Detection and Characterization of a Novel Herpesvirus from the Trachea of Two Common Loons (Gavia immer)
Abstract
Avian herpesviruses associated with respiratory disease include infectious laryngotracheitis virus of chickens (Ga-HV1),1 Amazon tracheitis virus (not sequence characterized),2 and passerid herpesvirus-1 in Gouldian finches.3 The common loon (Gavia immer), a migratory fish-eating Gaviiform, is an important indicator of aquatic ecosystem health.4-6 Two wild adult common loons were evaluated after being found stranded in mainland North-Central Florida at separate occasions. On the basis of upper airway endoscopic and cytologic findings, severe ulcerative tracheitis was diagnosed antemortem in one of the birds, while more subtle lesions were observed in the other. A novel herpesvirus was detected antemortem in both birds from tracheal samples using nested consensus PCR amplification of the polymerase gene and sequencing. Despite prolonged intensive medical care, the bird with severe lesions failed to improve and was euthanatized 9 days after endoscopy. No viral inclusions were evident histologically in the lesions. However, an undulating tracheal mucosa in a “mountain ridge” pattern, resulting from epithelial regeneration and hyperplasia, was present, as is seen in the late stages of infectious laryngotracheitis in chickens.1 The second bird recovered and was subsequently released. The genetic distance seen between this and other characterized herpesviruses supports placement of this virus as a novel species, referred to as Gaviid herpesvirus 1 (GavHV1). The phylogenetic analysis showed that GavHV1 clusters within the genus Iltovirus. The relationship between the observed lesions and the virus remains to be demonstrated. Further studies are indicated to investigate the role of this virus in morbidity and mortality of free-ranging and captive loons.
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