K, you did everything you could for that duck... hopefully this information will help others identify and prevent avian botulism in their flock. Keeping pools clean is paramount.
Found this on Avianweb...
Treatment / Recovery:
Birds which live through 48 hours of illness usually recover.
At this time, there are two primary Botulinum Antitoxins available for treatment of wound and foodborne botulism:
Trivalent (A,B,E) Botulinum Antitoxin - deriived from equine sources utilizing whole antibodies (Fab & Fc portions). This antitoxin is available from the local health department via the CDC.
Heptavalent (A,B,C,D,E,F,G) Botulinum Antitoxin - derived from "despeciated" equine IgG antibodies which have had the Fc portion cleaved off leaving the F(ab')2 portions. This is a less immunogenic* antitoxin that is effective against all known strains of botulism where not contraindicated. (*Immunogenicity is the ability of a particular substance to provoke an immune response.)
Under favorable environmental conditions - access to clean water, fair weather conditions and no predation - birds can recover from low doses of the toxin without treatment. Birds that do recover from avian botulism do not show any increased tolerance for the poison and are not resistant to subsequent exposures. There is some evidence that birds may be protected for short periods of time with a vaccine.
The following cause of action is recommended:
Sick birds should be isolated and provided with food and water.
Wounds should be treated, usually surgically, to remove the source of the toxin-producing bacteria.
Good supportive care with antibiotics and vitamins has been helpful in some cases.
Remove the source of the toxin. Keep birds away from suspect sources that cannot be removed.
Remove dead birds, supply clean feed and water, clean up around stagnant pools and ensure that all feed is fed in containers and not on the ground.
The toxin is also found in maggots and litter beetles so these must also be controlled.
Link:
http://www.avianweb.com/botulism.html