During the autumn of 1990, we had investigated the clinical features and followed the changes in the indirect immunofluorescent antibody (IFA) titers in 28 children with scrub typhus who resided in or near Chinju, Korea. All the children except
one
were
diagnosed by the peak IFA titers of 1:160 or higher.
@ES The results were as follows;
@EN 1) The clinical features of our children were not different, to a large degree, from those of adults ever described in Korean literatures. But the frequence rates of skin rash, eschar and conjunctival injection were higher, those of
proteinuria
and
hematuria were lower than those in adults and the characters of rash in our children were also quite different (faces were frequently the first site of eruption and even palms and soles were involved occasionally, initial bright red color of rash
was
changed into brown color during the acute phase).
2) IFA titers rose rapidly during the 2nd or 3rd week of illness and then formed plateau. When we suggest IFA titers of 1:80 or higher as the diagnostic criteria, the seropositivity of our children was 5/7(75%) in the 1 st week and over 95% in
the
2nd
through 5th week of illness, and suggest IFA titers of 1:160 or higher, then the seropositivity in the 1st, 2nd and 3rd through 5th week were 3/7 (43%), 23/31 (74%) and over 95%, respectively.
3) IFA titers in 6-8 months after disease onset were 1:80 (13 children) or 1:20(7 children), and in one and half year (our longest follow-up period), 1:20 (3 children) showing that IFA lasts longer than one and half year after sickness.
4) From the above above data ⑶ and the fact that majority of cases of scrub typhus occur in the autumn season in Korea, IFA titers of 1:40-1:160 should be used as the diagnostic criteria in order to distinguish between the present and past
infections.
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