Clin Infec Dis：鼠弓形虫可致孕妇早产及婴儿机体损伤

左边：弓形虫，可以通过孕妇的胎盘转移；右边：弓形虫（绿色）进入了包囊中(Credit: R. McLeod, University of Chicago.)

近日，来自美国国家过敏症和传染病研究所（NIAID）的科学家发现鼠弓形虫（T.gondii，可引起弓形体病）和新生儿严重的先天性缺陷高度相关。研究者运用血液检测技术从新生儿体内检测到了T.gondii的存在。怀孕妇女可以通过接触带有鼠弓形虫的猫引起感染，一旦感染鼠弓形虫，孕妇有可能会引起流产、早产或者生出的孩子患有眼睛和脑损伤等疾病。

研究者Anthony S.Fauci表示，如果没有发现感染了鼠弓形虫，那么先天性弓形虫病会对孩子一生的生活带来严重影响。本研究的发现支持早期弓形体病的筛查以便及早治疗。当前的血液检测法可以检测出某个人是否患上这种弓形虫属引发的疾病，目前NIAID的研究者发明的方法基于老方法，可以特异性的检测出菌株特异性抗体的存在，而且可以识别出不同种的弓形虫，这种方法由Michael Grigg和同事所发明。相关研究成果刊登在了近日的国际杂志Clinical Infectious Diseases上。

目前世界上一经发现了至少15种不同类型鼠弓形虫，在法国研究者发现了II型的弓形虫比较占优势，II型可以和其它类型轻松区分开，其它类型的弓形虫统称为 NE-II型。运用新方法，研究者可以从183对先天性弓形虫病母子体内轻松分离出II型弓形虫的感染，统计学分析揭示，NE-II型弓形虫很有可能与早产有关，而且感染此类弓形虫的婴儿比感染II型的婴儿会引起更严重的疾病。比如感染NE-II所引起的眼部损伤为67%，而感染II型的比例为39%。

Grigg表示，我们知道，在老鼠体内，特定的寄生虫和严重的疾病相关；但是我们并不清楚这些类型的寄生虫和疾病在人类身上也是如此。截止到现在，我们都不能确定美国和欧洲感染的人群出现的疾病症状和老鼠体内的这种寄生虫有关系。研究者还表示，他们的研究结果将会给出生后患病的孩子针对II型或者NE-II的弓形虫的不同治疗方法提出合理的治疗建议。

在法国，所有的孕妇都会接受弓形虫感染的检测，速效的治疗方法被用于每一个感染的孕妇，这样大大降低了婴儿的损伤风险。Mcleod博士表示，在美国，针对孕妇的弓形虫疾病筛查并不流行，我们这项研究给感染孕妇的治疗提供了很多建议，而且建议美国也进行这种弓形虫疾病的筛查，以降低婴儿因感染弓形虫所引起的眼部和脑部损伤疾病的风险。在法国，II型弓形虫为普遍流行的集成冲，和法国不一样，美国主要为NE-II型弓形虫（61%），而且在低收入人群和农村人口中多见。本项研究由NIH资助。

doi:10.1093/cid/cis258
PMC:
PMID:

Prematurity and Severity Are Associated With Toxoplasma gondii Alleles (NCCCTS, 1981–2009)

Rima McLeod1,2,3, Kenneth M. Boyer4,5, Daniel Lee1, Ernest Mui1, Kristen Wroblewski6, Theodore Karrison6, A. Gwendolyn Noble1,7, Shawn Withers6, Charles N. Swisher8, Peter T. Heydemann9, Mari Sautter1, Jane Babiarz1, Peter Rabiah7, Paul Meier6,10,a, Michael E. Grigg11, and the Toxoplasmosis Study Groupb

Background. Congenital toxoplasmosis is a severe, life-altering disease in the United States. A recently developed enzyme-linked immunosorbent assay (ELISA) distinguishes Toxoplasma gondii parasite types (II and not exclusively II [NE-II]) by detecting antibodies in human sera that recognize allelic peptide motifs of distinct parasite types.

Methods.ELISA determined parasite serotype for 193 congenitally infected infants and their mothers in the National Collaborative Chicago-based Congenital Toxoplasmosis Study (NCCCTS), 1981–2009. Associations of parasite serotype with demographics, manifestations at birth, and effects of treatment were determined.

Results.Serotypes II and NE-II occurred in the United States with similar proportions during 3 decades. For persons diagnosed before or at birth and treated in infancy, and persons diagnosed after 1 year of age who missed treatment in infancy, proportions were similar (P = .91). NE-II serotype was more common in hot, humid regions (P = .02) but was also present in other regions. NE-II serotype was associated with rural residence (P < .01), lower socioeconomic status (P < .001), and Hispanic ethnicity (P < .001). Prematurity (P = .03) and severe disease at birth (P < .01) were associated with NE-II serotype. Treatment with lower and higher doses of pyrimethamine with sulfadizine improved outcomes relative to those outcomes of persons in the literature who did not receive such treatment.

Conclusions.Type II and NE-II parasites cause congenital toxoplasmosis in North America. NE-II serotype was more prevalent in certain demographics and associated with prematurity and severe disease at birth. Both type II and NE-II infections improved with treatment.