Chapter one
Introduction
1.1 Background to the Study

 Water is an essential substance in human life as it is used for various purposes sucg as drunking washing cooking. Human noroviruses cause the most gastrointestinal illness in all regions of the world, with the vast majority thought to be acquired via person-to-person and then by food (Ahmed et al., 2014) given the predominance of genogroup II strains implicated. In waterborne cases, genogroup I is normally implicated (Mathew et al., 2012),  presumably due to increased environmental robustness. An interesting finding with human noroviruses and the second most common cause of gastrointestinal illness, rotavirus (although greatly diminishing due to childhood vaccination programs), is the need for certain histo-blood group antigen (HBGA) receptors for these pathogens to bind to target cells (Tan and Viang, 2014). Not only do certain gut bacteria have these HBGA binding sites but these bacteria may also facilitate infection, as recently demonstrated with human B cells (Jones et al., 2014). Therefore, one’s gut microbiome and blood group impact the likelihood of infection. Furthermore, there is now optimism that a routine cell culture system for human noroviruses may be developed, which would be of particular value to the water-treatment industry. Non-human, culturable noroviruses, such as murine noroviruses among others, are used as surrogates for treatment performance (inactivation studies) but there is limited understanding of the validity of these surrogates for any human norovirus genogroup or mode of inactivation (LI et al.,2014; Cromeans et al., 2014).

The classic waterborne enteric pathogens include Vibrio cholerae (serogroups O1 and O139, causing cholera), Salmonella enterica (subsp. enterica ser. Typhi, causing typhoid), and Shigella spp. (four species causing dysentery), which have largely been controlled by water treatment/disinfection and are therefore rarely an issue via drinking water in developed regions. However, person-to-person and foodborne spread maintains Shigella sonnei within the sewage of developed regions, along with closely-related shiga toxin and verotoxin-producing E. coli, and pathogenic species of Campylobacter, Salmonella, Arcobacter, Helicobacter and Yersinia. An emerging issue is that of AMR, which may occur within any of the bacterial members  but is noted here by example for E. coli in well waters associated with animal production (Coleman et al., 2013). These AMR genes may horizontally transfer between commensal and enteric pathogenic bacteria, and present a higher risk due to antimicrobial treatment failures (Ashbolt et al., 2013). Within healthcare facilities, there is also a considerable health burden due to the prevalence of AMR Pseudomonas aeruginosa and Clostridium difficile; with the latter being a spore-former it may persist in sewage and river waters and eventually make its way to drinking waters, and AMR-P. aeruginosa may grow post-water treatment

1.2  Statement of the problem

A common feature of the water-based pathogens is the ability to grow to problematic concentrations within biofilms on pipe walls and sediments, particularly during periods of water stagnation and warmer conditions; therefore, control below some critical concentration is necessary to manage these environmental pathogens. Hence there is need for comparative analysis of sources of water and water borne diseases.

1.3 Objectives of the study

The major objective of the study is the comparative analysis of sources of water and water borne diseases.

1.4 Research questions

(1) What are the various sources of water?

(2) what are water borne diseases?

(3) what is role of sources of water on water borne disease outbreak?

1.5 Significance of the Study

The research gives a clear insight into the comparative analysis of sources of water and water borne diseases. It also gives a clear insight into the role of water sources in water borne diseases. This research also serves as a preliminary study in identifying the common microorganisms in different water sources that may be responsible for water borne diseases.

1.6 Scope of the study

The research focus on the comparative analysis of sources of water and water borne diseases.

References

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.Matthews JE, Dickey BW, Miller RD, Felzer JR, Dawson BP, Lee AS, et al. The epidemiology of published norovirus outbreaks: a review of risk factors associated with attack rate and genogroup. Epidemiol Infect. 2012;140(7):1161–72. doi: 10.1017/S0950268812000234. [PMC free article] [PubMed] [Cross Ref]

Tan M, Jiang X. Histo-blood group antigens: a common niche for norovirus and rotavirus. Expert Rev Mol Med. 2014;16:e5. doi: 10.1017/erm.2014.2. [PubMed] [Cross Ref]

Jones MK, Watanabe M, Zhu S, Graves CL, Keyes LR, Grau KR, et al. Enteric bacteria promote human and mouse norovirus infection of B cells. Science. 2014;346(6210):755–9. doi: 10.1126/science.1257147. [PMC free article] [PubMed] [Cross Ref]

Li D, De Keuckelaere A, Uyttendaele M. Application of long-range and binding reverse transcription-quantitative PCR to indicate the viral integrities of noroviruses. Appl Environ Microbiol. 2014;80(20):6473–9. doi: 10.1128/AEM.02092-14. [PMC free article] [PubMed] [Cross Ref]

Cromeans T, Park GW, Costantini V, Lee D, Wang Q, Farkas T, et al. Comprehensive comparison of cultivable norovirus surrogates in response to different inactivation and disinfection treatments. Appl Environ Microbiol. 2014;80(18):5743–51.

Coleman BL, Louie M, Salvadori MI, McEwen SA, Neumann N, Sibley K, et al. Contamination of Canadian private drinking water sources with antimicrobial resistant Escherichia coli. Water Res. 2013;47(9):3026–36. [PubMed]

Ashbolt NJ, Amézquita A, Backhaus T, Borriello SP, Brandt K, Collignon P, et al. Human health risk assessment (HHRA) for environmental development and transfer of antibiotic resistance. Environ Health Perspect. 2013;121(9):993–1001.