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CHESAPEAKE BAY WATERSHED INTERDISCIPLINARY SCIENCE
PARTNERSHIP
University of MarylandThe MdBio Foundation
Anne Arundel Community CollegeHoward Hughes Medical Institute
Project Goals Understand the importance of scientific research in
improving human health Students will
• Learn about watershed ecology, sources and health consequences of bacterial contamination, and factors that affect levels of bacterial contamination (e.g., patterns of land use, rainfall)
• Design simple, hypothesis-driven investigations and will test their hypotheses with water samples they collect near their schools
• Compare their results to those obtained by students state-wide via a project website
Water Cycle
Cholera Severe Bacterial
Infection Targets Small
Intestine Profuse watery
diarrhea (gallons per day)
Vomiting Leads to dehydration
and electrolyte loss 20% of body weight in
24 hrs
http://commons.wikimedia.org/wiki/File:Cholera_hospital_in_Dhaka.jpg
Battling an Ancient Scourge, With Satellites and Sari Cloth
Published: July 6th, 2011 in Impacts, Climate, Oceans & Coasts, Health, Global, United States, Mid-Atlantic
“The world has seen seven global cholera outbreaks since 1817, and the current one seems to have come to stay. Rising temperatures and a stubbornly persistent, toxic bacteria strain appear to have given the disease the upper hand.”
By Doug Struck, DailyClimate.org
Vibrio cholerae Causative agent of
cholera Symptoms caused
by bacterial toxin (CTX or cholera toxin)
http://dhiez.files.wordpress.com/2008/05/cholera.jpg
Scanning Electron Micrograph of Vibrio cholerae O1
Cholera Kills in Developing Nations
Primarily passed in contaminated drinking water and shellfish
Harbored in zooplankton outbreaks often follow
zooplankton blooms Water temperature
Dependent Last outbreak in US was
in 1911 Water chlorination,
ozone, UV, or cloth filter and boiling
June 23, 2010; Kenya
http://www.nation.co.ke/News/regional/Crisis%20feared%20as%20cholera%20outbreak%20kills%2060/-/1070/945376/-/t2lpkm/-/
Cholera Outbreaks
http://gamapserver.who.int/mapLibrary/Files/Maps/Global_CholeraCases0709_20091008.png
Cholera outbreak in HaitiDecember 30, 2010
• First reported case: 2nd week of October, 2010• As of December 30, 2010: reported hospitalized
cases:70,865• Reported Deaths: 2,761 deaths
Overall fatality rate of 2.1 per cent nationwide. The fatality rates in South- East reached to 12-13% in early December.
http://ochaonline.un.org/tabid/6412/language/en-US/Default.aspx
Climate Change and HealthClimate can have a profound influence on health, both
directly and indirectly Direct effects include deaths and illnesses related to excessive heat or cold exposureIndirect effects via waterborne vector borne diseases influenced by: occurrence and geographic distribution of known vectors, e.g., mosquitoes, rodents and copepods have been implicated with diseases, such as
Malaria, Dengue feverCholeraEncephalitis &Haemorrhagic fever.Hanta virus
Susceptibility to Cholera People with Type O
are most susceptible, AB least susceptible
Heterozygous carriers of Cystic Fibrosis gene have some protection
Malnourishment or immunocompromized
http://en.wikipedia.org/wiki/Cholera
1915
A Model for Cholera Epidemic
SunlightPrecipitationTemperatureNutrients
Zooplankton & Animal
larvae
Increase of V. cholerae population
Infectious dose is now readily available
Phytoplankton: micro & macro-algae
Disease Outbreak
Phage – another player?
Infectious Dose of Bacteria that Can Cause Cholera
(Cash et al, 1974)
Inoculum Symptom10,000 with antacids Mild
diarrhea1,000,000 with food Severe
diarrhea>1,000,000 with water Severe
diarrhea
Vibrio spp in the Chesapeake Bay
Vibrio’s infect cuts “hand swollen to the size of
a catchers mitt” Infected shellfish cause GI
illness Public health websites
suggest to protect yourself against infection: Avoid swimming 48 hours
after any heavy rainfall Do not swim with an open
cut or wound If you get cut while in the
water, wash it thoroughly and cover with a waterproof bandage
Try not to swallow water while swimming
Chesapeake Bay Foundation. 2009. Bad Water 2009
Fecal Bacteria“Where do the bacteria come from? There are about 180 failing septic tanks in the Severn River’s suburbanized watershed, according to the Maryland Department of the Environment (MDE).
A far more significant source of bacteria in the river is pet waste, which produces an estimated 69 percent of the E. coli bacteria in Voith’s section of the Severn River, with wildlife contributing 24 percent, livestock three percent, and humans three percent, according to an April 2008 MDE analysis of pollution in the Severn River.
About 41 percent of dog owners in the area admit they do not pick up after their animals most of the time, the report says“
Chesapeake Bay Foundation. 2009. Bad Water 2009
Our GI Microflora There are 10-100
times more microbes in your gut than cells in your body with your DNA
Source: www.nature.com
This is a two-way street Benefits the
bacteria We keep them
warm We protect them
from the environment
We send food
Benefits Us Bacteria help fight
off pathogens Bacteria help us
digest our food Bacteria produce
useful products for us (e.g., Vitamins)
Bacteria also interact with our body systems to help us keep balanced
The Operative Word is BALANCE When pathogenic
bacteria invade us, we usually get sick
When good bacteria end up in the wrong place, we sometimes get sick
When bacteria get into improper balance (“dysbiosis”), we can get sick
When our immune system gets confused about the good guys, we can get sick
http://commons.wikimedia.org/wiki/File:Balanced_scales.svg
One Member of the GI Microflora
Enterococcus faecalis Part of normal flora
of all mammals and birds
About 10 million Enterococci per gram of human feces.
Gram-positive cocci, facultative anaerobe
Tolerate a wide range of growth conditions including salt and oxygen
Enterococcus faecalis infecting lung tissue. Source: Wikipedia
ColiformsColiform bacteria include genera that originate in feces
(e.g. Escherichia) as well as genera not of fecal origin (e.g. Enterobacter, Klebsiella, Citrobacter).
Basics of fecal coliformsIn general, increased levels of fecal coliforms provide a
warning of failure in water treatment, a break in the integrity of the distribution system, or possible contamination with pathogens. When levels are high there may be an elevated risk of waterborne gastroenteritis. Tests for the bacteria are cheap, reliable and rapid (1-day incubation).
http://en.wikipedia.org/wiki/Fecal_coliform
Opportunistic pathogen Can cause:
Bladder infections Endocarditis (infection of heart lining) Bacteremia (bacteria in blood) Peritonitis (infection in abdominal cavity) Meningitis (brain infection)
Most cases are hospital-acquired (“nosocomial”) infections
Hard to treat Naturally antibiotic resistant to penicillins Acquired resistance to many other antibiotics
E. Faecalis is a Good Indicator Organism in the Environment
Stays alive but doesn’t grow in environment
So… numbers stay constant
So…counts are representative of volume of pollution sources Scanning Electron Micrograph of
Enterococcus faecalis. Sources: CDC Public Health Image Library (PHIL), Photo by Janice Haney Carrhttp://phil.cdc.gov/Phil/details.asp
How might pathogens reach our water?
Our Activity Step 1- Collect
water samples Step 2- Filter water
samples and culture overnight 2 different volumes
10 ml 100 ml Allows for best
opportunity to get a countable plate of 20-60 colonies
http://www.umesc.usgs.gov/aquatic/drug_research/capabilities.html
Our Activity Step 3- (Next Day)
Count Colonies
Example of bacterial growth on selective media. Photo courtesy of Hornor Lab, Anne Arundel Community College, Arnold, MD.
Equipment Setup Completely
assembled filtration apparatus
Water samples in ice bucket
Field data sheet Sterile 10 ml
syringe Beaker with
ethanol holding forceps
Sterile paper filter
Sterile Technique Forceps removed
from ethanol, flamed
THEN handed to students
Place Filter 1 Peel cover off filter
(best done by instructor or partner)
Grab edge with sterilized forceps
Place Filter 2 Place paper filter
grid side up on top of metal screen
Paper must completely cover screen to get proper filtration
Reassemble Filtration Apparatus
Place filter funnel on top of paper filter
Clamp glassware in place
10 ml Sample Wet filter with 10
ml sterile, distilled water Water removes
static from syringe When the water
has suctioned through filter, apply 10 ml of water sample to filter
Wash Filter Funnel With clean syringe,
wash the sides of the funnel to get any splashes
Remove Filter Unclamp filter
funnel Flame forceps Grab edge of filter
and break vacuum seal
Place on Plate Hold plate tilted
downward and away
Place filter at bottom edge of plate
Roll onto media to minimize bubbles
Cover and incubate 24 hrs
Repeat for 100 ml Place new filter on
filtration apparatus Wet filter and
suction through Pour 100 ml into
funnel Wash sides of
funnel Place filter on
media
After Incubation This is what the
students will see after a 24 hour incubation at 41˚C (chicken body temperature)
Left-hand plates came from Patuxent River
Right-hand plates came from Warehouse Creek off South River
Top plates are 10 ml, bottom plates are 100ml samples
What issues affect the Chesapeake Bay?
Chesapeake Bay Foundation
http://www.youtube.com/watch?feature=player_embedded&v=o7kB7-UN7m4
Antibiotics--Are You Drinking Them in Your Tap Water?