|Proposed alert signals (triggers for early response) as suggested by the WHO-TDR expert meeting (June 2012)|
|Trigger||Evidence or expert opinion**||Feasibility||Further research needed***|
|New predominant serotype introduced||+++||Most countries||+++|
|Changes in age group distribution||++||Most countries||+++|
|Increased number of hospitalised/outpatient fever cases/probable dengue*||+++||Most countries||+++|
|Increase in vector presence||++||Most countries||+++|
|Increase in news reporting dengue outbreaks, social network comments||+||Few countries||++++|
|Climate changes: increase in rainfall/temperature/humidity||++||Most countries||+++|
|Increase in % positive serology*||++++||Most countries||+|
|Increase internal displacement/population mobility||+||Context dependent||++++|
|Cluster identified through GIS mapping||++||Few countries||++|
|Identification of outbreak in a neighboring geographical unit (state, district, province, country)*||++++||Most countries||++|
*Particularly useful indicators/ triggers.
** ++++ very strong; +++ strong; ++fairly strong; + weak.
*** ++++highest priority; +++ high priority; ++ necessary.
Badurdeen et al.
Badurdeen et al. BMC Public Health 2013 13:607 doi:10.1186/1471-2458-13-607