1. Giardiasis is caused by the parasite Giardia lamblia and commonly results in diarrhea and abdominal pain.
原文：Giardiasis 是由Giardia lamblia寄生虫引起的，常见症状为腹泻和腹痛。

2. The most common route of transmission for giardiasis is through contaminated water or food.
原文：Giardiasis最常见的传播途径是通过污染的水或食物。