Animal Waste, Water Quality and Human Health

52Animal Waste, Water Quality and Human Healthprocesses (Chénier & Juteau 2009, Sharma et al. 2009). Thermotolerant,naturally-persistent (spore-forming) pathogens, such as tetracycline andmacrolide resistant Clostridium perfringens have been shown to transfer theirresistance genes to bacteria, such as Enterococcus faecalis (Soge et al. 2009).Hence, antibiotic-resistant environmental C. perfringens also appear capable ofacting as reservoirs for antibiotic resistance genes.As mentioned above, AMR encoding integrons are central players in theworldwide problem of antibiotic resistance, because they can capture and expressdiverse resistance genes, and are often embedded in plasmids and transposons,which facilitate their lateral transfer into a wide range of pathogens (Gillingset al. 2008). Gillings et al. have shown that class 1 integrons are present in thechromosomes of nonpathogenic soil and freshwater Betaproteobacteria, and thatlateral transfer between animal commensal bacteria and pathogens is inevitable.Sulfonamide-resistant pathogens, including Shigella flexneri, Aerococcus spp.,and Acinetobacter baumannii, have also been identified in slurry-amended soiland soil leachates, suggesting a potential environmental reservoir (Byrne-Baileyet al. 2009). Further, Byrne-Bailey et al. (2009) have recently demonstratedsulfonamide resistance outside members of the family Enterobacteriaceae andreported this resistance determinant to be common in soil bacteria. Clearly therole of water in the transport, transmission and maintenance of AMRdeterminants and AMR resistant pathogens requires further study.2.3.3 VirusesEnteric viruses RANK 4 Viruses generally have a narrow host-range and mostanimal viruses do not infect humans and vice-versa. Animal and human virusesthat are closely related such as calciviruses, enteroviruses, coronaviruses,picoranviruses, influenza and rotaviruses have the potential to cross speciesboundaries and cause zoonotic disease. However, the role of water in thetransmission of many of these zoonotic viruses is either thought be minor or isunknown. For example, while there is convincing evidence that lineages 3 and 4of Hepatitis E virus can be acquired by humans from pork and contact withswine, disease associated with this agent tends to be sporadic. Waterbornetransmission of these Hepatitis E lineages has not been convincinglydemonstrated (Pavio et al. 2010, Rutjes et al. 2009, Teshale et al. 2010).2.4 CONCLUSIONSRecent advances in population-based molecular genotyping have helped todifferentiate zoonotic waterborne pathogens (i.e. those that originate in animal