Chlamydia pneumoniae Polioencephalomyelitis and Ganglionitis in Captive Houston Toads (Anaxyrus houstonensis)

Alycia Fratzke, Lauren L. Howard, Maryanne E. Tocidlowski, Anibal Armién, Fabiano Oliveira, Branson Ritchie, Erin Berlin, Eric Snook

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Chlamydia pneumoniae is a ubiquitous pathogen causing disease in humans, mammals, birds, reptiles, and amphibians. Since 2012, C. pneumoniae infection has caused neurologic disease and mortality in a breeding colony of endangered Houston toads (Anaxyrus houstonensis) at the Houston Zoo. The purpose of this report is to present the histopathologic and ultrastructural characteristics of C. pneumoniae infection in Houston toads. Fourteen cases were evaluated by histopathology and 1 case was evaluated by electron microscopy. The major histopathologic finding was necrotizing and histiocytic polioencephalomyelitis and ganglionitis. Bacteria formed intracytoplasmic inclusions within neurons but frequently extended into the surrounding tissue from necrotic cells. Ultrastructural evaluation showed the bacteria formed reticulate and elementary bodies characteristic of Chlamydia spp.

Original languageEnglish (US)
Pages (from-to)789-793
Number of pages5
JournalVeterinary pathology
Issue number5
StatePublished - Sep 1 2019

Bibliographical note

Funding Information:
We thank Dr. Allan Pessier of Washington Animal Disease Diagnostic Laboratory for initial molecular identification of the Chlamydia spp. isolates, the Houston Zoo Veterinary Department and Herpetology Department for assistance in sample collection, and the Dean Muldoon of Minnesota Veterinary Diagnostic Laboratory for the electron microscopy preparations. The author(s) received no financial support for the research, authorship, and/or publication of this article.

Publisher Copyright:
© The Author(s) 2019.


  • Chlamydia pneumoniae
  • Houston toads
  • brain
  • encephalomyelitis
  • endangered species
  • ganglionitis
  • spinal cord


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