Marine mammal virology is a nascent field. We know that the ocean harbors a huge diversity of viruses, but we have very limited knowledge as to which viruses marine mammals are susceptible. Our laboratory has focused on development of tools for virus discovery in these species and on assessment of clinical relevance of viruses that have been discovered using these tools. Some of the tools that have been most useful for virus discovery include consensus primer PCR and rolling circle amplification.
This work has resulted in the identification of over 50 new viruses from 13 different families. We have demonstrated at least one case of genetic recombination between a virus of humans and marine mammals. This virus belongs to an RNA-based virus family, the astroviruses, that frequently cause gastroenteritis in humans. It appears that much greater diversity is present in the astroviruses of marine mammals, and they may be a reservoir for these viruses.
Medicine has traditionally waited for viruses to cause epidemics or epizootics before significant surveillance occurs. With our increased understanding of virus ecology and evolution, it becomes more feasible to identify probable candidates for future novel disease outbreaks, and increase surveillance. Understanding of the marine ecosystem is necessary to comprehend viral ecology, and has great significance for terrestrial animal health as well.
1. Colegrove, K. M., J. F. X. Wellehan, R. Rivera, P. F. Moore, F. M. D. Gulland, L. J. Lowenstine, R. W. Nordhausen, and H. H. Nollens. 2010. Polyomavirus infection in a free-ranging California sea lion (Zalophus californianus) with intestinal T-cell lymphoma. J. Vet. Diagn. Invest. 22. In press.
2. Nollens, H. H., R. Rivera, G. Palacios, J. F. X. Wellehan, J. T. Saliki, S. L. Caseltine, C. R. Smith, E. D. Jensen, J. Hui, W. I. Lipkin, P. Yochem, R. S. Wells, J. St. Leger, and S. Venn-Watson. 2009. New recognition of Enterovirus infections in bottlenose dolphins (Tursiops truncatus). Vet. Microbiol. 139: 170–175.
3. Nollens, H. H., J. F. X. Wellehan, L. Archer, L. J. Lowenstine, and F. M. D. Gulland. 2010. Detection of a respiratory coronavirus during a pneumonia epizootic in free-ranging Pacific harbor seals (Phoca vitulina richardsii). Dis Aq. Org. In press.
4. Nollens, H. H., J. F. X. Wellehan, J. T. Saliki, S. L. Caseltine, E. D. Jensen, W. Van Bonn, and S. K. Wong. 2008. Isolation and characterization of a parainfluenza virus from bottlenose dolphins (Tursiops truncatus). Vet. Microbiol. 128: 231–242.
5. Rivera, R., H. H. Nollens, S. Venn-Watson, F. M. D. Gulland, and J. F. X. Wellehan. 2010. Characterization of phylogenetically diverse astroviruses of marine mammals. J. Gen. Virol. 91:166–173.
6. Wellehan, J. F. X., A. J. Johnson, A. Childress, K. E. Harr, and R. Isaza. 2008. Six novel gammaherpesviruses of Afrotheria provide insight into the early divergence of the Gammaherpesvirinae. Vet. Microbiol. 127: 249–257.
7. Wellehan, J. F. X., F. Yu, S. Venn-Watson, E. Jensen, C. Smith, W. G. Farmerie, and Nollens, H. H. 2010. Characterization of San Miguel sea lion virus populations using pyrosequencing-based methods. Infect. Genet. Evol. 10:254-260.