1. Disease Outbreak Maria del Rosario, MD, MPH www.wvidep.org Infectious Disease Epidemiology Program WVDHHR/BPH/DSDC February 2009 1

2. Objectives 2 o Understand why a disease outbreak requires immediate attention. o Recognize an outbreak when it occurs. o Know what to do when a disease outbreak is recognized.

3. What is an OUTBREAK? (1) Outbreaks (aka epidemics): an increase in the number of cases* of disease over and above the expected number of cases. __________ *certain diseases specify the number of cases 3

4. 4 What is an OUTBREAK? (2) Foodborne disease outbreak is defined as > 2 persons who experience a similar illness after ingestion of a common food. A single case constitutes an outbreak:  Category A agents - Anthrax, Botulism, Smallpox, Viral Hemorrhagic Fever,  Emerging infectious disease,  Chemical poisoning,  Rare diseases - diphtheria, polio, monkeypox, novel influenza virus, human rabies, Salmonella typhi, Vibrio cholerae Methicillin-resistant Staph. aureus (MRSA) Outbreak:  > 2 epidemiologically-linked cases of CA-MRSA occurring in at least 2 distinct households,  A case on a sports team,  An increase in the incidence of CA-MRSA over the expected incidence. 4

5. How would I know that there is an outbreak? o Through surveillance records and other data sources o Someone notifies you, e.g. medical/ nursing provider, corrections officer, inmates, etc. 5

6. Public Health: Steps in Outbreak Investigation 1.Establish existence of an outbreak 2.Preparation 3.Verify the Diagnosis 4.Establish a case definition, Identify and count cases 5.Perform Descriptive Epidemiology 6.Develop hypotheses 7.Test hypotheses 8.Refine hypotheses and do additional studies 9.Implement Control /Prevention Measures 10.Communicate the Findings 6

7. I think, maybe…there is an outbreak of…something. Now, what? (1) A.Report/notify public health authorities Legislative rule 64CSR7 states: “Suspected or confirmed outbreak or cluster of any illness or condition needs to be reported IMMEDIATELY to the health department.” http://www.wvidep.org/LinkClick.aspx?fileticket=a0cnCHjajzg%3d&tabid=1473 7

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9. B.Investigate o Reasons to investigate -Control /prevention -Public, political, legal concerns -Education 9 …there is an outbreak of…something. Now, what? (2)

10. 10 B.How to Investigate o What information to collect o Collect samples (stool, etc.) …there is an outbreak of…something. Now, what? (3)

11. …there is an outbreak of…something. Now, what? (4) C.Evaluate the data collected o Health department can help with collation, analyses, and interpretation o Response to outbreak will be based on initial findings 11

12. D.Initiate control/preventive measures o Implement control measures as soon as possible o May be aimed at agent (organism), source, or reservoir o Short or long term 12 …there is an outbreak of…something. Now, what? (5)

13. Summary o Surveillance is important in detecting an outbreak. o Early detection of a disease outbreak is critical to clinical and public health management. 13