chapter 30 Leishmaniasis: Protozoan Dermatitis........................
DEFINITION/OVERVIEW
Flagellate protozoal infection causing cutaneous and visceral disease.
Affects dogs, cats, rodents, horses, cattle, and human beings; canids are important
reservoirs for human disease.
Public health concern; zoonotic potential for fatal disease.
Prevalence varies by geographic location.
Dermatologic lesions caused by protozoa other thanLeishmania(e.g., babesiosis, tox-
oplasmosis) are extremely rare and are not discussed in this chapter.
ETIOLOGY/PATHOPHYSIOLOGY
Over 30 species identified; 8–10 considered pathogenic for dogs.
L. infantum: most significant cause of leishmaniasis worldwide; Mediterranean basin,
Portugal, and Spain; sporadic cases in Switzerland, northern France, West Africa,
South Asia, Latin America, and the Netherlands; endemic populations recognized in
the United States.Canine cases reported in Texas, Maryland, Oklahoma, Ohio, Alabama, Michigan, and
North Carolina.
L. donovanicomplex orL. braziliensis: endemic areas of South and Central America
and southern Mexico.
DifferentLeishmaniaspecies can produce different symptoms (e.g.,L. infantumcaus-
ing disseminated disease andL. braziliensiscausing cutaneous/mucocutaneous dis-
ease); specific host incompetence in cellular immunity and compensatory humoral
response leads to eventual tissue damage and the individual’s unique clinical signs.Two-host flagellated parasite: vertebrate (including canids, rodents, human beings)
and insect; transferred into the dermis of a host by sandfly vectors (Phlebotomus–
Old World;Lutzomyia– New World); a competent insect vector in the United States
has not been definitively identified.During feeding, female sand flies acquire amastigotes from the dermis and later
deposit metacyclic promastigotes; organisms are entirely intracellular in mono-
cytes/macrophages within the skin, bone marrow, and visceral organs.Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dermatology, Third Edition.
Karen Helton Rhodes and Alexander H. Werner.
©2018 John Wiley & Sons, Inc. Published 2018 by John Wiley & Sons, Inc.
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