Animal Waste, Water Quality and Human Health

Assessing the importance of zoonotic waterborne pathogens 27conditions and is responsible for transmission through person-to-person contact,contact with companion and farm animals, and ingestion with contaminated food,drinking-water and recreational water. Although Crypto. oocysts can bemicroscopically identified, they lack morphologic features for speciesidentification; therefore, molecular tools are essential for species identification.Most species and genotypes of Crypto. appear host-specific or have a primary hostand one or more less frequently infected host species. Of the current 20 speciesand approximately 60 genotypes of Crypto. that infect fish, amphibians, reptiles,birds and mammals nine species and seven genotypes are known to haveinfected humans (Plutzer & Karanis 2009). The two major species infectinghumans are Crypto. hominis, transmitted from humans to humans, and Crypto.parvum, found primarily in pre-weaned (monogastric) ruminants, especiallybovines. Crypto. meleagridis, described from avian and mammalian hosts, mayalso infect humans. Species causing rare infections include Crypto. andersoni,Crypto. baileyi, Crypto. canis, and Crypto. felis. The cervine genotype, foundworldwide, is the only genotype with broad host range, found in wild anddomestic ruminants, rodents, carnivores, and primates. It is the most commongenotype found in rivers, streams and storm water and has been reported in over20 human infections. Other rare infections include those caused by the monkey,pig, skunk, horse, rabbit and mouse genotypes. Most species and genotypes havebeen identified by SSU rRNA gene sequence data, although actin, HSP-70, andother genes are also used.Crypto. hominis and Crypto. parvum subgenotypes have been defined byglycoprotein (GP) 60 gene sequence data, enabling more precise host (source)identification. Examination of this hypervariable locus and microsatellites hasidentified subgenotypes of Crypto. parvum found in animals, others found inboth humans and animals, and still others found only in humans. Sequences ofthe GP60 gene strongly links Crypto. parvum from cattle with many of the samesubgenotypes of Crypto. parvum found in sporadic human infections in Slovenia,Italy, Portugal, Spain, Ireland, Canada, the USA, Kuwait, Japan and Australia(Stantic-Pavlinic et al. 2003, Alves et al. 2003, Wu et al. 2003, Chalmers et al.2005, Sulaiman et al. 2005, Trotz-Williams et al. 2006, Xiao et al. 2007,Thompson et al. 2007, Quilez et al.2008). Other mini- and micro-satellites usedfor subgenotyping also have identified human adapted strains of Crypto. parvumfrom humans and cattle (Mallon et al. 2003) and from persons reporting contactwith animals (Hunter et al. 2007). The same subgenotype found in humans andcattle in Portugal also was detected at sampling sites from which water issupplied to the city of Lisbon (Alves et al. 2006).Cattle are the major animal source of Crypto. parvum oocysts; infection in cattleis age-related. The prevalence of cryptosporidiosis in pre-weaned dairy calves (1–8