Pathogenesis and clinical management of arboviral diseases

Table 4 Final case classification of yellow fever

Classification	Criteria
Probable case	A suspected case and at least one of the following
	Presence of YF IgM antibody in the absence of YF immunization within 30 days of illness onset
	Epidemiological link to a confirmed case or an outbreak (e.g., household members or persons in close proximity through work, residence in past month)
Confirmed case	A probable case and at least one of the following
	Negative results of differential neutralization testing with flaviviruses endemic in the area of exposure
	Seroconversion in appropriately paired samples tested by YF neutralization testing
	And absence of YF immunization within 30 days before onset of illness
	Or a suspected case and at least one of the following
	Detection of YFV genome in blood or other organs by real-time reverse transcriptase polymerase chain reaction
	Detection of YF antigen in liver or other organs by immunohistochemistry
	Isolation of YF virus
	And absence of YF immunization within 14 days before onset of illness
Discarded case	A person who tests negative for YF antibody testing (with specimen collected > 7 days post onset)
	Or negative immunohistochemistry on tissue samples

YF: Yellow fever; YFV: Yellow fever virus.