title: Persistence of Clostridium botulinum type C toxin in blow fly (Calliphoridae) larvae as a possible cause of avian botulism in spring.
abstract: Diverse samples were examined at a site of water-bird mortality, caused by Clostridium botulinum type C toxin in southern Moravia (Czechoslovakia). The toxin was detected in high concentrations in mute swan (Cygnus olor) carcasses (less than or equal to 1 x 10(6) LD50/g) as well as in necrophagous larvae and pupae of the blow flies Lucilia sericata and Calliphora vomitoria (less than or equal to 1 x 10(5) LD50/g) collected from them. It was detected in lower concentrations (less than or equal to 1 x 10(3) LD50/g) in other invertebrates (ptychopterid fly larvae, leeches, sow-bugs) associated with these carcasses, and occasionally in water samples (8 LD50/ml) close to the carrion. The toxin was not detected in the samples of water, mud or invertebrates collected at a distance greater than or equal to 5 m from the carcasses. The toxin-bearing larvae of L. sericata and C. vomitoria, containing 80,000 LD50/g of type C toxin, were exposed in the mud at the study site for 131 days from November to March. Although the toxin activity decreased 25-fold and 40-fold in the two samples of maggots exposed during this period, it remained very high (less than or equal to 3,200 LD50/g). Birds ingesting a relatively low number of these toxic larvae (or pupae) in the spring could receive a lethal dose of the toxin.
authors.affiliation: Czechoslovak Academy of Sciences, Institute of Systematical and Ecological Biology, Brno.
authors.forename: Z
authors.initials: Z
authors.lastname: Hubálek
authors.forename: J
authors.initials: J
authors.lastname: Halouzka
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000209:etiology*; D001717:Birds; D001905:Botulinum Toxins / Q000032:analysis*; D001906:Botulism / Q000209:etiology / Q000662:veterinary*; D004175:Diptera / Q000032:analysis*; D004199:Disease Vectors; D007814:Larva / Q000032:analysis; D012621:Seasons
chemical_list: D001905:Botulinum Toxins