Our study showed a very limited level of knowledge about Chagas disease among practicing obstetricians-gynecologists in the United States. The most common response to our survey questions was “I don't know,” suggesting a lack of information rather than misinformation. Based on our data, obstetricians-gynecologists rarely consider the possibility of Chagas disease, even when their patient population includes people from endemic countries in Latin America. Also, most respondents reported that they did not know the risk of congenital transmission for Chagas disease or testing procedures for at-risk mothers and infants when the disease is suspected.
We found that serving a population where > 10% of patients are from Chagas-endemic areas, having completed residency more than 20 years ago, and male gender were associated with knowledge about congenital transmission of Chagas disease. Obstetricians-gynecologists providing care for substantial numbers of patients from endemic areas may have had more opportunities to learn about Chagas disease through their clinical experiences. Similarly, those who trained more than two decades ago may have had more opportunities to encounter cases of Chagas during their years of clinical practice; alternatively, the association between years since training and correct responses may reflect a change in medical school or residency curricula over time. Although the difference in Chagas disease knowledge by gender was statistically different, we investigated the role of gender primarily to adjust for the increasing proportion of female obstetrician-gynecologists over time as we examined the impact of years since completing training. The observed association between gender and knowledge about Chagas disease may be the result of unmeasured confounders. Overall, even among the groups with more frequent correct responses, the level of knowledge and index of suspicion for Chagas disease were suboptimal.
Reports in the literature show that cases of Chagas disease among pregnant women in the United States have been newly diagnosed by their obstetric providers.12,13
Although there have been no documented cases of congenitally acquired Chagas in the United States, it is likely that such transmission has occurred. Studies of Chagas disease among blood donors in the United States have identified three suspect cases of congenital transmission; however, the source of infection could not be confirmed.14,15
A cross-sectional study of pregnant women in Houston, Texas by Di Pentima and others16
found that 0.4% of Hispanic pregnant women had antibodies to T. cruzi
present in their sera. Based on census data and an assumed congenital transmission rate of 1–4%, the authors estimated that ~10–40 cases of congenital Chagas disease occur annually in the state of Texas. Buekens and others17
used the seroprevalence reported by Di Pentimi and others16
and national data on live births of Hispanic origin to estimate that 189 cases of congenital Chagas disease occur annually in the United States.17
Bern and Montgomery9
applied country-specific seroprevalence and birth rates to estimated populations of authorized and unauthorized immigrants from endemic countries residing in the United States and assumed a congenital transmission rate of 1–5%; the authors estimated that each year, there are 63–315 new cases of congenital Chagas in the United States.9
Cases of congenital transmission of Chagas disease have been documented in other non-endemic areas, including Spain,18,19
and areas in South America with no vectorial transmission.21,22
Congenital Chagas disease cases are most commonly asymptomatic or may present with non-specific findings such as low birth weight, hepatosplenomegaly, or respiratory distress.23
The lack of defining clinical characteristics in infected newborns highlights the importance of detecting T. cruzi
infection among pregnant women. If a mother is known to be infected, her baby can be promptly tested and treated, if necessary. Cord blood or a blood sample from the newborn should be tested by culture, smear, serology, and polymerase chain reaction (PCR; if available); if initial results are negative, testing should be repeated at 4–6 weeks, and serology should be tested again at 9–12 months.24
Infected babies should be treated as soon as possible, because treatment is more efficacious when initiated in the first days to weeks of life.25
Two anti-parasitic medications used for treatment of Chagas disease—nifurtimox and benznidazole—are available in the United States only through the CDC. In order for cases of congenital Chagas disease to be promptly detected and treated, obstetric providers must consider the diagnosis in their patients and be aware of the need to test pregnant women and their children. However, we found that obstetrician-gynecologists rarely suspected the diagnosis, and most were unaware of testing recommendations.
Although congenital Chagas disease is relatively rare in the United States, the estimated number of annual cases is not dissimilar from other rare diseases for which all newborns are screened, such as phenylketonuria (estimated 215 cases) or congenital adrenal hyperplasia (estimated 202 cases).26
Because untreated congenital Chagas may lead to substantial morbidity or death and effective treatment is available, it is important for obstetric providers to be aware of the risk factors for disease among their patient population. Furthermore, there is increasing evidence that treatment of chronic asymptomatic Chagas disease in older children and adults may help prevent or halt the progression of clinical manifestations, and treatment is now advocated for a much wider group of patients with chronic Chagas disease.27
Therefore, detection of Chagas disease among obstetric patients can facilitate treatment of the mother (generally after delivery because of potentially adverse effects of the medications on the fetus) as well as the diagnosis and treatment of Chagas disease in the newborn and any older siblings.
This study was limited by the use of self-reported data, which may be subject to social desirability bias. We also had a relatively low response rate, which may limit the ability of generalizations of the findings more broadly to all obstetrician-gynecologists. However, neither of those limitations would be expected to lead to an underestimation of respondents' knowledge about Chagas disease. Our data suggest that a greater awareness of Chagas disease may help to detect treatable congenital cases in the United States.