Page 1164 - Cote clinical veterinary advisor dogs and cats 4th

580 Leishmaniasis

RISK FACTORS in accordance with the infecting species. suspected exposure; titers > 1:100 are
• Dogs that have traveled to endemic areas Feline leishmaniasis caused by L. infantum consistent with active infection. Specific
VetBooks.ir where sandflies are endemic and without same species. ELISA, IFAT, or crude-antigen ELISA may
quantitative recombinant antigen rK39
is similar to the canine disease caused by the
• Outdoor dogs living in geographic areas
protection from specific topical insecticides
also detect subclinical infection.
• In the United States, foxhounds are at
increased risk. DIAGNOSIS TREATMENT
Diagnostic Overview
CONTAGION AND ZOONOSIS • Highly sensitive and specific diagnostic Treatment Overview
Dogs are an important reservoir for human serologic and molecular techniques to detect Current drugs used for treating canine
disease. In people, the disease occurs most Leishmania infection are now widely available leishmaniasis, including synergistic combina-
commonly in infants, children, and immuno- in commercial laboratories. tions of drugs, have limited efficacy and do
suppressed or malnourished individuals. • Quantitative serologic and molecular (poly- not clear infection completely in most dogs.
merase chain reaction [PCR]) techniques are Long-term drug combination therapy decreases
GEOGRAPHY AND SEASONALITY the assays of choice. These should be used the parasite load in the dog’s tissues and allows
Disease is mostly limited to temperate or warm wisely and take into consideration that in its immune system to recover and control the
areas where vector sandflies are present. The endemic areas, a large part of the canine infection. Treatment of dogs is usually fol-
sandfly vectors in the Old World (Middle East, population may be infected subclinically and lowed by clinical improvement, but treated
southern Europe) are Phlebotomus spp and in can present for veterinary care for unrelated dogs can remain latent carriers that may
the New World (Central and South America) reasons. relapse.
are Lutzomyia spp. • Diagnostic testing is usually performed to
confirm disease in dogs with suggestive Acute and Chronic Treatment
Clinical Presentation clinical signs, monitor response to treatment, • Sodium stibogluconate (Pentostam; available
HISTORY, CHIEF COMPLAINT or evaluate possible infection in apparently from the Centers for Disease Control and
One or more of the following: chronic weight healthy blood donors, imported dogs, or dogs Prevention in Atlanta, GA) 30 mg/kg q 24h
loss, exercise intolerance, skin lesions, polyuria/ that have traveled to endemic areas. IV or SQ for 3-4 weeks, or
polydipsia (due to renal injury), eye lesions/ • Quantitative serology is the test of choice • Meglumine antimonite (Glucantime) 50 mg/
vision loss, lameness, epistaxis for confirmation of clinical disease in dogs kg SQ q 12h or 100 mg/kg SQ q 24h for
with compatible clinical signs; quantitative 4-6 weeks with allopurinol 10 mg/kg q 12h
PHYSICAL EXAM FINDINGS PCR is the choice for confirmation of infec- PO for 6-12 months
• Lymphadenopathy tion in dogs that do not necessarily have • Allopurinol 10 mg/kg q 12h PO for 6-12
• Splenomegaly clinical signs. Bone marrow, lymph node, months; can be administered in combina-
• Skin lesions or spleen PCR are more sensitive than tion with meglumine antimoniate at the
○ Alopecia blood PCR. same doses and durations as above for
○ Ulcerative skin lesions of pinnae, face, both drugs
and limbs Differential Diagnosis ○ Consider stopping allopurinol treatment
○ Exfoliative dermatitis • Tick-borne diseases: borreliosis, ehrlichiosis when the dog becomes seronegative and
○ Nodular dermatitis • Leptospirosis all clinical manifestations normalize.
○ Papular dermatitis • Dirofilariasis • Miltefosine 2 mg/kg PO q 24h for 4 weeks
• Abnormal growth and elongation of nails • Pyoderma with allopurinol 10 mg/kg q 12h PO for
(onychogryposis) • Immune-mediated skin diseases, vasculitis, 6-12 months
• Ocular discharge secondary to keratocon- glomerulonephritis
junctivitis • Demodicosis Possible Complications
• Miosis, photophobia secondary to uveitis • Lymphoma • Dogs may develop kidney disease during
• Malnutrition, poor husbandry treatment.
Etiology and Pathophysiology • Xanthine urolithiasis with chronic allopurinol
• Leishmania infantum is the cause of human Initial Database treatment
and canine visceral leishmaniasis in Europe, • CBC: may show leukopenia or leukocytosis, • Resistance to allopurinol may develop in
the Middle East, Africa, Asia, China, and the nonregenerative anemia, thrombocytopenia dogs under treatment.
Americas. Other Leishmania species infect • Serum chemistry profile: hyperglobulinemia,
dogs, including Leishmania braziliensis in hypoalbuminemia ± azotemia Recommended Monitoring
South America and Leishmania tropica and • Cytologic evaluation of lymph node, skin, Repeat quantitative serology and PCR every 3-6
Leishmania major in Asia and North Africa. splenic, and bone marrow aspirates may months during follow-up. Periodic monitoring
• The parasite’s life cycle is diphasic (vector and reveal amastigote forms of Leishmania. of renal parameters every 3 months for dogs
host phases). Female sandflies take a blood • Urinalysis: may reveal isosthenuria and with no initial azotemia and more frequently
meal from an infected animal. Promastigotes proteinuria secondary to immunoproliferative in dogs with azotemia at admission.
develop in the gut of the sandfly and migrate glomerulonephritis
to the proboscis. They are transmitted to ○ Urine protein/creatinine ratio may be PROGNOSIS & OUTCOME
the mammal host during a blood meal and increased (>0.5).
are phagocytized by macrophages. Inside • Prognosis is good for dogs with no renal
the macrophage, they become amastigotes Advanced or Confirmatory Testing disease and guarded for progressive stages.
and multiply by binary fission until the • Histopathologic evaluation and immuno- ○ Dogs with severe renal insufficiency and
macrophage ruptures, and the amastigotes histochemical staining of skin biopsies may protein-losing nephropathy generally do
are then disseminated to other macrophages reveal organisms. not respond well to therapy.
and throughout the body. • PCR test: most sensitive test; also can detect • Infection may persist due to inability to
• Cats are infected by several species of subclinically infected dogs completely eradicate the organism.
Leishmania, and disease may manifest as • Serologic tests: indirect immunofluorescent • Euthanasia should be considered for dogs
primarily cutaneous or visceral and cutaneous antibody test (IFAT) titers > 1:32 indicate with chronic, poorly responsive disease.

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