STUDY OF CONGENITAL CHAGAS' DISEASE

在本次研究中，2072名孕妇中有640名（30.8%）抗克氏锥虫抗体阳性，640名新生儿中有32名（5.00%）被诊断为先天性恰加斯病。虽然很难追踪，但32人中有17人仍在接受调查。它们有很多环境因素；134例血清阳性患者中52例（38.8%）居住在晒干砖（土坯）房屋中，41例（30.61%）居住在有裂缝的土墙房屋中。发现居民的生活环境是克氏锥虫的主要病媒——感染三角瘤（Triatoma infestans）的理想孳生条件。我们还可以设想，与克氏锥虫感染率较高的锥蝽虫的日常接触会导致其在妊娠期间反复感染并侵入胎儿。另一方面，恰加斯病慢性期（潜伏感染）患者的血液中常发现克鲁氏锥虫，但密度较低。克氏锥虫有可能通过脐带血侵入胎儿体内。我们试图用PCR方法对妊娠血清阳性患者的T.cruzi-DNA进行确证，但结果与其他人的不一致。考虑到本病的特点，PCR诊断还需进一步研究。可靠的诊断方法是脐带血法和异种诊断法。大多数血清阳性为潜伏性感染，因此现在期望建立PCR诊断。虽然该病引起的心功能障碍报道较少，但我们分析了确诊为先天性恰加斯病的9例新生儿的动态心电图，9例中有4例平均心率升高（P<0.05）。我们将从这方面进行更详细的研究，并建议预防这种疾病。

During this research, 640 out of 2072 (30.8%) of pregnant women showed positive anti-Trypanosoma cruzi (T.cruzi) antibody, and 32 out of 640 (5.00%) newborns were diagnosed as congenital Chagas' disease. Though it is hard to follow them up, 17 out of 32 are still under investigation. They have many environmental factors ; 52 out of 134 (38.8%) of the seropositives live in the house of sun-dried brick (adobe) and 41 out of 134 (30.61%) live in the house of clay wall with cracks. We could find the living environment of inhabitant is the ideal condition for infestation of Triatoma infestans (T.infestans), the main vector of T.cruzi. We could also envision that the ordinary contact with triatomine bugs with high rate of T.cruzi infestation caused the repeated infection and invasion into fetus during their pregnancy. On the other hand, T.cruzi is always found in the blood of chronic phase of Chagas' disease (latent infection), although the density is low.It is possible that T.cruzi invades into fetus through umbilical cord blood. We tried to confirm T.cruzi-DNA from the pregnant seropositives by PCR method, but the result was not consistent with the others'. The diagnosis by PCR needs further study considering the characteristic of this disease. The reliable diagnosis method of this disease seems strout method using umbilical cord blood and method of xenodiagnosis. Most of the seropositives are latent infection, so the establishment of diagnosis by PCR is now expected. Though the cardiac disturbance coursed by this disease has been little reported, we analyzed the Holter E.C.G of 9 newborns diagnosed as congenital Chagas' disease and 4 out of 9 showed rising of average heart rate (P<0.05). We are going to study in further detail from this aspect, and advise to prevent this disease.