Page 1573 - Cote clinical veterinary advisor dogs and cats 4th

790.e4 Plague

Etiology and Pathophysiology Advanced or Confirmatory Testing Chronic Treatment
• Wild rodents (prairie dogs, squirrels, chip- • The local public health department can Treatment with antibiotics for a minimum of
VetBooks.ir • Rodent fleas carry the infectious bacteria detection using immunofluorescent antibod- of clinical signs
21 days and continuation beyond resolution
confirm the diagnosis of plague with antigen
munks, wood rats, mice) and rabbits are
reservoir hosts.
ies on tissue samples or aspirates. Samples
Drug Interactions
and transmit the infection to humans and
should not be frozen.
animals through a bite. Domestic species may • Acceptable samples include lymph node Gentamicin should not be used in combination
be infected through ingestion of a reservoir aspirates, liver, spleen, lung, or blood. with other nephrotoxic, ototoxic, or neurotoxic
rodent. • Do not attempt an in-house culture of drugs. Gentamicin must be used carefully
• After flea bite, replication in polymorpho- any material from an animal suspected of when in combination with cephalosporins or
nuclear cells results in cell destruction. having Y. pestis. If samples are sent for culture nonsteroidal antiinflammatory drugs (NSAIDs)
• Y. pestis can also replicate in the host elsewhere, warn the laboratory about clinical because of renal effects.
mononuclear cells, which carry the organ- suspicion of plague.
ism to the lymph nodes, resulting in the • Serologic confirmation can be made by Possible Complications
formation of characteristic buboes (abscessed submitting two samples drawn 10-14 days When zoonosis occurs, veterinary professionals
lymph nodes). Alternatively, the infection apart. A fourfold or greater increase in titer are most commonly affected.
may develop rapidly into septicemia is necessary to confirm the diagnosis.
with hematogenous spread to multiple PROGNOSIS & OUTCOME
organs. TREATMENT
• Bacteria may spread faster when ingestion • Mortality rate for cats approaches 50%; the
of an infected animal carcass occurs. Y. pestis Treatment Overview pneumonic and septicemic forms are the
produces an F1 capsular envelope antigen • Intensive therapy should be started before most lethal.
that protects it from destruction. definitive diagnosis due to the rapid course • Cats with spontaneously draining wounds
• Septicemia, edema, and disseminated of the disease. may have better outcomes.
intravascular coagulation are the result of • Gentamicin is the antibiotic of choice for • Cats with previous exposure to plague may
endotoxins produced by Y. pestis. seriously ill animals but should not be given have a shortened disease course.
until the patient is rehydrated and stabilized • Cats with prolonged fever > 104°F (>40°C)
DIAGNOSIS with IV fluid therapy. Antibiotic therapy have a poorer prognosis.
should be continued for 3-4 weeks. In less • Dogs may not show clinical signs or may
Diagnostic Overview severe cases (i.e., bubonic form), doxycy- have self-limited disease. Most dogs with
• Presumptive diagnosis is based on physical cline or fluoroquinolones are acceptable moderate to severe disease respond well to
exam, relevant history, or suspicion of treatments. antibiotics, although death is possible for
exposure in endemic areas. Treatment must • Patients should remain hospitalized dogs too.
be initiated before the disease is confirmed. and isolated because of the contagious
• Diagnosis can be made from isolation of and zoonotic risks for at least first 72 PEARLS & CONSIDERATIONS
Y. pestis through culture; direct fluorescent hours.
antibody testing of tissue imprints on slides Comments
from lymph node aspirates, pharyngeal Acute General Treatment • Veterinarians who suspect a clinical case of
mucosal or wound swab specimens; or a • Fluid resuscitation of infected animals that plague should immediately contact the public
fourfold or greater change in titer between have concurrent dehydration, shock, or other health department and observe precautions
acute and convalescent serologic samples. hypovolemic states (pp. 907 and 911) described above to protect human life.
Care must be used to avoid zoonotic exposure • Administration of supplemental oxygen and • People who have been exposed to an infected
when specimens are submitted for cytologic other critical care measures to address clinical animal should seek medical advice from a
exam, Gram stain, and culture. signs (pp. 795 and 1146) physician as soon as possible.
• The local public health department should • Institution of treatment with the antibiotic
be contacted if there is suspicion of of choice (gentamicin 5-8 mg/kg IM or IV Prevention
plague. q 24h), brisk rehydration and fluid diuresis, • Prevent unsupervised outdoor activities.
and monitoring of renal function • Apply a flea preventive to cats and dogs,
Differential Diagnosis • Alternative antibiotics: doxycycline 10 mg/kg especially during high-risk months.
• Tularemia IV or PO q 24h, trimethoprim-sulfonamide • Eliminate rodent attractants, including rock
• Bite wound abscess 15 mg/kg PO q 12h, or fluoroquinolones piles, wood piles, and organic debris.
• Other causes of systemic bacterial infection (e.g., pradofloxacin 7.5 mg/kg PO q • Although human vaccines are available,
• Feline panleukopenia virus 12h). Comparative efficacy studies are there is no vaccine available against plague
• Lymphoma (buboes) lacking. Chloramphenicol has been used in animals.
• Feline infectious peritonitis in animals with central nervous system
• Pneumonia (other bacterial and non-bacterial involvement. Technician Tips
causes) • Surgical incision and flushing of abscessed • Educate owner on importance of flea
lymph nodes for drainage (extreme caution preventive.
Initial Database because of public health risk) • To decrease risk of zoonosis, all veterinary
• CBC: possible marked leukocytosis, neutro- • Treat patients for fleas (e.g., nitenpyram; professionals should where mask and gloves
philia in dogs Capstar), and treat all exposed animals with when evaluating plague suspects, including
• Gram stain of draining material/fluid: gram- appropriate flea medication even if fleas are any cat residing in an endemic area with
negative coccobacilli, bipolar, safety pin shape not seen. signs of pneumonia, abscess, or sepsis.
• Chest radiographs: diffuse interstitial pattern • Tetracyclines (e.g., doxycycline 10 mg/kg q
or development of abscesses 24h for 7 days) can be used as a prophylactic Client Education
• Fine-needle aspiration and cytologic exam in animals exposed to plague (including • Inform clients of the increased risk of infec-
of enlarged lymph nodes or other affected exposure to other pets diagnosed with tious diseases among outdoor cats.
tissues plague). • Emphasize proper flea and rodent control.

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