CIC Outbreak Investigation 5

Question 1

In an outbreak investigation, the population attributable risk percent (PAR%) is useful because it estimates:

Accepted Answer

The proportion of disease in the total population attributable to the exposure

Answer

PAR% estimates what proportion of all disease in the population is attributable to the exposure, which is valuable for prioritizing public health interventions.

Question 2

A unit-level outbreak investigation reveals that three nurses cared for all cases but no other cases occurred among patients of other nurses. This finding most strongly suggests:

Accepted Answer

Healthcare worker carriage or technique as a potential transmission source

Answer

When cases cluster around specific healthcare workers, it raises the hypothesis of HCW carriage or technique-related transmission as a contributing factor.

Question 3

Which type of bias occurs when cases are more likely to recall an exposure than controls in a case-control outbreak study?

Accepted Answer

Recall bias

Answer

Recall bias occurs when cases, motivated by their illness, remember exposures more completely than controls, potentially inflating the apparent association.

Question 4

When a healthcare facility experiences an outbreak of Legionella pneumophila, what is the most critical environmental source to investigate first?

Accepted Answer

Potable water system including cooling towers and hot water distribution

Answer

Legionella amplifies in water systems, and the potable water distribution system and cooling towers are the primary environmental sources to sample and remediate.

Question 5

In the investigation of a nosocomial outbreak, which laboratory result would most strongly support clonal transmission from a single source?

Accepted Answer

All isolates are indistinguishable by whole genome sequencing with fewer than 5 SNP differences

Answer

Isolates with fewer than 5 SNP differences by WGS are considered highly related and strongly support clonal transmission from a common source.

CIC - Certification in Infection Prevention and Control Practice Test

CIC - Certification in Infection Prevention and Control Practice Test

CIC Outbreak Investigation 5