Page 1043 - Clinical Small Animal Internal Medicine

108 Actinomycosis, Nocardiosis, and Mycobacterial Infections 981

slow‐growing mycobacteria (SGM) groups, including the canine agent via insect vectors seems likely. Case
VetBooks.ir the M. avium‐intracellulare complex (see Table 108.2). clusters of disease in related foxhounds suggest addi-
tional environmental or genetic factors may be involved.
The saprophytic mycobacteria are widely distributed in
the environment. They have variable geographic preva-
lence likely associated with environmental factors such Signalment
as warmer temperatures that support their growth.
Infection with RGM usually follows cutaneous, pulmo- Younger animals tend to be more commonly affected by
nary or gastrointestinal inoculation. Disseminated dis- mycobacteriosis, particularly cutaneous forms of the dis-
ease may develop in immunosuppressed animals. ease. This may be associated with increased exposure to
Canine and feline leproid syndromes are characterized environmental organisms and precipitating injuries that
by discrete cutaneous lesions. The causative agents are allow infection. Patients that develop disseminated dis-
fastidious and cannot be cultured readily. Feline leprosy ease are often suspected to be immunocompromised
results from infection with one of a number of sapro- although supportive evidence for this may not be appar-
phytic species (see Table 108.2). M. lepraemurium infec- ent. Tuberculosis is most commonly observed in animals
tion is thought to be transmitted to cats by rodent bites. with prolonged close contact with an infected primary
Insect vector transmission has also been proposed but is host. Adult nonpedigree cats with outdoor access are
unverified. most commonly affected, although Siamese cats are also
It is not clear whether canine leproid granuloma syn- overrepresented. Feline leprosy is most common in
drome results from infection with one or more species. young cats and in older cats that are immunosuppressed.
Partial characterization using gene sequencing has Canine leproid granuloma syndrome is most common in
shown that genetically identical organisms have been large‐breed, short‐haired dogs, especially boxers. Bassett
associated with the disease worldwide; however, the hounds, schnauzers, and Abyssinian cats are overrepre-
causative species remains incompletely defined due to sented in disseminated saprophytic mycobacteriosis,
inability to culture it in the laboratory. Transmission of suggesting genetic immunodeficiencies in these breeds.

Table 108.2 Mycobacteria spp. and their manifestations in dogs and cats

Canine Feline
Tuberculous M. bovis DCP M. bovis CD
M. tuberculosis DCL M. microti CDL
M. microti D M. tuberculosis CD
Saprophytic Rapid growing M. fortuitum LC M. fortuitum PCL
M. goodii CP M. smegmatis PD
M. smegmatis CP M. chelonae‐abscessus PC
M. chelonae‐abscessus L M. alvei P
M. goodii D
M. thermoresistibile PL
M. phlei P
M. mucogenicum C
C
M. massilence
Slow growing M. avium complex D M. avium complex CDL
M. ulcerans C M. ulcerans C
M. kansasii L M. terrae C
M. xenopi PD
M. simiae D
M. celatum D
M. malomense C
M. heckeshornense D
M. kansasii D
Leproid syndromes Unclassified species C M. lepraemurium C
M. visibile C
Canditatus ‘M. tarwinense’ C
Canditatus ‘M. lepraefelis’ C,D
Unclassified species C
C, cutaneous lesions; D, disseminated disease; L, pulmonary disease; P, panniculitis.