Table 4.

Syntactic patterns for collecting context triggers

	Trigger patterns	Examples
1	{noun} of [bacteria] loc_prep [location]	∙elimination of [Helicobacter pylori] Bin the [antrum] L
		∙attachment of [Escherichia coli O157:H7] Bto [apple surfaces] L
2	[bacteria] {n/v/p} loc_prep[location]	∙Heat-killed [C. burnetii] Bpurified with [normal yolk sacs] L
		∙ [Non-O1 Vibrio cholerae] Bbacteremia in [patients with cirrhosis] L
3	[location] {n/v/p} prep [bacteria]	∙ [Respiratory] Lcarriage of [Kingella kingae] B
		∙Twenty-eight [blood culture] Lisolates of [non-O1 V. cholera] B

Underlined expressions are context triggers to be collected. [bacteria] and [location] are bacteria and location mentions annotated in BB-event training data, respectively. prep and loc_prep are a general preposition and a locational preposition, respectively. {n/v/p} is either a noun, a verb, or a participle. Examples on the right show actual snippets from the BB-event training data matched by syntactic patterns on the left. B and L in boldface refer to bacteria and location entities, respectively