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MFOM Preparation Course Session 4 Title: Biological Hazards Faculty: Dr Natalie Green & Dr Dipti Patel Some of the images featured in this presentation have specific usage rights. These can be found on final slide. © EOPH www.eoph.co.uk Delegate Question I am planning on taking Part 2 next June...
MFOM Preparation Course Session 4 Title: Biological Hazards Faculty: Dr Natalie Green & Dr Dipti Patel Some of the images featured in this presentation have specific usage rights. These can be found on final slide. © EOPH www.eoph.co.uk Delegate Question I am planning on taking Part 2 next June / July. I’m a little stuck with how to start my revision. Do you have any advice on when to start it? I am stuck on how to structure my revision. I have the list of topics from the introduction booklet but I want to make a timetable etc. Have you any advice on how to go about revision planning and how much depth to go into the topics? © Cordell Health www.cordellhealth.co.uk Aim To give an overview of biological hazards for MFOM Example questions & group work © Cordell Health www.cordellhealth.co.uk Introduction Why? MCQ, MEQ & Hygiene exam What do you need to know? For each agent learn: Description / type of pathogen Exposure industry & route(s) Health Effects Treatment? Controls © Cordell Health www.cordellhealth.co.uk Biological Hazards – Key Topics Zoonoses Tropical parasites and diseases Travel medicine Tuberculosis Blood borne viruses Food borne diseases Food handlers fitness standards COSHH principles in relation to biological hazards © Cordell Health Principles of biological hazard control for healthcare workers Pre-commencement immunity screening requirements EPP workers and blood borne viruses Body fluid exposure risk assessment and management Principles of biological hazard control in other industries www.cordellhealth.co.uk Recent Papers MCQ Body fluid exposure Malaria Hydatidosis Tuberculosis Q fever Rabies Hepatitis B Dengue Mosquito borne infections © Cordell Health Hepatitis C Orf Atypical pneumonia Anthrax Vaccinations by occupation Hepatitis A Lyme disease www.cordellhealth.co.uk Recent Papers MEQ Orf Lyme disease Hepatitis A Hepatitis C Tetanus Tuberculosis Rabies Leptospirosis © Cordell Health Hygiene paper Sewage workers Forestry workers Mosquitos www.cordellhealth.co.uk General principles © EOPH www.eoph.co.uk Key definitions Biological agents are “substances hazardous to health” Biological agent = a micro-organism e.g. bacteria, viruses, fungi and the agents that cause transmissible spongiform encephalopathies (TSEs) cell cultures, if the cell being cultures is itself hazardous Parasites that live inside their host e.g. malaria or helminths NB it’s not just the ability to infect, but also the potential to cause other health effects e.g. allergy Micro-organisms relevant to human health = bacteria, viruses, fungi, and protozoa. © Cordell Health www.cordellhealth.co.uk Poll Poll According to COSHH 2002, ticks and mosquitos are considered a “biological agent” as they have the capacity to cause disease in humans. a) True b) False © Cordell Health www.cordellhealth.co.uk Poll Poll According to COSHH 2002, ticks and mosquitos are considered a “biological agent” as they have the capacity to cause disease in humans. a) True b) False © Cordell Health External larger parasites, such as ticks and mosquitoes, are not biological agents, but their bite may be the route by which a parasite or pathogen can infect a human. www.cordellhealth.co.uk Micro-organisms Viruses 20-450nm DNA or RNA surrounded by a protein coat and other components Increased risk of exposure: veterinarians, laboratory workers, farming Transmission: airborne / water droplet – person-person or personobject contact. E.g. influenza Transmission: blood-borne e.g. HIV / hepatitis B © Cordell Health Bacteria 500nm Forms: cocci / bacilli / spirochetes / actinomycetes Fungi Bigger than bacteria May produce mycotoxins e.g. aflatoxins produced by Aspergillus – carcinogenic Common occupational fungi: aspergillus sp., penicillium sp. www.cordellhealth.co.uk Classification of occupational biological hazards The Advisory Committee on Dangerous Pathogens, classify biological agents into four hazard groups according to infection criteria: Ability to cause infection Severity of the disease Risk of spread to the community Availability of vaccines / effective treatment © Cordell Health PEST P: pathogenicity to humans E: employee hazard level (severity) S: spread to community T: treatments / vaccines www.cordellhealth.co.uk Classification of occupational biological hazards P E S T Human pathogen? Employees at risk? Spread to community? Treatment / prophylaxis? Group 1 Unlikely - - - Group 2 Can cause human Possible disease Can cause severe Possible human disease Unlikely Available Possible Usually effective Causes severe human disease Likely None Group 3 Group 4 © Cordell Health Likely www.cordellhealth.co.uk Examples of biological agents “The Approved List of biological agents” Advisory Committee on Dangerous Pathogens Group 2 agents Borrelia burgdorferi Measles virus Legionella sp. Influenza type A, B and C Group 3 agents Bacillus anthracis Rabies virus Mycobacterium tuberculosis SARS-CoV-2 Group 4 agents Ebola virus Congo haemorrhagic fever virus Lassa fever virus Far Eastern tick-borne encephalitis virus © Cordell Health www.cordellhealth.co.uk Group discussion Group discussion point: © Cordell Health What are the limitations of the COSHH Hazard Group system? www.cordellhealth.co.uk Group discussion Group discussion point: What are the limitations of the COSHH Hazard Group system? Does not take into account vulnerable staff – underlying medical condition, immunosuppression, breast feeding or pregnancy © Cordell Health www.cordellhealth.co.uk Risk assessment Work activity Other requirements Control measures Potential health effects © Cordell Health Hazards Exposed population Type / extent of exposure www.cordellhealth.co.uk Assessing risk from any biological hazard Infection is dependent on a number of variable factors and not necessarily the amount of agent that is present. It is important to consider whether the work activity can provide a route by which the employee may be exposed to the biological agent. For exposure to biological agents, the employer should also consider •the hazard groups of any biological agents that may be present and what form they may be in, e.g. infectious stages or hardy spores •how and where they are present, how they are transmitted and the diseases they cause •the likelihood of exposure and consequent disease Don’t forget to consider vulnerable groups © Cordell Health www.cordellhealth.co.uk Implications Anyone working with HG2,3 or 4 biological agents must be subject to a risk assessment COSHH specifies four containment levels for activities which involve working with these agents, these correspond with the hazard group level e.g. Hazard Group 2 biological agents should be handled in Containment Level 2 facilities. © Cordell Health www.cordellhealth.co.uk Control measures Elimination / substitution: substitute with something less hazardous Control at source: use engineering controls and give collective controls priority Minimise risk through appropriate systems of working: e.g. hand hygiene policy, PPE etc NB. The hierarchy of controls should always been applied where practicable, but there is a different emphasis when it comes to biological agents: e.g. all lab workers may wear a lab coat, but not all will always need to use a safety cabinet. Underpinning everything should be principles of good microbiological practice e.g. use of good aseptic techniques © Cordell Health www.cordellhealth.co.uk General control measures for any biological agent Viable micro-organisms should be contained in a system which physically separates the process from the environment – a closed system. Measures for the closed system: SAME S: Seals in the closed system should minimise / prevent release A: Air filtration of exhaust gases to minimise / release M: Movement of the microorganisms to minimise / prevent release E: Effluent from the closed system deactivated Closed systems should be located within a containment area. © Cordell Health www.cordellhealth.co.uk General control measures for any biological agent Closed systems should be located within a containment area. Measures for every containment area: Virus Spread Risks Public Death V: ventilation to prevent air contamination S: signage - biohazard R: restricted access P: personal protective equipment for staff e.g. protective clothing D: decontamination for staff on leaving containment area © Cordell Health www.cordellhealth.co.uk Additional control measures for HG 3/4 biological agents Additional measures for Group 3 or 4: (S2AF2E) S: showering before leaving containment area S: spillages – containment area to contain whole spillage A: air – negative pressure F: filters – HEPA filtering of input / output gases F: fumigation possible – area must be sealable E: effluent – treatment of effluent to inactivate microorganisms © Cordell Health www.cordellhealth.co.uk Vaccination If the risk assessment concludes there is a risk of exposure to biological agents for which effective vaccines are readily available, these should be offered. A pre-exposure screening programme and appropriate follow-up should be arranged. It is recommended that employers keep a vaccination record. The HSW Act requires that the employer provides protective measures such as immunisation to workers free of charge. Immunisation should be seen only as a useful supplement to reinforce physical and procedural control measures, not as the sole protective measure. Employers should consider the implications for those who refuse a vaccine, are unable to receive the vaccine because of a medical contraindication, or who fail to respond to a vaccination. © Cordell Health www.cordellhealth.co.uk Biological agent diseases caused by work RIDDOR Any disease which is caused by work exposure to a biological agent must be reported under the RIDDOR reporting of occupational diseases. Industrial Injuries Disablement Benefit Some occupational infections are Prescribed Diseases … CATCHABLES © Cordell Health CATCHABLES C: Coxiella burnetti A: Anthrax T: Tuberculosis C: Chlamydiae H: Hydatidosis / Hepatitis ABC A: Ankylosomiasis B: Borellia burgdorferi / Brucellosis L: Leptospirosis E: External allergic alveolitis S: Streptococcus suis www.cordellhealth.co.uk Breakout Session a) How are biological agents defined under the COSHH Regulations? (2) b) List four factors which are used to decide the COSHH category if previously unknown (2) c) Name two Group 2 agents and four measures of control and containment (3) d) Name two Group 3 agents and four specific measures of control and containment (3) © Cordell Health www.cordellhealth.co.uk Breakout Session You are the consultant occupational physician for an organisation performing research on zoonotic diseases. The health and safety manager contacts you for advice. A group of laboratory workers are planning to start researching Monkey Pox, and he needs advice on performing the risk assessment. Describe your approach in performing this risk assessment. © Cordell Health www.cordellhealth.co.uk Answers What – what strain / GM / live or attenuated When – how long / how frequent / how much contact with the virus How – how will it be handled / aerosolised / risk of skin contact / control measures in the laboratory – containment unit? Containment level of the lab? Who – how many / any vulnerable workers Where – one lab or many? Again control measures Vaccination – how / who / where / sfx / effectiveness / repeated Ethics – autonomy / beneficence / non-maleficence / distributive justice Law – HASAW / COSHH © Cordell Health www.cordellhealth.co.uk Specific fitness to work principles and specific infections © EOPH www.eoph.co.uk Healthcare workers Pre-commencement immunity requirements Body fluid exposure risk assessment Blood borne viruses and exposure prone procedures © EOPH www.eoph.co.uk Pre-commencement immunity requirements Greenbook Chapter 12: Immunisation of healthcare & laboratory staff: https://assets.publishing.service.gov.uk/government/uploads/system/upl oads/attachment_data/file/147882/Green-Book-Chapter-12.pdf HASAWA: SFAIRP protect the health of those at work and others who may be affected by their work activity. COSHH: assess the risk of biological hazards and take steps to mitigate the risk as far as reasonably practicable. © Cordell Health www.cordellhealth.co.uk Pre-commencement immunity requirements All staff must undergo pre-employment health assessment A new private community care agency contacts you for advice regarding Group discussion immunity requirements for community point: nurses providing domiciliary care for end of life patients in Oxfordshire. What factors should be taken into consideration when determining the immunity requirements at the precommencement health assessment? © Cordell Health www.cordellhealth.co.uk Pre-commencement immunity requirements All staff must undergo pre-employment health assessment The immunity requirements should be based upon: The pathogens which staff may be exposed to: Local epidemiology of disease Frequency of contact with potentially infected material Nature and frequency of patient contact The severity of the disease The likelihood of infection The vulnerability of the worker Safety of the vaccination Efficacy of the vaccination NB staff considered not to be at risk need not routinely be offered immunisation although post-exposure prophylaxis may be considered in specific circumstances © Cordell Health www.cordellhealth.co.uk Group discussion Group discussion point: © Cordell Health Following your advice regarding suitable pre-commencement immunity requirements, the Employee Safety Representative contacts you. The current staff are concerned regarding the need for the programme. What are the benefits of a pre-commencement vaccination programme for workers? www.cordellhealth.co.uk Advantages Following your advice regarding suitable pre-commencement immunity requirements, the Employee Safety Representative contacts you. The current staff are concerned regarding the need for the programme. What are the benefits of a pre-commencement vaccination programme for workers? Employer: meeting statutory obligations under the Health and Safety at Work Act 1974 and Control of Substances Hazardous to Health Regulations 2002; efficient running of services without disruption Employee: protection against communicable diseases; protection for family members against communicable diseases; protection of colleagues against communicable diseases Others: patient protection against communicable diseases (especially vulnerable groups who may not mount full response to their own vaccination) © Cordell Health www.cordellhealth.co.uk Next Routine vaccinations Selected vaccinations © Cordell Health www.cordellhealth.co.uk Routine vaccinations / immunity Diphtheria, tetanus and polio (DTP) – 5 doses over childhood usually Measles mumps and rubella (MMR) – 2 doses of MMR or satisfactory evidence of immunity to measles and rubella Varicella immunity – history of chicken pox (beware those with hx of VZV from tropical / subtropical countries), or immunisation © Cordell Health www.cordellhealth.co.uk "An infant in a hospital with measles (rubeola). Original image sour from US Government department: Public Health Image Library, Cen for Disease Control and Prevention. Under US law this image is copyright free, please credit the government department wheneve can”." by Centers for Disease Control and Prevention is licen under CC0 1.0 Measles P: Rubeola = Paramyxovirus = Morbillivirus Infects 90% of non-immune contacts T: airborne spread, contact with infected surfaces (lives for 2h outside body) I: 10-14 days HFX: Prodromal period: high fever + 3Cs (cough, conjunctivitis, coryza), enanthem (rash on mucous membranes) Rash phase: maculopapular rash head to toe Late effects: pneumonia, encephalitis, diarrhoea, bacterial superinfection, subacute sclerosing panencephalitis (children <2y, 710y later) RX: PEP: Human normal immunoglobulin (HNIG) – high risk contacts – young children, non-immune pregnant, immunocompromised Vaccination Efficacy of 2 x vaccination = 95% © Cordell Health www.cordellhealth.co.uk Tetanus P: Clostridium tetani = spore forming toxin producing organism, toxin = tetanospasmin Features: Generalised: lockjaw, rhesus sardonicus, opisthotonus, respiratory muscle paralysis Localised: weakness in proximity to the injury, pain, stiffness Cephalic: facial nerve palsy, difficulty swallowing, extraocular muscle weakness Sympathetic overactivity: tachycardia, hypo/hypertension, arrhythmia, agitation, fever © Cordell Health www.cordellhealth.co.uk Tetanus SHORTFALL S: Swallow difficulty H: Hypotension O: Opisthotonus R: Resus sardonicus / resp muscle paralysis T: Tachycardia F: Fever A: Arrhythmia / agitation L: Lockjaw L: Localised pain / stiffness © Cordell Health RX: Immunisation: 5 doses + 10y booster Post-exposure prophylaxis may need to be considered for “tetanus prone wounds”: S: wound / burn with sepsis A: animal bite / scratch F: wound with foreign body E: puncture wound in contaminated environment HTIG Vaccination www.cordellhealth.co.uk Breakout Session You in the midst of an influenza pandemic. In your role as occupational physician you are approached by a new client who is requesting your advice regarding the precommencement immunity requirements for new clinical staff. The company are operating an NHS relief programme, delivering influenza vaccinations to patients in community settings with the aim of improving public vaccine uptake. a) Apart from measles, mumps and rubella, list two other pre-commencement immunity requirements which apply to all NHS clinical staff. (5 marks) b) The infection control lead for the company states that the staff are non-NHS and do not require MMR vaccination. How would you assess the risk of measles transmission in this context? (3 marks) c) Using your risk assessment above, what advice do you give the company? (2 marks) © Cordell Health www.cordellhealth.co.uk Breakout Session a) Diphtheria, tetanus, polio b) Measles Risk of transmission: highly infectious; even very short exposures capable of transmitting the virus, especially in the immunocompromised. Significant risk of transmission between vaccinator and patient. Risk of disease: can be debilitating in even the immunocompetent; frequent complications – more likely in children and immunocompromised. c) Outcome: significant risk of transmission between vaccinator and patient. The outcome of infection is extreme – both to the individual and on a public health level – risk of an outbreak. Therefore advise the company that based on the risk assessment to the role, immunity to measles would be advisable. © Cordell Health www.cordellhealth.co.uk Next Routine vaccinations Selected vaccinations © Cordell Health www.cordellhealth.co.uk Tuberculosis © EOPH www.eoph.co.uk "Oil Rig Cromarty Firth." by Alan Cruickshank Photographic is licensed under CC BY-ND 2.0 Breakout session You are an occupational physician for a company operating offshore oil and gas platforms in UK waters. One of the platforms is hosting trainees from overseas. After three months on a platform, one of the trainees develops fever, weight loss and cough. He is transferred onshore for evaluation and is diagnosed with open pulmonary tuberculosis. You have been advised of this by the onshore medical personnel. Management and employees from the platform have received informal feedback from a reliable source that the trainee has a "communicable disease" requiring isolation in hospital. Describe how you would manage this situation. © Cordell Health www.cordellhealth.co.uk Breakout session Communication strategy Consider confidentiality of the index case Notification to Health Protection Agency Identify close contacts Determine who needs further investigation Consider vaccination programme for close contacts who are screened negative for latent / active TB infection Consider risk to the wider workforce – is a pre-commencement vaccination programme required – based on risk assessment © Cordell Health www.cordellhealth.co.uk TB contact tracing All close contacts of a confirmed case of pulmonary TB should be offered screening “Close contact”: shares a room / partner / frequent visitor / given CPR or chest physiotherapy and cumulative exposure > 8h All symptomatic close contacts should be clinically assessed for pulmonary TB: respiratory examination / chest x-ray / sputum samples Asymptomatic close contacts: offer standard screening for latent TB (Mantoux / IGRA) Positive: assess for active TB; offer treatment Negative: consider vaccination with BCG © Cordell Health www.cordellhealth.co.uk Tuberculosis Symptoms of pulmonary TB: cough, haemoptysis, pleuritic chest pain Systemic symptoms of active TB: weight loss, fevers, chills, night sweats, loss of appetite Latent TB: asymptomatic Notifiable disease Prescribed disease Transmission: inhaled droplets and close contact with sputum positive cases Occupational groups at risk: HCW – aerosol generating procedures (bronchoscopy, NIV, intubation, tracheostomy, CPR, sputum induction) Vets – handling animals prone to TB Prison staff, working in homeless hostels, D&A units “Close contact”: shares a room / partner / frequent visitor / given CPR or chest physiotherapy Endemic areas = population incidence > 40 / 100 000 – for up to date incidence rates see gov.uk website © Cordell Health www.cordellhealth.co.uk Poll The most common cause of tuberculosis in UK healthcare workers is: a) Unprotected occupational exposure during an aerosol generating procedure on a patient known to be infected. b) Unprotected occupational exposure on a patient not previously known to be infected with TB. c) Non-occupational exposure - recreational travel to endemic areas. d) Occupational exposure in an endemic country e.g. aid work. e) Reactivation of latent TB in those from endemic areas. © Cordell Health www.cordellhealth.co.uk Poll The most common cause of tuberculosis in UK healthcare workers is: a) Unprotected occupational exposure during an aerosol generating procedure on a patient known to be infected. b) Unprotected occupational exposure on a patient not previously known to be infected with TB. c) Non-occupational exposure - recreational travel to endemic areas. d) Occupational exposure in an endemic country e.g. aid work. e) Reactivation of latent TB in those from endemic areas. © Cordell Health www.cordellhealth.co.uk Testing for TB Mantoux Intradermal injection of purified protein derivative (PPD) Replaced the Heaf test in the UK in 2005 Produces a small wheal 6-10mm in diameter The result is read 48-96h later (72h is ideal) A person with immunological memory of TB (previous exposure or immunisation) will mount an immune response (type IV hypersensitivity reaction) The reaction is read by measuring the diameter of induration (palpable raised, hardened area) – erythema is not measured Result: <5mm: negative ≥5mm: positive – hypersensitive to tuberculin protein © Cordell Health www.cordellhealth.co.uk Testing for TB IGRA Interferon gamma release assays Two main types: QuantiFERON-TB and T.Spot.TB Both tests determine whether the person has been infected with TB The patient’s blood is stimulated with synthetic antigens and the amount of, interferon gamma (a cytokine) produced by the T cells, or number of activated T cells is measured. © Cordell Health www.cordellhealth.co.uk Testing for TB Group discussion point: © Cordell Health What are the advantages of IGRA testing over Mantoux for the diagnosis of latent tuberculosis? www.cordellhealth.co.uk Testing for TB What are the advantages of IGRA testing over Mantoux for the diagnosis of latent tuberculosis? 1. Only one appointment necessary – may be easier to access hard to reach groups 2. Less inter and intra observer variation than Mantoux – reading is dependent on competence of the clinician 3. Avoids false positive due to previous vaccination 4. Less chance of false negative e.g. immunocompromised 5. Less unnecessary chemoprophylaxis (less false positives) © Cordell Health www.cordellhealth.co.uk Pre-exposure screening of health care workers Examination for BCG scar / documentary evidence of BCG Symptom enquiry Further action dependent on the origin of the applicant High risk entrant = > 3 months in a high incidence (>40/100,000) country in the last 5 years, without previous entry screening < 3 months in a high incidence country in the last 5 years engaged in activity with high risk of TB exposure e.g. healthcare High risk entrants will require immunity evidence (Mantoux/IGRA) irrespective of BCG status © Cordell Health www.cordellhealth.co.uk Pre-exposure screening of health care workers Low risk entrants Evidence of previous BCG? (scar or documentation) Negative symptom enquiry If the role is deemed high risk of exposure to TB then BCG should be offered (in the absence of medical contraindication) If the role is deemed low risk of exposure to TB then no further action is required © Cordell Health www.cordellhealth.co.uk Pre-exposure screening of health care workers High risk entrants If the HCW is immunocompromised: offer IGRA Negative – non-infected - no further action. Do not offer BCG irrespective of the risks of the role – contraindicated. Consider other control measures to reduce risk of exposure to TB. Positive – possibly infected – assess for evidence of active TB, referral to TB clinic for treatment If the HCW is not immunocompromised: In the absence of prior history of BCG / TB infection: offer Mantoux: Negative – no immunological memory of TB - offer BCG if supported by the risk assessment Positive – immunological memory of TB - assess for evidence of active TB / latent TB – IGRA / CXR / referral to TB clinic In the presence of prior history of BCG / TB infection: offer IGRA. Negative – non-infected - no further action. Positive – possibly infected - assess for evidence of active TB, referral to TB clinic for treatment © Cordell Health www.cordellhealth.co.uk Treatment of tuberculosis Active tuberculosis: Isoniazid and rifampicin for 6 months; PLUS pyrazinamide and ethambutol for the first 2 months of treatment. NB no longer considered infectious after 2 weeks of treatment Latent tuberculosis: Isoniazid and rifampicin for 3 months OR Isoniazid alone for 6 months © Cordell Health www.cordellhealth.co.uk Breakout session You are an occupational physician for a research laboratory. The health and safety manager of the laboratory contacts you for advice regarding a new project which is being hosted in the laboratory where staff will be experimenting on strains of engineered Mycobacterium tuberculosis. The health and safety manager suggests that all staff in the laboratory will require a BCG vaccination and suggests that serial IGRA tests are performed for interim health surveillance. a) What factors would you consider within your risk assessment regarding the risk of exposure to tuberculosis to the lab staff? (5 marks) b) What is IGRA and what does it determine? (2 marks) c) What is your advice to the health and safety manager regarding how the risk of tuberculosis exposure should be managed? (6 marks) © Cordell Health www.cordellhealth.co.uk Body fluid exposures & blood borne viruses © EOPH www.eoph.co.uk HIV RNA retrovirus Attacks and destroys CD4 T cells Patients are immunocompromised and susceptible to opportunistic infections and malignancies Transmission: Vertical – mother to baby Horizontal – sexual intercourse, blood products, body fluid exposure See body fluid exposure section for details on PEP See BBV infected HCWs for further details on fitness standards © Cordell Health www.cordellhealth.co.uk Hepatitis B DNA virus Incubation: 40-160 days Risk of seroconversion 1:3 (HBeAg positive source) 30% cases asymptomatic Features: malaise, flu symptoms, myalgia, abdominal pain, jaundice Most clear the infection spontaneously 10% develop chronic carriage – risk of cirrhosis and hepatocellular carcinoma Rx: interferon (successful in 40%) Untreated 20-25% of chronic carriers will develop chronic liver disease; of these 15-25% will die Immunity may be acquired in two ways: Natural immunity following infection with hepatitis B virus Immunisation with hepatitis B vaccine © Cordell Health www.cordellhealth.co.uk Hepatitis B HBsAg: marker of on-going hepatitis B infection. HBsAg HBeAg Anti-HBc Anti-HBs: Development of HBsAb is generally associated with immunity. It can develop following infection and disappearance of the virus (natural immunity) or after inoculation with the vaccine. Anti-HBs Anti-HBe © Cordell Health Anti-HBc: will be present in all individuals who have had previous infection with hepatitis B. It only demonstrates previous exposure but not necessarily current infection. HBeAg: HBeAg is a marker of virus replication therefore usually a patient with HBeAg has high viral load and therefore is highly infective. Patients without HBeAg but HBsAg positive can still be infectious. www.cordellhealth.co.uk Interpretation of HBV serology HBsAg Anti-HBs Anti-HBc HBeAg Anti-HBe HBV DNAImmune Infectious EPP - - - N/A N/A N/A No No Yes - + - N/A N/A N/A Yes (by vaccination) No Yes - +/- + N/A N/A N/A Yes (by natural immunity) No Yes + +/- + + +/- N/A N/A Yes No + +/- + - +/- <200 N/A Very low Yes + +/- + - +/- >200 N/A Yes No © Cordell Health www.cordellhealth.co.uk Hepatitis B Immunisation Provides immunity in 90% cases Factors a/w non-response to vaccination: Age > 40y Immunosuppression Obesity Smoking Anti-HBs > 100 iu/L = immune Anti-HBs 10-100 iu/L = partial response Anti-HBs < 10 = non-response Schedule – usually 0, 1 and 6 months, but more rapid schedules are possible © Cordell Health www.cordellhealth.co.uk Group discussion Group discussion point: © Cordell Health Which occupational groups should be offered Hepatitis B immunisation? www.cordellhealth.co.uk Hepatitis B Immunisation Healthcare personnel who have direct contact with blood, blood stained body fluids or patient’s tissues Trainee health care workers Other occupational risk groups - morticians and embalmers Police, ambulance and rescue services in high risk situations Staff and clients of residential accommodation for the mentally handicapped Staff of custodial institutions Travellers to areas of high prevalence who intend to seek employment as health care workers or who plan to remain there for lengthy periods © Cordell Health www.cordellhealth.co.uk Hepatitis C RNA virus Incubation 6-9 weeks Acute infection usually asymptomatic Routes of infection: parenteral (IVDU / blood products prior to 1991); sexual contact; needlestick; perinatal Factors a/w rapid progression to liver disease: > 40y Alcohol Male Co-infection with HBV / HIV © Cordell Health Immunosuppression 15-20% spontaneously clear the virus – the remainder develop chronic infection Cirrhosis develops in 20-30% after 20 years 1-4% of those with cirrhosis develop HCC Serology: HCV-Ab – marker of present / past infection HCV-RNA – marker of current infection Rx: refer to specialist for interferon and antivirals – prevent progression to liver disease www.cordellhealth.co.uk Breakout session You are an NHS occupational physician. A consultant obstetrician attends your service as a walk-in. She sustained a needlestick injury 24 hours ago whilst performing an emergency caesarean section. She is anxious about the risk of blood-borne virus transmission from the mother, who was born in South Africa. No further information on the source’s blood borne virus status is currently available. a) Describe the factors which must be taken into consideration to determine the risk of BBV exposure in this case. (5 marks) b) What chances of transmission would you quote to the obstetrician if the source is found to be Hepatitis B (1 mark), Hepatitis C (1 mark), or HIV (1 mark) positive? c) How would you manage this case in the first instance? (3 marks) d) How would you manage this case if the source is found to be Hepatitis C positive? (3 marks) e) List six control measures which can be used to minimise the risk of needlestick injury for NHS clinical staff. (3 marks) © Cordell Health www.cordellhealth.co.uk Body fluid exposure risk assessment Injury Significant Insignificant © Cordell Health Blood fluid High risk Low risk Source Known BBV risk factors None / unknown risk BBV factors www.cordellhealth.co.uk Body fluid exposure risk assessment Significant injury = percutaneous injury / exposure of broken skin / mucous membrane exposure An injury that does not meet any of the above is insignificant © Cordell Health www.cordellhealth.co.uk Body fluid exposure risk assessment High risk = blood, amniotic fluid, cerebrospinal fluid, human breast milk, pericardial fluid, peritoneal fluid, pleural fluid, saliva in a/w dentistry, synovial fluid, unfixed human tissue and otgans, any other blood stained body fluid, semen or vaginal secretions. © Cordell Health www.cordellhealth.co.uk Body fluid exposure risk assessment High risk = known to have BBV, MSM, IVDU, from a country with high prevalence BBV (>1%), commercial sex workers, received blood products prior to Sept 1991, sexual partner at risk of BBV. © Cordell Health www.cordellhealth.co.uk HCWs living with blood borne viruses UK Advisory Panel for Healthcare Workers Living with Bloodborne Viruses (UKAP) https://assets.publishing.service.gov.uk/government/uploads/system/upl oads/attachment_data/file/1033571/Integrated_guidance_for_manageme nt_of_BBV_in_HCW_November_2021.pdf Key points: All HCWs should be offered BBV screening pre-commencement BBV is mandatory only for HCWs undertaking exposure prone procedures For HCWs undertaking EPPs there are mandated fitness standards which must be complied with © Cordell Health www.cordellhealth.co.uk HCWs living with blood borne viruses Exposure prone procedures EPPs include procedures where the worker’s gloved hands may be in contact with sharp instruments, needle tips or sharp tissues inside a patient’s open body cavity, wound or confined anatomical space where the hands or fingertips may not be completely visible at all times. Risk = bleed back from HCW to patient Three categories: Cat 1: HCW hands and fingertips are usually visible and outside the body most of the time; possibility of injury to HCW gloved hands from sharps is slight. E.g. local anaesthetic filtration Cat 2: fingertips may not be visible at all times but injury to HCW gloved hands from sharps is unlikely. E.g. dental extraction Cat 3: fingertips are out of sight for a significant part of the procedure, or during certain critical stages, and in which there is a distinct risk of injury to the worker’s gloved hands from sharp instruments and or tissues. E.g. caesarean section © Cordell Health www.cordellhealth.co.uk HCWs living with blood borne viruses For HCW performing non-EPP duties, no restriction of these duties is required where the HCW has a BBV (HIV / Hep C / Hep B). For HCW performing EPP duties, the following fitness standards apply: © Cordell Health www.cordellhealth.co.uk HCWs living with blood borne viruses Hepatitis B: HBsAb – if negative, offer immunisation HBsAg – if positive, perform HBV DNA HBV DNA < 200 iu Whilst on continuous antiviral therapy From natural suppression After a minimum of 12 months after stopping a course of antiviral (during which there must have been 2 x HBV DNA tests 6 months apart) Initial clearance requires 2 IVS samples taken 4 weeks apart Must be registered with UKAP-OHR Monitoring: HBV DNA every 6 months © Cordell Health www.cordellhealth.co.uk HCWs living with blood borne viruses HIV HIV Ag/Ab – positive HIV viral load > 200 copies/mL – no EPP < 200 copies/mL – cleared for EPP Initial clearance requires 2 IVS samples taken 12 weeks apart Monitoring – 12 weekly HIV viral load Must be registered with UKAP-OHR © Cordell Health www.cordellhealth.co.uk HCWs living with blood borne viruses Hepatitis C HCV Ab – positive HCV RNA – negative - previous infection – cleared for EPP HCV RNA – positive No EPP work May require antiviral rx Can do EPP when treatment finished and suppressed VL for 3 months After restarting EPP must have f/u 3 months later to check HCV RNA remains suppressed Does not require UKAP-OHR registration © Cordell Health www.cordellhealth.co.uk Travel medicine & tropical diseases © EOPH www.eoph.co.uk Considerations for the employer Moral and legal duty of care to employees How to effectively manage risks to health and safety overseas Good employment practices internationally Financial consequences of illness or injury whilst overseas Corporate social responsibility and reputation Not just the employee – partners / dependents of the travelling worker © Cordell Health www.cordellhealth.co.uk Considerations for the employee What are the consequences if I say no to travel? What will be the impact on my partner / children? What if I become unwell whilst working abroad? Will I be safe? Will I improve my career prospects? © Cordell Health www.cordellhealth.co.uk Breakout Room What are the factors that should be taken into consideration when performing a risk assessment for international work-related travel. Structure your answer using the following headings: Destination risk factors Individual factors Occupational factors Organisational factors © Cordell Health www.cordellhealth.co.uk Travel risk assessment Destination risk factors ❖ Local epidemiology of disease ❖ www.nathnac.org ❖ Foreign and Commonwealth Office advice on safe travel and active issues in the country e.g. civil unrest, terrorism risk etc ❖ Robustness of local healthcare facilities ❖ Natural terrain and ease of access to retrieve ill / injured personnel – urban or rural; connected or isolated; central or remote etc. Travel risk assessment Individual risk factors ❖ Past medical history ❖ Effect of travel, environment, endemic diseases ❖ Are local health care facilities adequate to handle the condition? ❖ Is liaison with treating physicians required? ❖ NB splenectomy patients at risk of overwhelming sepsis from malaria ❖ Medication history ❖ What supply of medication should be taken? ❖ Can supplies be replenished in the host country? ❖ Will travel across time zones impact on dosing schedule? ❖ Immunocompetence – susceptibility to infections - vaccinations ❖ Pregnancy or breast-feeding ❖ Level of experience – both in role and in international work travel ❖ Younger – higher incidence of accidents ❖ Older – higher incidence of ill-health ❖ Cultural dysphoria ❖ Jet lag Travel risk assessment Occupational risk factors ❖Tasks / duties of the role ❖Close personal contact ❖Contact with sick persons ❖Contact with body fluids ❖Contact with animals ❖Contact with chemicals ❖Hours ❖Contact with others – connected vs isolated ❖Frequency of travel Travel – preventative measures Vaccination Malaria prophylaxis Food and water hygiene Bite prevention Sexual education – safe sex UV protection Accident prevention – transport / activities First aid equipment and training © Cordell Health www.cordellhealth.co.uk Support Group discussion point: © Cordell Health What type of health and wellbeing support should be considered for employees and their families when working overseas? www.cordellhealth.co.uk Support General practitioner support Dental support Repatriation arrangements Plans for evacuation / disaster strategy planning Occupational health services Case management Health surveillance Vaccinations Mental health support – Employee Assistance Programme Health programmes for partners and dependents © Cordell Health www.cordellhealth.co.uk Break out session You are the occupational physician for an international aid agency. The agency are launching a project in South Africa and will send thirty aid workers and their families to assist in rural education projects. 1. What factors would you ask in a history before a worker travels overseas to work (3) 2. What advice would you give on preventing infection whilst abroad (4) 3. List 6 other factors to consider when advising pre-travel (3) 4. List 6 risk factors for DVT other than the length of flight (3) © Cordell Health www.cordellhealth.co.uk DVT risk factors THROMBOSIS T: travel H: hypercoagulant state / hormones (OCP/HRT) R: RTA O: operations M: malignancy B: blood disorder – polycythaemia O: obesity / old age / orthopaedic surgery S: serious illness I: immobilisation S: splenectomy © Cordell Health www.cordellhealth.co.uk Rabies Rhabdovirus Vector: Dog – infected bite Bat – infected guano Incubation 1-3 months Clinical features: Local: tingling / burning around the infection site Non-specific influenza like illness C2H2AS2E © Cordell Health C2H2AS2E Coma Cerebellar symptoms – ataxia Hypersalivation Hydrophobia Ascending paralysis Sweating Seizures Encephalopathy – agitation / irritabiity www.cordellhealth.co.uk Rabies Pre-exposure Immunisation = 3 doses (0, 7, 28 days) Who: Lab workers working with Rabies virus Workers in Defra quarantine facilities Bat handlers Veterinary and technical staff at increased risk Travellers who: © Cordell Health Animal control / vets working in endemic area Anyone if area endemic and • PEP may be delayed • High risk activities e.g. cycling / running • Staying > 1 month Treatment post-exposure Clean and disinfect wound Risk assess exposure Vaccination HRIG infiltrated into the wound www.cordellhealth.co.uk Insect borne tropical infections © EOPH www.eoph.co.uk What do I need to know? Typically appear as MCQs Malaria is the most likely to appear as an MEQ If you’re really unlucky you’ll be asked to identify the mosquitos – unlikely but it has come up! Revision list: Leischmaniasis Schistosomiasis Trypanosomiasis Bancroft filiarias Dengue Onchoceriasis © Cordell Health www.cordellhealth.co.uk © Cordell Health www.cordellhealth.co.uk TSETSE ANOPHELES AEDES TRIATOMA CULEX © Cordell Health www.cordellhealth.co.uk Leishmaniasis P: Leishmania V: Phlebotomes sand fly HFX: Cutaneous manifestation: disfigurement (see picture) Visceral manifestation: can be fatal, aka. Kala-Azar © Cordell Health Image usage rights can be found on final slide. www.cordellhealth.co.uk Schistosomiasis P: Schistosoma Aka: Bilharziasis Snail fever V: snails HFX: Acute: I: itching / urticaria T: temperature C: cough H: headache Chronic: Liver: portal HTN / hepatomegaly Bladder: haematuria / bladder cancer CNS: neuropathy / cerebellar syndrome / seizures © Cordell Health ITCH Itching Temperature Cough Headache SPiNaCH Seizures Portal hypertension Neuropathy Cerebellar syndrome Haematuria / hepatomegaly www.cordellhealth.co.uk What is this? Image usage rights can be found on final slide. Onchoceriasis © Cordell Health www.cordellhealth.co.uk Onchoceriasis P: Onchocera Aka. River blindness V: Blackflies HFX: Eye: Glaucoma Uveitis Optic atrophy Blindness Skin: Leopard skin rash Epidermal atrophy © Cordell Health Image usage rights can be found on finalwww.cordellhealth.co.uk slide. Bancroft filariasis V: Aedes and Culex mosquitos HFX: Fever Lymphadenopathy Lymphoedema - elephantiasis © Cordell Health www.cordellhealth.co.uk Trypanosomiasis South American Trypanosomiasis aka Chagas Disease P: Trypanosoma cruzi V: Triatoma (kissing bug) – faeces into bite wound (usually on face) HFX: Acute: Chagoma, fever, Romana sign (periorbital swelling and conjunctivitis) Chronic: cardiomyopathy – long latency 20y (autonomic ganglia © Cordell Health destruction) African Trypanosomiasis P: Trypanosoma brucei V: Tsetse fly HFX: Inflammation at bite site (chancre) Fever Neurological disturbance – latency months to years www.cordellhealth.co.uk Dengue P: Arbovirus V: Aedes mosquito I: 3-14 days HFX: 75% asymptomatic FR-HAMLET © Cordell Health FR-HAMLET Fever Rash Hepatolmegaly / headache Anorexia / anaemia Mucosal bleeding Lethargy Emesis Thrombocytopaenia www.cordellhealth.co.uk Malaria Plasmodium Vivax Ovale Falciparum Malariae Knowlesi V: Anopheles mosquito (female) HFX: FALCIPARUM © Cordell Health FALCIPARUM Fever (black water fever) Anaemia Low blood sugar Cerebral malaria (seizures / coma) Infection / icterus Pulmonary oedema ARDS Renal failure Urine output reduced Metabolic acidosis www.cordellhealth.co.uk Malaria Prevention: A: Awareness Awareness of the risk Seasonal rainfall B: Bite prevention Repellents DEET 20-50% Mosquito net Long clothing Evenings highest risk C: Chemoprophylaxis Eliminate merozoites / gametes / hypnozoites Usually chloroquine unless there is resistance D: Diagnosis + treatment Severe disease (ICU) add Artesunate © Cordell Health www.cordellhealth.co.uk Pathogen framework Pathogen (P) Vector (V) Transmission (T) At risk occupations (O) Incubation (I) Health effects: (HFX) Acute Chronic Treatment / vaccines (RX) Important points (NB) © Cordell Health www.cordellhealth.co.uk Zoonoses © EOPH www.eoph.co.uk Zoonoses Zoonoses are diseases that primarily infect animals but can be transmitted to humans. The chain of infection consists of the reservoir where the agent lives (which may be human, animal or environment); the portal of exit (respiratory, GI tract), the mode of transmission, the portal of entry and the susceptibility of the host (e.g. nutritional status and immunity). © Cordell Health www.cordellhealth.co.uk Occupations at risk of zoonotic disease Veterinarians Abattoir workers Farmers Laboratory workers Refuse disposal workers © Cordell Health www.cordellhealth.co.uk Features of “Influenza Like Illness” (ILI) FAMALAM F: fever A: anorexia M: malaise A: arthralgia L: lethargy A: abdominal pain M: myalgia © Cordell Health "Bacteria sample inside petri dish for biotechnology study" by IRRI Images is licensed under CC BY-NCSA 2.0 www.cordellhealth.co.uk Q fever P: Coxiella burnetti; “Query fever” Obligate intracellular bacterium V: sheep, cattle, goats T: Direct contamination and ingestion of infected milk; inhalation of infected biological matter (often POC during lambing); can live in soil many years I: 7-30 days HFX: Acute: ILI plus SHEEP • Chronic: only in 5%, usually endocarditis – high fatality if left untreated • RX: • Acute: doxycycline 7-14 days • Chronic: doxycycline 3 years © Cordell Health "I saw three sheep" by Tim Green aka atoach is licensed under CC BY 2.0 www.cordellhealth.co.uk "I saw three sheep" by Tim Green aka atoach is licensed under CC BY 2.0 Q fever P: Coxiella burnetti; “Query fever” Obligate intracellular bacterium V: sheep, cattle, goats T: Direct contamination and ingestion of infected milk; inhalation of infected biological matter (often POC during lambing); can live in soil many years I: 7-30 days HFX: Acute: ILI plus SHEEP Chronic: only in 5%, usually endocarditis – high fatality if left untreated SHEEP S: symptoms - only in 50% of infected and usually mild H: hospitalisation required in only 5% E: Encephalitis / meningitis E: Endocarditis / myocarditis P: Pneumonia RX: Acute: doxycycline 7-14 days Chronic: doxycycline 3 years © Cordell Health www.cordellhealth.co.uk Brucellosis P: B. abortus (cows); B. suis (pigs); B. melitensis (sheep/goats) Gram -ve V: as above T: non-intact skin, inhalation, ingestion I: 2-8 weeks HFX: Acute: ILI + weight loss + prolonged fever Chronic: can cause prolonged debilitating illness RX: Rx: streptomycin + rifampicin NB: Notifiable, Prescribed disease (B7) Now eradicated in UK © Cordell Health www.cordellhealth.co.uk Streptococcus suis STREP-MED P: Streptococcus suis = Gram +ve bacterium V: Pigs T: Non-intact skin HFX: ILI + STREP-MED RX: Penicillin NB: Individuals who have undergone splenectomy are recommended not to work with pigs. © Cordell Health S: Septic shock T: Toxic shock syndrome R: Rash – bleeding under skin E: Endocarditis P: Pneumonia M: Meningitis E: Encephalitis D: Deafness www.cordellhealth.co.uk Chlamydiae P: C. psittacosis; C. abortus CLAP-ME Gram –ve bacterium V: avian - birds (psittacosis); ovine - sheep (abortus) T: direct contact / inhalation of infectious particles I: 1-2 weeks HFX: C: cough L: liver dysfunction A: atypical pneumonia P: pericarditis M: myocarditis E: endocarditis Psittacosis: ILI, fever + CLAP-ME Abortus: miscarriage and stillbirth Rx: tetracyclines © Cordell Health www.cordellhealth.co.uk Weil’s disease P: Leptospirosis ictohaemorrhagicae (rats); Leptospirosis hardjo (cattle) Gram -ve spirochete T: non-intact skin / mucous membranes I: 7-21 days HFX: Biphasic illness Acute phase: ILI Immune phase: RAT LEAK RX: Doxycycline – can also be offered preexposure for prophylaxis in high risk exposures © Cordell Health www.cordellhealth.co.uk Weil’s disease P: Leptospirosis ictohaemorrhagicae (rats); Leptospirosis hardjo (cattle) Gram -ve spirochete T: non-intact skin / mucous membranes I: 7-21 days HFX: Biphasic illness Acute phase: ILI Immune phase: RAT LEAK RAT LEAK R: recurrent fever A: abdominal pain T: total organ failure L: liver failure E: eyes red A: arthralgia / myalgia K: kidney failure RX: Doxycycline – can also be offered preexposure for prophylaxis in high risk exposures © Cordell Health www.cordellhealth.co.uk Lyme Disease P: Borrelia burgdorferi Spirochete bacterium V: Ixodes Ricinus tick (deer) T: Tick bite to exposed skin I: 3-90 days HFX: Early: ILI + MEET-C Late: F-CAMP © Cordell Health www.cordellhealth.co.uk Lyme Disease Memory pegging: Let’s meet and go camping. It’s fun. But don’t catch Lyme Disease. MEET & Camp M: Myocarditis / endocarditis E: Erythema migrans E: Encephalitis / meningitis T: Transverse myelitis C: Cranial nerve neuropathy © Cordell Health Fun CAMP F: Fatigue C: Cognitive changes A: Arthritis M: Mood changes P: Peripheral neuropathy www.cordellhealth.co.uk Lyme Disease P: Borrelia burgdoferi Spirochete bacterium V: Ixodes Ricinus tick (deer) T: Tick bite to exposed skin I: 3-90 days HFX: Early: ILI + MEET-C Late: F-CAMP RX: Doxycycline © Cordell Health www.cordellhealth.co.uk Poll What is the most likely responsible pathogen for this lesion in a farmer: Image source DermNet https://creativecommons.org/licenses/by-ncnd/3.0/nz/legalcode © Cordell Health a) Leptospirosis b) Borrelia burgdorferi c) Coxiella burnetii d) Parapox e) Echinococcus granulosus www.cordellhealth.co.uk Poll What is the most likely responsible pathogen for this lesion in a farmer: Image source DermNet https://creativecommons.org/licenses/by-ncnd/3.0/nz/legalcode © Cordell Health a) Leptospirosis b) Borrelia burgdorferi c) Coxiella burnetii d) Parapox e) Echinococcus granulosus www.cordellhealth.co.uk Orf P: Parapox virus from sheep/goats T: Direct contact HFX: S: Skin ulceration E: Erythema multiforme L: Lymphadenopathy F: Fever (mild) RX: None, supportive, self-resolves (4-8w). Care to avoid secondary infection (antibiotics if reqd). © Cordell Health www.cordellhealth.co.uk Anthrax P: Bacillus anthracis – gram positive spore forming T: Cutaneous (direct contact): 1-7 days incubation Inhalation: 1-7 days Gastrointestinal: 48 hours HFX: Cutaneous: Eschar (painless black headed ulcer); 5-20% fatal if left untreated Respiratory: ILI + difficulty breathing + shock + death Gastrointestinal: ILI + D+V RX: Ciprofloxacin PO / IV PEP: antibiotics for 60 days NB: Prescribed and notifiable; spores can survive in soil for many years © Cordell Health www.cordellhealth.co.uk Ankylostomiasis P: Hook worm Definitive host = cats / dogs Intermediate host = humans / animals Life cycle: Adult hookworm lives in small intestine of definitive host and eggs passed into faeces. Eggs hatch and grow in soil. Become filariform and infect animals / humans on contact with skin. Carried through blood to lungs. Penetrate into alveoli and ascend to pharynx to be swallowed. Reach small intestine and mature into adult Rx: albendazole, mebendazole © Cordell Health www.cordellhealth.co.uk Echinosis P: Echinococcus granulosus – Hydatid disease Definitive host = dog / fox Intermediate host = sheep / human Life cycle: Adult tapeworm lives in dog small intestine and releases eggs into faeces. Sheep ingest infected faeces when grazing. Eggs hatch in the small intestine – oncospheres. Penetrate small intestine wall and travel in blood stream to other organs. Commonly form cysts in lungs / liver. Definitive host reinfected by consuming the infected meat of intermediate host. Humans infected through infected dog faeces. HFX: dependent on the location of the cyst RX: Surgery to remove cyst and Albendazole © Cordell Health www.cordellhealth.co.uk Echincoccosis © Cordell Health www.cordellhealth.co.uk Breakout Session a) What is a zoonosis? (1) b) What types of organisms cause zoonoses? (2) c) Write short notes on the causative organism (1), signs and symptoms in humans (1) occupations at risk (1) and prevention strategies (1) for each of: a) Anthrax b) Q fever c) Leptospirosis d) Lyme disease © Cordell Health www.cordellhealth.co.uk Food handlers © EOPH www.eoph.co.uk Food borne diseases You need some knowledge of food borne diseases Has come up as an MEQ in the past – describe the features of X etc Great resource here: https://www.gov.uk/government/pu blications/gastrointestinalinfections-guidance-for-publichealth-management © Cordell Health Suggested revision list: Salmonella typhi Salmonella paratyphi Salmonella spp. Campylobacter jejuni E.coli Vibrio Stap aureus Bacillus cereus Clostridium botulinum Clostridium perfringens Listeria monocytogenes www.cordellhealth.co.uk Food borne diseases Pathogen Source Incubation S.Typhi S. Paratyphi Travel to endemic T: 3-60d area PT: 1-10d /contamination by infected person Symptoms Notes Fever Test: bone marrow Diarrhoea culture most Complications: sensitive test; perforation / AKI / serum test = pneumonia Widdals test RTW Gen: 48h sx free FHs: 3 x neg stool 48h apart 1wk after completing rx. NB 2-5% chronic carriage for years © Cordell Health www.cordellhealth.co.uk Food borne diseases Pathogen Source Incubation Symptoms Notes Salmonella spp (non-typhoid) Raw/undercooked meat; eggs; raw milk 6h-6d Fever Nausea + vomiting Diarrhoea Rx only in severe cases RTW All: 48h symptom free Campylobacter jejuni Raw/undercooked poultry; raw milk 2-5d Fever Bloody diarrhoea Commonest cause of foodborne illness in the UK. RTW ALL: 48h symptom free © Cordell Health www.cordellhealth.co.uk Food borne diseases Pathogen Source Incubation Symptoms Notes E.Coli Raw/undercooked meat Raw milk / veg 3-4d Fever Diarrhoea Nausea + vomiting 5-10% serious – HUS = E0157 RTW Gen: 48h sx free FH: 2x –ve stool Vibrio Shellfish / water 2-48h Fever Diarrhoea Nausea + vomiting RTW 48h sx free S. Aureus Foods not cooked after handling 30min – 8h Diarrhoea Nausea + vomiting RTW 48h sx free Bacillus cereus Reheated food especially rice 2-12h Diarrhoea Nausea + vomiting RTW 48h sx free © Cordell Health www.cordellhealth.co.uk Food borne diseases Pathogen Source Incubation Symptoms Notes Clostridium botulinum Heat resistant spores in canned food 18-36h Slurred speech, diplopia, ptosis, symmetrical descending flaccid paralysis Rx: antitoxin RTW: on recovery Clostridium perfringens Cooked meat, gravies 6-24h Diarrhoea RTW 48h sx free Listeria monocytogenes Soft cheese, pate 1-4w Diarrhoea Fever Can be very serious in older adults / pregnant women RTW 48h sx free © Cordell Health www.cordellhealth.co.uk Food Safety Risks to health and safety during food management processes are addressed through a defined system: Hazard analysis and critical control point (HACCP) Hazard analysis Critical control points Identify the critical control points (where controls can be set to prevent hazard) Set criteria Monitoring Corrective actions Record keeping Verification © Cordell Health www.cordellhealth.co.uk Food safety Bacterial needs for growth: Warmth Moisture Food Time Food hygiene controls are based on these bacterial priorities Low protein / low moisture / high acid / high salt – low risk Maintain correct temperature – < 5C or > 63C Temperature controls must be linked with time as well: Prevent preparing food too far in advance Use rapid chill / freeze systems © Cordell Health www.cordellhealth.co.uk Control measures – Break out A new factory is opening which will mass manufacture cakes and baked goods for distribution across the UK. The health and safety manager requests your input as occupational physician to help with a risk assessment for the area to minimise the hazard of food borne infections. Describe the control measures which should be considered for implementation in a food production facility – try to categorise your answer into a logical format! © Cordell Health www.cordellhealth.co.uk Control measures Access •Restricted access •Food handlers medically fit to work •Appropriate clothing in the workplace © Cordell Health Facilities •Layout to minimise cross contamination •Good ventilation •Segregate storage and preparation areas •Separate designated prep areas •Washing facilities for staff Equipment •Colour coded boards and knives •Cooking canopy hoods to remove fumes •Waste bins easy – handsfree operation, closed lids, regularly emptied Procedures •HACCP •Equipment failure contingency plan •Monitor and record food temperature regularly Maintenance Housekeeping •Monitor and maintain equipment regularly •Extraction systems which are adequate and functional – test every 14 months •Check alarm systems •Record storage temperatures •Regular cleaning schedule •Procedure for spillages •Empty bins regularly •Store waste in an appropriate area to minimise pests www.cordellhealth.co.uk Fitness Standards for Food Handlers Read this: https://www.nhshealthatwork.co.uk/images/library/files/Clinical%20exce llence/InfectedFood_full_guidelines.pdf Key messages: Most outbreaks are attributable to Norovirus, Salmonella enteritidis and Salmonella typhimurium. Food handlers who continue to work with GI symptoms (diarrhoea / N+V) represent a significant public health hazard Hand washing is key to minimise the risk of infection Personal hygiene is also very important Gloves may give a false sense of security and reduce the frequency of hand washing © Cordell Health www.cordellhealth.co.uk Legionella © EOPH www.eoph.co.uk Legionella P: Legionella pneumophilia Spread is through infected aerosols HFX: Legionnaires disease 10-15% fatal Incubation 2-19d Influenza like illness Atypical pneumonia Diarrhoea Confusion Rx: erythromycin Susceptibility: male, >50y, smoker, underlying disease, immunosuppressed © Cordell Health www.cordellhealth.co.uk Group discussion Group discussion point: What are the fundamental two principles of legionella control? Can you give any examples? © Cordell Health www.cordellhealth.co.uk Legionella controls Temperature controls Stagnation controls Hot water cylinders > 60C Hot water distribution > 50C Cold water storage + distribution < 20C Mont
