Animal Waste, Water Quality and Human Health

Assessing the importance of zoonotic waterborne pathogens 41EHEC prevalence within countries appears to be associated with cattle densities(Michel et al. 1999) and may reflect greater occupational exposure, animalcontact, raw milk consumption as well as drinking-water and recreational waterexposure.Young children and the elderly are the most susceptible to severe infections(Karmali et al. 2010). Epidemiological evidence suggests that as few as 2 CFUof E. coli O157 are capable of causing illness (Tuttle et al. 1999, Hara-Kudo &Takatori 2011).Salmonella spp RANK 2 Salm. enterica is the cause of gastrointestinaland systemic illness in human populations around the world. Although there aresix different subspecies of the organism, most human infections are associatedwith Salm. enterica subspecies enterica which includes more than 1500different serovars of the organism (Litrup et al. 2010). The widespreadoccurrence of illness and the high levels of morbidity and mortality associatedwith the organism have made it the target of control programmes around the world.A distinction must be made between salmonellosis associated with humanhost-restricted typhoid Salmonella serovars (Typhi, Paratyphi A, Paratyphi B,and Paratyphi C) (TS) and salmonellosis associated with non-host restrictednontyphoid Salmonella serovars (NTS). Following infections with TS serovarsthere is an incubation period from 5–9 days which is followed by fever lastingfor approximately three weeks. During this period the organism becomesdisseminated throughout the body and can be isolated from the liver, blood,spleen, bone marrow, lymph nodes and gallbladder. In infections with TSserovars, antimicrobial treatment may be necessary to ensure recovery (Thaveret al. 2009). NTS infections, by contrast, are characterized by a short incubationperiod (