Mycobacterium kansasii Infection in a Farmed White-Tailed Deer (Odocoileus virginianus) in Florida, USA

Abstract

A 7-year-old farmed white-tailed deer doe was transported to a Levy County, Florida property and began to decline in health, exhibiting weight loss and pelvic limb weakness. The doe prematurely delivered live twin fawns, both of which later died. The doe was treated with corticosteroids, antibiotics, gastric cytoprotectants, and B vitamins but showed no improvement. The doe was euthanized, and a post mortem examination was performed under the University of Florida's Cervidae Health Research Initiative. We collected lung tissue after the animal was euthanized and performed histological evaluation, using H&E and Ziehl-Neelsen (ZN) staining, and molecular evaluation, using conventional PCR, followed by Sanger sequencing. The microscopic observations of the H&E-stained lung showed multifocal granuloma, while the ZN-stained tissue revealed low numbers of beaded, magenta-staining rod bacteria inside the granuloma formation. Molecular analysis identified the presence of Mycobacterium kansasii. This isolation of a non-tuberculous Mycobacterium in a white-tailed deer emphasizes the importance of specific pathogen identification in cases of tuberculosis-like disease in farmed and free-ranging cervids. We report the first case of M. kansasii infection in a farmed white-tailed deer (Odocoileus virginianus) in Florida. Although M. kansasii cases are sporadic in white-tailed deer, it is important to maintain farm biosecurity and prevent farmed cervids from contacting wildlife to prevent disease transmission.

Keywords: captive cervid; deer farming; non-tuberculous Mycobacterium; pneumonia.

Figure 1

Gross appearance of the lungs in the M. kansasii-infected deer. (a) Open thoracic cavity demonstrating lungs with multifocal, granulomatous pneumonia. Arrows indicate granulomas. (b) Focal area of atelectasis with numerous granulomas.

Figure 2

Microscopic observations of lung tissue from the M. kansasii-infected deer. (a) H&E-stained histologic section of lung with a focal granuloma (bar = 200 µm); asterisk indicates necrotic center. Arrow indicates fibrous capsule with macrophages. (b) Ziehl–Neelsen acid-fast stain with low numbers of beaded, magenta-staining rod bacteria (bar = 10 µm).