Transcript Occupational infection - Isfahan University of Medical

BIOLOGIC AGENT
By : Dr ASLANI
OCCUPATIONAL MEDICINE SPECIALIST
CONTENTS:
Definition of biologic agent
 Types
 Spreading
 Definition of occupational infection
 TB
 HBV
 HCV
 HIV
 Zoonoses
 Controlling the risks

DEFINITION OF BIOLOGIC AGENT:
Biological agents are living organisms or
products of living organisms.,
which may cause infection, allergy,
toxicity or otherwise create a hazard to
human health.’

TYPES:
They include:
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
bacteria
viruses
fungi (yeasts and moulds)
parasites
plants
BIOLOGICAL OCCUPATIONAL
HAZARDS
occup. biohazards
 infectious
 allergic
 toxic
Markku Seuri, FIOH, 2004
8
=
SPREADING
 by
inhalation
 by ingestion (from hand to mouth)
 by sharps injuries
 by blood or other body fluid contact
 by bites


Work-related infection has been reported in the
literature as the third leading cause of occupational
disease.
Healthcare workers (HCWs) who are most often at
the frontline of outbreaks of emerging agents and
infectious patients are more at risk.
DEFINITION OF OCCUPATIONAL INFECTION
 Work-related
infectious disease is
referred to as disease that is caused or
aggravated by occupational exposure to
biological agents including bacteria,
fungi, viruses and parasites (helminths,
protozoa) through human, animal
and/or environmental contact.
OCCUPATIONAL INFECTION CAN OCCUR
FOLLOWING:
 contact
with infected persons, as in the case of
health care workers.
 with infected animal or human tissue,
secretions, or excretions, as in laboratory
workers.
 with infected animals, as in agriculture.
 ………………………….
OCCUPATIONAL ILLNESS THROUGH CONTACT WITH
HUMAN
Type of
contact
Agents
Prevention
Percutaneous
inoculation
Hepatitis B, C
Gloves, needle stick
prevention
Air born transmission
TB, VZV,SARS, measles
Respiratory isolation,
air filtration(TB)
Respiratory droplet
SARS, rubella, influenza, mycoplasma, Respiratory isolation,
diphteria, etc
respiratory droplet
precautions
Fecal- oral
Shigella, vibrio, clostridium difficiel, E
coli, etc
Hand washing, gloves
Direct contact
HSV, VZV, SARS
Gloves, protective
clothing
TUBERCLOSIS
TUBERCULOSIS
‫مایکوباکتریوم توبرکلوزیز‬:‫ عامل‬
(+PPD)4-12W :Incubation Period 
The risk of development of clinical disease 
following infection is higher in
‫سوء تغذیه‬‫نقص ایمنی‬)HLA Bw15(‫ژنتیک‬)‫ سال‬16-21 ‫سن(کودکی و‬(‫دیابت‬،UpperGI ‫ کارسینوم‬،‫ لنفوم‬،‫ لوسمی‬،‫بیماری ها(سیلیکوز‬-
TUBERCULOSIS

HIGH RISK WORKS:
Staffs of laboratories and necropsy rooms
 health care settings (especially hospitals,
long-term care facilities, and dialysis
centers)
 substance abuse treatment centers

TUBERCULOSIS

Tubercle bacilli may be present in :
gastric fluid
cerebrospinal fluid
urine
sputum
TUBERCULOSIS

Transmition:
coughing
sneezing
talking by expelling small infectious
droplets that may remain suspended in
the air for several hours and then inhaled
by susceptible persons
TUBERCULOSIS

PPD>=5mm:
close contacts of infectious patients
 immunosuppressed
 persons with known or suspected human
immunodeficiency infection (HIV)
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TUBERCULOSIS

PPD>=10mm:
high-prevalence (> 5%),
 high-risk occupational groups (above)
 high-risk groups such as
-immigrants from high prevalence areas
-alcoholics,
-intravenous drug users, and
-those with other disease states mentioned
above
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TUBERCULOSIS
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PPD>=15mm:
persons with no risk factors in areas of
low prevalence
TUBERCULOSIS

PPD:Neg
measles
Hodgkin disease
sarcoidosis
immunosuppressive states
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TUBERCULOSIS
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Occupational candidates for periodic PPD
testing include
those having contact with suspected or known
infected patients,
persons working with potentially infected cattle
(veterinarians, zoo keepers)
all others working in the higher-risk environments
mentioned above.
Hepatitis B Virus (HBV)
INDIVIDUALS AT OCCUPATIONAL RISK

Hepatitis B vaccination is recommended for the
following groups who are considered at increased
risk:
healthcare workers
laboratory staff
other occupational risk groups:
-morticians and embalmers
-prison service staff.
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The prevalence of HBV infection among health care
personnel was 10 times higher than the general
population
Blood contains the highest titers of virus in
infected individuals
with lower levels in various other body fluids,
cerebrospinal,
synovial,
pleural,
peritoneal,
Pericardial,
amniotic fluids,
semen and vaginal secretions.

Viral titers in
urine,
 feces,
 tears
 Saliva

are low enough that these are not felt to be
routes of transmission

The risk for transmission of HBV through
needlestick injuries is approximately 30%.
HBV can remain viable for at least 1 month on dried
surfaces at room temperature.
-This poses additional opportunities to acquire
occupational HBV infections when individuals with
 open cuts
or
 abraded skin or mucous membranes contact
contaminated surfaces
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PRESCREENING SEROLOGIC TESTING

The current recommendations
check for surface antibodies 4 weeks to 6 months
following the primary series.
 If the person tests negative for antibodies,
--- three additional doses (for a total of six doses) will
induce antibodies in 30–50% of nonresponders.

 Those
who do not develop
antibodies after six total doses
should consider changing
positions at work not involving
blood or blood products.
Hepatitis C Virus (HCV)
OCCUPATIONAL EXPOSURE
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It has been well-documented that transmission
of hepatitis C in a health care situation can
occur.
The current estimate for transmission of HCV
following a needlestick injury from a positive
carrier of HCV is approximately 1.8%.
Transmission following mucous membrane
exposure is rare.
FOLLOWING EXPOSURES TO KNOWN HCVPOSITIVE BLOOD OR BLOOD PRODUCTS
HCV
RNA testing is often
considered 2–4 weeks after
exposure
FOLLOWING EXPOSURES TO UNKNOWN
SOURCE
HCV
Ab testing is often
considered 6–8 weeks after
exposure
Human Immunodeficiency
Virus (HIV)
HIV TRANSMISSION
occurs
via blood and sexual contact.
Fortunately, occupationally acquired
infection has been a relatively
infrequent (albeit serious)
occurrence.
BODY FLUIDS CONSIDERED HIGHER RISK
FOR
HIV TRANSMISSION
 Blood
 semen
and vaginal secretions
 cerebrospinal
 synovial
 pleural
 peritoneal
 pericardial
 amniotic fluids
THE ESTABLISHED RATE OF TRANSMISSION
FOLLOWING A POSITIVE HIV EXPOSURE
FROM A NEEDLESTICK INJURY
 is
approximately 0.3%,
 making it approximately 10-fold less
transmissible as HCV
 and 100-fold less transmissible as HBV.
POSTEXPOSURE
TEST
 Baseline
testing for preexisting
infection at the time of the exposure
 follow-up
testing at 6 weeks and 3
and 6 months.
ZOONOSES
 Zoonoses
are defined as any disease and/or
infection that is naturally transmissible from
vertebrate animals to humans.
 Occupations
involving contact with infected
animals and/or their infected secretions or
tissues or contact can result in workrelated
zoonotic disease.
ZOONOSES(OCCUPATION AT RISK)
 veterinary
medicine
 farm workers
 zoo keepers
 meat processing plant workers and butchers
 leather industries
 pet shop workers
ZOONOSES
 Zoonoses
involve different types of agents:
 bacteria (eg, salmonellosis and
campylobacteriosis),
 parasites (eg, cysticercosis/taeniasis),
 Rickettsia (eg, Q-fever),
 viruses (eg,rabies and avian influenza),
CONTROLLING THE RISKS
 eliminating

risks:
eg by substituting a hazardous biological
agent with something less/non-hazardous:
 eg using a non-toxigenic strain of a
biological agent when carrying out laboratory
quality control (QC) tests;
CONTROLLING THE RISKS
 controlling

risks at source:
by using engineering controls and giving
collective protective measures priority:
 eg,using needle safety devices to prevent and
control needlestick injuries;
CONTROLLING THE RISKS
 minimising
risks by designing suitable
systems of working:
eg having an effective hand hygiene policy in place in
laboratory or healthcare settings.