in vitro culture and isoenzyme analysis of giardia lamblia

Association of Giardia with allergy has previously been reported by others,
(Farthing et al., 1983; Perez et al. 1994). In the present study, a general
observation wherein 5 and 17% of the 78 hospital patients harbouring this
protozoan presented with eosinophilia and asthma respectively was noted.
However, no strict statistical analyses were undertaken because there were no
matching controls against which to measure this variable (outside the scope of this
dissertation) .
In preliminary experiments, the ZnS04 floatation and the 1 M sucrose step gradient
purification methods were shown to yield better retrieval of cysts from stools than
the sucrose discontinuous gradient method. Isaac-Renton et al. (1986) reported
that the ZnS04 method generally yielded cleaner samples and produced larger
numbers of organisms than the sucrose gradient technique. We found this to be
true in the sense that the cysts were indeed cleaner, and the numbers were higher
as revealed by the highest frequency. However, cysts separated by the former
method appeared morphologically abnormal. This finding is in keeping with results
obtained by Truant and colleagues (1981), who reported that the morphology of
Giardia cysts was better preserved with sedimentation procedures than with the
ZnS04 floatation technique. However, increased cyst losses were noted when
using the sucrose gradient separation method, a finding similar to that of Jyothi et
al. (1993).
It was essential to determine the viability of purified cysts, as it would impact on
the interpretation of all subsequent excystation experiments (described in chapters
3 and 4) in the present work. Isaac Renton (1993) reported that viable cysts are
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