title: Evidence for a natural humoral response in dairy cattle affected by persistent botulism sustained by non-chimeric type C strains.
abstract: Bovine botulism is a sporadic acute disease that usually causes catastrophic losses in the herds. The unusual clinical evolution of a persistent mild outbreak in a dairy herd, prompted us to characterize the neurotoxin gene profile of the strain involved and to evaluate whether seroconversion had occurred. Diagnosis was based on mild classical symptoms and was supported by PCR and bacteriological findings, which revealed the involvement of a non-mosaic type C strain. An in-house ELISA was developed to detect antibodies to botulinum neurotoxin type C and its performance was evaluated in a vaccination study. Fifty days after the index case, fecal and serum samples were collected from the 14 animals of the herd and screened for Clostridium botulinum and anti-botulinum neurotoxin antibodies type C, respectively. The in-house developed ELISA was also used to test 100 sera samples randomly collected from 20 herds. Strong ELISA reactions were observed in 3 convalescent and 5 asymptomatic animals involved in the studied outbreak. The ELISA-positive cows all tested positive for non-mosaic C. botulinum type C in the feces and the same strain was also detected in the alfalfa hay, suspected to be the carrier source. Ten out of the 100 randomly collected sera tested positive for anti-botulinum neurotoxin type C antibodies: 7 had borderline values and 3 from the same herd showed titers three times higher than the cut-off. We concluded that type C botulism in cattle may occur with variable severity and that prolonged exposure to sublethal doses of botulinum neurotoxin C may occur, resulting in detectable antibodies.
authors.affiliation: Diagnostic and Microbiology Laboratory, Istituto Zooprofilattico Sperimentale delle Venezie, Vicolo Mazzini 4 int. 5/6, 31020, Villorba di Treviso, Italy. Electronic address: lbano@izsvenezie.it.
authors.forename: Luca
authors.initials: L
authors.lastname: Bano
authors.affiliation: Diagnostic and Microbiology Laboratory, Istituto Zooprofilattico Sperimentale delle Venezie, Vicolo Mazzini 4 int. 5/6, 31020, Villorba di Treviso, Italy.
authors.forename: Ilenia
authors.initials: I
authors.lastname: Drigo
authors.affiliation: Diagnostic and Microbiology Laboratory, Istituto Zooprofilattico Sperimentale delle Venezie, Vicolo Mazzini 4 int. 5/6, 31020, Villorba di Treviso, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Tonon
authors.affiliation: Diagnostic and Microbiology Laboratory, Istituto Zooprofilattico Sperimentale delle Venezie, Vicolo Mazzini 4 int. 5/6, 31020, Villorba di Treviso, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Berto
authors.affiliation: Veterinary Diagnostic Laboratory, Istituto Zooprofilattico Sperimentale delle Venezie, Via Conti 4, 39100, Bolzano, Italy.
authors.forename: Alexander
authors.initials: A
authors.lastname: Tavella
authors.affiliation: Food Safety Laboratory, French Agency for Food, Environmental and Occupational Health Safety, 23 Avenue du Général de Gaulle, 94706, Maisons Alfort Cedex, France.
authors.forename: Cedric
authors.initials: C
authors.lastname: Woudstra
authors.affiliation: Epidemiological Unit, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, 35020, Legnaro, Italy.
authors.forename: Katia
authors.initials: K
authors.lastname: Capello
authors.affiliation: Diagnostic and Microbiology Laboratory, Istituto Zooprofilattico Sperimentale delle Venezie, Vicolo Mazzini 4 int. 5/6, 31020, Villorba di Treviso, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Agnoletti
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D001906:Botulism / Q000276:immunology / Q000382:microbiology / Q000503:physiopathology / Q000662:veterinary*; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000382:microbiology / Q000503:physiopathology; D003014:Clostridium botulinum / Q000276:immunology* / Q000302:isolation & purification / Q000502:physiology; D005243:Feces / Q000382:microbiology; D005260:Female; D056724:Immunity, Humoral; D007774:Lactation
chemical_list: D000907:Antibodies, Bacterial
keywords: Cattle; Clostridium botulinum; ELISA; Non-chimeric type C; Persistent botulism