2. 它由什麼所引起？
陰虱是一種以血為食的非常微小的昆蟲。因為它的形狀與海洋螃蟹相似，為了簡便，人們通常也稱它為“海蟹 (crab)”。陰虱只有一個月的壽命，但是每一隻雌陰虱產卵50枚，她把卵附著在一根陰毛的基部，一周後就孵化了出來。如此，隨著時間的過去，症狀會趨於惡化。

3. 它如何傳播？
陰虱在陰毛內生活和繁殖，而且通過密切的性接觸從一個人傳播給另一個人。確實，從蟲害滋生的性伴那裏是很容易沾染到這種小害蟲的。有一些罕見的病例，雖然不可能從衛生間座便器上染上陰虱，衣服或床單卻可能沾有它們，並由此傳播給他人。總之，陰虱傳染病是所有性傳播疾病中傳染性最強的疾病。

1. What is it?
An insect infestation, usually in a person’s pubic hair, causing persistent itching.

2. What causes it?
Pubic lice or crab lice are very small insects that feed on blood. Often they are also simply called “crabs” for short, because their shape resembles that of sea crabs. They have a life span of about one month, but each female lays about 50 eggs (nits) which she attaches to the base of a hair strand, and which hatch in about a week. Thus, the problem tends to get worse over time.

3. How is it transmitted?
Pubic lice live and breed mostly in pubic hair and thus can be transmitted from one person to another by close sexual contact. Indeed, it is very easy to pick them up from an infested partner. In rare instances, the transfer may also occur through infested clothing or bed linen, although not from toilet seats. All in all, a pubic lice infestation is the most contagious of all STDs.