Antitoxin therapy of natural avian botulism outbreaks occurred in Brazil

The Latent Threat in Wild Birds: Clostridium botulinum

Avian botulism caused by Clostridium botulinum emerged in 1910, affecting birds across North America, leading to severe outbreaks exacerbated by climate change, decreasing water levels, and inadequate wastewater management. While deadly for birds, its epidemiological impact on humans and other animals remains limited. Despite its significance, understanding and controlling the disease remain challenging. This review delves into the pathogen's epidemiology in wild bird populations, exploring the transmission, pathogenicity, clinical symptoms, diagnosis and treatment. The disease's growing concern in wild birds relates to the bacterium's adaptability and expansive spread, evident through genetic similarities among strains across countries. Outbreaks are influenced by environmental factors such as temperature and soil characteristics. Wild birds inadvertently transmit the bacterium, perpetuating the cycle through carcasses and flies. Some species suffer severely, while others, like scavengers, show resistance. Understanding disease mechanisms, involving potential toxin ingestion or internal production, remains ongoing. Clinical signs vary, affecting diverse bird orders. Diagnostic methods evolve, with treatment success varying among affected populations. Prevention and surveillance take precedence due to treatment challenges, emphasising population-based strategies and preventive measures to manage the widespread presence of C. botulinum.

Snakebite Envenoming in Avian Species: A Systematic Scoping Review and Practitioner Experience Survey

Snakebite envenoming in avian species is infrequently reported in the veterinary literature, although perhaps not as rarely as recent publications suggest. A systematic scoping review was performed on the topic using PubMed and Google Scholar, 21 veterinary textbooks, and 139 conference proceedings. A practitioner experience survey was also performed, with recruitment from Facebook groups for exotic animal practitioners and professional organization email listservs. Only 31 texts met our inclusion/exclusion criteria, which meant they described clinicopathologic signs of snakebite envenomation in avian species, the treatment of snakebite envenomation in avian species, or expanded the geographic range or the number of captive avian and snake species involved. Reports included approximately 15-20 different species of both snakes and birds worldwide; however, no reports described clinicopathologic signs of naturally occurring snakebites from Asia, Australasia, or Europe. The few responses from our practitioner experience survey suggest that snakebite envenomation may be more common than previously reported. Clinical signs of snake envenomation in birds appear to depend on the snake species involved but often include local swelling and subcutaneous edema or hemorrhage with paired fang marks; weakness, bleeding, neurologic deficits, and death may follow. A wide variety of treatment protocols have been used to counter snakebite envenomation in birds, including the successful use of antivenom. Based on this body of evidence, much remains to be learned about snakebite envenomation of birds, particularly about the efficacy of different treatment protocols.

Identification of the avian tracheal trematode Typhlocoelum cucumerinum (Trematoda: Cyclocoelidae) in a host-parasite-environment system: diagnosis, life cycle and molecular phylogeny

Typhlocoelum cucumerinum is a tracheal parasite of birds widely distributed across the globe. Nevertheless, aspects of the biology of this cyclocoelid are still poorly understood. Herein, we report the finding of T. cucumerinum in definitive and intermediate hosts from an urban waterbody of Brazil. The parasite was initially detected during the necropsy of domestic Muscovy ducks (Cairina moschata) found dead in the locality. Coproparasitological tests in live animals revealed that 12/47 (25.53%) Muscovy ducks and 2/8 (25%) mallards (Anas platyrhynchos platyrhynchos) were infected with T. cucumerinum. Moreover, rediae and metacercariae morphologically similar to T. cucumerinum were found in 3/248 (1.33%) Biomphalaria straminea collected in the same waterbody frequented by the birds. The conspecificity between the adult and the larval stages was confirmed molecularly (100% similarity in Cox-1). Moreover, the phylogenetic position of T. cucumerinum was determined for the first time based on partial fragments of the 28S, Cox-1 and Nad-1 genes. The species grouped with other members of the subfamily Typhlocoelinae with sequences available, but the data obtained do not support the distinctiveness of the genera Typhlocoelum and Tracheophilus. Further studies involving a broader range of species can result in taxonomic rearrangements in Typhlocoelinae.

Type C botulism outbreak in feedlot cattle fed contaminated corn silage

A large outbreak of botulism in feedlot steers fed corn silage contaminated with Clostridium botulinum neurotoxin type C (BoNT/C) is reported occurring in Midwestern Brazil in August 2017. The onset of the outbreak occurred 15 days after 1700 steers started to be fed the contaminated corn silage. Affected steers were alert and afebrile with varying degrees of flaccid paralysis in various muscle groups. A total of 1100 steers were affected, 1090 of which died within four days. Ten steers recovered after treatment with antitoxin. No gross or microscopic lesions were found in affected steers. The diagnosis was based on epidemiological data, characteristic clinical signs, and positive mouse bioassay results. This outbreak is interesting due to the high number of fatally affected cattle and the on-site diagnostic approach. This case report demonstrates the difficulties in diagnosing and treating botulism in cattle.