Page 982 - Clinical Small Animal Internal Medicine

920 Section 9 Infectious Disease

Table 96.1 Species of Bartonella detected in dogs, cats, and other hosts
VetBooks.ir Bartonella spp. Preferred host Other hosts Vector

B. bovis Cattle Dog, cat, deer, elk Biting flies?
B. clarridgeiae Cat Dog, human Cat flea
B. elizabethae Rat Dog, human Rodent fleas
B. grahamii Wild mouse, vole Dog, human Rodent fleas
B. henselae Cat, dog Human, other terrestrial Cat flea
and marine mammals
B. koehlerae Cat Dog, human Cat flea
B. quintana Human Dog, cat, monkey Body louse
B. rochalimae Dog and other canids, Human Fleas
raccoon
B. taylorii Wild mouse Dog Rodent fleas
B. vinsonii subsp. arupensis Wild mouse Dog, human Ticks?
B. vinsonii subsp. berkhoffii Dog and other canids Cat, human, sea turtle Fleas? Ticks?
B. volans‐like Squirrel Dog, human Unknown
B. washoensis Squirrel Dog, human, rat Unknown
Candidatus B. merieuxii Dogs and other Unknown Unknown
canids

followed by B. clarridgeiae and B. koehlerae. It is believed and sex can become infected with Bartonella spp. Young
that infection with these Bartonella species in dogs and cats (≤1 year) are more likely to be bacteremic, while older
cats has a worldwide distribution, but epidemiologic cats are more likely to be seropositive. Stray or feral cats
data are limited. Bartonella spp. are more frequently are more likely to be infected than pet cats.
documented in temperate regions of the world, espe-
cially in warm and humid areas.
Bacteremia documented by polymerase chain reaction History and Clinical Signs
(PCR) ranges from 1% to 17% in sick or healthy dogs,
depending upon the geographic location evaluated. In the Bartonella spp. have been associated with a wide range
United States, up to 10% of sick dogs with clinical manifesta- of diseases in dogs and cats (Box 96.1). Endocarditis is
tions compatible with tick‐borne diseases are infected with the most commonly reported manifestation in dogs
Bartonella spp. Exposure to Bartonella spp. in dogs, docu- (Figure 96.1).
mented by serology methods, is generally ≤10% of tested In one study, Bartonella spp. infection was confirmed
dogs, with higher prevalence detected in sick dogs and in as the cause of culture‐negative endocarditis in 20% of
some tropical countries. Conversely, bacteremia prevalence canine cases presented at a US tertiary hospital. Aortic
in cats ranges from 5% to 40%, with prevalence of ≥ 80% in valve involvement and congestive heart failure are more
some populations (feral cats, colonies with frequent flea frequent in dogs with endocarditis from Bartonella spp.
infestation). Seroprevalence is also frequently high, with infection despite most of these patients having no fever.
some colonies having over 90% of cats seroreactive to Because of the cyclic shedding of the pathogen into the
Bartonella species. Because of its ubiquitous presence in bloodstream, several other organs can be affected.
cats, establishing a causal relationship between Bartonella Consequently, the most frequent signs in dogs are nonspe-
infection and illness is challenging in this species. cific, including fever (40% of cases), lethargy (40%), weight
loss (34%), anorexia (32%), and lymphadenopathy (30%). In
one study, weight loss was significantly associated with
Signalment Bartonella when compared to other dogs suspected of vector‐
borne diseases. Although Bartonella spp. DNA has been
Dogs from any breed, sex, and age can be infected but in detected in dogs and cats with diverse signs and syndromes
one study, over 95% of dogs bacteremic for Bartonella spp. (see Box 96.1), causal relationships have mainly been con-
were older than 12 months. Outdoor access, residence in firmed in dogs and cats with endocarditis, myocarditis,
a rural environment, and tick exposure are considered risk fever of unknown origin, and specifically in cats, fetal reab-
factors for infection in dogs. Similarly, cats from any breed sorption and stillbirth. (see Box 96.1).