Outbreak Investigation Terms An increase incidence rate over

Outbreak Investigation

Terms • • • An increase (incidence rate) over the Incidence Rate expected occurrence (prevalence) of an the number of cases of a specific The incidence rate is the number event. Prevalence disease present in a given of new cases per population in a Episode of increased disease Outbreak; population at a certain time. given time period incidence due to enhanced Note that a single case of an unusual a grouping of health-related events that are http: //medical. Cluster; surveillance or other factor not disease or pathogen may constitute an closely related temporally and in proximity dictionary. thefreedictionary. com/Prevalence+(epidemiolog y) related to the disease under study. outbreak. The number of cases in the cluster may or Pseudo-outbreak There is a rise in test results may not exceed the expected number. E. g. , SSI with GAS without actual clinical disease HAI with Legionella

Cluster vs. Outbreak �Both require prompt investigation �Determined by cluster analysis �HAIs surveillance provides both the baseline rate and ongoing monitoring �MC-ICD-P/16 . &20.

Outbreak Management 1 2 3 4 5 • Recognise outbreak and prepare to investigate. • Verify the diagnosis and confirm that an outbreak exists. • Establish case definition and find cases. • Characterise outbreak by person, place, and time. • Determine who is at risk. 5

Outbreak Management 6 7 8 9 10 • Develop hypothesis – the ‘how’ and ‘why’. • Test hypothesis with established facts. • Carry out further studies if necessary. • Communicate findings. • Implement ongoing infection control / prevention measures. 6

I C Interventions Infection control measures : Patient isolation of the HAI -infected patient. Cohorting HAI -infected patients. Personal Protective Equipment (PPE). Hand hygiene. Visitors instructions. Environmental cleaning .