Abstract

Bacterial infections of the respiratory tract are commonly encountered in phocids and often occur in conjunction with parasitic infections. Bronchoalveolar lavage (BAL) can be a useful tool to better characterize these infections. Even though BAL analysis is used in phocids on an occasional basis, there is very limited information available regarding this technique in this group of mammals. The objectives of this study were to describe an unguided BAL technique, to evaluate its safety in seals, and to establish reference values for leucocyte differential counts in BAL from juvenile harp seals (Phoca groenlandica). The seals were housed in indoor tanks at the Maurice-Lamontagne Institute. A total of 35 BAL were performed on 14 clinically healthy weaned female harp seals (wt: 24.4 to 41.5 kg; aged from 3.5 to 11 wks) under Isoflurane anesthesia. Briefly, a sterile urinary catheter (8 Fr, 22 inches long) was inserted in an endotracheal tube and gently advanced until resistance was encountered or up to full insertion of the catheter. Between 9 and 17 ml of warm sterile saline was then injected and immediately reaspirated. Cytospins and direct smears of the post-centrifugation sediments were stained with a modified Wright-Giemsa and subjectively evaluated for inflammatory cells and noninflammatory cells. Inflammatory cell differentials were determined in 31 of the 35 BAL. The BAL samples were also submitted for standard microbiology. No mortality nor other complications occurred during the 35 BAL performed. No statistical difference was observed over time with respect to leukocyte differential counts. Consequently, means were calculated for each of the animals sampled, and mean ± SD were then calculated using the means of each of the 14 seals (Table 1). The obtained percentages of neutrophils were much higher than that reported in most species, including phocids. The significance of this finding is unclear at this time. Bacterial growths were obtained in approximately half of the samples and most likely result from oral contamination of the endotracheal tubes during intubation.

Table 1. Results of leucocyte differential counts for BAL (n = 31) from 14 juvenile harp seals. Means per seals (1 to 4 BAL per seal).