> Howdy, all--
> Loren Muldowney's story about "limberneck" resulting from feeding
> chickens on maggots is one I'd heard from a local knowledge
> perspective out east, as well. My dad worked on some friends' pig
> farms in Essington, PA, before and after his service in World War
> Two. Most of those farms were diversified and also had poultry, and I
> can remember him talking about this. He was a compassionate man, and
> couldn't stand to see animals suffering.
> Loren--good question you raised--because you've challenged my
> thinking that these maggots could be biocontrolled by birds in an
> urban composter. See below.
> "Limberneck" is a condition caused by avian botulism. I posted here
> recently about ponds as reservoirs of avian botulism.
> --U.S. Fish and Wildlife service info:
> The authors are at the National Wildlife Health Laboratory, in Madison.
> "Avian Botulism affects the nervous system, causing muscle paralysis.
> Depending on how far the disease has progressed, various levels of
> paralysis will be
> observed. An early sign in birds is the inability to fly. Once the
> ability to fly is lost and leg muscles become paralyzed, ducks
> suffering from botulism often propel
> themselves across the water and mud flats with their wings. This
> sequence of signs is in contrast to that of lead-poisoned birds,
> which have difficulty flying but
> remain able to walk and run.
> "Paralysis of the inner eyelid and neck muscles follows. These are
> the two most easily recognizable signs associated with avian
> botulism. The inability of the bird to hold its head erect is the
> reason this disease is called "limberneck." Frequently, birds will
> drown once they reach this stage in the disease. Those that do not
> drown will eventually die from respiratory failure as paralysis
> "Favorable environmental conditions occur in the tissues of decaying
> animal and insect carcasses. The decomposition process uses up all
> available oxygen in the
> carcass, creating anaerobic conditions. Bacterial spores ingested
> during the life of the animal germinate after death. As the bacteria
> multiply and die, the toxin is
> "The cycle of avian botulism
> "Outbreaks of avian botulism occur when the toxin is taken in by
> birds. The die-off may begin as birds feed directly on invertebrate
> carcasses that contain the toxin, or as a result of feeding on live
> maggots of flesh-flies and blowflies. Flies lay their eggs on dead
> vertebrates, and the resulting maggots store botulinal toxin in their
> bodies as they consume the carcass. More than 5,000 maggots can be
> produced by a single bird carcass; consumption of just two to five
> toxin-bearing maggots is
> often enough to kill a duck!"
> Note that the difference between this and Kate's situation is that
> the source of the botulinal toxin is dead vertebrates and
> invertebrates. Kate is decomposing/composting vegetables. Which is
> what I was thinking when I suggested laying the heap open to the air
> for city birds to pick at.
> However, from
> --Texas A&M
> comes this:
> "Botulism is a disease caused by the ingestion of a toxin produced by
> the anerobic bacterium Clostridium botulinum. All domestic fowl and
> most wild birds are susceptible. An interesting exception is the
> vulture, which is apparently immune and feeds on decaying carcasses.
> Many human deaths have been attributed to their consuming food or
> water containing the toxin.
> "Cause: Botulism is not a bacterial infection, but a condition
> produced by ingestion of a toxin produced by the bacterium Cl.
> botulinum. The organism is
> common in nature and is widely dispersed in soils. Ingestion of the
> organism is not harmful. It becomes dangerous only when conditions
> are favorable for the
> growth and multiplication of the bacteria and its subsequent toxin
> production. The organism grows best under high humidity and
> relatively high temperature and
> in an environment containing decaying organic material. Acid
> conditions are detrimental. Stagnant pools or damp areas containing
> decaying matter with an
> alkaline reaction are a danger area. Botulism may result from
> consumption of any decaying animal or vegetable. Decaying carcasses
> are a frequent source of
> toxin, and fly maggots feeding on such tissue may contain enough
> toxin to cause the disease when ingested. The toxin is water soluble;
> consequently, water
> sources may become contaminated.
> "The toxin is one of the most potent, being about 17 times as deadly
> as cobra venom for the guinea pig. The toxin is relatively heat
> stable but may be destroyed by boiling. There are different types of
> the toxin. Types A and C usually are responsible for the disease in
> birds, while type B most frequently affects man."
> So this indicates that maggots in partly-finished compost *could* be
> a problem for birds, under certain circumstances?
> There is some good informationon avian botulism/limberneck at:
> --Environment Canada
> See especially,
> --"Methods of tranfer" for info on maggots:
> That site also has an EXTENSIVE annotated bibliography on avian botulism
> See especially:
> This one intrigued me: it lists a bunch of antibiotics that people
> can feed chickens to control botulism; this refers back to the
> ongoing SANET discussion of antibiotics in the food chain, and the
> notion of drugging animals to overcome pathogens caused by systemic
> One last resource:
> --Skipio's (breeder of insects for kept birds and reptiles)
> "Insects are a natural nutrition source for all birds at some point
> in their development except for some who obtain their animal protein
> from fish, mammals, reptiles or amphibians. Live mealworms and
> crickets, originally marketed as fish bait, have long been available
> for feeding birds and other animals. These insects were grown on
> vegetable diets. Some bird breeders to their dismay tried feeding
> their birds maggots that were grown on offal or wastes from the local
> butcher shop. The maggots were suitable for fish bait but could carry
> claustridium botulinum that resulted in fatal limberneck disease. A
> mistaken idea associated with those larvae was that they could be
> cleansed with corn meal. That was not true. Only insects that have
> been grown on vegetable diets should be fed to birds!"
> Sooooo. Not sure where that leaves us. My guess would be that if the
> conditions in the heap weren't too alkaline, and what went into it
> was clean (not rotted) food, the chance of botulin toxin accumulating
> in the maggots would be relatively low.
> Comment, anyone?
> Hope this is of use to you-all with poultry, as well. I've seen
> chickens go after maggoty produce, either gleaning in the garden, or
> something left too long in the scrap bucket (which is also risking
> Finally, Loren, you asked about feeding maggots to fish.
> Here's a nice little site that looks like a student one, very well referenced:
> The student was apparently in a course on Microbial Disease and Human
> Society. The above URL has an item about botulism in fish, and
> Now that we've had this discussion, watch for Dennis Avery to show up
> claiming that composting causes botulism.
> (not sure why I'm smiling)
> Michele Gale-Sinex
> Communications manager
> Center for Integrated Ag Systems, UW-Madison
> UW voice mail: 608-262-8018
> Home office: 415-504-6474 (504-MISH)
> Home office fax: Same as above, phone first for enabling
> I eat everything. If anything is there, I eat it. I presume it is
> safe and good. --U.S. Secretary of Agriculture Dan Glickman
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