Six diethylaminoethyl-cellulose fractions of a larval
Trichinella spiralis
extract, an
Ascaris suum
extract, and a nonrelated protein were used for cutaneous tests in guinea pigs with 8-, 14-, and 73-day-old
T. spiralis
infections, in guinea pigs with 13-day-old
A. suum
infections, and in normal guinea pigs. A selected
T. spiralis
fraction was used in hemagglutination (HA) tests with sera of 8
T. spiralis
-infected rabbits, 41 sera of trichinellosis patients positive by bentonite agglutination tests, and 50 sera of clinically healthy persons. Immediate-type cutaneous reactions revealed extensive cross-reactivity between both parasites, although the establishment of conventional limits for considering a reaction positive allowed the specific diagnosis of acute or chronic trichinellosis with different fractions. Delayed-type reactions were specific with all fractions except one, and different fractions reacted during either the acute or the chronic phase of trichinellosis. HA detected anti-
Trichinella
antibodies in all the rabbits 9 to 10 days postinfection, in all trichinellosis patients, and in none of the healthy people. Correlation between HA and bentonite agglutination titers and other considerations suggest that HA with the selected fraction detects early antibodies. HA inhibition tests with
A. suum
extract suggest lack of HA cross-reactivity between the
A. suum
- and
T. spiralis
-selected fractions. The use of different fractions in diverse tests for clinical or epidemiological studies is suggested.
Persistence of Lassa Virus Associated With Severe Systemic Arteritis in Convalescing Guinea Pigs (Cavia porcellus)
