Maud Lafortune1, DMV, MSc; Thomas Gobel2, DMV; Elliot Jacobson1, DVM, PhD, DACZM; Dan Brown3, MS, PhD; Rick Alleman1, DVM, PhD, ADCVP, ABVP; Kent Vliet4, PhD; Jorge Hernandez5, DVM, MPVM
Department of 1Small Animal Clinical Sciences and 5Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA; 2Small and Exotic Animal Practice, Berlin, Germany; 3Mycoplasma Research Laboratory, Department of Pathobiology, and 4Institute of Zoology, University of Florida, Gainesville, FL, USA
Respiratory diseases are common in captive and wild American alligators (Alligator mississippiensis) but are difficult to diagnose ante-mortem. Bronchoscopy permits direct visualization of the respiratory tract and sample collection, but cytologic and microbiologic reference values are lacking for crocodilians. Twelve (three males and nine females) 3-yr-old, 1-m long, 4.5- to 9.0-kg captive-born alligators were used in this study. Bronchoscopy, using a flexible endoscope (3.3 x 700 mm choledochofiberscope OES, Olympus, Hamburg, Germany), was used to separate the alligators into two groups. The criterion for separating them was the absence or presence of respiratory inflammation, mucous, blood, secretions, parasites and/or masses. Six alligators without any abnormalities were placed in Group A. The other six alligators had respiratory lesions and were placed into Group B. Endoscopy was repeated every 3 mo for 12 mo. A tracheal wash (at the bronchial bifurcation) was collected each time an alligator was evaluated and submitted for Mycoplasma spp., aerobic, and fungal cultures. Microscopic slides were prepared for cytologic examination.
Mycoplasma spp. were not isolated from any animal. Low numbers of samples (11 out of 48; 23%) resulted in scant growth of bacterial colonies. Similarly, low numbers of samples (9 out of 48; 19%) resulted in scant growth of fungal agents. These organisms were considered to be nonpathogenic and likely the result of oral contamination. Cytologic evaluation of collected material found most samples (90%) contained only a small amount of mucus, low numbers of ciliated columnar epithelium and keratinized squamous cells. Less than 10% of the samples contained large amounts of mucus, reactive macrophages or heterophils, which would be considered evidence of irritation/inflammation to the airways. No bacteria or parasites were observed in any of the samples.
This research project was supported by the St. Augustine Alligator Farm fund. The assistance of Darryl Heard, Jeff Davidson, Jennifer Long, Heiko Shultze, Kelly Daigle, Alexander Valverde, Jean Pare, Hendrik Nollens, April Johnson, Ian Bessel and University of Florida veterinary students is also gratefully acknowledged.