一位俄罗斯姑娘在从莫斯科郊外游玩回来之后发现，她被蚊子叮咬的包居然会移动？
A 32-year-old Russian woman found a mysterious migrating mosquito bite on face, which was later diagnosed as a parasite, according to the New England Journal of Medicine’s case report on June 21.
这个包在两周之内，从左眼下方，移动到左眼上方，又移动到了嘴唇上。她将这个“神奇”的包用自拍记录了下来。医生一看却随即发现，这是寄生虫！
被蚊子叮咬的包会移动？是寄生虫！
世界顶级医学期刊《新英格兰医学杂志》(The New England Journal of Medicine)于上周四收录了一个新病例。
一位32岁的俄罗斯姑娘最近发现，脸上被蚊子叮咬的包会居然移动。
The patient captured her symptoms through selfies. The nodule was found below her left eye at first. Five days later, it moved to left eye’s upper eyelid. Ten days after that, the nodule appeared again, but was located differently. This time, it was on her lip.
最开始，这个包出现在眼睛下方；五天后，又移动到了眼皮上面；十天后，嘴唇又肿了起来。这个小包与被蚊子叮咬后出现的包非常相似，它经常在几分钟之内出现，并伴有灼热、瘙痒，又在短时间内消失。除此之外，并无其他明显不适或症状。
The nodule was oblong, tender, and with an occasional localized itching and burning sensation, but with no other symptoms. It appeared and disappeared in minutes, just like normal mosquito bites, except that it can migrate.
不堪其扰的她在两周后决定就医。幸运的是，她遇到了一位很有经验的医生。俄罗斯罗斯托夫国立医科大学的医学教授Dr. Vladimir Kartashev很快确诊了姑娘的病并非寻常蚊虫叮咬，而是感染了匐行恶丝虫(Dirofilaria repens)。
The nodule was diagnosed as an infection of the Dirofilaria repens, a zoonotic filarid nematodes in the genus Dirofilaria.
“我至少看到过10个这样的案例，”教授说，“这样的‘非常规移动’真的十分具有迷惑性，红肿经常在几分钟之内出现，又在几分钟之后消失。经验不足的医生往往不会相信这样的说辞。这也是我让她自拍记录病情的原因”。
The doctor, Dr. Vladimir Kartashev, a professor of medicine at Rostov State Medical University, told CNN in an email that he had seen at least 10 patients with the same presentation before. But doctors who are not familiar with the disease may not believe the patients since idea of it “migrating” is extremely confusing.
确诊后，教授随即为姑娘做了一场“小手术”——用镊子将寄生虫取了出来。整个过程不超过15分钟。由于恶丝虫在人体内不具备繁殖能力，在虫体取出后姑娘已经痊愈。
The parasite worm has been removed from the patient with forceps, using local anesthesia. The trivial surgery took only less than 15 minutes. To remove the parasite through a small incision is a kind of common approach to cure the Dirofilaria repens infected patients, the doctor added.
在医生的询问下，姑娘回忆起自己近期曾在莫斯科的郊外游玩，并且受到了频繁的蚊子叮咬，应该就是在那时感染上的寄生虫。
As recalled by the patient, she had traveled to a rural area outside Moscow not long ago, where she was frequently bitten by mosquitoes.
恶丝虫“家族”和人类
匐行恶丝虫，属于恶丝虫属。它的*亲近**还包括细弱恶丝虫、犬恶丝虫、厄氏恶丝虫、皮下丝虫、条纹丝虫等，是一种宿主为犬及其他肉食性动物的寄生虫。
According to the US Centers for Disease Control and Prevention (CDC), the worms’ normal hosts in nature are usually carnivores, especially dogs. Humans are only accidental hosts entered through larva from mosquito bites, where the parasite can’t develop or is infertile.
在极少数情况下，恶丝虫可由蚊虫叮咬传染给人类，并出现皮下、结膜肿块、*麻疹荨**或淋巴炎等症状。在中国通常统称恶丝虫病。中国于2011年到2012年之间在香港发现三起“香港型恶丝虫”感染案例，已经属于较大范围的感染。
根据美国疾病预防控制中心(CDC)的定义，匐行恶丝虫、厄氏恶丝虫、以及细弱恶丝虫在进入人体后，一般会在皮下组织中游移或者形成肉芽型红肿，但也有曾进入肺部的案例。其中比较明显的特征就是产生“可移动”的柔软椭圆形皮下红肿，并伴随疼痛、灼热、瘙痒等症状，就像这次不幸中招的俄罗斯姑娘一样。
As stated by the CDC, Dirofilaria repens usually does not cause serious symptoms or fatal illnesses in humans. They wander in the subcutaneous tissue or present as a large nodule. Only a few cases were reported that the parasite caused pulmonary diseases.
而感染它们的*亲近**，犬恶丝虫，病情则会稍嫌严重。它们在进入人体后会遵循和在最终宿主体内一样的迁移模式，进入人体肺部，寄宿于小血管中，造成血管梗塞和硬币性病变（孤立性肺结节），这种病变可通过X光片观察到，进而引起胸痛、咳嗽、发烧、浑身发冷、咳血等症状。
However, patients who got caught by its “relatives”, known as the Dirofilaria immitis, may seem comparably unfortunate. The species, following embolization, will largely follow the same migratory pathway in the canine host, and eventually residing in small-caliber vessels in the lungs. The parasite will then cause infarcts and “coin lesions” following chest pains, coughing, fevers, chills, and other complications.
发育成熟的匐行恶丝虫身长可达到170毫米，犬恶丝虫可达到310毫米，并存活5到10年之久。从世界的范围来看，欧洲、亚洲、非洲是匐行恶丝虫的三大中招重灾区。
According to CDC, the length of the adult parasite can be as long as 170 mm for Dirofilaria repens and 310mm for Dirofilaria immitis respectively. Both of them can live up to 10 years. Although it is rare for humans to contract the worm, cases have been mostly reported in the past from places such as Asia, Europe and Africa.
由于人类并非恶丝虫的最终宿主，所以它们并不会在体内繁殖，也不会人传人，在大多数情况下病人不会有即时的生命危险。并且，人类感染恶丝虫的病例十分罕见，所以不用太过恐慌和担心。
但即便如此，一旦感染，及时就医和治疗也是非常必要的。一般情况下，病人在手术后即可痊愈。
怎样预防？
由于恶丝虫病主要通过蚊虫叮咬的途径感染人类，所以最简单的预防就是避免蚊虫叮咬。如果想要用药物预防，还是需要咨询专业的医生。
The simplest way to guard against the parasite is to protect yourself from insect bites and stings. Also, for people who have dogs as pets, it is crucial to get them vaccinated at regular intervals.
另外，比起人类，恶丝虫病对犬类的危害严重太多，这也是为什么恶丝虫又经常被称为“犬心丝虫”的原因。
作为恶丝虫的最终宿主，恶丝虫不仅会在犬类体内发育和繁殖，还会进入犬类心脏以及其他内脏，对犬类心肺造成不可逆转的致命损伤。
所以，养宠物的朋友一定切记定期给家里犬类进行驱虫和免疫，尽量避免让宠物在蚊虫聚集的野外玩耍。
