Classroom Resources: Sea Sick

Sea Sick

By Rebecca Kessler

July-September 2010/ Vol. 11 No. 3

Discussion Questions

1. This article reviews scientific literature to suggest that the ocean, and particularly marine mammals may be a new source of zoonotic diseases. To really understand this, you need to first be able to answer the following questions:

a. What is a zoonotic disease? What are some familiar examples from land animals?

b. What is RNA? How is it different from DNA? Why do you think it is responsible for more than 1/3 of emerging or re-emerging pathogens?

c. What is an astrovirus and why are researchers particularly concerned (i.e., what age group of humans does it most infect)?

d. What does it mean that viruses “trade genes”?

2. What events inspired the researchers (reported in Bogolmoni et al. 2008) to survey the diseases of marine organisms? Is this a typical example of how science is done? Would the research itself appeal to you (see the photo on page 33)?

3. What are the ways (i.e., mechanisms) that human-borne microbes could come into contact with marine mammals, and what are some of the ways marine mammals could come into contact with people, and potentially transmit disease? Does it have to be direct contact? Are there disease vectors you could think of, that might move between the two populations?

4. Why is it so powerful in the evolution of viruses to switch among hosts?

5. If zoonotic disease transmission is really entering the marine realm, what are some strategies and solutions for a) limiting the transmission of human-borne microbes to marine animals, and b) conversely, limiting contact between people and these animals?

Websites for Further Information

Astrovirus fact sheet: http://www.nlv.ch/Astrovirus/Astrofactsheet.htm
Woods Hole Oceanographic Institution: http://www.whoi.edu/
NOAA information on marine mammals by species: http://www.nmfs.noaa.gov/pr/species/mammals/
CDC information on zoonotic diseases: http://www.cdc.gov/ncidod/dpd/animals.htm

Zoonotic Disease in the News

Dolphin disease linked to human ailments and ocean health (Environmental News Service, February 19, 2010): http://www.ens-newswire.com/ens/feb2010/2010-02-19-02.html

Peer-reviewed Literature (in addition to the citations listed in the article)

Herrmann, J.E. et al. 1991. Astroviruses as a cause of gastroenteritis in children. New England Journal of Medicine 324:1757-1760.
Domingo, E. and J.J. Holland. 2003. RNA virus mutations and fitness for survival. Annual Review of Microbiology 51: 151-178.

Key Concepts