事实上，骚痒和抓挠帮助动物去掉寄生虫、植物体或其它不想要的垃圾。
In nature, itching and scratching help animals get rid of parasites, plant material, or other unwanted baggage.
动物有寄生虫或携带各种各样的病毒。一旦传染给人类，这将会是非常麻烦的事。
Animals have parasites or carry a variety of viruses. Once transmitted to humans, it would be a very troublesome thing.
寄生虫的一个典例是绦虫，它生活在更大的动物的肠道内，从宿主那里吸收营养。
An example of a parasite is a tapeworm that lives inside the intestines of a larger animal and absorbs nutrients from its host.
在脊椎动物中，免疫系统提供了对体内寄生虫的多重防御。
In vertebrates, the immune system provides a multiple defense against internal parasites.
表面看来，为其他动物整理毛发是有实际功用的：可以保持皮毛洁净，去除寄生虫。
On the face of it, grooming another animal is functional. It keeps the pelt clean and removes parasites.
它们通过被携带人类致病寄生虫的人类或动物感染的采采蝇(舌蝇属)叮咬传播给人类。
They are transmitted to humans by tsetse fly (Glossina genus) bites which have acquired their infection from human beings or from animals harbouring the human pathogenic parasites.
各种生活方式，如清洁的食物和水，抗生素，减少和寄生虫，动物，病毒和传染病的接触，也许引起了全球范围过敏症的蔓延。
Either way, clean water and food, antibiotics, reduced exposure to parasites, animals, viruses and infectious diseases may have caused our progressive worldwide allergies.
随着那些寄生的人们的离去，动物们有了更多的食物，也有了更多的闲暇，尽管他们还缺乏经验。
With the worthless parasitical human beings gone, there was more for everyone to eat. There was more leisure too, inexperienced though the animals were.
此工程的目的是给人一种居住在蜗牛内部的感觉，像软体动物一样从一个房间爬到另一个房间，像寄居在一座大型化石修道院里的寄生动物一样。
The goal of this project was to make it feel like an internal inhabitant of a snail, like a mollusk moving from one chamber to another, like a symbiotic dweller of a huge fossil maternal cloister.
锥虫属其它种和亚种的寄生虫对动物具有致病性并可在野生和家养动物种类中引起动物锥虫病。
Other parasite species and sub-species of the Trypanosoma genus are pathogenic to animals and cause animal trypanosomiasis in wild and domestic animal species.
史密斯博士说这些虱子不会在他的系统树上出现，除非它们转变成寄生在胎盘类哺乳动物身上的物种，而大多数虱子不会经常变换宿主。
These lice would not show up in his tree, Dr. Smith said, unless they had been able to transfer to the placental mammalian species, and most lice do not regularly switch hosts.
同时，穿上鞋我们的脚就不会和地上危险的生物直接接触，包括植物、动物还有寄生虫。
It also prevents exposure of the feet to harmful creatures lying around us, be it plants, animals or parasites.
在只是动物王国的一个简单的寄生的例子罢了，这个从另一个方面证明了不用竞争也可以生存。
This is just one striking instance of the immensity of pain in the animal kingdom, which defies explanation except via the unyielding calculus of competitive survival.
假如寄生虫很幸运的话，寄生弓形虫的啮齿目动物被猫吃掉，然后循环再次开始。
Eventually, if the parasites are lucky, their rodent host is eaten by a cat and the whole cycle starts again.
涉及的寄生虫是一种原生动物，归类为锥虫属。
The parasites concerned are protozoa belonging to the Trypanosoma genus.
在这项研究中，唯一变简单的甲壳纲动物不是寄生物，就是那些生活在偏远栖息地的生物，比如说在与世隔绝的海蚀壁龛里。
In this study, the only crustaceans that became simpler were either parasites or those living in remote habitats, such as isolated Marine caves.
由于甜燃料匮乏，这些寄生虫工作再努力也不足以分解通过动物肠道的大团植物。
Starved of sweet fuel, the bugs cannot work hard enough to break up great wads of vegetation as they progress through the animal.
他们甚至可以推算疟疾寄生虫为了在其他宿主比如哺乳动物上传播的进化比例。
They were able to estimate the rate at which malaria parasites would have had to diversify in order to spread to other hosts, like mammals.
我们越来越大的压力来自于对未开发世界的恐惧：包括未开发的土地；野生动物，和寄生虫。
Increased stresses included a fear of the wild: unproductive wild lands; wild animals; and vermin.
小心周围的动物-因为它们可以是一个来源，寄生虫感染。
Be careful around animals - as they can be a source of parasitic infection.
隐孢子虫病（crypto）和等孢球虫病都是由原生动物寄生虫引起的。
Cryptosporidiosis (crypto) and isosporiasis are both caused by protozoan parasites.
动物们感染了全部的寄生虫，同时用抗生素进行治疗。
The animals are infected with whole parasites and treated with antibiotics at the same time.
给一只被感染的猫换猫砂。因为感染这种寄生虫的猫会通过粪便传染给其它的动物。
Changing an infected cat's litter box. Cats infected with the parasite pass it on to others through their feces.
跳蚤蚤目的各种小型、无翅吸血昆虫中的任一种，长有适于跳跃的腿，寄生在温血动物身上。
Any of various small wingless bloodsucking insects of the order siphonaptera that have legs adapted for jumping and are parasitic on warm-blooded animals.
夏----幼虫寄生在小动物身上并且感染了可至莱姆病的微生物。
Summer----Larvae feed on small animals and become infected with bacteria that cause Lyme disease.
夏----幼虫寄生在小动物身上并且感染了可至莱姆病的微生物。
Summer----Larvae feed on small animals and become infected with bacteria that cause Lyme disease.
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