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ABSTRACT. Avian botulism is a paralytic disease caused by a toxin produced by Clostridium botulinum type C. Since type C isolates from cases of avian botulism produced a neurotoxin consisting of a mosaic form of parts of type C and D neurotoxins, we examined the antitoxin titers in the convalescent sera of botulism-affected birds which belonged to family Anatidae. ELISA using the C/D mosaic neurotoxin as an antigen revealed that the antibody was detected in the sera at 2 weeks, but not at 5 weeks after the onset, suggesting that the antibody only appeared for a short period in the convalescent phase. However, we failed to detect the antibody titers with antichicken IgG instead of anti-duck IgG. We therefore examine the immunological properties of IgG among different families and species. The results revealed that different species of IgG in the same family exhibited strong cross-reactivity. Ducks immunized once with the toxoid together with a commercial oil-adjuvanted vaccine were found to develop sufficient antibody to protect against a challenge with a lethal toxin dose. The ELISA titers did not correspond to the neutralization titers in the sera of immunized ducks at the early stage during immunization. These findings suggest that the neutralizing titer was more useful than the ELISA titer for evaluating the protection against the toxin, but the ELISA technique may be applicable for detecting the occurrence of botulism. KEY WORDS: avian botulism, C/D mosaic toxin, Clostridium botulinum, vaccination.

The volatile compounds originating from fresh clove (Syzygium aromaticum) buds cultivated in a medicinal plant garden located in southern Tokyo were investigated. The volatile compounds originating from fresh clove buds were adsorbed onto polydimethylsiloxane‐coated devices and then analysed using gas chromatography‐mass spectrometry. Sampling was performed at three different development stages of clove buds, i.e., phase I (green), phase II (pink), and phase III (red). In thermal desorption‐gas chromatography‐mass spectrometry procedure volatile compounds: eugenol, β‐caryophyllene, α‐humulene, α‐farnesene, and eugenol acetate were the predominant constituents in most cases. Methyl salicylate, α‐copaene, β‐ocimene, 2‐nonanone, ethyl hexanoate, and acetophenone were additionally found as the buds ripened. Volatile compounds obtained from clove leaves were analysed using the same method, and β‐caryophyllene, eugenol, α‐humulene, 3‐hexen‐1‐ol, 3‐hexen‐1‐yl acetate, and hexyl acetate were identified. The antioxidant activity of both water and methanol extracts of clove buds and leaves collected from the medicinal plant garden was confirmed using electron spin resonance spectrometry. Scavenging activities against superoxide anion radical and hydroxyl radical were evaluated. Copyright © 2015 John Wiley & Sons, Ltd.