Table 1. Surveillance definitions.

Passive case detection	Involves a system in which data are routinely received by a central health authority based on a set of rules and laws that need a health-care provider or health facility to report some diseases or disorders on an ongoing basis and at specific intervals [29]
Reactive case detection	Is triggered whenever a case is identified by passive case detection and involves visiting the household of the locally acquired case, screening family members, and screening neighbors within a defined radius [30]
Proactive case detection (e.g. passenger screening)	Involves the screening of focal populations without the trigger of a passively identified case based on the knowledge that transmission is more likely during some periods of the year, in specific high-risk groups, or in target geographical areas [30]