I shot a mallard last weekend and started to breast it out when I immediately noticed it had small oblong shaped parasites in the breast meat. I cut down to the bone and the parasites or what I assumed to be parasites were all through its breast. I discarded the meat, I have never seen or heard anyone ever having parasites in duck meat before, do you know what this is? –John Luber-
A few years ago I shot a mallard drake that had a strange condition. As I field dressed the duck, I noticed small round objects about an inch long with mushroom shaped heads inside the body cavity. At first I thought it was just something it ate, but these objects were not in the intestinal tract. I overlooked the objects and proceeded to clean the bird. As I separated the skin from the breast meat I noticed numerous small rice like grains in the breast meat. Whatever it was I didn’t think would be safe to eat so I threw the duck away. What do you suppose this could have been? –Jonathan Dunbar-
John and Jonathan,
Rather than re-invent the wheel, the following article (Understanding “Ricebreast”) previously written by Dr. Serge Larivière, will give you the answer you were looking for:
You’ve all been there. You get back to your home or lodge after a great morning of hunting and you settled in the shop to clean your birds. It’s early in the season, so you figure you’ll breast them out and grill them or cut in strips and cook in the frying pan. But as you peel the skin from the breast muscle, your eyebrows jump: the breast meat is spotted with white, lots of white “rice grains” embedded in the meat. “Darn ricebreast!” you exclaim. “Ricebreast” properly describes what it looks like, so much in fact that even scientists use “ricebreast” to describe the all too common infection of ducks by a parasite called “Sarcocystosis”.
Parasites are organisms that make a living off of feeding on other organisms. Tapeworms, ticks, fleas, and Sarcocystosis are all parasites. The parasite strategy is simple: feed on the “host” but not enough to kill it. Indeed, parasites not only need a host for food, they also need a host as a “vehicle” to help them complete their life cycle. The only way for a parasite to “move” from one host to another, is to be eaten by another host, or to release eggs some place where another host might ingest them. Because of this lifestyle, scientists refer to parasites as having “life-cycles”.
For Sarcocystosis, the life cycle is simple although not completely understood. The cysts embedded in the muscle of ducks are ingested by a carnivore (such as a fox getting a hen during the breeding season). Once in the carnivore stomach, the parasite reproduces and the eggs are released in the carnivore’s excrements. The eggs survive outside for long periods of time, and may end up being eaten by invertebrates such as snails or flies, which are in turn consumed by ducks. If the carnivore excrements end up in the water, ducks may also consume contaminated water and become infected. The parasite then “migrates” into the muscle tissues of the waterfowl host, and there await to be consumed by another carnivore so they can reproduce again. Skunks, possums, raptors and even humans may function as final hosts for Sarcocystosis. Interestingly, dabbling ducks are more commonly infected than divers. Possibly, divers may escape infections by feeding on pond sediments where invertebrates infected with the eggs of Sarcocystosis are less common. Many waterfowl species such as shovelers, mallards, pintails, as well as snow and Canada geese are vulnerable, but shovelers are most commonly infected. Interestingly, young ducks (duckling to immatures in the fall) have low infection rates, possibly because the parasite is most active in wintering areas. The parasite itself does not cause morbidity or mortality in waterfowl, and the cysts have little effects on the waterfowl host. Apparently, the cysts become “invisible” during cooking, and health officials tell us that ingesting cooked Sarcocystosis cysts (cooking and eating ricebreast ducks) does not pose a health hazard. However, Sarcocystosis infections are one of the most conspicuous parasitic conditions of wild ducks, and infected ducks are definitely not appealing, and most are understandingly discarded by hunters. For hunters that harvest “ricebreast” ducks, it is important to not feed infected birds to pets, or to throw such birds where they can be consumed by wild carnivores as this may only help the cycle of the parasite. Dispose of any infected birds in garbage or by burning.
Thanks for taking the time to send in your questions!
Joel Brice