What Are We Missing?

Flo Tseng

Assistant Professor, Cummings School of Veterinary Medicine

The whole question of warming temperatures, warming marine ecosystems—global warming is one factor but things like increased agricultural runoff, increasing nitrogen waste in the sea, are really affecting coastal environments to the point where we're starting to see more things like harmful algal blooms (red tides) which are causing mortality events in coastal birds and mammals. There's also the obvious shift in prey availability for seabirds due to climate change. There have been interesting sorts of mortality events in seabirds that have been seen all along but we're certainly documenting more of them now on the east coast with our SEANET program. For instance, for the past several years we've seen a large die off of common eiders, a type of sea duck, on Cape Cod and Martha’s Vineyard. Over the past couple years, we've been doing necropsies here at the Wildlife Clinic, and these birds are very thin and have a very heavy parasite load. The question is what's causing them to starve like this. Is it a shift in prey availability? One of the theories is that the birds hav been forced to shift fromtheir preferred food which is blue mussels, because these have been decreasing in number. Now they're eating more shore crabs. These crabs are the intermediate hosts for these acanthocephalan parasites. Is there a link between shifts in prey availability, the causes of which could include things like climate change, and increased incidences of things like parasitic diseases?

"We're starting to see more things like harmful algal blooms (red tides), which are causing mortality events in coastal birds and mammals. There's also the obvious shift in prey availability for seabirds due to climate change."

Another example of the effect of climate change is the movement of certain kinds of insects and different organisms northwards from warmer climates, bringing different things like disease and parasites that can threaten native fauna that don't have any kind of immune response. We can also look at the whole question of avian influenza and (whether it's carried by wild birds and/or the poultry trade) we have things like climate change affecting migration patterns of wild birds. Even in our clinic, we certainly saw that we were getting species that were coming through at different times than we normally would have expected them to. There are probably multiple causes but certainly climate change could be one thing.

"The public needs to be more aware how much of a contribution the changes that we are making to our environment are affecting animals, which in turn affect us, and then what that might mean for the long run in terms of public health threats."

Animals are sentinels of disease or other ecological pathology. It's certainly something that has been known in the scientific community and is coming more and more on the public health radar. We're using the animals that come in through the clinic to signal if we have a cluster of something like tularemia in a certain species in a certain part of the state, and does that signal any kind of public health or bioterror threat? I think that members of the public health community are becoming more aware of domestic and wild animals not just as sentinels but as real factors that should be taken into consideration where they are looking at diseases or other facets of public health. There needs to be increased awareness in the public health field of potential contributions veterinarians can make to the discussion. The public needs to be more aware how much of a contribution the changes that we are making to our environment are affecting animals, which in turn affect us, and then what that might mean for the long run in terms of public health threats.

[ Learn more about Tseng's work ]

Interviews by Georgiana Cohen, Office of Web Communications

Homepage photo by John McConnico / Associated Press. Tseng photo by Melody Ko, University Photographer. Islam, Metcalf, Rappaport, Reed and Shimshack photos by Alonso Nichols for Tufts University. Portney photo by Zara Tzanev for Tufts University. Kirshen photo by Aaron Schutzengel (A'07) for Tufts University. Najam photo by Brian Loeb (A'06) for Tufts University.

This story originally ran on Oct. 22, 2007.