Human pathogens and coastal ocean processes
Abstract
Gast and Amaral
This project examines the diversity, distribution and persistence of human pathogens in the coastal marine environment of Mt. Hope Bay, Massachusetts. This estuarine environment has been heavily impacted by human activity, including significant thermal pollution, several sewage outfalls and the effects of past industrial activities. The Bay is used for recreation such as boating and fishing, but shellfishing is closed in many areas due to bacterial contamination. Although outbreaks of bacterial or protistan caused human diseases have not been reported, low levels of unreported endemic disease may persist. Monitoring for bacterial contamination occurs in the shellfish areas, but outside of these regions, very little is known about the occurrence of either bacterial pathogens or protistan pathogens that are likely introduced into the Bay through sewage. The potential impact of the thermal plume on these microbial populations has not been examined at all. We hypothesize that both bacterial and protistan human pathogens are present in Mt. Hope Bay and nearby rivers, and that their distribution and persistence are affected by physico-chemical condition in the Bay, including the constant thermal output of the Brayton Point Power Plant. To examine this hypothesis we propose to accomplish the following specific aims:
Aim 1: Determine the distribution and persistence of human protistan parasites in Mt. Hope Bay.
We will conduct a molecular survey of human pathogens within the Mt. Hope Bay estuarine system, including sewage outfalls near and removed from thermal point sources, contaminated shellfish beds and shorebird nesting grounds, to better characterize the types of protistan pathogens present in this coastal environment. Our project will specifically target Giardia, Cryptosporidium, Naegleria, and Acanthamoeba, but will also perform general microbial eukaryotic and prokaryotic diversity assessments to determine whether there are novel sequence types present that are related to known pathogen groups (might represent unidentified human pathogens).
Aim 2: Determine whether naturally occurring marine amoebae can serve as reservoirs for pathogenic bacteria, and look for evidence of the natural occurrence of these associations in Mt. Hope Bay.
We will test whether locally collected marine amoebae are capable of harboring the pathogenic bacteria Vibrio parahaemolyticus, Vibrio vulnificus, and Legionella pneumophila. The research will test for the induced presence and replication of bacteria in actively growing and dormant phases of the amoebae, and will utilize both PCR-based and in situ hybridization based methods to detect naturally occurring associations.
Aim 3: Establish physico-chemical parameters associated with pathogen presence in Mt. Hope Bay and test predictive capability of water quality models regarding these correlations.
We will correlate measurements of water and sediment physico-chemical parameters with microbial community structure, including the presence of human pathogens. These measurements and our biological data will be used to assist in establishing and validating a water quality model for Mt. Hope Bay that may also be used to understand and predict the potential presence of pathogens.
Participants
Dr. Rebecca J. Gast, Principal Investigator
Woods Hole Oceanographic Institution, MS 32
Biology
Woods Hole, MA 02543
Ph: 508-289-3209
Fax: 508-457-2169
rgast@whoi.edu
Education:
B.S. The Ohio State University, 1987,
Microbiology
Ph.D. The Ohio State University, 1994, Molecular Genetics
Research Interests:
Protistan molecular phylogeny and ecology and the genetic regulation of algal/protist symbiotic interactions.
Dr. Linda Amaral Zettler
Marine Biological Laboratory
7 MBL Street
Woods Hole, Massachusetts 02543-1015
Ph. 508-548-3705 X6615
Fax: 508-457-4727
amaral@mbl.edu
Education:
1990 Sc.B. with Honors. Brown University, Aquatic Biology.
Thesis title, "Applications of rRNA eukaryotic fluorescently-lablelled oligonucleotide probes using marine protists."
1996 Ph.D. Massachusetts Institute of Technology/Woods Hole Oceanographic Institution, Biological Oceanography.
Thesis title, "A Molecular Approach to Questions in the Phylogeny of Planktonic Sarcodines."
Dawn Moran
Woods Hole Oceanographic Institution, MS 32
Biology
Woods Hole, MA 02543
Ph: 508-289-4918
Fax: 508-457-2169
dmoran@whoi.edu
Mark Dennett
Woods Hole Oceanographic Institution, MS 32
Biology
Woods Hole, MA 02543
Ph: 508-289-2564
Fax: 508-457-2169
mdennett@whoi.edu
Education
B.A. Nasson College, 1974, Biology
Research Interests
Marine and freshwater protistan ecology;microbial food chain dynamics; design and development of oligonucleotide and immu-nological probes for the identification, distribution and physiology of microbial populations; primary productivity; continuous culture assays.
Abby Latsch
Marine Biological Laboratory
7 MBL Street
Woods Hole, Massachusetts 02543-1015