Transcript BMT INFECTIOUS DISEASES

INFECTIOUS DISEASES
Infectious diseases continue to be a major
cause of human suffering & death, both in
the U.S. & the world.
DISCUSS THE INFECTIOUS
DISEASE PROCESS
A. NATURE OF INFECTIOUS DISEASES
•
PATHOGEN – microorganisms that are capable of
causing disease
– True pathogen – an infectious agent that
causes disease in virtually any susceptible
host
– Opportunistic pathogens – potentially
infectious agents that rarely cause disease in
individuals with healthy immune system
INFECTION
• results when a pathogen invades &
begins growing within a host
•
•
DISEASE – results only if & when tissue
function is impaired from the invasion &
growth of a pathogen
1. genetic or metabolic – inherited or
abnormality
2. aging – atherosclerosis
3. infectious – caused by invasion of host
by agents whose activities harm the
host’s tissue
The body has defense mechanisms to prevent
infection (see D)
CAUSE OF DISEASE
– pathogens must be able to enter the host
body, adhere to specific host cells, invade
& colonize host tissues, & inflict damage
on those tissues.
• ENTRANCE to the host typically occurs
through natural orifices such as the mouth,
eyes, or genital openings, or through
wounds that breach the skin barrier to
pathogens.
GROWTH OF PATHOGENS
– may occur at initial entry site or invade areas of
body by attaching to specific host cells.
Some pathogens then multiply between host cells
or within body fluids, while others such as
viruses & some bacterial species enter the host
cells & grow there.
Pathogen’s growth may be enough to cause
tissue damage in some cases, damage is
usually due to the pathogen’s production of
toxins or destructive enzymes
• Some normal flora prevent diseases (see D)
B. MICROBES THAT CAUSE
INFECTIOUS DISEASES
BACTERIA – Unicellular with no organized
internal membranous structures.
Reproduce by growing & dividing into two
cells in a process known as binary fission.
MORPHOLOGIES:
• Bacillus ( rod-shaped)
• Coccus (spherical)
• Spirillum (helical rods)
Larry’s sayings
“Support bacteria. They're the only
culture most people have.”
ENERGY sources vary
• photosynthetic
• oxidize inorganic compounds
• breaking down organic compounds.
CONDITIONS THAT AFFECT THE
GROWTH OF BACTERIA
1.
2.
3.
4.
5.
6.
FOOD
MOISTURE
TEMPERATURE
OXYGEN
LIGHT
LIVING & DEAD MATTER
.
• OK. So what's a fomite?
A fomite is any object that may be
contaminated with infectious organisms and
serve in their transmission.
If this seems obscure, think of the word
"foment."
These inanimate objects carry
germs that cause infection, acting
as one of the most common ways
that people—children in particular—
get sick. In fact, illnesses that
spread by droplet transmission,
fecal-oral transmission, or contact
transmission often do so by means
of fomites
• EX:
cutting boards, kitchen sponges,
toothbrushes and cups; the ordinary devices
of modern life—that, when exposed to
bacteria and unsanitary conditions, heighten
the risk of serious infection for countless
individuals.
Germs can survive on fomites for minutes,
hours, or even days in some cases, thus
proving that we need to safeguard ourselves
from these sorts of risk and further promote
the cause of proper hygiene.
• Bear in mind that fomites can also provide
an opportunity to disrupt the spread of
infection, provided we recognize and avoid
them. At the very least, we should disinfect
these objects or clean our hands after
touching them. Too few people recognize
that simple hand washing is perhaps the
easiest, cheapest, and most effective way
to guard against common viral and
bacterial infections.
Diseases that typically spread by
means of fomites include:
• common cold
• cold sores,
• conjunctivitis,
• hand-foot-mouth disease
influenza
• lice infestation
• meningitis, pinworms, diarrhea,
and strep infections.
In health care settings…..
Antibiotic-resistant bacteria have
been found on:
blood pressure cuffs, dietary trays,
intravenous pumps, stethoscopes,
utility room sinks, bathroom doors,
and within sink drains in patient
rooms. Fomites and pathogens are
just about everywhere!
• health care experts generally cite hand
washing as the single most effective way
to prevent the transmission of disease.
• Hand washing is particularly important
before eating and cooking, after using the
bathroom, or after touching animals,
including family pets.
• Common sense and good hygiene can go
a long way toward neutralizing the threat
posed by fomites. But, we need to take
this challenge seriously. Otherwise, we
compromise our own health and the health
of those close to us.
CELL WALL STRUCTURES
Determine if Gram negative or positive
• Negative:
Salmonella typhi causes typhoid fever
Yersinia pestis causes plague
• Positive:
Staphylococcus aureus causes skin,
respiratory, & wound infections
• Both gram-positive and gram-negative bacteria have a
cell wall made up of peptidoglycan and a phospholipid
bilayer with membrane-spanning proteins. However,
gram-negative bacteria have a unique outer membrane,
a thinner layer of peptidoglycan, and a periplasmic space
between the cell wall and the membrane. In the outer
membrane, gram-negative bacteria have
lipopolysaccharides (LPS), porin channels, and murein
lipoprotein all of which gram-positive bacteria lack.
• As opposed to gram-positive cells, gram-negative cells
are resistant to lysozyme and penicillin attack. The gramnegative outer membrane which contains LPS, an
endotoxin, blocks antibiotics, dyes, and detergents
protecting the sensitive inner membrane and cell wall.
•
Gram-positive
Gram-positive bacteria differ from gram-negative bacteria in the
structure of their cell walls. The cell walls of gram-positive bacteria are
made up of twenty times as much murein or peptidoglycan than gramnegative bacteria. These complex polymers of sugars and amino acids
cross-link and layer the cell wall.
• The thick outer matrix of peptidoglycan, teichoic acid, polysaccharides,
and other proteins serve a number of purposes, including membrane
transport regulation, cell expansion, and shape formation.
• Almost all bacteria can be classified as gram-positive or gramnegative. The classification relies on the positive or negative results
from Gram’s staining method, which uses complex purple dye and
iodine. Because gram-positive bacteria have more layers of
peptidoglycan in their cell walls than gram-negative, they can retain the
dye.
• Six common gram-positive bacteria that infect humans and their
shapes follow:
Streptococcus (cocci)
Staphylococcus (cocci)
Bacillus (bacilli, protective spore) - causes anthrax and gastroenteritis
Clostridium (bacilli, protective spore) - causes botulism, tetanus, gas
gangrene, and pseudomembranous colitis
Corynebacterium (bacilli, no protective spore) - causes diphtheria
Listeria (bacilli, no protective spore) - causes meningitis
VIRUSES
Are not organisms & apart from host cell they have
no metabolism & cannot reproduce
• CLASSIFIED by shape, size, & type of genome
• DNA virus uses host cell enzymes to replicate its
DNA
• Ex: Herpes virus – chicken pox, cold sores,
genital lesions
•
Pox virus - smallpox
Retrovirus (RNA virus)
Uses a unique enzyme called reverse
transcriptase to copy the RNA genome into
DNA, frequently exhibit long latent periods in
which their genomes are copied & distributed to
progeny cells each time the cell divides.
• Ex: HIV, Rhinovirus cause common colds,
myxovirus that cause influenza, measles,
mumps
• Rotavirus – cause gastroenteritis
• Retrovirus – cause AIDS & several types of
cancer
• Viral activity may weaken cell membranes
& lysosomal membranes, leading to cell
autolysis.
• Some viral proteins are toxic to cells, &
the body’s immune defenses also may kill
virus-infected cells.
FUNGI
Reproduce primarily by
forming spores. Most are
multicellular but some are unicellular.
Together with bacteria, fungi fulfill the
indispensable role of decomposers in the
environment. Can infect plants & animals.
• Ex: ringworm & histoplasmosis (mild to
severe lung infections caused by bird or
bat droppings)
Opportunistic pathogens
yeasts of the Candida
genus in
Immunocompromised
or undergoing
antibiotic
therapy.
PROTOZOA
Unicellular that do not have cell walls so
they are capable of a variety of rapid &
flexible movements.
ACQUIRED through contaminated food or
water or by the bite of an infected arthropod
such as a mosquito.
Usually a tropical illness
• The protozoa are one-celled microorganisms. You need a
microscope to see them. They do breathe, move, and
reproduce like multi-celled animals. They live in water or at
least where it is damp.
• Some protozoans are harmful to man because they can cause
serious diseases. Others are helpful because they eat harmful
bacteria and are food for fish and other animals.
• There are three different types of protozoa: Ameba,
Paramecium, Euglena.
• Ameba - It can be found in ponds and rivers and on the surface
of the leaves of water plants. It looks like a grayish blob under a
microscope. Its shape is constantly changing as it moves
along.
• One characteristic of the ameba is its false feet that scientists
call pseudopodia. In order to move, the ameba extends its false
feet out, and the rest of the body follows the false feet along.
The ameba eats little animals and plants. It reaches out with its
false feet to surround a plant or animal and then puts it right
into the cell.
HELMINTHES
• – simple, invertebrate animals some of which
are infectious parasites.
• Animals with a physiology similar to ours, makes
parasitic helminthes infections difficult to treat
because drugs that kill helminthes are frequently
very toxic to human cells.
• Have complex reproductive cycles that include
multiple stages, many or all of which require a
host.
.
•
http://media2.foxnews.com/112008/worm_tumor_700.wmv
• Ex: Schistosoma – a flatworm causes mild
disease of swimmer’s itch in U.S.
• Schistosomiasis – eggs hatch in fresh
water & larvae infect snails. When snail
sheds these larvae, they attach to &
penetrate human skin. They feed, mate, &
grow in the human bloodstream. Sharp
spines from eggs result in symptoms of
diarrhea & abdominal pain.
• Trichinosis – caused by roundworm
Trichinella Spiralis ingested from
improperly cooked pork from infected pigs.
Early symp.: vomiting,diarrhea, fever
– Later symp:. – muscle pain because the
larvae grow & mature in those tissues.
FATAL cases often show CHF &
respiratory paralysis
PRIONS
Degenerative disorders of CNS caused by
infectious particles that consist only of proteins.
The following diseases result in brain tissue
riddled with holes. While some prion diseases
are inherited, others are apparently due to
infection by eating infected tissue or
indadvertently through medical procedures such
as tissue transplants.
• Ex: Creutzfeldt-Jakob (in humans) - Scrapie
(sheep) - Bovine Spongiform Encephalopathy
(“mad cow disease” in cattle)
BED BUGS
Since much of our clothing, sheets, towels,
etc. now comes from companies outside of
America, (sad but true), even the most
expensive stores sell foreign clothing from
China, Indonesia, etc. The bed bugs are
coming in on the clothing as these countries
do not consider them a problem
if you buy any new:
clothing, even underwear and socks,
sheets, towels, etc. that you bring
them into the house and put them in your
clothes dryer for at least 20
minutes. The heat will kill them and their
eggs. DO NOT PURCHASE
CLOTHES AND HANG THEM IN THE
CLOSET FIRST .
It does not matter what the
price range is of the clothing, or if the
outfit comes from the most
expensive store known in the U.S. They
still get shipments from these
countries and the bugs can come in a
box of scarves or anything else
for that matter. That is the reason why so
many stores, many of them
clothing stores have had to shut down in
NYC and other places.
All
you need is to bring one item into the
house that has bugs or eggs and
you will go to hades and back trying
to get rid of them.
C. OCCURRENCE OF
INFECTIOUS DISEASES
1. EPIDEMIOLOGY – study of occurrence of
disease in populations.
EPIDEMIOLOGISTS – concerned with
infectious diseases, non-infectious diseases
(cancer, atherosclerosis, environmental
diseases) Act as “detectives” who track down
cause of a “new” disease, determine its
reservoir & mode of transmission, organize
HCW to bring disease under control
2. DISEASE RESERVOIRS
Site where the infectious agent survives.
Animals serve as reservoirs for diseases
that infect humans. There are also nonliving reservoirs.
• Ex: Yersinia pestis – wild rodents that carry
plague
Soil – reservoir for many pathogenic fungi as
well as some pathogenic bacteria such as
Clostridium Tetani – which causes tetanus
3. MODE OF TRANSMISSION
Infectious agents may be transmitted through
either direct or indirect contact
• DIRECT CONTACT - infected by contact with
reservoir (touching an infected person,
ingesting infected meat or being bitten by
infected animal or insect, inhaling infectious
agent in droplets emitted by sneezing or
coughing, and through intimate sexual contact.)
• Ex: AIDS, rabies, ringworm, influenza, malaria
INDIRECT CONTACT
When a pathogen can withstand the
environment outside its host for a long
period of time before infecting another
individual. (used tissue, toy touched by a
sick child, food & beverages contaminated
by contact with disease reservoir, fecal –
oral route in which sewage contaminated
water is used for drinking – washing – or
preparing food
HORIZONTAL TRANSMISSION
• passed from person to person in a group
VERTICAL TRANSMISSION
transmitted from parent to child during
process of reproduction, fetal development
or birth (AIDS, Herpes encephalitis)
D. HOST DEFENSES AGAINST
INFECTIOUS DISEASES
1. NONSPECIFIC MECHANISMS – body’s primary
defense against disease
A. ANATOMICAL BARRIERS
a.) Nasal opening to respiratory system –
long convoluted passage covered by
mucous membranes that trap airborne
particles & prevent most of them from
reaching lungs, also
b.) skull & vertebral column
few pathogens can penetrate bone
(c.) Skin
• Surface layer of dead, hardened cells is
relatively dry & skin secretions make
surface somewhat acidic – low moisture,
low pH, & high salinity prevent most
microorganisms from growing &
multiplying on the skin.
B. PHYSIOLOGICAL
DETERRENTS
• Protect natural openings – vaginal
secretions discourage growth of many
pathogens, eye-mouth-nasal openings
protected by tears, saliva, or nasal
secretions (that break down bacterial cell
walls)
• Blood has many elements that defend it
from disease causing organisms (WBC,
Plasma, Clotting factors ) & the
inflammation process helps prevent
infection from spreading.
C. NORMAL FLORA • Organisms that survive & grow on the skin & in
the mouth, GI tract & other areas of the body.
• Do not cause disease because their growth is
kept under control by the host’s defense
mechanisms & by the presence of other
microorganisms.
• (when growth of normal flora is suppressed
opportunistic agents may be able to infect &
cause disease)
2. SPECIFIC MECHANISMS
• IMMUNITY – when a host encounters an antigen
that triggers a specific immune response for the
second or later time
• the memory lymphocytes recognize it & quickly
begin growing & dividing –
• immune response occurs so quickly in a second
encounter with the pathogen that the pathogen
does not have enough time to reproduce to
levels that result in disease before the host’s
body has destroyed it.
Passive acquired • acquired artificially by injecting antibodies
to protect from a specific disease
• immediate immunity
• lasts 3-5 weeks
• used when someone exposed to
measures, tetanus, infectious hepatitis
• mother provides newborn with some
passive immunity
Active acquired immunity
lasts longer, two types
1. NATURAL ACQUIRED IMMUNITY –
result of having had and recovered from
a disease ( if you have had measles will
probably not get it again – you have
manufactured antibodies)
2. ARTIFICIAL ACQUIRED IMMUNITY –
come from being vaccinated
3. VACCINATION
• Vaccine is either killed or weakened (attenuated)
strain of a particular pathogen, or solution
containing critical antigens from the pathogen.
Body’s immune system will respond to these
vaccines as if they contain the actual pathogen,
even though the vaccine is not capable of
causing the disease. Rapid activation of
immune cells prevents disease
•
MEASLES OUTBREAK ACTIVITY
It began with Naoko Yomata. She and her
family had just moved when she started
the second half of their junior year at
Western High in a small town in
Washington State. One week into the
semester, she had a sore throat, felt
exhausted, and developed a fever of
102F. Soon, she had a red rash all over
her body – measles.
Ten days later, Caleb Miller and Jessica
Johnson came down with measles. These
students were in Naoko’s biology class,
and Jessica was her lab partner. The
following week, a sophomore, Michael
Chen, had measles and so did the
students’ biology teacher, Ms. Baker.
The local public health officer was alarmed.
Western High hadn’t had a case of
measles in 10 years, and now there were
five cases in less than a month.
A little sleuthing revealed the following:
Naoko had just arrived in the United States from
her home country, Japan, where she apparently
contracted measles. She had not been
vaccinated as a child. Caleb was also
susceptible to measles because his parents had
objected to vaccinations. Jessica and Michael
were vaccinated when they were 15 months and
18 months old, respectively, but they had missed
the required “booster shot” during elementary
school.
Ms. Baker was vaccinated in 1966 when
she was 5 years old. Later studies
showed that the initial “killed measles”
vaccine was not very effective compared
with the currently used “live measles”
vaccine, first available in 1968. Ms. Baker
was unaware that her vaccination was not
effective or that she needed a booster
shot.
The results of the public health officer’s detective
work explained why Naoko, Caleb, Jessica,
Michael, and Ms. Baker go the measles. But
there is another question:
In the 1950’s and 1960’s (before the measles
vaccine was developed), most people got this
disease as preschool children or as elementary
school students. Why didn’t the unvaccinated or
inadequately vaccinated students and teacher at
Western High get the measles when they were
children, rather than now, as teenagers or
adults?
BT06.02 ANALYZE THE ROLE OF
PUBLIC HEALTH IN THE PREVENTION
OF INFECTIOUS DISEASES
• Developed countries have regulations that
help protect the general public from
infectious diseases. Public health
measures typically involve eliminating the
pathogen from its reservoir or from its
route of transmission.
Those measures include:
1. ENSURING A SAFE
WATER SUPPLY
2. EFFECTIVELY MANAGING SEWAGE
TREATMENT AND DISPOSAL
3. INITIATING FOOD SAFETY
4. ANIMAL CONTROL
VACCINATION PROGRAMS
Rabies
• This vaccine is given after your dog is 12 weeks of age and then at
one year and every three years after that. Rabies is a severe
disease that affects an animal's neurologic system and can make
them more aggressive, stumble; seizure, and they can act like they
are in a stupor. Conversely, wildlife with rabies will often act more
friendly. Any warm-blooded animal can have and transmit rabies,
but bats are the most common carriers in the northwest Rabies is
transmitted through bite wounds. Rabies vaccination is so important
because of the severity of the disease, the fact that it is an incurable
disease, and because of the public health implication (people can
contract rabies).
DHLPP
• (D = Distemper, H = Infectious Canine
Hepatitis, L = Leptospirosis, P =
Parainfluenza, P=Parvovirus) This vaccine
is given at 8, 10, 12, 16 and sometimes 20
weeks of age and then yearly.
Distemper
A viral disease transmitted by aerosolization
of infective droplets. It can cause
neurologic disease, respiratory disease,
conjunctivitis, and seizures.
Leptospirosis
This is a bacterial disease that is shed in
the urine and can be found in standing
water. It can cause liver and kidney
disease manifesting as fever, inappetance,
and increased thirst or decreased urine
production.
• Parainfluenza
• This is a virus transmitted by
aerosolization. It is part of the kennel
cough disease complex and often will
manifest itself as a cough.
• Bordetella
• This is a bacterial disease that is part of
the kennel cough complex. Animals with
the disease will often present with a
cough. The vaccine is recommended for
dogs that are going to board in a kennel or
will be around other dogs in a confined
space (dog shows or obedience classes).
The vaccine is given yearly but it is best to
have your dog vaccinated 7-10 days
before they arrive at the kennel.
A. Public health measures toward
prevention
1. Safe water – many pathogens that cause GI diseases
are transmitted via water. Water used for washing,
drinking, and preparing food is purified before it goes into
homes.
• In the U.S. water is purified through
SETTLING, FILTRATION, AND
CHLORINATION. Well water and springs
are usually safe if guidelines about
distance from sewage disposal facilities
are followed.
• **Purification systems may be
overwhelmed and breakdown due to
unusual flooding. Because GI pathogens
leave the body in the feces, public water
must be guarded against contamination
from sewage.
2. SEWAGE TREATMENT
• and disposal is mandated by the U.S.
government. Solid matter (sludge) is
separated from liquid portion (effluent).
The effluent is chlorinated to kill pathogens
before it is released to rivers or lakes. The
sludge is burned or dumped.
3. FOOD SAFETY
The U.S. has many standards, inspection
plans, and regulations about food
preparation, handling, and distribution.
• Meat packing facilities are inspected
regularly to detect & eliminate diseased
animals, residues from pesticides &
antibiotics, and contamination by bacteria
and other parasites.
Process of meat cutting &
refrigeration observed
• Restaurants & supermarkets are
inspected. Industry standards for canning
& preserving foods are maintained through
periodic quality control checks. Any
contamination found – entire batch
recalled.
Milk is pasteurized and dated
for sale.
4. ANIMAL CONTROL
PROGRAMS
Animals are carriers of many diseases that also
affect humans.
Domestic herds are inspected for a variety of
diseases.
Pet owners must have their pets vaccinated for
rabies.
Health officials are mandated to impound and
destroy animals wild and stray animals that have
bit humans.
Many diseases are spread by rodents therefore
there are rat control programs in urban areas.
5. VACCINATION PROGRAMS
Mandate that children be vaccinated prior to
attending school.
• THRESHOLD PROPORTION – if a certain
proportion of a population is immune to a
disease, the pathogen that causes that disease
will be unable to reproduce itself at a high
enough level to maintain itself in the population.
• Vaccination programs aim to achieve the
immunization of at least the threshold number of
individuals for the population
6. PESITICIDES
To block vector-borne disease – those
carried by mosquitoes.
Can be controlled by eliminating breeding
areas for insects (draining areas where
stagnant water collects)
B. PUBLIC HEALTH
ORGANIZATIONS
Enforce regulation, provide public health
services
l. NATIONAL INSTITUTES OF
HEALTH (NIH) supports health related
research aimed at understanding,
preventing, treating, and controlling
infectious and other diseases of
humankind.
2. CENTER FOR DISEASE CONTROL –
investigate disease outbreaks, publish a
summary of current epidemiological
reports, and sponsor a variety of
education programs, research projects,
and reference laboratories.
3. FOOD AND DRUG
ADMINISTRATION
– monitors the safety of our food, medicines,
and many other products that we use
daily.
4. WORLD HEALTH
ORGANIZATION(WHO) – provide international surveillance
and control of disease. Coordinates
multinational vaccination campaigns.
C. BENEFITS OF PUBLIC
HEALTH RESEARCH
1. New research techniques – rapid
identification
2. HIV protease inhibitors
3. Vaccine research
4. Identification of better preventative
measures
BT06.03 INVESTIGATE THE TREATMENT
OF INFECTIOUS DISEASES
A. DRUGS USED TO TREAT bacterial diseases
can be grouped into categories based on their
modes of action.
• PENICILLINS/CEPHALOSPORINS – interfere
with certain layers of cell wall
• CHLORAMPHENICOL, TETRACYCLINES,
ERYTHROMYCINS – may be toxic when used
in high doses or prolonged periods of time
• RIFAMPIN – used for treatment of TB
B. DRUGS THAT EFFECTIVELY
INHIBIT VIRAL infections
Are highly toxic to host cells because viruses
use the host’s metabolic enzymes in
reproduction. Most viral illnesses are treated
symptomatically until the host’s immune system
controls & eliminates the pathogen
• Antiviral drugs target virus-specific enzymes
• Acyclovir – used in treatment of genital herpes
• Amantadine – used to prevent or moderate
influenza
• AZT – inhibit replication of HIV genome
C. DEVELOPMENT OF DRUGS USED TO
TREAT FUNGAL, PROTOZOAN, &
HELMINTHIC DISEASES
are also highly toxic to mammals. Drugs
target key components of their replicative
or biosynthetic pathways.
1. AZOLE derivatives inhibit sterol
synthesis
2. AMPHOTERICIN B – disrupts cell
membrane
D. ANTIMICROBIAL RESISTANCE
PRESENTS ONGOING PROBLEMS
in the fight against infectious diseases.
• PENICILLIN RESISTANCE noted as early
as 1943
• Mycobacterium tuberculosis – some
strains resistant to all drugs
• Resistance to antibiotics result of
changes in genetic information
•
Watch Debi’s story on NIH CD at bottom – movies files folder DB 5A-5D
Debi’s story
1. Debi contracted tuberculosis from…
2. The symptoms Debi had were……
3. The treatment to cure TB is…..
4. When Debi started the treatment…….
5. On Valentine’s Day 1994, Debi learned…
6. The drugs Debi took to cure her TB were
not working because…..
7. Debi had a relapse (developed an active
case of TB again), even though her
health had improved and she was still
taking the drugs to cure TB, because….
8. Debi was finally cured of TB by …….
9. Debi’s warning about infectious diseases
like TB is…….
Antibiotic Concerns
Each of these statements describes a potentially
inappropriate use of antibiotics. How would you
persuade people to eliminate unnecessary use
of antibiotics in these cases?
#1 – In response to pressure from patients
to “give me something” some doctors
prescribe antibiotics before they know
whether a patient’s illness is caused by a
virus or a bacteria.
#2 – Antibiotics are widely used in livestock
feed to improve the growth of animals.
#3 – A popular marketing strategy for some
products intended for healthy people (for
example, hand soaps and children’s toys)
is to include antibacterial drugs in the
products.
Watch Phage video on favorites
BT06.04 ANALYZE EMERGING & REEMERGING INFECTIOUS DISEASES
** Globally,
infectious diseases
remain the leading cause of
death, & they are third leading
cause of death in the U.S.
watch DA1 NIH dvd
CAUSES OF DEATH QUIZ
1. Which of the following diseases has
been recognized since antiquity?
a. AIDS
b. Ebola hemorrhagic fever
c. Guinea worm disease
d. Legionnaire disease
2. In the 1700’s and 1800’s, a terrible,
wasting disease killed thousands of
European and American city dwellers.
What disease was this?
a. AIDS
b. Lung cancer
c. Polio
d. tuberculosis
3. What infectious disease causing severe
fever and chills plagued settler in the
Southern and Midwestern U.S. during
the 1800s and early 1900s?
a. Legionnaire disease
b. Lyme disease
c. malaria
d. schistosomiasis
4. Most deaths among U.S. servicemen in
1918 were due to what cause?
a. Automobile accidents
b. Flu
c. injuries sustained on the battlefields of
World War I
d. plague
5. In 1994, a terrible disease nearly killed
an 18 year old high school student in
California. Which of the following
diseases was it?
a. AIDS
b. Breast cancer
c. Cystic fibrosis
d. tuberculosis
6. According to the World Health
Organization, which of the following
diseases caused more deaths in 1998
than the others?
a. AIDS
b. Diabetes
c. Lung cancer
d. pneumonia
A.EMERGING INFECTIOUS
DISEASES
• Have not occurred in humans before
(difficult to establish & probably rare)
• Have occurred previously but affected
only small numbers in isolated places
(AIDS & Ebola hemorrhagic fever)
• Or have occurred throughout human
history, but only recently recognized as
disease due to infectious agent (Lyme
Disease & Gastric ulcers)
• Contributing factors – environmental
changes are related
EX: (when humans began encountering
insect vector or rodent host in greater
numbers than ever before. Changing
technologies (air conditioning, & mass
food production
B. RE-EMERGING INFECTIOUS
DISEASES
Once were major health problems
globally or in a particular country,
then declined dramatically, but are
again becoming health problems for a
significant proportion of the
population
•
Examples: Malaria & tuberculosis
• Contributing factors:
• Tuberculosis – evolution of causative
bacteria – acquired resistance to the
antibiotics used to treat it
• Malaria – has become drug resistant &
vector mosquito has acquired resistance
to pesticides as well
• Diptheria & Pertussis (whooping cough)
– inadequate vaccination of population
• Activity of disease cards –
• Graph to put answers – smartboard file
BT06.05 EXAMINE THE
CONTAINMENT OF BIOTERRORISM
AGENTS
Agents
 Bacterial- Anthrax and Plague
 Viral- Small Pox

Toxins- Botulism and Ricin
Anthrax
• Acute infectious disease caused by bacillus anthracis.
• Infections in humans:
• Skin contact – cutaneous, ingestion-gastrointestinal, inhalationpumonary
• Person-to-person transmission of inhalation disease does not occur.
*
• *direct exposure to vesicle secretions of cutaneous anthrax can
result in a secondary infection.
• Pulmonary signs and symptoms:
• Flu-like symptoms that may briefly improve two to four days after
initial symptoms
• Abrupt onset of respiratory failure
• Hemodynamic collapse
• Thoracic edema
• Widened mediastinum on xray
• Positive blood culture in 2-3 days of illness
Prognosis:
• Good if treated early. Increased mortality rate if treated after
respiratory onset.
• Cutaneous signs and symptoms:
• Local skin involvement with direct contact
• Commonly seen on head, forearms, or hands
• Localized itching followed by popular lesion that turns vescular
within 2-6 days – develops into depressed black eschar
• Prognosis:
• Good if treated with antibiotics.
• Gastrointestinal signs and symptoms:
• Abdominal pain, nausea, vomiting, fever
• Bloody diarrhea, hematemesis
• Positive culture after 2-3 days
• Prognosis:
• If progression to toxemia and sepsis, prognosis is poor.
Modes of transmission
•
•
•
•
•
•
•
•
•
Inhalation of spores
Skin contact
Ingestion of contaminated food
Incubation period:
Pulmonary: 2-60 days
Cutaneous: 1-7 days
Gastrointestinal: 1-7 days
Transmission:
Anthrax is not airborne person to person. Direct contact
with infectious skin lesions can transmit infection.
• Prevention:
• Vaccine available-limited quantities.
Botulism
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Potent neurotoxin caused by an anaerobic bacillus- colstridium
botulinum.
Transmission:
Contaminated food
Inhalation
Signs and symptoms:
Gastrointestinal symptoms
Drooping eyelids
Weakened jaw clench
Difficulty swallowing or speaking
Blurred vision
Respiratory distress
Incubation period:
Neurological SxS for food borne botulism – 12-36 hours after ingestion
Neurological SxS for inhalation botulism – 24-72 hours after exposure
Prevention: Vaccine available
Botulism cannot be transmitted person to person.
Plague
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Plague is an acute bacterial disease caused by yersinia pestis.
Signs and Symptoms:
Fever
Cough
Chest pain
Hemoptysis
Watery sputum
Bronchopneumonia on xray
Mode of Transmission:
Plague normally transmitted from an infected flea
Can be aerosol-probable use in bioterrorism
Can be transmitted person to person
Incubation period:
Flea bite – 2-8 days
Aerosol – 1-3 days
Prognosis: Good if treated with antibiotics early.
Ricin
• Ricin is a potent protein toxin derived from Castor
beans. Castor beans are found easily all over the
world and the toxin is fairly easily produced. For
this reason ricin could be used as a biological
weapon with relative ease.
• Infections in Humans
• Aerosol
• Ingestion
• Signs and Symptoms:
•
18-24 hours
• Weakness
• Fever
• Cough
• Pulmonary edema
• 36-72 hours
• Severe respiratory distress
• Death from hypoxemia
•
Incubation period:
• 8-18 hours
• Prognosis:
• Poor-no vaccine available
• Ricin does not spread easily person to person.
Smallpox
• Smallpox is an acute viral illness caused by
the variola virus.
• Mode of transmission: Airborne: droplets
• Signs and symptoms:
• Flu like symptoms-fever, myalgia
• Skin lesions appear quickly progressing from
macules to papules to vesicles
• Rash scabs over in 1-2 weeks
• Rash occurs in all areas at once, not in crops
• Incubation period:
• From 7 to17 days, average is 12 days
• Contagious when the rash is apparent and
remains infectious until scabs separate (approx.
3 weeks)
• Prognosis:
• Vaccine available and effective post-exposure
• Passive immunization is also available in the
form of vaccina- immune-globulin (Vig)
• Smallpox has a high mortality rate.
B. CONTAINMENT OF
BIOTERRORISM AGENTS
ISOLATION PRACTICES –
use of STANDARD PRECAUTIONS –
designed to reduce transmission from both
recognized & unrecognized sources of
infection in healthcare facilities, & are
recommended for all patients receiving
care, regardless of their diagnosis or
presumed infection status. Prevent direct
contact with all body fluids (blood,
secretions, excretions, non intact skin
(including rashes), & mucous membranes.
•
• HANDWASHING
• GLOVES
• MASKS/EYE PROTECTION OR FACE
SHIELDS
• GOWNS
PATIENT PLACEMENT
Infection control practices should be followed
unless number of patients is too large to allow
routine triage & isolation strategies.
•
Group patients with similar syndromes
into a special area that:
– Has controlled entry to minimize possibility of
transmission
– Reasonable access to vital diagnostic
services
– Based on patterns of airflow & ventilation
– Availability of adequate plumbing & waste
disposal
– Capacity to safely hold potentially large
numbers of patients
PATIENT TRANSPORT
Most infections associated with bioterrorism
agents cannot be transmitted from patient
to patient.
.
• In general, the transport & movement of
infected patients should be limited to
movement that is essential to provide
patient care, thus reducing the
opportunities for transmission of
microorganisms within healthcare facilities
• CLEANING, DISINFECTION, &
STERILIZATION OF EQUIPMENT &
ENVIRONMENT –
principles of standard precaution should be
generally applied for the management of
patient-care equipment & environmental
control
DISCHARGE MANAGEMENT
Ideally, infected patients will not be
discharged until deemed noninfectious.
Depending on exposure & illness, home
care instructions:
• use appropriate barrier precautions,
handwashing, waste management,
cleaning & disinfection of environment &
patient care items
POST MORTEM CARE
Pathology departments & clinical labs
should be informed of a potentially
infectious outbreak prior to submitting any
specimens for examination or disposal.
All autopsies should be performed carefully
using all personal protective equipment.
Instructions for funeral home directors
should be developed.
• Demonstrate handwashing technique
Bioterrorism
• Terrorism is defined in the United
States Code, Title 18, section
2331(18 USC 2331) as “Violent acts
or acts dangerous to human life
that…appear to be intended:
• To intimidate or coerce a civilian
population;
• To influence the policy of a
government by intimidation or
coercion; or
• To affect the conduct of a government by
assassination or kidnapping.
• Biological weapons used in bioterrorism
are living microorganisms such as
bacteria, viruses, fungi, that can kill or
incapacitate.
• Health care facilities may be the initial site
of recognition and response to
bioterrorism activity. Because of this, the
names and telephone numbers for internal
and external departments or agencies that
need to be contacted should be kept by
each facility in its bioterrorism readiness
plan.
Response to bioterrorism agents:
• Internal reporting requirements (within a
facility):
– Infection control personnel
– Epidemiologist (local and state)
– Administration (health care facility and health
department)
– Office of public affairs in the health facility
External contacts (outside of
facility)
– Local health department
– State Health Department
– FBI
– CDC
– Local police
– EMS