuberculosis complex: Mycobacterium tuberculosis, Mycobacterium bovis and Mycobacterium microti
Although Mycobacterium avium is a member of the Mycobacterium avium-intracellulare complex (MAC) and a slow-growing saprophyte, it is sometimes considered with these bacteria as it can result in disease indistinguishable from that caused by members of this group
Outline feline leprosy
mycobacterial infections in cats with single or multiple cutaneous or subcutaneous granulomas, where the bacteria cannot be cultured using traditional technique
How is tuberculosis transmitted in cats and dogs?
may be transmitted via the inhalation or ingestion of infectious particles, or by direct penetration of the skin. Not fully understood in cats but thought to be:
■ Direct spread from wild rodents. Most cases of tuberculosis in cats present as cutaneous lesions, typically affecting fight and bite sites. Since a risk factor for feline tuberculosis is hunting rodents, it is likely that this is how most cats become infected;
■ Direct infection from cattle or badgers. Infection could possibly follow heavy environmental contamination (eg, by badgers visiting the garden)
how is leprosy transmitted in cats?
believed to arise from contaminated rodent bites, and may possibly occur secondarily to soil or plant contamination of cutaneous wounds
What predisposes pets to tuberculosis infection?
Tuberculosis is seen mainly in adults, although MAC can also cause disease in younger animals. No gender predisposition is seen in dogs, but male cats are over-represented. There is little evidence of immunosuppression except with MAC infections, which also appear to be more common in certain breeds such as Siamese and Abyssinian cats, and, possibly, bassett hounds and miniature schnauzers.
Are some mycobacteria zoonotic?
Yes although there are no recent documented cases of spread
What are the clinical signs of tuberculosis?
In cats, the typical presentation is cutaneous lesions, with localised lymphadenopathy. Currently, there are too few cases in dogs to comment, but most appear to have pulmonary and/or alimentary signs.
Skin lesions typically involve the head, legs and tail base. They form firm, raised, dermal nodules, and ulceration may be present, as may sinus tracts
What are the signs of feline leprosy
typically consists of single or multiple granulomatous nodules on the head, limbs and, occasionally, the trunk, which may be haired, alopecic or ulcerated, non-painful and freely mobile
What are the signs of pyogranulomatus paniculitis
multiple punctate draining tracts occur with subcutaneous nodules and coalescence produces large areas of ulcerated, non-healing tissue
Inguinal fat pads, flanks and the tail base are affected most frequently. Although systemic spread is rare, affected cats may show fever, anorexia and a reluctance to move, and affected areas can be painful.
What specific tests are available for tuberculosis, aside from general ix
An interferon (IFN)-gamma test is being developed and is available on request from the VLA. It has the potential to detect members of the tuberculosis complex in cats by evaluating whether or not a cat’s white blood cells can produce antigen-specific IFN-gamma antigens
histopathology/ ziehl neeson stain to look for acid fast bacilli
PCR is expensive and only available for a few options
culture often gives false -ves
What are the considerations for treating mycobacteria?
■ The potential zoonotic risk. The authors do not advise treatment in animals that live with potentially immunosuppressed people, or if animals have generalised disease, significant respiratory involvement or extensive draining lesions;
■ M bovis is notifiable. DEFRA must be notified and it can recommend that the pet is euthanased, although it rarely does so;
■ Treatment is long-term and difficult to maintain given patient non-compliance, drug toxicity and financial costs. Some cases require indefinite treatment. Uncomplicated cutaneous disease has the most favourable prognosis;
■ There are no drugs licensed for treating mycobacterial infections in cats and dogs;
■ Tailoring treatment is difficult as sensitivity testing does not always correlate with in vivo results;
■ Surgical excision of small cutaneous lesions may be considered, but debulking larger lesions risks wound dehiscence and local recurrence.
How do you treat tuberculosis?
The initial phase usually requires two to three drugs and lasts for two months, while the continuation phase requires two drugs and lasts for a further four to six months, depending on the extent of disease.
an initial phase of rifampicin-fluoroquinolone-clarithromycin/azithromycin, followed by a continuation phase of rifampicin and either a fluoroquinolone or clarithromycin/azithromycin
How can you treat feline leprosy?
Surgical removal of small nodules is the treatment of choice and spontaneous regression has been reported. If surgery is not possible, clarithromycin, clofazimine, rifampicin, fluoroquinolones, aminoglycosides and even doxycycline have all been used with variable responses (Table 1). The use of two or three drugs has been recommended (eg, clarithromycin and rifampicin), which are best given for two months beyond apparent clinical resolution
How do you treat pyogranulomatous panniculitis
Pyogranulomatous panniculitis requires long-term antibiotics and radical well-planned surgery. This may involve the administration of doxycycline for several weeks, followed by radical surgical excision and local reconstruction plus parenteral gentamicin perioperatively for three to five days, and a prolonged (three to six months) course of a fluoroquinolone.
