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Control of infection in the community

Control of infection in the community. Darina O’Flanagan Director Health Protection Surveillance Centre. Learning objectives. Importance of Surveillance/ Epidemic Intelligence New International Health Regulations Clusters of unusual diseases Iceberg concept

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Control of infection in the community

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  1. Control of infection in the community Darina O’Flanagan Director Health Protection Surveillance Centre

  2. Learning objectives • Importance of Surveillance/ Epidemic Intelligence • New International Health Regulations • Clusters of unusual diseases • Iceberg concept • Importance of “reporting culture” • Primary prevention of infection in the community: Vaccination • Secondary Prevention • Chemoprophylaxis • Haemophilus influenzae meningitis • Invasive Meningococcal disease, Invasive Group A Strep, TB • Outbreak Management in the Community • Foodborne Outbreaks – done with Dr McNamara • Legionnaire’s Disease • Responding to Emerging Diseases: Pandemic Influenza

  3. Definition of public health surveillance “The ongoing systematic collection and analysis of data and the provision of information which leads to action being taken to prevent and control a disease, usually one of an infectious nature.”

  4. Epidemic intelligence Risk Assessment vs. Risk Management Risk monitoring Monitor information Assess signal Risk assessment Investigate PH alert Implement control measures Risk management Disseminate information Risk communication

  5. Epidemic Intelligence Framework Important for new International Health Regulations Event-based component Indicator-based component “Surveillance” systems • Event monitoring Report Data CaptureFilterVerify CollectAnalyseInterpret Signal • EWRS • Rapid inquiries • E-Alerts • IHR • Epi bulletin • WEB Assess Disseminate Public health Alert Investigate Control measures

  6. Epidemic IntelligenceDefinition « Epidemic intelligence is the process to detect, verify, analyze, assess and investigate signals that may represent a threat to public health. It encompasses all activities related to early warning surveillance functions but also signal assessments and outbreak investigation. »

  7. Indicator-based EI componentHealthcare settings • Identified risks • Mandatory notification • Laboratory surveillance • Emerging risks • Syndromic surveillance • Mortality monitoring • Health care activity monitoring • Prescription monitoring • Poison centres

  8. Risk monitoringEvent-based surveillance • Domestic • Media monitoring • EI focal points • International • Information scanning tools (GPhin, MedISys) • Distribution lists/Networks • PROMED • WHO-OVL • International agencies

  9. Event-based surveillanceInfo scanning tools - GPhin

  10. Outbreak detection • May 2000 Scotland • Severe soft tissue abscesses systemic illness and death in IDU • EU rapid alert issued • Surveillance set up in A & E • Irish outbreak identified • 22 cases, 8 deaths • Clostridium novyii identifed • New methadone clinics offered • Messages to IDU not to muscle pop • Attend early if any abscess

  11. Surveillance: “you see what you look at” Laboratory-based surveillance Report Pos. specimen Clinical specimen Clinically-based surveillance Seek medical attention Disease Community-based surveillance Infected Serological survey Exposed

  12. Acute Gastroenteritis Survey*North and South • Frequency of IID4.5% per 4 week period • 9000 new episodes per day • 3.2M episodes per year • Days of illness12.6M per year • GP Consultations3000 per day (7.5% lab spec - 2% ill) • 1.1M per year • Working Days lost1.5M per year • Loss of Earnings€173M per year Source: FSPB. Acute Gastroenteritis in Ireland, North and South, FSPB, Dublin: 2003

  13. Invasive Meningococcal Disease(IMD)A highly succesful example of primary prevention of infectious disease in the community

  14. IMD in Ireland 1999- 2004Monthly number of cases Oct 2000 Men C vaccine

  15. Invasive Haemophilus influenzae type b (Hib) diseaseAn example of surveillance data being used to influence the childhood immunisation schedule

  16. Quarterly immunisation uptake rates at 24 months in Ireland

  17. Invasive Hib in Ireland 1987- 2005

  18. Summary Hib in Ireland • In 2005 • Incidence of invasive Hib disease increased in <5 yr olds • Majority of Hib cases in <15 yr olds occurred in vaccinated children: 93% • Number of true vaccine failures increased dramatically in 2005 • 14 TVFs in 2005, 6 in 2004 (4/6 occurring in Q4) and 3 in 2003 • A selection of Hib vaccines associated with these failures • 12/14 TVFs in 2005 occurred in children aged 13 months – 4 years • Response to these trends • National Immunisation Advisory Committee recommended that a catch up Hib dose be offered to children <4 years of age, in order to further protect this age group from Hib disease. • The catch up campaign was launched by HSE on 21 November 2005 • HPSC continuing to closely monitor the situation through surveillance

  19. Chemoprophylaxis

  20. Chemoprophylaxis- Meningococcal • Aim • Eliminate carriage from network of close contacts* • Prevent further cases among susceptible close contacts • Saliva inhibitory to meningococcal growth • Secondary cases are rare • less than 3% of all cases are considered secondary cases. • Risk of disease is highest amongst household contacts • Highest risk in the 1st week, and falls over next 2-3 months. With chemoprophylaxis this is extended up to 6 months Attack rate x 500-1000 = 1% households in 1st month (1 in 300 secondary contacts) • Secondary cases in crèches etc: v. rare, 4 cases over 3 years in population 56 million. (1 in 1500 for crèche, 1 in 1800 for primary school and 1 in 33000 for secondary school. A randomised control trial is impossible.)

  21. Chemoprophylaxis-Meningococcal • For index patient • as soon as can tolerate oral medication (unless treated with ceftriaxone – if cefotaxime still need chemo) • For close contacts • If contact within 7 days prior to the onset (incubation 3-5 days;) Eligible close contacts are • household contact: shared living/sleeping accommodation; includes baby minders • mouth kissing contact (usually close contact) • Gave mouth to mouth resuscitation (1 in 100,000, wear masks!) • in same nursery/crèche : where nature/duration of contact is similar to to that for household contacts

  22. Chemoprophylaxis- School setting (1) • School contacts • Prophylaxis not indicated for sporadic cases, but give advice • If 2 or more cases in the same class in the same term give to class members and teachers

  23. Chemoprophylaxis- School setting (2) • in different classes management depends on factors such as • interval between cases, size of the contact group, carriage rate in the school, whether due to vaccine preventable strain, • incidence of the disease in the community ? community outbreak • the degree of public concern

  24. Chemoprophylaxis • Not recommended routinely on public transport e.g. bus and train • Special consideration to party esp with pre-school children present - if decide to give give to all adults and children • Special consideration to members of extended family where overcrowding or adverse living conditions • Simultaneous administration is ideal but if someone missed then give up to within a month

  25. Chemoprophylaxis used • Rifampicin • Frequently used, oral (two days) • Ciprofloxacin • Becoming more frequently used (one dose) • Ceftriaxone • Often used for pregnant contacts • IM injection

  26. Chemoprophylaxis - Hib disease • Rifampicin recommended for 4 days • 4 days needed to eradicate carriage (more days than for meningo) 20mg/kg/day (up to a max of 600mg daily) once daily for four days • Recent recommendations from UK recommend rifampicin to all household members if at risk individuals in household (regardless of immunisation status) i.e. • Children < 4 years in household • Immunocompromised individual • In crèche or playgroup • Two or more cases in 120 day period, offer to all room contacts (children and adults)

  27. Invasive Group A Strep iGAS • Most GAS infections mild such as strep throat or impetigo. Rare occasions can become invasive e.g. necrotising fasciitis or Streptococcal toxic shock syndrome • Close contacts should receive chemo (oral penicillin) if symptoms suggestive of localised GAS infection • Mother and baby if either develops iGAS in the neonatal period • Other contacts should be given leaflet and warned to look out for symptoms for 30 days after diagnosis in the index case – see leaflet on www.hpsc.ie

  28. TB

  29. TB notification rates per 100,000 population, Europe, 2003

  30. National Notifications of Tuberculosis 1952 - 2003 BCG introduced early 50s Source: DoHC 1952-1997, HPSC 1998-2003

  31. What do we want to do? Stop people getting TB • How? • Find people with infectious TB as soon as possible and treat them • Find their contacts and examine them to ensure that they have • Not got TB • Are not developing TB (TB infection / latent TB) • Find people who have a high risk of having latent TB, test them and if positive for TB, treat them with chemoprophylaxis (new entrant screening) • BCG

  32. Incidence rate per million population of legionnaires’ disease in various European countries, 2004

  33. Incidence of Legionnaires’ Disease • Less than 5% of cases are notified through passive surveillance (Marston,1997) • Legionella causes 2 to 16% of community acquired pneumonia cases in industrialised countries (Bohte,1995) • Legionella causes 14 to 37% of severe cases of community acquired pneumonia, with associated mortality in excess of 25% (Hubbard,1993)

  34. Case Legionnaires in Ireland1999-2004 • Of 30 cases notified in this time period • 11 were community acquired (36.8%) • 2 was nosocomial (6.6%) (Laboratory confirmed case that occurs in a patient who was in hospital for all 10 days before onset of symptoms.) • 17 were travel acquired (56.6%) (A case who in the ten days before onset of illness stayed at/visited an accommodation site – reported to EWGLI) • Countries acquired included: France, Ireland, Italy, Malta, Mexico, Portugal, Spain, Tunisia and USA. • Male:female ratio is 2.2:1 • Age Range between 19-80 years and median age is 53 years

  35. Diagnosis and follow up • Notify MOH • Check 14 day diary • Notify EHO who will sample water at hotels +/- domestic houses

  36. SARS in Ireland

  37. Influenza report available weekly at www.hpsc.ie ILI rate per 100,000 population and the number of positive influenza specimens detected by the NVRL during the 2000/2001, 2001/2002, 2002/2003, 2003/2004 & 2004/2005 seasons, summer 2005 and the 2005/2006 season.

  38. Why is there concern about avian influenza A/H5N1? • H5N1 has causes the largest outbreak in birds on record, since late 2003 • Despite culling >150 million birds, its become endemic in parts of SE Asia

  39. Why is there concern about avian influenza A/H5N1? • May mutate and start the next pandemic • Domestic ducks can excrete large quantities of H5N1without signs of illness - silent reservoirs • H5N1 viruses now more lethal to experimentally infected mice and to ferrets (a mammalian model) • H5N1 has expanded its host range. • The behaviour of the virus in its natural reservoir, wild waterfowl, may be changing. • Spring 2005 die-off of circa 6,000 migratory birds at a nature reserve in central China, due to H5N1, was highly unusual and probably unprecedented.

  40. Why is there concern about avian influenza A/H5N1? • When humans become ill with AI: • unusually aggressive clinical course with severe disseminated disease affecting multiple organs and systems • Rapid deterioration • High fatality • It causes death in >50% of those affected • Most cases have occurred in previously healthy children and young adults

  41. Controlling Spread?

  42. Guidance re avian influenza at Phase 3 • Clinical assessment of people with ARI coming from country affected by H5N1 • Algorithm/guidelines for assessment • Travel advice • No travel restrictions • Avoid wet markets, contact with poultry • If ill on return contact GP • General public concerns • Seasonal flu vaccine for poultry workers • If an outbreak of AI occurred in birds, exposed workers might be under public health surveillance and given oseltamivir prophylactically Details available at www.hpsc.ie/A-Z/Respiratory/AvianInfluenza/

  43. Lessons from past pandemics  • Occur unpredictably, not always in winter • Great variations in mortality, severity of illness and pattern of illness or age most severely affected • Rapid surge in number of cases over brief period of time, often measured in weeks • Tend to occur in waves - subsequent waves may be more or less severe •     Key lesson – unpredictability  • Will also depend on the availability and effectiveness of antiviral drugs and vaccines

  44. Emergence of pandemic virus: 3 requirements • Novel virus subtype emerges, with little or no immunity in humans • Virus can replicate in humans and cause serious illness • Can be transmitted efficiently from person-to-person

  45. WHO alert phases

  46. Four EU alert levels • Alert level • 0 No cases anywhere in the world • 1 Cases only outside the EU • New virus isolated in the EU • Outbreak(s) in the EU • 4 Widespread activity across the EU

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