in vitro culture and isoenzyme analysis of giardia lamblia

The second group consisted of "apparently healthy" children from various
institutions: (i) Othandweni Home, (an institution that cares for abandoned
children) located 15 km south of Durban. Stools were collected mostly from
children aged from six months to ten years (ii) children (2-5 years of age)
attending pre-school and day care centres at the following residential areas for the
Black African community: (a) Clermont, (Kideo Pre-school), 30km west of Durban;
(b) Amanzimtoti (Siyakuthanda Creche) 45 km south of Durban.
2.2.2 Sample Preparation for Microscopic Detection
One thousand and twenty-three faecal specimens collected from the day care
centres and Hlabisa laboratory were concentrated by the formol-ether technique to
amplify cyst detection.
2.2.2.1 Formol-ether Concentration of faeces for microscopic examination
The modified method of Ritchie (1948)
Approximately O,35g (pea-size) of stool was placed in a 15ml polypropylene
centrifuge tube followed by the addition of 7ml of 10% formalin. The faecal matter
was broken up with an applicator stick and the suspension was filtered through
two layers of wet gauze into a paper cup. The filtrate was returned to a clean
centrifuge tube and 3ml of diethyl ether added. The tube contents were thoroughly
mixed by shaking vigorously for 30 seconds prior to centrifugation at 400xg for
5min at 22°C. The supernatant formalin-ether layers were discarded and the
deposit was screened microscopically for the presence of Giardia forms. After
systematically scanning the entire area covered by a coverslip on the slide, all
Giardia positive samples were semi-quantitated as shown in Table 2.1.
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