Communicable Disease Control Public Health, Year 4, MMS Yr 4 PH Paediatrics 1

Why do Outbreaks occur? Groups of 3Groups of 3 5 minutes5 minutes Rapid feedbackRapid feedback 2 PUBLIC HEALTH PEP

How do outbreaks occur? Need to have epidemiological disease-cause triad of:Need to have epidemiological disease-cause triad of: –agent –host –environment And a chain of transmission that links the aboveAnd a chain of transmission that links the above PUBLIC HEALTH PEP 3

Status: Susceptible/ Immune/ Infected Response: No illness/ Typical illness/ Atypical or v severe illness (e.g. immunocompromised) Infectivity Pathogenicity Virulence conditions or influences not part of agent or host, which influence their interaction Host Agent Environment The host-agent-environment triad PUBLIC HEALTH PEP 4 CHAIN OF TRANSMISSION

Age Genetic determinants Nutritional status Underlying medical condition Immunosuppression Co-infection Treatment with antimicrobials Behaviour Psychogenic factors Ability to survive in environment Mode of transmission Ability to attach, invade, multiply in host Duration of infectivity Evasion of host immunity Resistance to antimicrobial therapy Immunity of immediate contacts Incidence of infection in contacts Human population density, movement & mixing Vector/ reservoir density Disease incidence in vector/reservoir Resistance to interventions in vector/reservoir Climate & environmental change Antibiotics in the environment Other pathogens Water supply Sanitation Host Agent Environment from Cohen J, Powderly. Infectious Diseases, Second edition. Edinburgh: Mosby; 2004 The host-agent-environment triad PUBLIC HEALTH PEP 5

6 PATHWAY SOURCE RECEPTORS

Key terms Index case first case to come to the attention of the investigator: not always the primary case Primary case case that introduces the disease into the family/group/population Secondary case catches infection from primary case Incubation period time between between infection and developing first symptoms PUBLIC HEALTH PEP 7

Key terms 2 Latent period= time between infection and becoming infectious Incubation period= the time interval between acquisition of infection and onset of illness/symptoms Attack rate= proportion of exposed population that becomes clinically ill PUBLIC HEALTH PEP 8

SURVEILLANCE Yr 4 PH Paediatrics 9

What is disease surveillance? systematic process of: – –Collecting and collating data – –Analysing data – –Interpreting the results – –feeding back the information to those who need to take action “INFORMATION FOR ACTION” 10 PUBLIC HEALTH PEP

It’s not new ’s-1830’s: Bills of Mortality weekly statistics for numbers buried in each parish who died of the plague & other causes C19 th : Medical Officer of Health Reports Since late C19 th : statutory notification of infectious diseases PUBLIC HEALTH PEP 11

Surveillance – a classical model PUBLIC HEALTH PEP 12 Event Real world – Expect changes Intervention Data Analysis and interpretation Information Health care system Public Health Authority Reporting Decision (feedback)

Surveillance vs. Research Surveillance Applies existing knowledge to guide the health system in the use of known control measuresApplies existing knowledge to guide the health system in the use of known control measures - directly relevant to monitoring and control measures - directly relevant to monitoring and control measuresResearch Pursues new knowledge from which better control measures will resultsPursues new knowledge from which better control measures will results - systematic investigation, testing and evaluation designed to develop or contribute to knowledge 13 PUBLIC HEALTH PEP

Creating a Surveillance system TASK: What do you do when you are ill?TASK: What do you do when you are ill? 14 PUBLIC HEALTH PEP

Sources of data 15 PUBLIC HEALTH PEP Community

Clinicians Yr 4 PH Paediatrics 16

Health Protection Regulations 2010 Requires : Registered medical practitioners to notify the proper officer of the local authority if a patient: has a notifiable disease has an infection that could present significant harm is contaminated has died with a disease or infection that could present significant harm Diagnostic laboratories to notify PHE when evidence of infections caused by specified agents / PUBLIC HEALTH PEP 17

DISEASES NOTIFIABLE UNDER THE PUBLIC HEALTH (INFECTIOUS DISEASES) REGULATIONS 2010 Acute encephalitis Acute infectious hepatitis Acute meningitis Acute poliomyelitis Anthrax Botulism Brucellosis Cholera Diphtheria Enteric fever (typhoid or paratyphoid fever) Food poisoning Haemolytic uraemic syndrome (HUS) Infectious bloody diarrhoea Invasive group A streptococcal disease Legionnaires’ Disease Leprosy Malaria Measles Meningococcal septicaemia Mumps Plague Rabies Rubella SARS Scarlet fever Smallpox Tetanus Tuberculosis Typhus Viral haemorrhagic fever (VHF) Whooping cough Yellow fever PUBLIC HEALTH PEP 18

19 PUBLIC HEALTH PEP

Laboratory Yr 4 PH Paediatrics 20

Patterns of reporting to national surveillance for Campylobacter, Salmonella, norovirus and rotavirus, UK 2008–9. Tam C C et al. Gut doi: /gut Copyright © BMJ Publishing Group Ltd & British Society of Gastroenterology. All rights reserved. PUBLIC HEALTH PEP 21

Evaluating surveillance systems SimplicityIs system easy to access & use from perspective of various users FlexibilityHow readily can it be adapted Data qualityIs data of sufficient quality & consistency to assure reliable use for intended purpose AcceptabilityAre procedures for obtaining data nonintrusive, are the data useful, perceived as wise investment SensitivityProbability that a case will be identified What percentage of epidemics or outbreaks are detected Predictive valueProbability of the disease/event given the surveillance data Likelihood that alerts represent events that we are seeking to detect RepresentativenessTo what extent is the pattern representative of the health of the population TimelinessDoes system provide data that allows timely investigations & effective intervention StabilityIs there assurance that trends reflect health/illness & not changes in how data collected/managed 22 PUBLIC HEALTH PEP

? Why is surveillance important? 1. 1.Enables timely public health action for sporadic cases e.g. contact tracing 2. 2.Detection of outbreaks/clusters 3. 3.Monitor trends in disease 4. 4.Estimating magnitude of problem 5. 5.Can monitor and evaluate prevention and control programmes 6. 6.Feeds into policy decisions and planning PUBLIC HEALTH PEP 23

Success looks dull…. 24MMHSC Study Day

OUTBREAK INVESTIGATION

Recognising Outbreaks 26 PUBLIC HEALTH PEP Measles in a local authority area

What is an outbreak? An outbreak or an epidemic exists when there are more cases of a particular disease than expected in a given area, or among a specific group of people over a particular period of time Or One case of serious/rare disease e.g. Ebola/plague/smallpox PUBLIC HEALTH PEP 27

Why investigate outbreaks? To control it To understand what happened To prevent future outbreaks Research and training opportunities Programme evaluation Public, political or legal concerns PUBLIC HEALTH PEP 28

Steps of an outbreak investigation 1. 1.Verify diagnosis 2. 2.Confirm the outbreak 3. 3.Define a case 4. 4.Conduct case finding 5. 5.Descriptive epidemiology 6. 6.Formulate and test hypotheses 7. 7.Analytical epidemiology 8. 8.Microbiological and environmental investigation 9. 9.Implement and evaluate control measures Communicate findings These steps may occur simultaneously or be repeated as new information is received PUBLIC HEALTH PEP 29

INFECTION CONTROL Yr 4 PH Paediatrics 30

HCAI Mandatory Surveillance – –Meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia – –Meticillin-sensitive Staphylococcus aureus (MSSA) bacteraemia – –Escherichia coli (E. coli) bacteraemia – –Clostridium difficile infection (CDI) Emerging issues – –CPE – –VRE 31MMHSC Study Day

Infection Control Hierarchy PPE Administrative Controls Engineering Controls Elimination of potential exposures 32MMHSC Study Day

Your 5 moments for hand hygiene

Hand Hygiene- its not difficult in the UK! Yr 4 PH Paediatrics 34

And so to group workAnd so to group work Yr 4 PH Paediatrics 35