Download Anthrax

Fundamentals of
Occupational Medicine:
Biological Hazards
Asst. Prof. Dr. Sumattana Glangkarn
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Biological hazards
 Sources of biological hazards include bacteria,
viruses, insects, plants, birds, animals, and
humans.
 These sources can cause a variety of health
effects ranging from skin irritation and allergies
to infections (e.g., tuberculosis, AIDS), cancer
and so on.
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 Bacterial infection disease: Tetanus,
Tuberculosis, Leptospirosis, Anthrax,
Brucellosis, Melioidosis, and Others
 Viral infection disease: AIDS, Avian Flu, Viral
Hepatitis, Rabies, and Others
 Other microbial infection: Fungal infection,
Parasite, Rickettsia
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Tetatus
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Tetanus
 Tetanus is a vaccine-preventive disease
 Tetanus is an acute, often fatal
 Disease caused by an exotoxin produced by the bacterium
“Clostridium tetani”
 It is characterized by generalized rigidity and convulsive
spasms of skeletal muscles.
 Muscle stiffness usually involves the jaw (lockjaw) and
neck and then becomes generalized
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Mode of Transmission
 Contaminated wounds: major or minor follow; elective
surgery, burns, deep puncture wounds, crush wounds,
animal bites
 Tetanus is not contagious from person to person
 Organism are found primarily in the soil and intestinal
tracts of animals and humans
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Tetanus Complications
 Laryngospasm (Spasm of vocal cord)
 Fractures
 Hypertension
 Nosocomail infections
 Pulmonary embolism
 Aspiration pneumonia
 Death
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Tuberculosis
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Tuberculosis
 TB is an infectious bacterial disease caused by Mycobacterium
tuberculosis, which most commonly affects the lungs.
 It is transmitted from person to person via droplets from the
throat and lungs of people with the active respiratory disease.
 The symptoms of active TB of the lung are coughing, sometimes
with sputum or blood, chest pains, weakness, weight loss, fever
and night sweats.
 Tuberculosis is treatable with a six-month course of antibiotics.
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6 components of the stop TB strategy
 pursuing high-quality DOTS expansion and
enhancement
 addressing TB/HIV, MDR-TB and the needs of
poor and vulnerable populations
 contributing to health system strengthening based
on primary health care
 engaging all care providers
 empowering people with TB and communities
through partnerships
 enabling and promoting research
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Influenza
 Influenza viruses circulating in animals pose threats to
human health.
 Humans can become ill when infected with viruses from
animal sources, such as avian influenza virus subtypes
H5N1 and H9N2 and swine influenza virus subtypes H1N1
and H3N2.
 The primary risk factor for human infection appears to be
direct or indirect exposure to infected live or dead animals
or contaminated environments.
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What is avian influenza?
 Avian influenza has been around for over 100 years. It was
first reported as "fowl plague" in 1878 when it caused a lot
of deaths in chickens in Italy.
 Avian flu can affect the respiratory, gastro-intestinal,
reproductive or nervous system (or combinations of these)
in many kinds of birds. The earliest signs of infection in
chickens are a loss of appetite and a decrease in egg
production.
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 Symptoms of avian flu can range widely from mild illness to
a highly infectious disease that can kill an entire flock of
chickens within hours. Some wild birds and waterfowl (like
ducks and geese) can carry the virus without showing signs
of infection.
 Pigeons appear resistant to the infection.
 Domestic chickens are very susceptible to influenza
infections which can easily spread to other chickens and
quickly turn into epidemics (in poultry).
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How is avian flu spread between birds?
 Avian influenza is mainly spread by direct contact between
infected birds and healthy birds. It can also be transmitted
when birds come in contact with equipment or materials
(including water and feed) that have been contaminated with
feces or secretions from the nose or mouth of infected birds.
 People can also spread the disease indirectly from farm to
farm by their carrying the virus on their clothing, boots or
vehicle wheels.
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How does avian flu spread to humans?
 Disease specialists believe that avian influenza in humans
is mainly caused by contact with: infected chickens or
other birds.
 The virus does not spread easily from birds to humans, or
from human to human.
 All influenza viruses have the ability to change, this
current virus may eventually gain the ability to spread
between people easily.
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Anthrax
 Anthrax is an infectious disease that can affect the skin, the
lungs, as well as the mouth, throat and gastrointestinal
tract.
 The infection sometimes can spread to other parts of the
body, especially if treatment is not started early.
- Anthrax could (very rarely) lead to inflammation of the
meninges (meningitis).
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What causes it?
 Anthrax is caused by a bacterium called Bacillus anthracis.
 The bacteria occur in living tissue of infected animals.
 The bacteria can form spores under certain conditions when,
for example, body fluids infected with the bacteria are
exposed to the air.
 The bacteria cannot live for long outside an animal. On the
other hand, the spores can survive in soil and some other
materials for decades.
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How is anthrax contracted?
 Bacillus anthracis produces small spores.
 When these spores enter a cut or abrasion on the skin they
start a skin infection usually called cutaneous anthrax.
 If the spores are inhaled, they are small enough that they
enter the lungs and cause inhalation anthrax.
 Eating contaminated, undercooked meat can cause
oropharyngeal (mouth and throat) and gastrointestinal
anthrax.
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Is anthrax contagious?
 No.
 Spreading anthrax from person to person is extremely
unlikely to occur.
 It also requires a relatively large dose to infect a person one would have to inhale 8,000 to 50,000 spores.
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What are the symptoms of anthrax?
 Depending on
how the disease
was contracted.
Symptoms usually
occur within 7
days of exposure
(2 to 5 days).
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 The skin infection begins with itchy bumps that resemble
insects bites. Skin bumps develop into painless black blisters.
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 Inhaled anthrax, the initial signs of disease are usually flu-like
symptoms including fever, muscle pain, fatigue, cough and chest
discomfort. The symptoms may progress to severe breathing
problems and shock.
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 Intestinal anthrax symptoms usually begin a few days after
ingestion of the contaminated meat. The symptoms include
abdominal pain, fever, nausea, vomiting and diarrhea.
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How is anthrax recognized?
 Confirmation of a anthrax diagnosis requires laboratory
examinations which identify Bacillus anthracis in the blood,
skin lesions or respiratory secretions.
How is anthrax treated?
 Anthrax can be controlled with antibiotics. To be effective,
treatment should start early after exposure. If left untreated
or if treatment starts too late, anthrax can be fatal.
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Is anthrax an occupational concern?
 Human anthrax is unusual in North American.
 Anthrax can be an occupational hazard of workers who
process hides, hair, bone and bone products and wool.
Animal breeders, slaughterhouse workers, trappers and
hunters, fur industry workers, tanning and leather industry
workers, veterinarians, wildlife, agricultural, and laboratory
workers who handle infected animals can also be at risk for
the infection.
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How can we prevent anthrax?
 Workplaces which process animal products should have adequate
ventilation systems; local exhaust system to reduce dust levels.
 Workers who handle raw animal materials should be informed
about modes of transmission.
 Workers should follow good personal hygiene practices including
care of skin abrasions.
 Workers should use adequate protective clothing and facilities for
washing and changing clothes after work.
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Symptoms: Fever, Chill, Myalgia, Jaundice
Leptospirosis
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How you can get infected
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Rabies
 Rabies is an infectious
disease that spreads from
animals to humans.
 The rabies virus causes the
disease by infecting nerves
in animals and people.
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 The rabies virus travels to the brain (through nerves inside
the brain), the virus reproduces, and then it travels back
through the nerves to most parts of the body.
 Eventually, the virus reaches the salivary glands where it is
released into the saliva in the mouth. By this time, the
disease has usually damaged the brain, sometimes
producing violent behaviour.
 It eventually causes death.
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How long does it take for rabies to develop?
 In people, the incubation period generally ranges from 2 to 8
weeks. (Rare cases, 10 days to 2 years). The incubation
period is shorter in children and in people exposed to a large
dose of the rabies virus. The dose of virus depends on the
size, severity and location of an animal bite or scratch.
 In animals, the incubation period depends on the species of
animal. For dogs it normally ranges between 14 and 60
days, but it can be much longer.
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What is the source of rabies?
 The major risk of rabies comes from contact with the saliva,
body fluids, or tissue of infected animals.
 Animals that can be infected with rabies include all
mammals, but in particular:
- wild animals: foxes, skunks, bats, and raccoons
- livestock: cattle, occasionally horses, sheep, goats, pigs
- pets: cats and dogs
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How do rabies infections occur?
 Rabies virus must enter the body and reach nerve cells.
The virus can enter the body through broken skin.
Droplets containing the virus can pass through mucous
membranes in the eyes, nose, mouth, or intestine.
 Transmission occurs when rabid animals, with the virus
in their saliva, bite people.
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 Farmers or veterinarians can become infected when they
work with their hands in the mouths of rabid cows
which often appear to be choking on food.
 Laboratory workers have also contracted rabies from
cuts or sticks from contaminated needles, scalpels or
other contaminated laboratory equipment.
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What occupations have increased risk of rabies?
 Exposure to wild animals: hunters, trappers, forestry
personnel, wildlife biologists, forest rangers, veterinarians,
zoo personnel
 Exposure to livestock: farmers, farm workers,
veterinarians, laboratory animal researchers and
technicians, slaughterhouse workers, and meat packers and
processors.
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 Exposure to pets: veterinarians, pet groomers, letter
carriers, meter readers, delivery personnel, laboratory
animal researchers and technicians, animal control
officers, and hunters.
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What is the treatment for rabies?
 There is no successful treatment for rabies once the disease
has progressed to the point where signs appear.
 It is very important to stop the disease from developing in
people who may have been exposed to the rabies virus.
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How can workers be protected from rabies?
 Vaccination programs, established to immunize dogs and cats,
have been effective in reducing rabies in pets. However, rabies
will continue to be a threat until the virus can be eliminated from
the wild animals that spread the virus to pets and people.
 Some workers such as veterinarians or animal control officers
have continuing risk of encountering a rabid animal, should be
immunized to ensure that they have protection before having
contact with any animal.
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Workers who have come into contact with saliva, body fluids, or tissue
of animals suspected of having rabies must take the following steps
without delay.
 Immediately clean and flush the wound to full depth with water for
several minutes. If available, use soap or detergent to help kill the
virus. Washing the wound is probably the most effective procedure in
the prevention of rabies.
 Apply a household antiseptic, 70 % alcohol (ethanol), tincture or
aqueous solution of iodine.
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Needlestick injuries
 Needlestick injuries are wounds caused by needles that
accidentally puncture the skin.
 Needlestick injuries are a hazard for people who work with
hypodermic syringes and other needle equipment.
 These injuries can occur at any time when people use,
disassemble, or dispose of needles.
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 When not disposed of properly, needles can become
concealed in linen or garbage and injure other workers who
encounter them unexpectedly.
 Needlestick injuries transmit infectious diseases, especially
blood-borne viruses.
 Concern about AIDS (Acquired Immune Deficiency
Syndrome), hepatitis B, and hepatitis C has prompted
research to find out why these injuries occur and to develop
measures to prevent them.
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What are the hazards of needlestick injuries?
 Accidental punctures by contaminated needles can inject
hazardous fluids into the body through the skin.
 Even small amounts of infectious fluid can spread certain
diseases effectively.
 Accidental injection of blood-borne viruses is the major
hazard of needlestick injuries, especially the viruses that
cause AIDS(the HIV virus), hepatitis B, and hepatitis C.
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 The risk of infection after exposure to infected
blood varies by blood-borne pathogen.
 The risk of transmission after exposure to HIVinfected blood is about 0.3%, whereas it is
estimated to be up to 100 times greater for hepatitis
B virus (30%) and could be as high as 10% for
hepatitis C virus.
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Clean and Care
 Proper hand hygiene is one of the most simple and
effective ways to reduce health care-associated infections,
which affect hundreds of millions of patients every year.
However, about 60% of health workers do not always
follow best hand hygiene practices.
 WHO is raising global awareness about hand hygiene in
patient care to reduce the known burden of these
infections.
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