Summary ofSea Duck Disease Studies in Dutch Harbor: A Case for Restoration in Unalaska Bay March 21 , 2008 Kimberly Trust, U.S. Fish and Wildlife Service

Tuula Hollmen, Alaska SeaLife Center Paul Flint, Alaska Science Center Background: In 2004. USGS, USFWS and the Alaska Sea Life Center CASLC) were investigating the exposure oftwo near-shore species, harlequin ducks (HADU) and Steller's eiders (STEI) to petroleum hydrocarbons from industrial and non-industrial areas around Dutch Harbor. As part ofthat study, we also collected movement data on both ofthese species using standard radio telemetry techniques. Several ofthe birds carrying transmitters died, and four carcasses (3 STEI and I HADU) were recovered and sent to the Alaska Sea Life Center (ASLC) for necropsy. The dead ducks had low body weight and tested positive for microbial organisms, including E. coli. E.coiL a bacteria usually found in the intestinal tract of vertebrates was found in skin tissue at the transmitter site (on the outside ofthe body cavity)

. In an ancillary study, birds captured from Dutch Harbor were transported live to the ASLC. Many ofthese birds arrived at the facility with oral lesions and other signs ofillness. E. coli cultured from one ofthese birds was found in the air sac. an organ not typically associated with this bacteria. Researchers familiar with avian diseases determined that such a high prevalence ofobviously ill individuals from a single wild bird population was of concern, and studies were initiated to identify pathogens found in these birds and the extent to which they were exposed. 

### In a current study, the following objectives are being investigated: • We are using moleculartyping to characterize duck and water
-borne organisms and to compare strains and track transmission ofE

.coli a) between ducks and waterand b) among ducks We are evaluating the pathogenicity 

### otE
.coli to ducks using field data by comparing bacterial culture results with a panel ofhealth indicators from each bird.

Results to Date: From 2005-2007, fecal and oral swab samples were collected from HADU and STEI around Dutch Harbor and from a "clean" control site, Izembek Lagoon. Birds were screened for a variety ofpathogens. including bacteria. viruses and parasites. Water samples were also collected and screened for coliforms and viruses. The results for the E. coli analyses are the most complete to date. Samples from I 17 STEI and 21 HADU from Dutch Harbor were cultured for bacteria. In 2004 and 2007, 20 and 27 samples, respectively were collected from STEI in Izembek lagoon as reference samples. No HADU samples were collected from Izembek. Overall, 16% ofthe STEI and 67% ofthe HADU from Dutch Harbor were found positive for E.coli. In 2005, no STEI from lzembek tested positive for E. coli and only one bird was positive in 2007.In DNA tests, avian pathogenic E. coli was identified in STEI and HADU. Thistype ofE. coli is associated with disease in birds

. In two HADU, DNA tests identified additional types ofE. coli: enterotoxigenic and enterohemorhaggic

. These E
.coli are associated with disease in mammals and are likely mammalian in origin. Additionally, coliforms, including E. coli, were found in water samples collected ITom Unalaska Bay. and an E. coli from a water sample was found to match an E
.coli isolated from a duck

. Based on the large number of known existing individual E. coli subtypes (-50,000) and the odds against finding a match between the water and an individual duck, it is extremely unlikely thatthe birds were exposed to these bacteria away from the site

. Other disease results are pending.