Download Emerging Diseases Escherichia coli

Emerging Diseases
Escherichia coli
Food-borne disese
Escherichia coli
 pathogenic strains frequent agents of
infantile diarrhea – greatest cause of
mortality among babies
 causes ~70% of traveler’s diarrhea
 causes 50-80% UTI
 indicator of fecal contamination in water
Escherichia coli O157:H7
E. coli O157:H7
 E. coli O157:H7 is one of hundreds of
strains of the bacterium Escherichia coli.
 Although most strains are harmless, this
strain produces a powerful toxin that can
cause severe illness.
 E. coli O157:H7 has been found in the
intestines of healthy cattle, deer, goats,
and sheep.
E. Coli 0157:H7 outbreak
1-4
5-9
10-14
15 +

September 28, 2006 : 187 people infected in 26 states (97
hospitalized…29 developed HUS [hemolytic-uremic syndrome])
Escherichia coli O157:H7
 Escherichia coli O157:H7 is a leading cause of
foodborne illness. Based on a 1999 estimate, 73,000
cases of infection and 61 deaths occur in the United
States each year.
 Infection with E. coli often leads to bloody diarrhea, and
occasionally to kidney failure. People can become
infected with E.coli O157:H7 in a variety of ways.
Though most illness has been associated with eating
undercooked, contaminated ground beef, people have
also become ill from eating contaminated bean sprouts
or fresh leafy vegetables such as lettuce and spinach.
Forensic use of DNA
patterns
“DNA Fingerprints”
The E. coli outbreak in spinach
was investigated using DNA
fingerprinting techniques to trace
the strain of bacteria.
Using restriction fragment patterns to distinguish DNA from different alleles
DNA fingerprints from a murder case
Newer Outbreaks
 Nestle Toll House cookie dough (E. coli) June
2009) http://www.cdc.gov/ecoli/2009/0630.html
(72 cases in 30 states)
 Ground beef (E. coli) ( July 2008)
http://www.cdc.gov/ecoli/june2008outbreak/ (49
cases in 7 states)
 Pepperoni pizza (E.coli) (Oct-Nov 2007)
http://www.cdc.gov/ecoli/2007/october/103107.h
tml (21 cases in 10 states)
 Peanut Butter (salmonellosis) (2007)
http://www.cdc.gov/ncidod/dbmd/diseaseinfo/sal
monellosis_2007/022207_outbreak_notice.htm
(over 600 people from 47 states)
Lyme Disease
B. burgdorferi - Lyme
disease
 transmitted by ticks
 complex 2-year cycle involving mice & deer
 nonfatal, slowly progressive syndrome that
mimics neuromuscular & rheumatoid conditions
 70% get bull’s eye rash
 fever, headache, stiff neck, & dizziness
 if untreated can progress to cardiac &
neurological symptoms, polyarthritis
 tetracycline, amoxicillin
 vaccine for dogs, human vaccine discontinued
 Prevention-insect repellant containing DEET
Lyme disease
SuperBug ?
 MRSA: Methicillin Resistant Staphylococcus
aureus
 A strain of staph that is highly resistant to broadspectrum antibiotics.
 Once found almost exclusively in hospital settings
the bacteria is now showing up in the wider
community
 People can be colonized by the bacteria (skin and
nose primarily) and be healthy but act as carriers to
spread the microbe.
 It is thought that perhaps 25-30% of people may
harbor S.aureus.
MRSA-2
 A CDC survey completed recently suggests that in
2005 there were ~ 94,000 cases of MRSA in the US
and that perhaps 19,000 people died. (A higher rate
than AIDS in the US)
 85% of the cases were in hospitals, nursing homes etc.
But many are concerned about the large number of
infections acquired in normal community environments.
 Spread may be by hands (direct contact) or from
contaminated surfaces.
 Infections range from an inconsequential skin lesion to
a fatal septicemia or pneumonia
TB-Tuberculosis
Tuberculosis (statistics-1)
 Tuberculosis (TB) kills about two million
people each year
 One-third of the world's population is
infected with TB. Five to 10 percent of
people who are infected with TB become
sick with TB at some time during their life
 Each year, more than 8 million people
become sick with TB
Tuberculosis (statistics-2)
 Between 2000 and 2020, it is estimated
that:
 Nearly one billion people will be newly
infected with TB.
 200 million people will become sick
from TB.
 TB will claim at least 35 million lives.
Treatment of TB
 6-24 months of at least 2 drugs from a list
of 11
 one pill regimen called Rifater (isoniazid,
rifampin, pyrazinamide)
 vaccine based on attenuated bacilli
Calmet-Guerin strain of M. bovis used in
other countries (not U.S.)
 Success rate of vaccination ~80% in
children and 20-50% in adults.
Directly Observed Therapy (DOT)
…to assure that medication is actually taken
MDR
(multiple-drug-resistant)
TB
 Most TB patients do not complete their full 6-9
month regimen. The TB bacillus becomes
resistant due to incomplete, erratic or
inadequate treatment. –
 Often a few months into a cumbersome and
lengthy treatment process, patients feel better
and may stop treatment altogether.
 Up to 20% of TB cases are drug-resistant in TB
hot-spots –
 4% of TB cases globally are resistant to at
least one drug –
 MDR-TB could be growing as rapidly as
400,000 cases each year
MDR
(multiple-drug-resistant)
TB
Papillomavirus
Papillomavirus
 papilloma – benign, squamous epithelial
growth or wart
 caused by 40 different strains of HPV
 Common warts (seed warts) – on fingers, etc
 plantar warts – on soles of feet
 genital warts – prevalent STD
 transmissible through direct contact or
contaminated fomites, autoinnoculation (self-spread)
 Incubation – 2 weeks – more than a year
 For most people the virus goes away on its
own
Papillomavirus
Plantar wart
Common wart
Genital wart
Genital warts
 most common STD in US?
 over 6 M new cases each year
 20+ million carriers (U.S.) of one of the 5
types of HPV associated with genital
warts
 strong association with cervical & penile
cancer
 CDC estimates sexually active people
have a 50% chance of catching HPV
during a lifetime
HPV Vaccine
 For girls and women 9-26 years of age
 Three doses
 Initial
 2 month booster
 6 month booster
 For prevention only…not a treatment
Influenza






Influenza type A
acute, highly contagious respiratory illness
Seasonal (potential for pandemics)
among top 10 causes of death in US
respiratory transmission
binds to ciliated cells of respiratory mucosa
causes rapid shedding of cells, stripping the
respiratory epithelium, severe inflammation
 fever, headache, myalgia, pharyngeal pain,
shortness of breath, coughing
 Several drugs are available for treatment:
amantadine, rimantadine, zanamivir &
oseltamivir
 annual vaccine
Vaccination for “seasonal flu”
 There are two types of vaccines:
 The "flu shot"— an inactivated vaccine (containing killed virus) that is
given with a needle, usually in the arm.
 The nasal-spray flu vaccine — a vaccine made with live, weakened
flu viruses that do not cause the flu (sometimes called LAIV for “live
attenuated influenza vaccine” or FluMist®). LAIV (FluMist®) is
approved for use in healthy* people 2-49 years of age who are not
pregnant.
 Each vaccine contains three influenza viruses-one A (H3N2) virus,
one regular, seasonal A (H1N1) virus, and one B virus. The viruses
in the vaccine change each year based on international surveillance
and scientists' estimations about which types and strains of viruses will
circulate in a given year.
 About 2 weeks after vaccination, antibodies that provide protection
against influenza virus infection develop in the body.
 Seasonal flu peaks in the U.S. in Jan and Feb
2009 H1N1…”swine flu”
INFLUENZA
Is an Avian Flu pandemic on
the way??
Avian Flu
Avian Flu
NOVA Science NOW
Pandemic flu video (2006)
http://www.pbs.org/wgbh/nova/scien
cenow/3302/04.html
Avian Flu
 Pandemic viruses
appear as the result of
antigenic shift, which
causes new
combinations of
proteins on the surface
of the virus. If the new
virus spreads easily
from person to person
a pandemic can result.
Avian Flu
 Culling of infected Poultry
Is a Pandemic coming????
Nations with confirmed cases of H5N1 avian flu
Coronavirus
Coronavirus
 relatively large RNA viruses
 common in domesticated animals
 3 types of human coronaviruses have been
characterized
 HCV causes a cold
 an enteric virus
 Severe Acute Respiratory Syndrome (SARS)
Coronaviruses
SARS (severe acute respiratory
syndrome)
2003 Outbreak…
8,098 people worldwide became ill, 774
died. Spread to 30 countries before the
outbreak was contained.
SARS
Coronavirus- SARS
Global Spread…
Feb 21,2003 …infected medical doctor
from Guangdong Province spent a night
at a Hong Kong hotel. 12 people staying
at or visiting that floor of the hotel
became infected.
These travelers then dispersed the
disease to other countries worldwide
SARS Dispersal
Superspreaders
144 of Singapore’s 206 cases linked to
contact with just 5 individuals
Palm civets (SARS
reservoir??)
Did the SARS
epidemic start in
Guangdong Province,
China as a “civet
meal”?
Masked Palm Civet at market
Water rat at a market
Cost of SARS
Togaviruses
(Flavivirus
subcategory)
 Dengue
 “breakbone fever” severe pain in muscles and joints.
Infections usually mild, but dengue hemorrhagic
shock can be lethal
 Concern over possible spread to the continental
U.S.
 Yellow Fever
 Fever, headache, muscle pain, may progress to
organ failure and death.
 Mosquito control has greatly decreased its impact
 West Nile
 Emerging concern in U.S.
Dengue
Distribution of Aedes aegypti (red
shaded areas) in the Americas in
1970, at the end of the mosquito
eradication program, and in 1997
American countries with
laboratory-confirmed
hemorrhagic fever (red shaded
areas), prior to 1981 and from
1981 to 1997.
Dengue
West Nile
 It is estimated that about 20% of people who
become infected with WNV will develop West Nile
fever.
 Symptoms include fever, headache, tiredness, and
body aches, occasionally with a skin rash (on the
trunk of the body) and swollen lymph glands.
 illness can be as short as a few days, but even
healthy people have reported being sick for
several weeks.
 About 1 out of 150 infected people develop
serious disease. Encephalitis. Meningitis.
 Incubation period 2-15 days
West Nile Virus-1999-2001
West Nile Virus-2002
West Nile Virus – 2004
rd
(march 3 )
West Nile Virus – 2005
(Jan 11Th)
For all of 2007, more than 1,200 cases of severe West Nile illness were
reported, and 124 deaths. The peaks occurred in 2002 and 2003, when severe
illnesses numbered nearly 3,000 and deaths surpassed 260.
West Nile Virus - Life
Cycle
HIV
 Worsening Epidemic
 25 million Africans have HIV
 United Nations warns that the next two
decades could see 89 million new
cases
 Up to 10% of the continent’s population
AIDS
 first emerged in early 1980s
 HIV-1 & HIV-2 are not closely related
 HIV viruses may have originated from a
monkey/chimpanzee viruses
 1959 first documented case of AIDS
 HIV is found in blood, semen, & vaginal
secretions.
 HIV is transmitted by sex, sharing needles, and
mother to child.
 HIV does not survive long outside of the body.
HIV
 attacks the T helper cells & macrophages
 first signs of AIDS are opportunistic
infections such as Pneumocystis carinii
pneumonia (PCP) and cancers such as
Kaposi sarcoma
Risk categories
 homosexual or bisexual males – 45% of U.S.
cases
 intravenous drug users – 30%
 heterosexual partners of HIV carriers – 11%
 blood transfusions & blood products – since
testing, no longer a serious risk
 inapparent or unknown risk – 9% (unexplained risk due to patient denials,
death, unavailability)
 congenital or neonatal – 5%, can be reduced
with antiviral drugs
 medical & dental personnel – 1/500 chance
from needlestick accident
Progression of HIV disease
 initial infection – mononucleosis-like
symptoms that soon disappear
 asymptomatic phase 2-15 years (ave. 10)
 antibodies are detectable 8-16 weeks
after infection
 HIV destroys the immune system
 when T4 cell levels fall below 200/mL
symptoms appear including fever, swollen
lymph nodes, diarrhea, weight loss,
neurological symptoms, opportunistic
infections & cancers
Opportunistic
infections
Kaposi sarcoma of arm
HIV
 treatments
 inhibit viral enzymes: reverse transcriptase,
protease, integrase
 inhibit fusion of virus to host cell
 inhibit viral translation
 no vaccine
 prevention
 monogamous sexual relationships
 condoms
 universal precautions (in handling of needles, blood
products etc.)
REFERENCES:
www.Slideshare.com