The prevalence and public health significance of human pathogenic vibrio species (v. cholerae, v. vulnificus, v. parahaemolyticus, v. alginolyticus) in Hawaiʻi's diverse tropical coastal water environments

Vithanage, Gayatri

The prevalence and public health significance of human pathogenic vibrio species (v. cholerae, v. vulnificus, v. parahaemolyticus, v. alginolyticus) in Hawaiʻi's diverse tropical coastal water environments

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Date

2011-05

Authors

Vithanage, Gayatri

Publisher

[Honolulu] : [University of Hawaii at Manoa], [May 2011]

Abstract

Studies on the prevalence and ecology of Vibrio species in tropical areas, such as Hawaii, is limited, and up to now, there have been no studies conducted in Hawaii to determine the prevalence of these pathogens in our coastal waters. The major goals of this study was to determine the prevalence of the four human pathogenic Vibrio spp. (V. cholerae, V. vulnificus, V. parahaemolyticus, V. alginolyticus) in coastal water environments of Hawaii (islands of Oahu and Hawaii), and to determine the public health significance these pathogens have to people who use these coastal water for recreational purposes. The study showed that water salinity and temperature affected the four human pathogenic Vibrio spp. V. vulnificus and V. parahaemolyticus were prevalent in low salinity sites that were impacted by land run-off but not detectable in high salinity, non-impacted swimming sites. Both species were also prevalent at low salinity swimming ponds on the island of Hawaii. V. alginolyticus was prevalent in all sites regardless of salinity. In addition to low salinity, high water temperature also had an impact. High temperature, low salinity ponds located on the Island of Hawaii were shown to select for V. vulnificus, V. parahaemolyticus and V. alginolyticus. These ponds have shown past evidence of infection and death due to V. vulnificus associated with the use of these ponds. Isolates recovered from these thermal ponds may potentially be more virulent as they have been adapted to survival at temperatures similar to that of human body temperature. V. cholerae was not recovered in either impacted or non-impacted sites. The prevalence of pathogenic Vibrio spp. in sediments followed a similar trend to what was seen with coastal beach samples. V. alginolyticus was prevalent in both primary and secondary beach sediment while V. vulnificus and V. parahaemolyticus were only prevalent in secondary beach sediment. Thus, apparently sediments from secondary coastal waters can spread pathogenic Vibrio species into the water column. Data from this study also showed that V. vulnificus and V. parahaemolyticus were sporadically present in raw and primary treated sewage from three different wastewater treatment plants, while V. cholerae was consistently recovered in raw and primary treated sewage from all three treatment plants. V. vulnificus can cause severe wound infections, which can rapidly lead to death. Thus, this species poses a public health significance. In summary, data gathered from this study was able to provide basic information, that was lacking, regarding the distribution of the four main human Vibrio pathogens in a tropical area such as Hawaii. This data was then used to make a basic assessment of the potential public health significance these pathogens have on humans who use Hawaii's coastal waters for recreational purposes, and to determine if and when warning signs would be warranted to notify the public of the potential risk for infection.

Description

Ph.D. University of Hawaii at Manoa 2011.
Includes bibliographical references.

Keywords

Vibrio species

URI

http://hdl.handle.net/10125/101779

Related To

Theses for the degree of Doctor of Philosophy (University of Hawaii at Manoa). Microbiology.

Collections

Ph.D. - Microbiology

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