Biased distribution of pathogenic Entamoeba histolytica

近年来，溶组织内阿米巴（Entamoeba histolytica）被认为是一种致病性阿米巴，即溶组织内阿米巴（E. histolytica和非致病性种E.差异这意味着传统的粪便镜检法不能确定致病性大肠杆菌的流行。从公共卫生的角度来看，这是更重要的。从孢囊中提取DNA的PCR方法已被证明可用于鉴别大肠杆菌。溶组织E. dispar，并结合显微镜方法，阐明了两种昆虫在菲律宾吕宋岛不同地区传播方式的差异。结果表明：（1）两种蠕虫的感染率均未超过15%，但贫民区的蠕虫感染率接近70%。这表明内阿米巴的传播方式不如某些蠕虫有效。溶组织E. 3）两种虫种在不同地区的流行程度不同。在公共卫生条件相似的情况下，较冷的气候为内阿米巴的传播提供了更好的条件。4）致病性内阿米巴的分布比非致病性内阿米巴的分布更多样。据推断，人与人之间的传播主要通过家庭中的亲密接触维持。5）5至14岁儿童的流行率较高，妇女的流行率高于男子。这可能与生活习惯的差异有关。dispar在日本大分县的高崎山的日本猴子中发现。这表明猴是大肠杆菌更适宜的宿主。比人类差。

Recently, Entamoeba histolytica has been recognized to consist of a pathogenic species, E. histolytica and a non-pathogenic species, E. dispar. This means that the conventional method using microscopic examination of fecal samples can not determine prevalence of pathogenic E. histolytica that is more important from the viewpoint of public health. Since the PCR method using extracted DNA from cysts has been shown to be useful for differentiation of E. histolytica from E. dispar, it was used in combination with the microscopic method to clarify the difference of the transmission mode between two species at various parts of Luzon in the Philippines. The following results were obtained.1) The prevalence of two species was not over 15% in all the places examined, although the prevalence of helminthic infection reached nearly 70% in the slum area. This indicated that the transmission mode of Entamoeba is less effective than some helminths.2) The prevalence of a pathogenic species, E. histolytica was less than a half of that of a non-pathogenic species, E. dispar in all the areas examined.3) Both species showed a with variety of prevalence according to places. If the condition of public health is similar, the colder climate provides the better condition for transmission of Entamoeba.4) The distribution of the pathogenic species was more varied than the non-pathogenic. Transmission from a human to a human is inferred to be maintained mainly by intimate contact in a family. Consequently the highest prevalence was found in the slum area.5) Higher prevalence was found in children aged from 5 to 14 years, and in women than in men. This may be caused by differences of their living habits.6) High prevalence of E. dispar was found in Japanese monkeys at the Takasaki mountain, Oita prefecture, Japan. This indicated that monkeys are more fitting hosts for E. dispar than humans.