SPATIAL-TEMPORAL VARIATIONS AND RISK DETERMINANTS OF VIBRIO PARAHAEMOLYTICUS INFECTIONS IN WASHINGTON STATE

Vibrio parahaemolyticus;spatial statistics;temporal analysis;nearest neighbor resampling;risk determinants;Environmental Health & Engineering

Sun, ZheSpannhake, Ernst W. ;

Johns Hopkins University

关键词: Vibrio parahaemolyticus;    spatial statistics;    temporal analysis;    nearest neighbor resampling;    risk determinants;    Environmental Health & Engineering;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/58695/Final%20Version.docx?sequence=4&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Vibrio parahaemolyticus is a naturally-occurring halophilic and asporogenous gram-negative bacterium widely distributed in marine environments and frequently detected in shellfish, particularly oysters. V. parahaemolyticus can secrete pathogenic proteins to cause self-restricted gastroenteritis combined with several other related illness symptoms, including but not limited to diarrhea, nausea, vomiting, and even septicemia. V. parahaemolyticus infections, also known as vibriosis, primarily occur due to consumption of undercooked contaminated shellfish, and have become an unneglectable health concern especially in regions where seafood harvesting activities are frequently undertaken, such as the estuarine and coastal waters of Washington State. Since it is impossible to eliminate V. parahaemolyticus from estuarine environments, necessary research of vibriosis such as space-time high-risk cluster detection and screening of risk determinants will help alleviate threats to the public’s health. The ongoing V. parahaemolyticus monitoring project in Washington State was launched and has been conducted by the Washington Department of Health since 2008, mainly including microbial genetic parameter determination, environmental and oceanographic risk factor monitoring, and single-source vibriosis case trace-back confirmed by epidemiological interviews. Only data collected during 2013-2016 were included into this study in consideration of the deficiencies of epidemiological documenting in the beginning years of the project. A geographical nearest-neighbor re-sampling approach was used for risk parameter interpolation for cases, after which binary logistic regressions were applied to the cases and controls for identifying statistically significant risk factors of vibriosis. Spatial statistics and longitudinal analyses were used to assess the spatial-temporal dependences and variations of vibriosis odds. Vibriosis odds did not increase significantly between 2013 and 2016, while cases were clustered specifically in several regions including Totten Inlet, Bay Center, and Nahcotta. Three environmental factors: ambient air temperature (OR=1.07), surface water temperature (OR=1.62), and water salinity (OR=1.62) contributed positively to the vibriosis odds with a negative interaction term observed between water temperature and salinity (OR=0.98). Three genetic factors: tlh (OR=0.46), tdh (OR=3.70), and trh (OR=1.51) most probable numbers were all responsible for odds, with a strong negative interaction term between tlh and tdh (OR=0.59). This effect modifier was important in exploring the association between vibriosis odds and tlh-tdh ratios. Although vibriosis odds varied between Puget Sound Estuary and Pacific Coastal Areas, risk associations were consistent across years and regions. In summary, this study is one of the very few research projects on vibriosis odds, environmental and microbial risk determinants, as well as spatial and temporal variations, which will be helpful in future infection prevention.