STUDY OF CONGENITAL CHAGAS' DISEASE

在这项研究中，2072名孕妇中有640名(30.8%)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。尽管很难跟进，但32人中有17人仍在接受调查。环境因素较多，134例阳性者中52例(38.8%)住在晒干砖(土坯)房，41例(30.61%)住在有裂缝的粘土墙房。可以发现，居民的生活环境是致病三角毛虫侵袭的理想条件，而致病三角毛虫是毛滴虫的主要媒介。我们还可以预见，在怀孕期间，与克氏毛滴虫高感染率的普通接触会导致反复感染和侵入胎儿。另一方面，克氏毛滴虫虽然密度较低，但在查加斯病慢性期(潜伏感染)的血液中仍可检出，可能是通过脐带血侵入胎儿体内。我们试图用聚合酶链式反应方法从孕妇血清中确认克氏毛滴虫DNA，但结果与其他人的结果不一致。考虑到该病的特点，对本病的PCR诊断有待进一步研究。脐带血Strout法和异种诊断法是诊断本病的可靠方法。大多数血清阳性者为潜伏感染，因此目前有望通过聚合酶链式反应建立诊断。虽然该病引起的心脏功能障碍的报道很少，但我们分析了9例先天性恰加氏病新生儿的动态心电图，其中4例表现为平均心率加快(P&lt；0.05)。我们将从这方面进一步详细研究，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.