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: bacteria viruses fungi (yeasts and moulds) parasites plants Occupations and workplaces where people may come into contact with biological hazards Medical staff, cleaning staff and laboratory technicians in the medical profession; Healthcare services; Cleaning services Agriculture, fishery, veterinary services, BIOLOGICAL OCCUPATIONAL HAZARDS = occup. biohazards infectious allergic toxic Markku Seuri, FIOH, 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 PreventionAgentsType of contact Gloves, needle stick prevention Hepatitis B, CPercutaneous inoculation air filtration(TB) Respiratory isolation, air filtration(TB) TB TB, VZV,SARS, measlesAir born transmission respiratory droplet precautions Respiratory isolation, respiratory droplet precautions mycoplasma, 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, SARSDirect contact TUBERCLOSIS tuberculosis : Incubation Period: (+PPD)4-12W The risk of development of clinical disease following infection is higher in - - - (HLA Bw15) - ( ) - ( UpperGI ( 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) 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 tuberculosis PPD>=15mm: persons with no risk factors in areas of low prevalence tuberculosis PPD:Neg measles Hodgkin disease sarcoidosis immunosuppressive states 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. 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. 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 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 3050% 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 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 HCV-positive blood or blood products HCV RNA testing is often considered 24 weeks after exposure Following exposures to Unknown Source HCV Ab testing is often considered 68 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 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 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. Controlling the risks If the contact with biological hazards cannot be prevented, use personal protective equipment adhere strictly to the practice of personal hygiene. the employees must use personal protective equipment and adhere strictly to the practice of personal hygiene. Controlling the risks