Post on 17-Dec-2015
Biological hazards
• Non infectious effects– Toxic effects :• Part of the membranes of bacteria (Endotoxins)• Toxins produced by moulds (mycotoxins)
– Allergy• Infectious effects– Bacteria, fungi, viruses …– We will focus on infection …
European Classification of biological agents (based only on the risk of infection)
Group Can cause human disease
Can be a hazard for workers
Can spread to the
community
Effective prophylaxis or
treatment available
1 No - - -
2 Yes Yes Unlikely Yes
3 Yes Yes Possible Yes
4 Yes Yes High risk No
Hazardous agents are those belonging to group 2, 3 and 4
Exemples :Group 2 : Clostridium perfringens, CytomegalovirusGroup 3 : Mycobacterium tuberculosis, Hepatitis B virus, Plasmodium falciparumGroup 4 : Lassa virus, Ebola virus
Sources of exposure
• Patients in hospital settings• Bugs (ticks, sarcoptes …)• Animals (veterinarians, slaughterhouses)
The way to infection
Emission of germs AerialContact – ingestionPercutaneous
Infection if susceptible
ReservoirReservoir
HostHostDispersionDispersion infectioninfection
Main occupations exposed
• Healthcare workers (many viruses)– hazards represented by biological agents present
in patients• Farmers (brucellosis, zoonosis)• Outdoor workers (Leptospirosis, lyme disease)
Hepatitis A
• Spread in the feces of infected individuals– Risk for travellers in low income countries
• Risk of spreading to the community by infected food handlers
Hepatitis B
• A high risk for healthcare workers (HCWs)• Blood exposure– Needlestick exposures for HCWs• Up to 45% of risk to be infected in case of needlestick
exposure with a needle that have been used for an infected patient
– Skin contact (rescuers)– Wounds (police officers, fire fighters)
Tuberculosis
• Occupational risk for– HCWs– People working with migrants from high
prevalence countries• Transmition by small dropplets released by
infected patients– Dropplets too small to settle– Can spread at several meters from the patient
Risk assessment
• Identify the sources of biological agents• Identify the possible ways of transmission• Identify susceptible workers
Avoid exposure
ReservoirReservoir
HostHostDispersionDispersion
Barriers
GlovesMasks
Long sleeves for outdoor workers
Which mask for HCWs ?• Big dropplets (pertussis, meningococcal
infection, influenza …)– Settle at short distance (1m) & straight trajectory– Surgical mask enough
• Small dropplets (tuberculosis, chickenpox …)– Don’t settle (airborne transmission)– Respirator needed (N95 or FFP2)
Avoid contamination
ReservoirReservoir
HostHostDispersionDispersion
Hand washing
Standard precautionsDesinfection of surfaces
Early removal of ticks
Vaccination
Hepatitis B vaccine for HCWsHepatitis A vaccine for sewage workersLeptospirosis vaccine for foresters
ReservoirReservoir
HostHostDispersionDispersion
Avoid infection
Chemoprophylaxis for HIV in case of needlestick exposureAntibioprophylaxis in case of exposure to Bordetella pertussis
ReservoirReservoir
HostHostDispersionDispersion infectioninfection
Preventive treatment
Treat infection
Antibiotics in case of erythema migrans skin lesion following tick bite
ReservoirReservoir
HostHostDispersionDispersion infectioninfection
Early treatment
Treat infection
ReservoirReservoir
HostHostDispersionDispersion infectioninfection
Follow upScreaning
Don’t forget the WARP
• Work : could the work of the patient be (part of) the cause or the aggravation of his/her complaint or disease? • Skin lesion for a sewage worker
• Activities : could the complaint / disease of the patient have consequences for his/her activities and participation in work• Hepatitis B infection in a surgeon• Tuberculosis in an HCW
• Referral : should I refer my patient to an occupational physician or another specialist • Should this pregnant HCW, unprotected against rubella, take specific
precautions ?• Prevention : Can I do something to prevent the (return of the) complaint
or disease?• Is this HCW protected against hepatitis B ?
Some useful links• Siegel JD, Rhinehart E, Jackson M, Chiarello L, and the Healthcare Infection
Control Practices Advisory Committee, 2007 Guideline for Isolation Precautions: Preventing Transmission of Ifnectious Agents in Healthcare Settings, June 2007 – http://www.cdc.gov/ncidod/dhqp/pdf/isolation2007.pdf
• Canadian Centre for Occupational Health and Safety. Biological Hazards. http://www.ccohs.ca/oshanswers/biol_hazards/
• National Institute for Occupational Safety and Health (NIOSH). Health Care Workers. http://www.cdc.gov/niosh/topics/healthcare/
• National Institute for Occupational Safety and Health (NIOSH). Diseases & Injuries. http://www.cdc.gov/niosh/topics/diseases.html