title: An atypical case of Trypanosoma cruzi infection in a young English Mastiff.
abstract: A case of Trypanosoma cruzi infection in a young English Mastiff from Texas is presented. Clinical signs and laboratory findings included subcutaneous edema, lymphadenopathy, weight loss, and hypoalbuminemia. Cytology of a lymph node revealed numerous amastigotes. No trypomastigotes were observed in buffy coat preparation of peripheral blood, and on histologic evaluation, most organs contained numerous interstitial pseudocysts. Initial serology was positive for both T. cruzi and Leishmania, and immunohistochemistry supported a diagnosis of Leishmania. However, additional serology supported a T. cruzi infection, and cultivation of organisms isolated from a lymph node revealed morphology consistent with T. cruzi. In addition, PCR analysis resulted in a 504 bp fragment with 99% homology to a flagellar protein of T. cruzi. Although uncommon, autochthonous cases of both T. cruzi and Leishmania have been reported in the United States. Clinical signs observed with both diseases can show many similarities, cytology may be indistinguishable, as in this case, and serological cross-reactivity is common. This case demonstrates an unusual presentation of T. cruzi and the use of multiple testing strategies to support its diagnosis.
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA. mnabity@cvm.tamu.edu
authors.forename: M B
authors.initials: MB
authors.lastname: Nabity
authors.forename: K
authors.initials: K
authors.lastname: Barnhart
authors.forename: K S
authors.initials: KS
authors.lastname: Logan
authors.forename: R L
authors.initials: RL
authors.lastname: Santos
authors.forename: A
authors.initials: A
authors.lastname: Kessell
authors.forename: C
authors.initials: C
authors.lastname: Melmed
authors.forename: K F
authors.initials: KF
authors.lastname: Snowden
mesh_terms: D000818:Animals; D014355:Chagas Disease / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D003429:Cross Reactions; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000175:diagnosis* / Q000473:pathology; D004285:Dogs; D017809:Fatal Outcome; D005260:Female; D007150:Immunohistochemistry / Q000662:veterinary; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D014349:Trypanosoma cruzi / Q000276:immunology / Q000302:isolation & purification*