Emerging Infectious Diseases in the Water Supply and How that Affects Immunocompromised Persons : Emerging Infectious Diseases in the Water Supply and How that Affects Immunocompromised Persons Educational Objectives:
Why are Elderly Persons at a higher risk for infectious diseases?
Understand the factors that lead to
increases in water-borne infectious diseases
Factors are different for the developed versus the developing world
Discuss a disease example for each
Emerging Infectious Diseases and Water What has changed? : Emerging Infectious Diseases and Water What has changed? More centralized water sources
Better detection methods
Increase in immunocompromised people
Food imported from developing countries, using
unclean water for irrigation and washing
Global conflicts creating increasing refuge camps
Increasing Numbers of Immunocompromised Persons : Increasing Numbers of Immunocompromised Persons HIV is still increasing worldwide
Older persons (aging baby boomers)
Patients treated for cancer, transplants, diabetes, etc.
13 Factors of Emerging Infectious Diseases:
Human Demographics and Behavior
Human Susceptibility to Infections
Technology and Industry
Impact of Aging on Infections : Impact of Aging on Infections Physiological Changes of Aging:
Immune changes increase infection risks (e.g. TB)
Organ changes increase infections risks
-skin
-stomach acid reduced- first line a/ enteric pathogenes
-bladder changes increase UTIs
Age-related diseases (e.g. cancer, diabetes, dementia etc.)
increase infection risks
Immune Changes with Age : Immune Changes with Age Protective immunity drops with age
-poor priming to new antigens
(efficacy of immunization is decreased)
-poor recall of old antigens (i.e. antigens you saw
when you were young)
-poor affinity maturation- low IgG (i.e. not high affinity)
Poor proliferation of T cells, poor IL-2 production
Many changes in later cytokine production (IL-4, IFN)
T cell subsets: naïve are down and memory are up
T cell microclones-as much as 50% of T cells are clones
(5000 to 10,000 each) thus not a broad repartee
Physiological Changes of Aging : Physiological Changes of Aging Organ changes in older persons:
-produce less stomach acid (1st defense a/ enterics)
-organ transplants or plastic and metal parts internally
these increase chances for infection
Older persons spend more time in hospital,
exposing them to more infectious diseases
Older persons have more medical procedures performed
e.g. catheterization increases UTIs
Institutionalization (nursing homes) increases infections
e.g. aspiration pneumonia, infected pressure ulcers
Chronic Diseases with Infectious Etiology : Chronic Diseases with Infectious Etiology Does chronic inflammation from infectious diseases
make other diseases worse? (Alzheimer’s)
Infections cause or contribute to chronic diseases and cancers.
-Helicobacter pylori -linked with stomach ulcers cancer
-Borrelia burgdorferi (Lyme disease) is linked to arthritis
-Chlamydia pneumoniae is linked to atheroslerosis
-Hepatitis B and C are linked to liver cancer
-Schistosoma is linked to colon and bladder cancers
If disease is caused by infection, is it easier to treat?
U.S. Drinking Water : U.S. Drinking Water Our drinking water supply is normally safe.
Diseases are spread when:
-there’s a water main break or interruption
-you camp or travel
-you swim or play in lakes, streams, pools, or waterparks?
Parasites cause the majority of problems: Cryptosporidium,
Giardia, sometimes Toxoplasma
But also can have Escherichia coli O157:H7, and Viral Hepatitis A
Water and Food Connection : Water and Food Connection Fecal contamination of water used for crop irrigation,
processing, and preparation.
“If people don’t have clean water to drink…imagine with they
irrigate and wash their crops with”-Michael Osterholm
Rapid increase in aquaculture
-7 million tons in 1984 to 23 million tons in 1996
-in developing countries, it is 87% of fish production
-in the U.S. it is still only 15% but rising
Parasites and Water in the U.S. : Parasites and Water in the U.S. CDC estimates 2.5 million cases annually due to
food and beverage parasites
Especially the long-surviving encysted forms
In the U.S., the CDC links 71% of waterborne disease to two
parasites: Giardia lamblia and Cryptosporidium
Cryptosporidium is in the subclass coccidians including Eimeria,
Plasmodium, Toxoplasma, Cyclospora, Babesia, Isospora
Cryptosporidium parvum : First described in 1907 as an intracellular protozoan parasite
In 1976 two cases of human diarrhea
Increased dramatically with the AIDS epidemic, by 1986
4% of AIDS patients had cryptosporidiosis with a
61% fatality rate
In 1993 national attention was focused on Cryptosporidium
-Milwaukee over 400,000 cases
-Las Vegas thousands more
CDC says that currently there are at least 30,000 cases of
Cryptosporidium annually Cryptosporidium parvum
Cryptosporidium : Cryptosporidium Cryptosporidium is in the subclass coccidians which includes
Plasmodium (malaria), Toxoplasma, Cyclospora, Babesia,
Sarcocystis, Isospora, and Eimeria
Large reservoir of wild animals and livestock
Lifecycle is completed within a single host
Diagnoses can now be done by immunofluorescence
Immunofluorescence of Cryptosporidium Cysts : Steve J. Upton, PhD
Kansas State University Immunofluorescence of Cryptosporidium Cysts
Lifecycle of Cryptosporidium : Steve J. Upton, PhD
Kansas State University Lifecycle of Cryptosporidium
Cryptosporidium in Human Disease :
Transmission is fecal/oral: outbreaks associated
with faulty water purification
1-2 week incubation with PROFUSE watery diarrhea (12L/day)
We shead oocysts in stool; cysts are very rubust,
resistant to chlorination must boil
Self-limiting except in immunocompromised patients
No effective drugs; treat with oral rehydration Cryptosporidium in Human Disease
Cryptosporidium Prevention : Cryptosporidium Prevention Existing water testing and treatment methods fail to reliably
detect or remove it
EPA estimates that over the next 20 years, $138.4 billion is needed
to upgrade or replace our drinking water infrastructure
Cryptosporidiosis has been linked to drinking and recreational
water, food, person to person and farm animal contact
-Over 3000 cases in NY’s Seneca Lake Park (Coon Lake MN)
Low doses can lead to infection in healthy volunteers (3000 cysts)
HIV-infected patients with fewer than 200 CD4 cells/mm3
should drink boiled or bottled water
Slide17 : Cyclospora Previous underestimate of foodborne illness attributed
to parasites: lack of effective monitoring.
Underdeveloped scientifically: cannot culture most
parasites and lack of natural models.
Cyclospora, like Cryptosporidium, cannot be grown
in the lab
Cyclospora outbreaks highlight the role of international
food distribution and the emergence of previously
unknown pathogens
CDC says that are 15,000 cases of Cyclospora annually
Slide18 : Cyclosporiasis and Raspberries Outbreaks in 1995, 1996, 1997, and 2000 (Canada) associated
with Guatemala raspberries
Last 1980s USAID pushed Guatemala after their civil war to
grow raspberries for U.S. markets
First bushes went in 1988-1989, first years birds were “berry
naïve”, then they started to eat a lot of them
Where is the Cyclospora coming from? What is the reservoir?
1) contaminated irrigation or washing water
2) birds…birds come to eat the raspberries and poop
Cyclospora is related to Eimeria (chicken coccidious)
Raspberries have tiny hairs, nearly impossible to wash
Slide19 : Cholera Descriptions of epidemics on the Indian subcontinent in the 1400s
but it did not spread to Europe and the Americas ‘til 1800s
Cholera was prevalent in the U.S. during the 1800s, but has been
virtually eliminated by modern sewage and water treatment
Currently it is common in Asia, Africa, and Latin America
(growing problem in the former Soviet Union, Iran, and Pakistan
current outbreak in Africa (110 new cases per day)
As of Sept 28, 2006 there are 22,101 cases with 219 deaths in Ethiopia
Angola has had >50,000 with 2089 deaths
Sudan has had >5,000 with 165 deaths
.
Cholera : Cholera Etiological agent is Vibrio cholerae- serogroups O1 (El Tor) or
O139 (Bengal) that produce cholera toxin
Clinical features vary from asymptomatic to profuse watery
diarrhea with vomiting, circulatory collapse and shock
25-50% of cases at fatal if untreated- treatment is oral rehydration
therapy (sugar and salt mixed with clean water)
hard to deliver in remote areas and during epidemics
Risk group is persons living in poverty in the developing world,
low risk for travelers, virtually no risk for persons in the U.S.
Cholera cont. : Cholera cont. Transmission is through contaminated drinking water or food
-large epidemics often related to fecal contamination of
water or street vended foods
-occasional transmission from undercooked shellfish
that have been naturally contaminated
Ongoing global pandemic in Asia, Africa, and Latin America (Iraq)
since 1995, >80% have occurred in Africa
In Africa 2005-Nigeria: up to 100 dead in Benue State by the Benue River
Conflict in Sudan has MANY cases in the refugee camps
In DRC-1420 cases, 29 dead, Guinea-Bissau- 280 deaths, 18,000 sick (50 cases/day)
Senegal had 23,325 cases and 321 deaths, Muslim pilgrimage in the city of Touba
In developing countries, population migrations into urban centers
have strained the existing water and sanitation infrastructure
The O1- El Tor Strain : The O1- El Tor Strain Isolated in 1905 from Mecca pilgrims at the El Tor quarantine camp
Since 1961 the El Tor variant has spread across Asia, Africa,
the Middle East, and recently into parts of Europe
In 1969, first seen in the Ganges Delta (heartland of cholera) and
by 1974 it had replaced the “classic” cholera strain
In 1982 in Bangladesh mix of classic and El Tor = O139 (Bengal)
In January 1991, the El Tor variant broke out in Peru and quickly
spread throughout Latin America (currently large epidemics)
-carried over on ships from Africa and came out of the bilge
Phenotypes of the El Tor Strain : Phenotypes of the El Tor Strain The El Tor strain has been isolated as free-living bacteria or
with phytoplankton, zooplankton, crustacea, and mollusks
The El Tor strain can produce a “rugose” phenotype which is
exopolysaccharide production that confers chlorine
resistance and biofilm formation
The survival of El tor is decreased if the seawater is filtered
Attachment to surfaces is important for marine organisms
-surfaces absorb and concentrate scarce nutrients
-biotic surfaces (chitin) can be degraded by attached bacteria
Colony Morphology and EPS Production : Colony Morphology and EPS Production Yildiz F.H. et.al. 2001
J. Bact. 183 p.1716-26
Biofilms : Biofilms Definition “a structured community of bacterial cells enclosed
in self-produced polymeric matrix and adherent to an
inert or living surface
3 ingredents: microbes, a surface, and glycocalyx (called the
slime layer or force field)
Sessile (inner dormant) bacteria differ profoundly from the
planktonic (floating) bacteria
Biofilm Structure Cartoon : Biofilm Structure Cartoon
Cholera Prevention : Cholera Prevention Epidemics are markers for poverty and lack of basic sanitation
Need infrastructure for sanitation and safe water handling
- addition of sodium hypochlorite solution
Vaccine offers incomplete protection for a short duration:
- no multivalent vaccine for O139 strain
- O139 has changed its antigenic surface
Natural reservoir in warm costal waters makes eradication highly unlikely
- How did Bengal replace El Tor? Now they co-exist?
Travelers should “Boil it, cook it, peel it, or forget it”
- drink water that has been boiled or treated
- eat only foods that have been cooked and are still hot
- eat food that you peel yourself