Outbreak of avian botulism in a backyard poultry farming / Surto de botulismo aviário em criação de aves domésticas

The purpose of this study is to report an outbreak of avian botulism in backyard poultry farming. In 2019, a botulism outbreak in a flock of laying hens was investigated in Brazil. In the flock of 30 hens, clinical signs of botulism occurred after they ate decaying vegetables. A type C botulism outbreak was confirmed using the mouse lethality assay for detection of botulinum toxin in serum and ELISA test to detect Clostridium botulinum in intestinal contents and serum. Botulism in laying hens has rarely been reported. The chickens developed cyanotic comb and wattle, dyspnea, different degrees of flaccid paralysis in the neck, and detachment of feathers. No macroscopic lesions were observed, as were microscopic findings. The chicken's serum was neutralized by C antitoxin, confirming the botulism diagnosis, and also toxin was detected in intestinal contents.

Manure contamination with Clostridium botulinum after avian botulism outbreaks: management and potential risk of dissemination

BackgroundPersistence of Clostridium botulinum in the environment is well known. Getting rid of it after animal botulism outbreaks is so tricky, especially as far as manure concerns. This study aimed at 1. describing manure management on 10 poultry farms affected by botulism and 2. assessing the persistence of C botulinum in poultry manure after the outbreak.MethodsEach farm was visited twice at two different manure storage times (two weeks after manure removal and two months later). Fifteen samples of manure were collected on each visit and C botulinum was detected using real-time PCR.ResultsManagement of manure varied among poultry farms (classical storage, addition of quicklime, bacterial flora or incineration). C botulinum was detected in the manure of all 10 farms, 56.5per cent of samples being positive. C botulinum was detected significantly more frequently at the second visit (65.8per cent vs 49.7per cent, P<0.01) and on the surface of the pile (63.1per cent vs 50per cent, P=0.025).ConclusionThis study shows the persistence of C botulinum in poultry manure over time after a botulism outbreak and highlights manure management as a key health issue in preventing spore dissemination in the environment and recurrence of the disease.

Development of An Innovative and Quick Method for the Isolation of Clostridium botulinum Strains Involved in Avian Botulism Outbreaks

Avian botulism is a serious neuroparalytic disease mainly caused by a type C/D botulinum neurotoxin produced by Clostridium botulinum group III, one of the entwined bacterial species from the Clostridium novyi sensu lato genospecies. Its isolation is very challenging due to the absence of selective media and the instability of the phage carrying the gene encoding for the neurotoxin. The present study describes the development of an original method for isolating C. botulinum group III strains. Briefly, this method consists of streaking the InstaGene matrix extraction pellet on Egg Yolk Agar plates and then collecting the colonies with lipase and lecithinase activities. Using this approach, it was possible to isolate 21 C. novyi sensu lato strains from 22 enrichment broths of avian livers, including 14 toxic strains. This method was successfully used to re-isolate type C, D, C/D, and D/C strains from liver samples spiked with five spores per gram. This method is cheap, user-friendly, and reliable. It can be used to quickly isolate toxic strains involved in avian botulism with a 64% success rate and C. novyi sensu lato with a 95% rate. This opens up new perspectives for C. botulinum genomic research, which will shed light on the epidemiology of avian botulism.

Avian-botulism risk in waterbird breeding colonies and implications for environmental water management

Avian botulism poses a significant risk to waterbird health in Australian wetlands. This paralytic, often fatal, disease occurs when birds ingest a neurotoxin produced by the bacterium Clostridium botulinum. Our current understanding of avian botulism comes largely from studies in the northern hemisphere, with many of these studies linking outbreaks of avian botulism with poor water quality. The Murray–Darling Basin provides the most important breeding habitat for colonial waterbirds in Australia, but the frequency of large-scale breeding events has declined, and waterbird populations are near record-low numbers. Avian botulism has the capacity to have significant impacts on waterbird recruitment if not managed appropriately. We propose that environmental water-management strategies that aim to maintain water quality through flow delivery to waterbird colonies could mitigate the risk of botulism outbreaks and contribute to waterbird population recovery.

Avian botulism – a recurring paralytic disease of wild UK waterbirds

This focus article has been prepared by Paul Holmes from the APHA Diseases of Wildlife Scheme.