1. OCCUPATIONAL MEDICINE SPECIALIST
BIOLOGIC AGENT
By : Dr ASLANI
OCCUPATIONAL MEDICINE SPECIALIST

3. Contents: Definition of biologic agent Types Spreading
Definition of occupational infection TB
HBV
HCV
HIV
Zoonoses
Controlling the risks

4. 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.’

5. Types: bacteria viruses fungi (yeasts and moulds) parasites plants
They include:
bacteria
viruses
fungi (yeasts and moulds)
parasites
plants

6. Occupations and workplaces where people may come into contact with biological hazards
Medical staff, cleaning staff and laboratory technicians in the medical profession;
Cleaning services
Agriculture, fishery, veterinary services,

9. BIOLOGICAL OCCUPATIONAL HAZARDS
= occup. biohazards
infectious
allergic
toxic
Markku Seuri, FIOH, 2004

10. SPREADING by inhalation by ingestion (from hand to mouth)
by sharps injuries
by blood or other body fluid contact
by bites

16. 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.

17. 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.

18. 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.
………………………….

22. Occupational illness through contact with human
Prevention
Agents
Type of contact
Gloves, needle stick prevention
Hepatitis B, C
Percutaneous inoculation
Respiratory isolation, air filtration(TB)
TB, VZV,SARS, measles
Air born transmission
Respiratory isolation, respiratory droplet precautions
SARS, rubella, influenza, mycoplasma, diphteria, etc
Respiratory droplet
Hand washing, gloves
Shigella, vibrio, clostridium difficiel, E coli, etc
Fecal- oral
Gloves, protective clothing
HSV, VZV, SARS
Direct contact

23. TUBERCLOSIS

25. tuberculosis عامل:مایکوباکتریوم توبرکلوزیز
Incubation Period: (+PPD)4-12W
The risk of development of clinical disease following infection is higher in
-سوء تغذیه
-نقص ایمنی
-ژنتیک(HLA Bw15)
-سن(کودکی و سال)
-بیماری ها(سیلیکوز، لوسمی، لنفوم، کارسینوم UpperGI،دیابت(

26. tuberculosis Staffs of laboratories and necropsy rooms
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

27. tuberculosis Tubercle bacilli may be present in : gastric fluid
cerebrospinal fluid
urine
sputum

28. 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

29. tuberculosis PPD>=5mm: close contacts of infectious patients
immunosuppressed
persons with known or suspected human immunodeficiency infection (HIV)

30. 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

31. tuberculosis PPD>=15mm:
persons with no risk factors in areas of low prevalence

32. tuberculosis PPD:Neg measles Hodgkin disease sarcoidosis
immunosuppressive states

33. tuberculosis Occupational candidates for periodic PPD testing include
those having contact with suspected or known infected patients,
persons working with potentially infected cattle (veterinarians,……)
all others working in the higher-risk environments mentioned above.

34. Hepatitis B Virus (HBV)

35. 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.

36. 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.

37. are low enough that these are not felt to be routes of transmission
Viral titers in
urine,
feces,
tears
Saliva
are low enough that these are not felt to be routes of transmission

38. 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

39. 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.

40. Those who do not develop antibodies after six total doses should consider changing positions at work not involving blood or blood products.

41. Hepatitis C Virus (HCV)

42. Occupational Exposure
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.

43. Following exposures to known HCV-positive blood or blood products
HCV RNA testing is often considered 2–4 weeks after exposure

44. Following exposures to Unknown Source
HCV Ab testing is often considered 6–8 weeks after exposure

45. Human Immunodeficiency Virus (HIV)

46. HIV transmission occurs via blood and sexual contact.
Fortunately, occupationally acquired infection has been a relatively infrequent (albeit serious) occurrence.

47. body fluids considered higher risk for HIV transmission
Blood
semen and vaginal secretions
cerebrospinal
synovial
pleural
peritoneal
pericardial
amniotic fluids

48. 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.

49. postexposure TEST Baseline testing for preexisting
infection at the time of the exposure
follow-up testing at 6 weeks and 3 and 6 months.

50. 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.

51. Zoonoses(occupation at risk)
veterinary medicine
farm workers
zoo keepers
meat processing plant workers and butchers
leather industries
pet shop workers

52. 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),

53. 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;

54. Controlling the risks Engineering controls such as improvement of
- ventilation,
-partial isolation of the contamination source,
-installationof negative pressure and separate ventilation and airconditioning system (e.g. in medical wards for infectiousdiseases)
-the use of ultraviolet lamps can help contain the spreadof contaminants.

55. Controlling the risks If the contact with biological hazards cannot be
prevented,
the employees must use personal protective equipment and adhere strictly to the practice of personal hygiene.

56. Controlling the risks

57. THANKS