Towards improving early diagnosis of congenital Chagas disease in an endemic setting.

: Congenital Trypanosoma cruzi transmission is now estimated to account for 22% of new infections, representing a significant public health problem across Latin America and internationally. Treatment during infancy is highly efficacious and well tolerated, but current assays for early detection fail to detect >50% of infected neonates and 9 month follow-up is low. : Women presenting for delivery in two urban hospitals in Santa Cruz department, Bolivia were screened by rapid test. Specimens from infants of infected women were tested by microscopy (micromethod), quantitative PCR (qPCR) and IgM trypomastigote excreted-secreted antigen (TESA)-blots at birth and 1 month, and by IgG serology at 6 and 9 months. : Among 487 infants of 476 seropositive women, congenital T. cruzi infection was detected in 38 infants of 35 mothers (7.8%). In cord blood, qPCR, TESA-blot and micromethod sensitivities/specificities were 68.6%/99.1%, 58.3%/99.1% and 16.7%/100%, respectively. When birth and 1 month results were combined, cumulative sensitivities reached 84.2%, 73.7% and 34.2%, respectively. Low birth weight and/or respiratory distress were reported in 11 (29%) infected infants. Infants with clinical signs had higher parasite loads and were significantly more likely to be detected by micromethod. : The proportion of T. cruzi infected infants with clinical signs has fallen from the 1990s, but symptomatic congenital Chagas disease still represents a significant, albeit increasingly challenging to detect, public health problem. Molecular methods could facilitate earlier diagnosis and circumvent loss to follow-up but remain logistically and economically prohibitive for routine screening in resource-limited settings.