Table 4. Clinical progression of illness for patients hospitalized with acute INKV (n = 4) or CHATV infection (n = 2), Finland*.

Virus and patient no.	Illness progression	Additional findings
INKV
1	Day 1: fever 38°C, influenza-like symptoms	Elevated HHV-6 antibody levels from same sample
	Day 3: disoriented
	Day 6: hospitalized, abnormal EEG, CAL IgM+
	Day 7: psychotic but discharged
	Day 10: follow-up EEG shows same abnormalities
	3 mo later: EEG almost normal
2	Day 1: fever 39.5°C, headache, nuchal rigidity, sore throat before fever, hospitalized	Tick bite 1 mo earlier, erythema migrans; day 1: BorrAb neg
	Day 2: nuchal rigidity, headache deteriorating, slowness but oriented
	Day 3: discharged, CAL IgM+
	Day 5: headache again, hospitalized
	Day 6: discharged
3	Day 1: vomiting
	Day 2: stomach pain, diarrhea, seizures,  hospitalized
	Day 3: fever 38.3°C, drowsiness, convulsions
	Day 4: More seizures, small changes in EEG
	Day 5: CAL IgM+
	Day 8: discharged
4	Day 1: fever 37.9°C, sore throat	Tick bite 3 wks earlier
	Day 3: CAL IgM+
	Day 4: nausea and vomiting
	Day 5: fever 39°C, headache, nuchal rigidity, hospitalized
	Day 10: recovered and discharged
CHATV
1	Day 1: vomiting continuing for 3 d
	Day 4: fever, hospitalized, disoriented at night
	Day 7: frontal headache, normal head CT and abdominal ultrasound
	Day 12: discharged, CAL IgM+
2	Day 1: fever 39°C, back pain	Back injury 2 wks earlier
	Day 7: hospitalized, high fever, back pain almost resolved
	Day 7–22: temporal pain, trembling of hands, fluctuating fever
	Day 17: CAL IgM+
	Day 23: discharged

*BorrAb, Borrelia antibody test; CHATV, Chatanga virus; CT, computer tomographic scan; EEG, electroencephalogram; HHV, human herpesvirus; INKV, Inkoo virus. CAL IgM+ indicates the day when IgM for California encephalitis group viruses was observed.