An estimated 1.2 million cases of salmonellosis occur annually in the United States (approximately 42,000 are laboratory-confirmed and reported to the Centers for Disease Control; CDC). Transmission comes primarily from contaminated food, water or contact with infected animals only some of which are wild animals. Of the 50 Salmonella outbreaks reported by the CDC between 2006 and 2013, only 5 (10%) were related to wildlife. These included the 2013 outbreak related to small turtles (Salmonella Sandiego, Pomona and Poona), two 2012 events associated with hedgehogs (Salmonella Typhimurium) and small turtles (Salmonella Sandiego, Pomona and Poona), the 2011 outbreak connected to Africa dwarf frogs (Salmonella Typhimurium) and the 2010 water frog-related outbreak (Salmonella Typhimurium).
At the 2014 North American Veterinary Conference, held in Orlando, Florida, Joe Gaydos presented a paper on diseases in river otters.
River otters were nearly eliminated over much of their home range, but have made comebacks. They can be found in freshwater habitats ranging from alpine lakes to rivers, streams, and swamps. From California to Alaska they sometimes occupy a nearshore marine habitat, where they play an important ecological role. They depend on fresh water for drinking.
River otters are host to various bacteria, viruses, fungi, and internal and external parasites. Some of these can cause disease in humans and domestic animals.
River otters are also sentinels to evaluate environmental contaminants including heavy metals, hydrocarbons and persistent organic pollutants.
The paper includes findings on successful anesthesia and capture methods.
North American river otters (Lontra canadensis; referred to simply as river otters from here on) are widely distributed across North America with the exception of the desert Southwest. Extirpated over much of their original range, reintroduction programs in 21 states have been extensive and river otters now occupy at least portions of their historic range in every state within the continental United States except New Mexico. Over most of their range they can be found in freshwater habitats ranging from alpine lakes to rivers, streams and swamps. From California to Alaska, they also occupy a nearshore marine habitat where they primarily feed on marine invertebrates and fishes and play and important ecological role moving marine nitrogen and phosphorus into nearshore vegetation. Their dependence on freshwater for drinking, however, limits them to marine habitats close land where freshwater is available. With river otter populations recovering, veterinarians have an increased chance to encounter them in both wildlife management and rehabilitation settings. Clinicians working with river otters should be familiar with their clinical anatomy and diseases.
Update January 21, 2016
Scientists from all over the US and Canada who are studying this disease came to share their research and learn from each other.
We still have a lot to learn about this disease, but data presented support: (1) this is an unsual mortality event, (2) the disease hits a wide range of sea star species, and (3) it affects different species of sea stars differently. Species that seem have been hit hard both in the wild and in captivity include the mottled star (Evasterias troschelii; pictured here), sunflower star (Pycnopodia heliantoides), spiny pink star (Pisaster brevispinus) and the ochre sea star (Pisaster ochraceus).
Joe Gaydos notes, “I’m impressed with and inspired by all of the great scientific minds working to unravel this mystery!”
Update November 17 2014
Work is continuing to better understand the other factors involved in this outbreak and how this massive loss of predators will reshape the marine ecosystem.
Understanding emerging threats to the health of our oceans is a key part of SeaDoc’s work, and donations to SeaDoc make it possible.
Read the paper by Ian Hewson, et al.: http://www.seadocsociety.org/?p=2949
Earthfix covered the study, noting that this virus is different from all known viruses infecting marine organisms. (Another little-known fact: a drop of seawater contains about 10 million viruses.)
Smithsonian Magazine also has a good article about the study and what it means.
Update October 2014
The article is well-worth a read, and here’s a video from it:
Update June 2014
Scientists are closer to having an answer to what’s causing the mortality outbreak in sea stars. Drew Harvell of Cornell University and Friday Harbor Labs is working with a team that has traced the cause.
Read the latest article from KUOW’s EarthFix team about the current status of the outbreak. There’s also a terrific video on that page featuring Drew Harvell.
Sea stars in various parts of the Salish Sea are experiencing a mass-mortality event. We’re not sure of the cause, but we’re working on it. (So are many other groups in the area.)
In October we looked for healthy and diseased sea stars during our dives for our new subtidal survey project. (See what else we found on those dives here.) During early November, we returned to two of the REEF monitoring sites from October where we saw the highest density of sea stars to see if sea star wasting disease has shown up since were were there last month. Fortunately we saw numerous sea stars and numerous species of sea stars and they all looked healthy. We will continue dives this weekend to look for more signs of disease.
Photos of diseased sea stars
Seastar expert Neil McDaniel, (www.seastarsofthepacificnorthwest.info) has graciously shared his photos showing the progression of the disease over a short period of a few weeks. This can give you an idea of what you’re looking for. The before-and-after photos are pretty shocking. View the photos at Janna Nichols’ SCUBA photo page.
Report sick and healthy sea stars
If you’re a diver or a beach-walker and you see sea stars (healthy or diseased), report them at the Vancouver Aquarium’s Sea Star Wasting Syndrome web page.
That page at the Vancouver Aquarium’s website also has an overview of the outbreak.
Also see these media articles:
The Vancouver Aquarium made a time-lapse video of a sea star disintegrating. Watch it here: http://youtu.be/mjrp3Eckr-E
Seattle Aquarium veterinarian Lesanna Lahner was interviewed on Science Friday on NPR on December 5, 2014.
The Northwest Indian Fisheries Commission posted a blog entry about how the Puyallup Tribe is tracking sea star wastage in the South Sound.
Scientist Drew Harvell and diver Laura James wrote a blog post for the Nature Conservancy about the outbreak. In it, Harvell, who is one of the scientists doing genetic research on possible disease vectors, makes the case for better funding of scientific investigations of disease in the ocean.
Page updated on December 10, 2014
In this newsletter: wildlife veterinarians rescue entangled sea lions, new study on how harbor seals get brucellosis, spotlight on Science Advisor Dr. Christine Kreuder Johnson, Marine Science Lecture Series kicks off with a lecture on underwater mapping, and a lot of upcoming events.
John Ryan of KUOW reported on the efforts in the United States and Canada to understand a starfish die-off.
“Every population has sick animals,” said SeaDoc Society wildlife veterinarian Joe Gaydos, on a boat off Orcas Island between research dives. “Are we just seeing sick animals because we’re looking for it, or is it an early sign of a large epidemic that may come through and wipe out a lot of animals?”
The timing of this news coincided with SeaDoc’s first year of monitoring subtidal fish and invertebrates at 10 sites in the San Juan Islands. This project, done in conjunction with REEF and Friday Harbor Labs, is a multi-year study to track understudied populations in the Salish Sea. It’s exactly the kind of effort that’s needed if we’re to have the right data to understand mortality events like these.
Gaydos cautions, “Despite the headline, we’re not certain that a mortality event is heading into Washington State. During our 120 dives we saw many more healthy animals than sick ones. We collected samples and they will be tested microscopically and for infectious agents and a parasites.”
Read the complete text or listen to the piece as broadcast: http://kuow.org/post/mass-starfish-die-may-be-headed-washington
Also see this article on King5.com featuring the work of the Seattle Aquarium: Biologists search for cause of sea star deaths.
Joe Gaydos was also interviewed for an article on KVAL in Eugene, OR. http://www.kval.com/outdoors/Whats-causing-sea-stars-to-waste-away–232121291.html
We kicked off our long-term subtidal intelligence gathering effort with 120 survey dives in October 2013.
Here are some beautiful photos of some of the creatures that live under the water in the Salish Sea: dironas, butterfly crabs, sea pens, rockfish, and a whole lot of starfish. (The slideshow can take a while to load…)
Salmonella enterica serovar Newport (Salmonella Newport) was isolated from multiple tissues in a neonate killer whale (Orcinus orca) that stranded dead in 2005 along the central coast of California, USA. Necrotizing omphaloarteritis and omphalophlebitis was observed on histologic examination suggesting umbilical infection was the route of entry. Genetic analysis of skin samples indicated that the neonate had an offshore haplotype. Salmonellosis has rarely been identified in free-ranging marine mammals and the significance of Salmonella Newport infection to the health of free-ranging killer whales is currently unknown.