The Role of Foxes in Transmitting Zoonotic Bacteria to Humans: A Scoping Review

Abstract

Zoonotic diseases inflict substantial burdens on human and animal populations worldwide, and many of these infections are bacterial. An Australian study investigating environmental risk factors for Buruli ulcer in humans detected the causative agent, Mycobacterium ulcerans , in the faeces of wild foxes, a novel finding that suggests foxes may be implicated in the transmission of this zoonotic bacterium. The aim of this scoping review was to systematically search and examine the global data for reports implicating foxes in the transmission of zoonotic bacteria to humans. A pre-tested search strategy was implemented in five bibliographic databases (PubMed, Embase, CAB Abstracts, Cochrane Trials, Google Scholar). Eligible studies presented primary research data about zoonotic bacterial diseases that were confirmed or presumed to have been transmitted via foxes (excluding exclusively blood- or vector-borne bacteria), with no restrictions on geographical setting or publication year. The final dataset included ten primary research articles, with varying study designs, settings, populations and testing methods. The described bacterial zoonoses were anthrax, cutaneous diphtheria, leptospirosis, faecal coliforms including E. coli , tularaemia, yersiniosis, and Buruli ulcer (the study that was the impetus for this scoping review). Fox-human bacterial transmission was confirmed in one human case and considered likely to have occurred in certain high-risk groups in another. The likelihood of fox-human transmission having occurred in the remaining studies was possible (n = 5) or unlikely (n = 3). Identified and hypothesised drivers of fox-human transmission included accidental and occupational factors. Published reports of fox-human transmission of zoonotic bacteria are few, and generally indicative of relatively low risk. However, foxes can transmit zoonotic pathogens including bacteria to humans in a variety of settings, and human-fox encounters are likely to increase with ongoing anthropogenic activities. Further research and public education campaigns would help increase knowledge and awareness of fox-associated zoonoses.