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A description of Biological Agents that could affect people in the workplace if Health and Safety protocols are not followed.

A description of Biological Agents that could affect people in the workplace if Health and Safety protocols are not followed.

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  • 1. Biological Agents
  • 2. Zoonoses Zoonoses are animal infections which may be transmitted to people in the course of their work. Common examples include: Brucellosis Q Fever Orf Psittacosis Anthrax Glanders
  • 3. Brucellosis Caused by the bacterium Brucella abortus, which may infect people handling cattle or pigs or their carcasses in abattoirs Not very severe but involves loss of appetite, headache, insomnia and slight fever In the UK a policy of eradication has been pursued since the 60’s by destroying any infected cattle
  • 4. Q Fever Known to occur in farm workers, abattoir workers and veterinary surgeons The causative agent, Coxiela burnetii, has been found in cows and sheep Not as serious as Brucellosis and takes the form of cold or `flu-like symptoms
  • 5. Orf A contagious pustular dermatitis of viral origin, mainly affecting farm workers, shepherds, sheep shearers, butchers and abattoir workers Lesion enlarges and often becomes ulcerated, exuding fluid and pus Complete recovery occurs in about 3 weeks
  • 6. Psittacosis A virus-like bacterium of poultry, game and other birds Can be fatal to man if untreated Illness sets in suddenly after an incubation period of 2 to 3 weeks with fever, headache and lethargy Pulmonary symptoms follow in a few days and mortality may be as high as 20%, particularly in the elderly
  • 7. Anthrax  An acute infectious disease of farm animals caused by a bacterium  Transmitted to man by contact with infected hair, hides, excrement or products such as bonemeal  Fatal without treatment  Initial lesion rapidly becomes ulcerated  Treatment is by penicillin  Inhaling the pathogen causes pulmonary anthrax which is usually fatal in 3 or 4 days
  • 8. Glanders An infectious disease of horses, donkeys and mules caused by the pathogen Pseudomonas mallei Transmitted to humans by nasal or mouth secretions from the infected animal Abscesses appear on hands, arms or face Lasts up to 4 months but is treatable with modern antibiotics
  • 9. Zoonose Control Strategies Most common route of entry is via the skin, by way of open cuts, sores or abrasions which provide direct entry to bloodstream Other routes include inhalation of contaminated dusts, contact with conjunctiva of eyes, direct injection by cuts from infected animals or animal bites, and direct ingestion via hands
  • 10. Zoonose Control Strategies First stage of control strategy is to assess those people at risk Factors to consider include: work being carried out susceptibility to infection of the workers how infections might occur how likely exposure to infection is
  • 11. Zoonose Control Strategies First priority for preventing occupational exposure to zoonoses is to eliminate the infections from the animal stock, usually by protecting exposed animals through immunisation and improvement of their environment Workers should be protected by suitable environmental hygiene controls and wearing protective clothing including hand, arm, foot and leg protection
  • 12. Zoonose Control Strategies Where animal products likely to emit infected dust are handled (e.g. wool, skin, hides, pelts), LEV and possibly RPE should be provided to prevent airborne infection Specific immunisation of workers may be necessary Clean & hygienic animal living conditions and disinfection of stalls will also ensure better hygiene in factory premises and will reduce probability of infection
  • 13. Zoonose Control Strategies Automation to reduce human contact and enclosure of aerosol-producing activities will reduce exposure to infection Finally, medical checks, training and information, procedures, instruction and records will give added protection to workers
  • 14. Legionnaires Disease  Caused by the bacterium Legionella pneumophilia  A type of pneumonia affecting the lungs and other organs  A number of conditions have been found to affect rate of growth: Water temp. in the range of 24-45o C. It does not survive about 60o C. Organisms may remain dormant in cool water Sediment, sludge, scale and organic material in water systems can act as a source of nutrients, as can organisms such as algae, amoebae and other bacteria Incorporation of Legionella in slime on surfaces can protect the organisms from biocides
  • 15. Legionnaires Disease Infection caused by inhaling airborne droplets or particles containing Legionella, which are small enough to pass deep into the lungs and be deposited in the alveoli People at greatest risk include smokers, alcoholics and patients with cancer, chronic respiratory or kidney disease Initial symptoms include high fever, chills, headache and muscle pain. A dry cough soon develops and most patients suffer difficulty with breathing
  • 16. Legionnaires Disease  Water systems potentially at risk include: Cooling towers Evaporative condensers Hot/cold water services where occupants are susceptible, I.e. health care premises Humidifiers and air washers creating a spray of water droplets above 20o C Spa baths & pools
  • 17. Legionnaires Disease  Employers should manage the risk of Legionella by: Identifying and assessing sources of risk, taking into account potential for drop formation, water temperature, exposure probability and adequacy of control Implementing and managing precautions and keeping records of the precautions  Particular attention should be paid to populations which contain a high proportion of susceptible people (hospitals or nursing homes) and situations where there is a large number of such people at risk
  • 18. Legionnaires Disease  Main aim of control measures is to avoid conditions where Legionella can proliferate and to avoid creating sprays or aerosols  Growth of Legionella can be inhibited by: Avoiding water temperatures between 20-45o C Avoiding water stagnation & slimes Avoiding use of materials which provide nutrient for the organisms Keeping the system clean and preventing a build-up of sediments Using appropriate water treatment chemicals
  • 19. Sick Building Syndrome Occupants suffer from measurably higher incidence of illness than would be expected, for no readily identifiable reason Symptoms may include ear, nose and throat irritation; skin rashes; lethargy; headaches; respiratory infections and nausea Occurs predominantly in air conditioned buildings Victims tend to be in low status repetitive jobs and have little or no control over their working environment
  • 20. Sick Building Syndrome Symptoms are more frequent in offices with large numbers of employees, and are also reported with greater frequency in the afternoons than in the mornings Cause is likely to be due to a number of factors, some of which may be biological, others not Airborne contaminants may cause SBS symptoms through several mechanisms, including toxicity, irritations, infection and allergy
  • 21. Sick Building Syndrome Other factors include inadequate ventilation and low humidity Several “temporarily sick buildings” have been “cured” by increasing ventilation, amongst other measures Overall conclusion is that SBS is a complex phenomenon with a number of causes, possibly influenced by the victims reaction and attitude to the working environment
  • 22. Leptospirosis - Weil’s Disease An infectious jaundice with symptoms of fever, jaundice, liver enlargement, haemorrhages and feverish relapses Causative organism is a spirochaete called Leptospira icterohaemorrhagiae Rats are the primary cause of the disease Found in the kidneys of rats and is excreted in urine
  • 23. Leptospirosis - Weil’s Disease  There is evidence that the spirochaete can pass through intact skin  Persons at risk include: canal workers sewer workers agricultural workers rat catchers pig workers butchers
  • 24. Leptospirosis - Weil’s Disease Primary control is through systematic destruction of rats in infested areas Prophylactic immunisation offers the best solution in sewer workers All “at risk” workers should carry a card warning of the dangers, stressing personal cleanliness and hygiene, explaining the need for protective clothing and alerting doctors to the possibility of the disease
  • 25. Leptospirosis - Weil’s Disease It is essential that people subject to potential risk are: aware of the causes and symptoms given instruction in suitable first-aid precautions (e.g. covering existing skin wounds, cleaning and disinfecting all fresh wounds), notifying a GP if `flu-like symptoms occur and notifying public authorities if rat infestation is noticed in a work area
  • 26. Fungi  Cause ill-health through inhalation of contaminated dust. Examples include:  Extrinsic Allergic Alveolitis is a type of pneumoconiosis of biological origin caused by exposure to organic dusts of vegetable and animal origin  Bagassosis is a similar disease to farmer’s lung resulting from exposure to spores present in the cellulose fibres of cane-sugar after the sugar has been extracted  Aspergillosis is an all-embracing term to describe the types of extrinsic allergic Alveolitis (asthma) caused by the spores of the Aspergillus fungus, found as a mould on cellulosic fibres such as hay, straw, jute, flax, hemp, sugar-cane
  • 27. Fungi  Farmer’s Lung is a specific disorder caused by exposure to spores from mouldy hay.  The disease is result of hypersensitivity due to an antigen present in the dust.  Symptoms are often mistaken for `flu, with extreme shortness of breath on exertion  Recovery is swift following removal of the individual from the dust source  However, with seasonal exposures the disease becomes chronic, leading to pulmonary fibrosis, emphysema and bronchiectasis, by which time it may be irreversible
  • 28. Hepatitis Those at risk include doctors, surgeons, nurses and porters Infection amongst health workers is a result of contact with blood or excreta of patients suffering from viral hepatitis or in whom the disease is still in its incubation stage Porters and refuse disposal are at risk from carelessly discarded syringes and other sharps - the problem is becoming worse with the increase in drug addiction
  • 29. Hepatitis  Course of disease is similar to Weil’s Disease, but is usually much less severe and normally self-limiting with recovery in about 6 weeks  In about 5% of cases, chronic infectious hepatitis follows, leading to cirrhosis and possibly death  Persons exposed to risk can be protected with injections of gammaglobulin  In all cases, protective disposable gloves should be worn and hands and arms washed regularly with disinfectant
  • 30. AIDS Acquired Immune Deficiency Syndrome Caused by Human Immunodeficiency Virus (HIV), which attacks the immune system Virus is found in most body fluids but is delicate and relatively easy to kill with heat and chemicals It has low infectivity and transmission is thought to be more likely with repeated exposure to infection rather than to a single contact
  • 31. AIDS Occupational risk comes from accidental inoculation or contamination of a cut or abrasion with blood or body fluids of an infected person Doctors, nurses, dentists, laboratory and hospital staff are at some risk, since they may come into close contact with body fluids Other workers possibly at risk might include community, welfare, custodial and emergency service workers and first aiders
  • 32. AIDS Many of the precautions taken against other infections, especially Hepatitis B, will be equally effective against HIV. They include: Prevention of puncture wounds, cuts and abrasions in the presence of blood and body fluids; and the protection of existing wounds and skin lesions Control of surface contamination by containment and disinfection Safe disposal of contaminated waste, especially sharps