Abstract
Vibrio cholerae is the cause of cholera, a devastating epidemic and pandemic disease. Despite its importance, the way of its global dissemination is unknown. V. cholerae is abundant in aquatic habitats and is known to be borne by copepods, chironomids and fishes. Our aim was to determine if fish-eating birds act as vectors in the spread of V. cholerae by consuming infected fish. We determined the existence of V. cholerae in the microbiome of 5/7 wild cormorants’ intestine. In three of these V. cholerae-positive wild cormorants, the presence of a gene for cholera toxin (ctxA) was detected. We subsequently tested eight captive, hand-reared cormorants, divided into two equal groups. Prior to the experiment, the feces of the cormorants were V. cholerae-negative. One group was fed exclusively on tilapias, which are naturally infected with V. cholerae, and the other was fed exclusively on goldfish or on koi that were V. cholerae-negative. We detected V. cholerae in the feces of the tilapia-fed, but not in the goldfish/koi-fed, cormorants. Hence, we demonstrate that fish-eating birds can be infected with V. cholerae from their fish prey. The large-scale movements of many fish-eating birds provide a potential mechanism for the global distribution of V. cholerae.
Highlights
Vibrio cholerae is the etiologic agent of cholera, a devastating diarrheal disease which causes epidemics and pandemics
Bacterial communities of intestine samples from the seven great cormorants were analyzed by sequencing the V4 variable region of the bacterial 16S ribosomal RNA gene on an Illumina MiSeq platform
Three intestine areas were examined for each bird. 1,245,131 quality sequences were obtained. These were classified into 59,299 operational taxonomic units (OTUs) using the cutoff of 97% sequence similarities
Summary
Vibrio cholerae is the etiologic agent of cholera, a devastating diarrheal disease which causes epidemics and pandemics. Green and Sanches[7] and Frisch et al.[8] found that chironomids and copepods can be transferred across waterbodies via waterbirds Considering these findings we hypothesized that V. cholerae may be dispersed by migratory waterbirds, which consume chironomids or copepods (endozoochory) or carry them externally (epizoochory)[6, 9]. Support for this hypothesis was found in the literature[10, 11]. Great cormorants are known as generalist foragers[21] or specialist piscivores[22], with a variety of regional[23] and seasonal[24] diets They are opportunistic predators that consume a wide range of fish species of diverse size[25, 26]. The Israeli authorities allow each fish farm to shoot down up to six cormorants per fish farm per day[30]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
