Giardia duodenalis may result in diarrhea, abdominal cramps, gas, and nausea; chronic infection might lead to dehydration and severe weight loss.

Giardia duodenalis can cause diarrhea, abdominal cramps, gas, and nausea. If the infection continues for a long time, persistent diarrhea may lead to dehydration and significant weight loss, so the statement is true.

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