In 2004, three of seven (43%) captive wild Pacific common murres (Uria aalge) and 11 of 11 (100%) captive reared pigeon guillemots (Cepphus columba) held at the Alaska SeaLife Center (ASLC) exhibited cutaneous and intraoral avian pox over the course of 7 months. Clinical findings observed during this outbreak were previously reported.
The surviving 7 pigeon guillemots (1 male and 6 females) were held in outdoor, mosquito netted isolation pools until July 2005. A thorough examination with collection of blood and choanal and cloacal swabs was performed every 3 months. The birds were clinically normal and viral cultures of the swabs were negative over the winter and spring. However, although no further skin or mucosal lesions were seen in these birds, recrudescence apparently occurred in the summer as poxvirus was cultured from tissue and from combined cloacal and choanal swabs collected in late July.
During this period, ASLC housed 49 additional birds of 8 species in the outdoor exhibit aviary including tufted puffin (Fratercula cirrhata), horned puffin (Fratercula corniculata), red-legged kittiwake (Rissa brevirostris), arctic tern (Sterna paradisaea), black oystercatcher (Haematopus bachmani), long-tailed duck (Clangula hyemalis), harlequin duck (Histrionicus histrionicus), and king eider (Somateria spectabilis). Between July 2005 and January 2006, four of 14 tufted puffins (28%) were found to have superficial scabs or vesicles on the skin of the foot web or metatarsus. These lesions healed uneventfully in one to two weeks with no treatment but were culture positive for poxvirus. After the first tufted puffin lesions were found in the exhibit aviary, the pigeon guillemot isolation was lifted and those birds were returned to the exhibit. To date, none of the other exhibit aviary birds has shown any suspicious lesions including the 10 common murre chicks and 10 horned puffin chicks added in the fall of 2004 and 2005.
An agar gel precipitation test (AGP) using a concentrated commercial fowl pox antigen was attempted in serum collected in 2004 from the affected pigeon guillemots. Some positive results were seen but they did not correlate with onset of clinical signs in all cases. Antigen for an AGP assay was then developed from poxvirus isolates obtained in 2004 from affected pigeon guillemots. To date, a total of 44 birds from the ASLC quarantine and aviary facilities have been tested once or multiple times for antibodies using this assay. Precipitating antibodies were detected in all three species (common murre, pigeon guillemot, and tufted puffin) that had developed clinical poxvirus lesions during 2004-2005 but no antibodies have been observed in any species that did not show clinical signs of poxvirus infection. In pigeon guillemots, circulating antibody was detectable in serum up to approximately one year post clinical disease. However, antibodies were not detected in two of five surviving pigeon guillemots, potentially reflecting individual variability in precipitating antibody responses, variability in the distribution and severity of lesions during infection or possibly variations in sample quality.