Serologic data were examined to determine whether infectious disease may have played a role in the decline of Steller sea lions (Eumetopias jubatus) in the Gulf of Alaska and Aleutian Islands, USA. Available published data, unpublished data, and recent collections (1997–2000) were compared and reviewed. Data were stratified by geography to compare the declining western Alaskan population in the Aleutian Islands through eastern Prince William Sound to the increasing population in southeastern Alaska. Prevalences of antibodies from the 1970s to the early 1990s were noted for Leptospira interrogans, Chlamydophila psittaci, Brucella spp., phocid herpesvirus-1, and calciviruses. Serum samples collected from 1997–2000 were tested for antibodies to these agents as well as to marine mammal morbilliviruses, canine parvovirus, and canine adenovirus-1 and −2. Conclusions could not be drawn about changes in antibody prevalence to these agents during the decline of Steller sea lions, however, because data were incomplete or not comparable as a result of inconsistencies in testing techniques. Despite these shortcomings, results provided no convincing evidence of significant exposure of Steller sea lions to morbilliviruses, Brucella spp., canine parvovirus, or L. interrogans. Steller sea lions have been exposed to phocid herpesviruses, caliciviruses, canine adenovirus, and C. psittaci or to cross-reactive organisms in regions of both increasing and decreasing sea lion abundance. Based on similar antibody prevalence estimates from the increasing and decreasing populations, these agents are unlikely to have been the primary cause of the population decline. They may have contributed to the decline or impeded population recovery, however, because of undetected mortality and morbidity or reductions of fecundity and body condition in animals under other stresses. Systematic monitoring for disease agents and their effects is needed to determine whether infectious disease currently plays a role in the decline and lack of recovery of Steller sea lions.

We present an analytical, Green-function-based model for the electric potential of DNA in solution, treating the surrounding solvent with the Debye-Huckel approximation. The partial charge of each atom is accounted for by modeling DNA as linear distributions of atoms on concentric cylindrical surfaces. The condensed ions of the solvent are treated with the Debye-Huckel approximation. The resultant leading term of the potential is that of a continuous shielded line charge, and the higher order terms account for the helical structure. Within several angstroms of the surface there is sufficient information in the electric potential to distinguish features and symmetries of DNA. Plots of the potential and equipotential surfaces, dominated by the phosphate charges, reflect the structural differences between the A, B, and Z conformations and, to a smaller extent, the difference between base sequences. As the distances from the helices increase, the magnitudes of the potentials decrease. However, the bases and sugars account for a larger fraction of the double helix potential with increasing distance. We have found that when the solvent is treated with the Debye-Huckel approximation, the potential decays more rapidly in every direction from the surface than it did in the concentric dielectric cylinder approximation.

Ft. Moultrie, Aug. 28, 1843, Half past 10 o’clock, A. M. My dear mother: We have another son, born today at 20 minutes past 12. Carry is better than she ever was before in similar circumstances. The boy is a prodigy, weighs 11 pounds. Six hours before the birth Carry entertained company, then had severe pains for 1% hours. The Doctor came 10 minutes before the child was born and is now gone. Carry sends her love. Yours very atfectionately, E. D. Keyes, Captain, 3rd Artillery, U. S. Army.

................................................................................................................................ 5 ACKNOWLEDGEMENTS...................................................................................................... 5 INTRODUCTION...................................................................................................................... 6 METHODS .................................................................................................................................. 6 SAMPLE COLLECTIONS ............................................................................................................ 6 SAMPLE ANALYSES....................................................................................................................7 Chlamydophila psittaci .............................................................................................................7 Caliciviruses (SMSV’s) ..............................................................................................................7 Phocid Herpesvirus-1 ................................................................................................................7 Canine adenoviruses 1 and 2 .................................................................................................... 8 Marine morbilliviruses............................................................................................................. 8 Toxoplasma gondii ................................................................................................................... 8 Leptospira sp. ........................................................................................................................... 8 Influenza A ............................................................................................................................... 8 Brucella spp.............................................................................................................................. 8 Canine parvovirus .................................................................................................................... 9 RESULTS..................................................................................................................................... 9 Chlamydophila psittaci ............................................................................................................ 9 Caliciviruses (SMSV’s) ............................................................................................................. 9 Phocid Herpesvirus-1 ..............................................................................................................10 Canine adenoviruses 1 and 2 ...................................................................................................10 Morbilliviruses ........................................................................................................................10 Toxoplasma gondii ..................................................................................................................10 Leptospira spp.........................................................................................................................10 Influenza A ..............................................................................................................................10 Brucella abortus ...................................................................................................................... 11 Canine parvovirus-2................................................................................................................ 11 Disease Agents in Steller Sea Lions in Alaska, Page 3 DISCUSSION.............................................................................................................................11 Chlamydophila psittaci ............................................................................................................11 Caliciviruses (SMSV’s) ............................................................................................................ 12 Phocid Herpesvirus (PhHV-1) ................................................................................................ 12 Canine Adenoviruses 1 and 2 (CAV-1 and –2)........................................................................ 13 Morbilliviruses........................................................................................................................ 13 Toxoplasma gondii.................................................................................................................. 14 Leptospira spp. ....................................................................................................................... 14 Influenza ................................................................................................................................. 14 Brucella abortus...................................................................................................................... 15 Canine parvovirus................................................................................................................... 15 Did Disease Cause the Decline of Steller Sea Lions?.............................................................. 15 Future Research...................................................................................................................... 16 LITERATURE CITED ............................................................................................................ 16 TABLES ..................................................................................................................................... 21 Table 1. Historical and retrospective prevalence of antibodies to C. psittaci ..................... 21 Table 2. Serology data by region for C. psittaci, calicivirus and PhHV-1 in pups and juveniles (1998-2000) .................................................................................... 21 Table 3. Serology data by age for C. psittaci, calicivirus and PhHV-1, CAV-1 and –2 in pups and juveniles (1998-2000) ....................................................................... 21 Table 4. Comparison of WADDL’s historical C. psittaci serology results to NVSL retrospective data...................................................................................................22 Table 5. Historical calicivirus results ..................................................................................22 Table 6. Serotypes of calicivirus reacted to by Steller sea lions ..........................................23 Table 7. Retrospective morbillivirus data ...........................................................................23 Table 8. Comparative morbillivirus serum neutralization titers.........................................24 Table 9. Historical, retrospective and current prevalence of antibodies Toxoplasma gondii by modified latex agglutination..................................................................25 Table 10. Historical prevalence of antibodies to phocid herpesvirus-1 ................................25 Table 11. Serologic tests with negative or negligible results..................................................26 A Research Report from the Marine Mammal Research Unit 26 pages © Fisheries Centre, University of British Columbia, 2003 FISHERIES CENTRE RESEARCH REPORTS ARE ABSTRACTED IN THE FAO AQUATIC SCIENCES AND FISHERIES ABSTRACTS (ASFA) Page 4, Fisheries Centre Research Reports 11 (4)