TABLE V. Most Frequently Features Interactions.

Level	Order	Features
Severe	Order-3	AD, PI, COUGH
		PI, HL, COUGH
		RT–PCR, PI, COUGH
	Order-4	ADV, COUGH, HL, CoxB
		CoxB, RT–PCR, HL, COUGH
		CoxB, TS,AD, COUGH
Fatal	Order-3	ADV, RT–PCR, COUGH
		ADV, AD, COUGH
		ADV, PI, COUGH
	Order-4	ADV, PI, HL, COUGH
		CoxB, AD, HL, COUGH
		ADV, COUGH, HL, CoxB

¹ full names of the abbrevations in this table can be found in Table VII.