有许多种类的物种会引起鞭毛虫。到目前为止，大约有6个物种被隔离和治疗。人们发现，每个国家都有其特有的Giardia物种，因为地理位置和栖息地。在这个鞭毛虫属中有许多种会导致心包状况。在英国比较流行的一些是“Giardia intestinalis,Giardia lamblia,Giardia duodenalis”等。世界上有许多种类的这种物种。它主要影响人的结肠、十二指肠和肠子。从分析中可以发现，这种病毒主要通过污染的水传播。尽管疾病的传播通过其他途径从人传播到人传播，但也有食物来源。受污染的水是感染这种疾病的主要来源，但其他来源不应被忽视。当这种物种通过任何媒介传播给人类时，它们会迅速繁殖并给人类的消化系统造成严重破坏。(Wright 2015)最常见的Giardia物种是“Giardia Duodenalis”。顾名思义，在人类十二指肠中发现了囊肿。值得注意的是，这个物种几乎在世界各地都能找到。这个鞭毛虫有很多的耐受性，可以承受很多不利的条件。它们能经受住大量的热和冷。在温暖潮湿的地区，发生率更高。同时也发现严重的免疫缺陷患者在发生心肌病时受到严重的影响。
There are many varieties of species that causes Giardia. Around six species have been isolated and treated so far. It has been found that each country has its own kind of the Giardia species owing to the geographical and the habitat of the place. There are a number of species in this Giardia Genus that causes Giardiasis condition. Some of the more prevalent ones in UK are “Giardia intestinalis, Giardia lamblia, Giardia duodenalis” etc. There are actually many varieties of this species that could exist around the world. It primarily affects the colons, duodenum and intestines of people. It has been found from analysis that this spreads primarily through contaminated water. Although the spreading of the disease happens through other sources from person to person transmission, food sources as well. Contaminated water is a major source of contracting this disease but the other sources should not be dismissed. The cyst of this species when it is spread to the humans via any medium they quickly reproduces and cause havoc to the digestive system to the people. (Wright 2015) The most commonly found Giardia species is “Giardia Duodenalis”. As the name suggests the presence of the cysts are found in the human duodenum. It should be noted that this species is found almost everywhere in the world. This Giardia has a lot of tolerance and can withstand a lot of adverse conditions. They can withstand a lot of heat and cold. The rate of occurrence is higher in areas that are warm and moist. It has also been found that people with severe immunodeficiency get affected severely when they develop Giardiasis.