Title: Soil based Helminth Infections
题目：土源性蠕虫感染
Author 作者: Jenny Reifel Saltzberg, MD, MPH

More than 1.2 billion people are infected with at least one species.
超过12亿的人口有至少一次的蠕虫感染。
Most helminth infections are contracted by ingesting the eggs, except strongyloides and hookworm whose larvae penetrate bare skin when it is contact with the soil.
最常见的蠕虫感染是通过食入了虫卵，但线虫和钩虫感染是由它们的幼虫穿透与土壤接触的裸露皮肤。
The roundworm (Ascaris lumbricoides) life cycle involves migration through the lung tissue which can cause pneumonitis.  Patients can present with interstitial infiltrates, wheeze, and blood tinged sputum.  Ascaris then migrates to the intestines where it can cause partial small bowel obstruction. In pediatric patients, the appendix may be invaded causing gangrene with symptoms indistinguishable from appendicitis.  In adults, the worms can invade the biliary tract and cause biliary disease or pancreatitis.  Fever causes this helminth to migrate and it can emerge from the nasopharynx or the anus.
蛔虫（Ascaris lumbricoides)生命路径包括迁移到肺部，造成肺炎。病人可有肺侵润，哮喘，和痰中带血的表现。然后，蛔虫会迁徙到肠道，造成部分小肠梗阻。在儿科病人中，蛔虫可侵入阑尾造成与阑尾炎难以分辨的坏疽。在成人，蛔虫会侵入胆道导致胆道系统疾病或胰腺炎。发烧促使蠕虫的迁徙，可以由鼻炎或肛门排除。
Whipworms (Trichuris trichiura) present as colitis or symptoms similar to inflammatory bowel disease.  Chronic illness can involve anemia and clubbing.  In severe cases, trichuris can cause dysentery and rectal prolapse. 
鞭虫（Trichuris trichiura）可表现位结肠炎或与炎症性肠病类式的症状。慢性感染可出现贫血和杵状指。严重的病例，鞭虫可导致痢疾和直肠脱垂。
Hookworms (Necator americanus or Ancylostoma duodenale) also have a pulmonary phase, but with milder symptoms than Ascaris.  Eventually hookworms cause iron deficiency anemia and malnutrition.  They can be a primary cause of anemia in pregnancy in endemic areas.
钩虫（Necator americanus or Ancylostoma duodenale)也有一个肺部期，只是症状要比蛔虫轻。最终会导致缺铁性贫血和营养不良。它们可能是在流行区导致妊娠期贫血的主要原因。
Threadworm (Strongyloides stercoralis) can cause a wide spectrum of disease presentations.  The infection can start with a rash, larva currens.  The infection may be subclinical or may invade the lung, intestinal wall, or the nervous system.  Eventually hyperinfection may develop which is a very large increase in worm burden and then the infection becomes disseminated. 
线虫（Strongyloides stercoralis)的临床表现会相当广泛，早期可有皮疹，幼虫移行症。感染也可以是亚临床或侵润到肺，肠壁，或中枢神经系统。最终会出现超感染期，蠕虫的大量快速增殖，导致感染的扩散。
Toxocara canis or toxocara cati have affected approximately 14% of the US population.  These helminthes reproduce in dogs or cats, and human infection is not part of the normal life cycle.  Most infections are subclinical but it can produce a mild pneumonitis that is very similar to asthma.  There can be pain and inflammation as the helminthes travel through organs such as the liver or lung and is called visceral larva migrans.  The helminth may also move through the eye and optic never causing an ocular form of the disease, ocular larva migrans. 
犬弓蛔虫或猫弓蛔线虫已感染大约14％的美国人口。这些蠕虫在狗或猫体内繁殖，人类感染不是正常生命周期的一部分。许多感染都是亚临床，但可出现类式与哮喘的轻型肺炎。当蠕虫迁移于各器官时（如肝脏或肺）可产生疼痛和炎症，这一过程叫内脏幼虫迁移。蠕虫也可能迁移到眼睛和视神经，导致疾病的眼部症状，既眼部幼虫迁移。
Pinworms (Enterobius vermicularis) are the cause of most common helminth infection in US and can present with anal pruritus leading to trouble sleeping.  When an infection is identified, everyone in the household should be treated, regardless of symptoms. 
蛲虫（Enterobius vermicularis)在美国是最常见的蠕虫感染，表现为影响睡眠的肛门瘙痒。如感染确定，不论有无症状，家里的每个人都要接受治疗。
 
References 参考文献

J Bethony, S Brooker, M Albonico, S M Geiger, A Loukas, D Diemert, P J Hotez.  Soil-transmitted helminth infections: ascariasis, trichuriasis, and hookworm. Lancet:  2006; 367: 1521–1532.
S Knopp, P Steinmann, J Keiser, J Utzinger.  Nematode Infections: Soil-Transmitted Helminths and Trichinella Infect Dis Clin N Am: 2012; 26:341–358.