Norovirus and Hepatitis A Virus (HAV) are the two most prevalent enteric viruses that cause gastroenteritis in the US and globally. To test for these enteric viruses indicators, organisms developed assess fecal contamination, and are used in place of directly testing for the viruses themselves. The goal of this study was to investigate which indicators were most prevalent in each environmental sample of the agriculture environment, including water, faeces, food, soil, hands, and surfaces. This systematic review examines, from US and global sources, a comprehensive list of indicators used to test for enteric viruses. The results were organized based on environmental sample and indicator group, including bacterial and viral. A total of 297 articles were included in the database of results. Out of these, 67 were included for final review. 98 viral indicators and 92 bacterial indicators were found in at least 49 articles regarding Norovirus. 37 viral indicators and 27 bacterial indicators were found in at least six articles discussing HAV. The most prevalent indicator for Norovirus in water was E. coli and the most prevalent indicator of HAV in food was also E. coli. E. coli and Adenovirus were the most strongly connected with Norovirus and HAV. This systematic review demonstrates which indicators would be the most prevalent for assisting with identifying enteric viruses in the agricultural environment.
Table of Contents
CHAPTER I: LITERATURE REVIEW 1 INTRODUCTION 1 US and Global Burden of Norovirus and Hepatitis A Virus 1 CLINICAL DISEASE AND EPIDEMIOLOGY OF NOROVIRUS AND HAV 2 Clinical Disease 2 Epidemiology 2 MORTALITY AND MORBIDITY ASSOCIATED WITH NOROVIRUS AND HAV 3 Norovirus and HAV Mortality and Morbidity in the US and the World 3 Serotypes and Geographic Distribution 5 THE SIX TRANSMISSION VEHICLES OF NOROVIRUS AND HAV 5 Stool 7 Water 7 Hands 8 Soil 9 Produce 10 Surfaces 10 DIFFICULTIES IN DETECTING ENTERIC VIRUSES 11 INDICATORS AND THE NEED FOR STANDARDIZED PROXY INDICATORS 11 Shortcomings of Laboratory and Testing Methods 11 OVERVIEW OF IDEAL INDICATORS FOR DETECTING ENTERIC VIRUSES 12 TYPES OF INDICATORS AND CURRENT USE WITH ENTERIC VIRUSES 13 Viral Indicators 13 Total Coliforms, Coliform Bacteria, and Fecal Coliforms 14 Fecal Streptococci 14 Bacteriophage 15 Other Indicators 15 GOALS AND AIMS 16 CONCLUSION 16 CHAPTER II: METHODS 18 PROTOCOL AND REGISTRATION 18 CRITERIA FOR NOROVIRUS AND HAV INDICATORS DATABASE 18 Research Protocol Objective 18 Possible Outcomes and Additional Information 19 Search Criteria for Systematic Review 19 Article Inclusion and Exclusion Criteria 19 Information Extracted from Articles into Database 20 STUDY SELECTION 20 CHAPTER III: RESULTS 21 DESCRIPTION OF DATASET 21 INDICATORS OF NOROVIRUS IN EACH ENVIRONMENTAL SAMPLE AND BACTERIAL OR VIRAL GROUP 22 INDICATORS OF HAV IN EACH ENVIRONMENTAL SAMPLE AND BACTERIAL OR VIRAL GROUP 22 INDICATOR RELATIONSHIPS FOUND FOR THE ENVIRONMENTAL SAMPLES 23 NO INDICATOR RELATIONSHIPS FOUND FOR THE ENVIRONMENTAL SAMPLES 24 INDICATORS WITH SIMPLE PRESENCE AND STATISTICAL MEASURES AND OR EFFECT SIZES 24 DESCRIPTION OF THE ASSOCIATIONS 25 Norovirus and the indicator 25 HAV and the Indicator 26 APPROVALS AND DISAPPROVALS OF USING INDICATORS 26 CHAPTER IV: DISCUSSION 29 LIMITATIONS AND STRENGTHS 30 IMPLICATIONS 30 CONCLUSIONS 31 PUBLIC HEALTH IMPLICATIONS 32 REFERENCES 33 TABLES AND FIGURES 39 TABLE 1: CRITERIA FOR AN IDEAL INDICATOR ORGANISM 39 TABLE 2: CRITERIA FOR DESIRABLE ATTRIBUTES OF METHODS FOR TESTING FOR INDICATORS 40 FIGURE 1: FLOW CHART OF SYSTEMATIC REVIEW 41 TABLE 3: INDICATORS OF NOROVIRUS IN SIX TRANSMISSION VEHICLES AND INDICATOR GROUPS (NUMBER OF ARTICLES FOUND IN SYSTEMATIC REVIEW) 43 TABLE 4: INDICATORS OF HAV IN SIX TRANSMISSION VEHICLES AND INDICATOR GROUPS (NUMBER OF ARTICLES FOUND IN SYSTEMATIC REVIEW) 44 TABLE 5: NUMBER OF ARTICLES WITH SIMPLE PRESENCE AND STATISTICAL MEASURES OF ALL INDICATORS OF NOROVIRUS AND HAV 45 TABLE 6: INDICATOR RELATIONSHIPS FOUND FOR THE ENVIRONMENTAL SAMPLES 46 TABLE 7: NO INDICATOR RELATIONSHIPS FOUND FOR THE ENVIRONMENTAL SAMPLES 52 APPENDIX 56 MORE INFORMATION ON INDICATOR RELATIONSHIPS FOUND 56 MORE INFORMATION ON NO INDICATOR RELATIONSHIPS FOUND 58
About this Master's Thesis
|Committee Chair / Thesis Advisor|
|The Indicators of Norovirus and Hepatitis A Virus In Six Environmental Samples Types: A Systematic Review ()||2018-08-28||