BRIEF REPORT
Prevalence and Vertical Transmission of Trypanosoma cruzi Infection among Pregnant Latin American Women Attending 2 Maternity Clinics in Barcelona, Spain Jose´ Mun˜oz,1 Oriol Coll,2 Teresa Juncosa,4 Mireia Verge´s,5 Marta del Pino,2 Victoria Fumado,4 Jordi Bosch,3 Elizabeth J. Posada,1 Sara Hernandez,2 Roser Fisa,5 Josep Maria Bogun˜a,4 Montserrat Ga´llego,5 Sergi Sanz,1 Montserrat Portu´s,5 and Joaquim Gasco´n1 Barcelona Centre for International Health Research, 2Perinatal Infectious Diseases Unit, Department of Maternal-Fetal Medicine, L’ Institut Clı´nic de Ginecologia, Obstetrı´cia i Neonatologia, and 3Microbiology Department, Hospital Clı´nic, Institut d’Investigacions Biome`diques August Pi i Sunyer, 4 Imported Diseases Unit, Paediatric Department, Hospital Sant Joan de De´u, and 5Laboratory of Parasitology, Faculty of Pharmacy, Universitat de Barcelona, Barcelona, Spain
1
We performed a prospective screening for Trypanosoma cruzi infection in 1350 Latin American pregnant women and their offspring in Barcelona, Spain. The rate of seroprevalence was 3.4%, and 7.3% of the newborns were infected. Routine screening and management programs in maternity wards may be warranted. Chagas disease or American trypanosomiasis is a zoonosis that affects ∼8 million people in Latin America. The transmission of Trypanosoma cruzi in areas where it is endemic occurs through a triatomine that releases excreta infected with the parasite into lacerated skin or mucosa. Other main routes of infection are blood transfusion and congenital transmission via infected mothers [1, 2]. Traditionally considered to affect poor people in rural communities of Latin America, T. cruzi infection is now progressively appearing in urban environments, including those in countries where it is not endemic [3]. In these areas where the vector is not present, T. cruzi may be acquired mainly through Received 22 September 2008; accepted 6 February 2009; electronically published 13 May 2009. Reprints or correspondence: Dr. Jose´ Mun˜oz, Barcelona Centre for International Health Research, Hospital Clinic Barcelona, IDIBAPS, c/ Villarroel, 170, 08036. Barcelona, Spain (
[email protected]). Clinical Infectious Diseases 2009; 48:1736–40 2009 by the Infectious Diseases Society of America. All rights reserved. 1058-4838/2009/4812-0017$15.00 DOI: 10.1086/599223
1736 • CID 2009:48 (15 June) • BRIEF REPORT
blood transfusions, organ transplants, and congenital transmission via infected mothers [1, 4–6]. Infants infected with T. cruzi may have a severe and lifethreatening disease, but most infections are asymptomatic [7]. Diagnosis of congenital T. cruzi infection in neonates should be done by parasitological methods such as direct microscopic examination and/or hemoculture or by newer DNA analysis techniques [2]. Thus, the prevalence of T. cruzi infection in pregnant women of Latin American origin and their neonates in industrialized countries is probably underestimated, because no routine screening is performed in most of these countries and most children who are infected vertically will follow an asymptomatic clinical course [4]. Although cases of congenital transmission have been reported in Europe [4, 5], few studies on Chagas disease in pregnant women have been performed in countries where T. cruzi is not endemic [8]. Consequently, the health authorities in these countries require data on the disease to aid in the management of this emerging public health risk. To establish the prevalence of T. cruzi infection in Latin American pregnant women and to assess the risk of vertical transmission in Barcelona, we performed a study in 2 maternity clinics in Barcelona. Participants and methods. This was a prospective study performed in 2 university hospitals in Barcelona from March 2005 through September 2007. Pregnant women from areas where Chagas disease is endemic were invited to participate in the study. After patients gave informed consent, clinical and epidemiological data were recorded. The study protocol was approved by the Ethics and Research Committee of both centers (Hospital Clı´nic and Hospital Sant Joan de De´u). Serologic diagnosis was performed using 2 enzyme-linked immunosorbent assays (ELISAs), 1 with recombinant antigens (BioELISA Chagas; Biokit S.A.) and 1 in-house ELISA with crude antigen from T. cruzi epimastigotes. Positive results were confirmed by a third ELISA that also used a T. cruzi lysate (Ortho-Clinical Diagnostics). For parasitological diagnosis, the microhematocrit technique was used. Parasite DNA presence in the blood of women and babies was studied using an inhouse real-time polymerase chain reaction assay (PCR) [9]. Clinical history, physical examination, electrocardiogram, human immunodeficiency virus serologic tests, basic hematologic tests, and biochemistry tests were performed for the infected participants. Barium esophageal and colonic examinations were performed only when gastrointestinal symptoms were detected. We defined the indeterminate form of infection as a T. cruzi–seropositive pregnant woman who showed
Table 1. Detailed laboratory results. Mother
Newborn at birth
ELISA Recombinant antigen
Crude antigen
1
6.2
100
2
5.8
3
4
Participant
a
Newborn at 8 months
ELISA
ELISA
PCR
Recombinant antigen
Crude antigen
Lysate
PCR
Recombinant antigen
7.6
Neg
4.9
116
…
Neg
0.0
4
…
…
179
5.02
Neg
4.5
174
5.34
Neg
0.2
10
…
Neg
8.9
217
5.86
Pos
8.7
228
…
Neg
…
…
…
…
6.2
205
8.54
Pos
2.2
…
…
Neg
0.1
10
0.6
Neg
…
Lysate
b
4.3
120
6.43
Neg
5.6
…
6.83
Neg
…
6
c
7.3
173
6.65
Pos
4.4
60
3.9
Neg
0.5
7
Pos
10.5
…
…
Neg
…
8.1
…
…
Neg
5
Crude antigen
Lysate
PCR
…
…
5
0.07
Neg
0.0
11
0.25
Neg
…
…
…
…
Neg
0.8
18
…
…
10.1
192
5.78
8
8.6
209
…
9
6.4
148
8.08
Neg
5.9
150
9.52
10
7.6
174
…
Pos
7.4
179
9.75
Neg
0.1
8
…
…
11
5.4
105
3.82
Pos
6
121
4.15
Pos
d
0.1
5
…
Neg
b
12
6.5
143
8.54
…
…
…
…
…
0.1
8
0.38
…
13
7.8
205
9.9
…
…
…
…
…
0.3
12
1.05
…
14
8.3
206
…
…
…
…
…
…
0.1
5
0.17
…
15
8.4
236
9.83
…
…
…
…
…
0.2
6
0.08
Neg
16
7.7
162
7.62
…
5.0
90
6.85
Neg
0.5
14
1.28
Neg
17
8.7
134
…
…
…
…
…
…
0.2
7
0.15
…
18
5.3
44
2.11
…
…
…
…
…
0.2
15
0.23
…
a
19
8.5
179
8.24
Pos
7.6
…
…
Neg
…
…
…
…
20
5.5
160
4.87
Neg
8.2
129
…
Neg
0.1
17
…
Neg
e
2.2
201
8.8
Neg
…
…
…
…
…
…
…
…
22
a
1.2
53
2.08
Neg
1.0
33
…
Neg
…
…
…
…
23
8.5
209
9.75
Neg
…
…
…
…
0.2
11
0.54
…
…
21
a
24
8.6
157
7.98
Pos
9.1
164
8.88
Neg
…
25
7.7
199
6.77
…
4.9
209
5.64
Neg
0.0
a
26
8.2
143
5.77
Neg
8.3
163
4.71
Neg
…
27
6.8
140
6.73
Neg
6.6
148
7.6
Neg
0.1
3.5
160
4.25
Neg
4.7
…
…
Neg
…
Twin A
7.5
203
8.63
Neg
7.8
189
8.12
Neg
Twin B
7.5
203
8.63
Neg
7.8
189
5.26
Neg
30
4.3
33
2.27
Neg
4.9
89
4.73
31
5.1
39
Neg
6.1
41
1.02
a
28
3 …
…
…
…
…
…
…
…
Neg
…
…
…
0.1
14
0.15
Neg
0.1
16
0.19
Neg
Neg
0.2
4
0.06
Neg
Neg
0.1
3
0.07
Neg
4
29
b
1,01
32
9.0
284
9.63
Pos
9.2
187
9.9
Neg
…
33
7.2
245
4.94
Neg
7.6
275
5.34
Neg
0.1
8
34
6.0
182
9.9
Pos
7.0
215
6.98
Neg
0.1
35
8.2
239
9.9
Pos
7.9
222
6.63
Neg
0.2
36
8.6
216
…
Pos
8.4
196
5.7
Neg
37
7.6
297
6.07
Pos
7.3
279
5.58
38
f
…
…
…
0.13
…
5
…
Neg
5
0.41
Neg
0.1
3
0.37
…
Pos
0.2
8
…
Neg Pos
5.6
170
6.01
Pos
3.1
141
4.37
Neg
8.5
182
5.66
39
9.8
209
9.9
Pos
8.7
223
6.7
Neg
…
…
…
…
40
9.9
166
9.9
…
6.8
221
6.47
Neg
0.1
0.68
Neg
a
a
41
8.3
240
9.9
Pos
8.2
199
6.26
Neg
…
42
8.2
239
9.28
Neg
…
…
…
…
0.1
5 … 6
…
…
0.1
Neg
b
8.7
231
9.75
Pos
9.0
230
5.81
Neg
…
…
…
…
44
g
8.3
162
8.3
Neg
9.3
168
4.86
Neg
…
…
…
…
45
8.4
193
…
…
…
…
…
…
6.7
89
…
Pos
46
7.8
215
…
Pos
7.4
189
…
Neg
0.1
10
…
Neg
43
NOTE. Three enzyme-linked immunosorbent assays (ELISAs) were used; 1 used a recombinant antigen and had a cutoff value of 1 (BioELISA Chagas; Biokit S.A.), 1 was an in-house assay that used crude antigen and had a cutoff value of 20, and 1 was a commercial assay that used crude lysate and had a cutoff value of 1 (Ortho-Clinical Diagnostics). Neg, negative; PCR, polymerase chain reaction; Pos, positive. a
Family was displaced and the analysis of the newborn at 8 months was performed in another hospital. Results were negative; the newborn was not infected at 8 months. b Family was lost to follow-up before the 8-month testing. c Newborn first tested at 1 month. d A false-positive result; newborn had negative result at 1 month. e Abortion. f Received treatment after positive results at 1 month of age. g Newborn died at birth.
Figure 1. Flow chart of the study. ELISA, enzyme-linked immunosorbent assay; PCR, polymerase chain reaction.
no cardiac or gastrointestinal tract alterations in the complete evaluation. Preterm delivery was defined as birth before 37 weeks of pregnancy, and small for gestational age was defined according to Santamarı´a et al. [10]. Infected neonates were treated with benznidazole. After breast-feeding was withdrawn, treatment was also offered to infected mothers. Data analysis. We initially calculated that we needed a sample of 1540 pregnant women because we expected a prevalence of infection of 1% (95% confidence interval [CI], 0.5%– 1.5%). However, we stopped the recruitment at 1350 participants, because the prevalence was found to be 3.4% (95% CI, 2.5%–4.5%). Proportions were compared using the x2 test or Fisher’s exact test. The Wilcoxon rank-sum test was used to compare age distributions. Odds ratios (ORs) and 95% CIs 1738 • CID 2009:48 (15 June) • BRIEF REPORT
were calculated for the association of lifestyle factors with Chagas infection. All statistical analyses were performed using Stata, version 9.0 (StataCorp). Results. A total of 1350 pregnant women of Latin American origin participated in the study. The mean age was 31 years (range, 18–43 years), and 25% of the women were aged !25 years. The most frequent country of origin was Ecuador (34%), followed by Peru (16%), Bolivia (14%), and Colombia (12%). Forty-six participants were seroreactive to T. cruzi, yielding a prevalence of 3.4% (95% CI, 2.43%–4.73%); 91% of these women were from Bolivia (OR, 106.5; 95% CI, 35.7–356.2). PCR was performed for 35 seroreactive women, and results were positive for T. cruzi for 18 (51.4%) (table 1). Among 1304 noninfected participants, 248 (19%) had lived in mud houses in their country of origin and 313 (24%) had
lived in rural areas. Among 46 infected participants, 30 (65%) had a history of living in mud houses (OR, 7.00; 95% CI, 3.55– 13.80; P ! .001) and 30 (65%) had a history of living in rural areas (OR, 7.51; 95% CI, 4.02–14.04; P ! .001). All the infected women were classified as being in the indeterminate stage of the infection. One woman experienced a late miscarriage. The remaining 45 women delivered a total of 46 infants (1 set of twins). Among the 45 mothers, 20 (44.4%) were nulliparous, and median gestational age at delivery was 39 weeks (range, 33–42 weeks). Only 3 (6.7%) women delivered prematurely. One of these premature neonates presented with a severe malformation (renal polycystic disease and lung hypoplasia) and died after delivery. In 13 cases, women gave birth by cesarean delivery. The median infant weight at delivery was 3500 g (range, 2500–4170 g), and 2 of the 46 neonates were small for their gestational age. No major complications occurred except for the 1 death and 1 preterm premature rupture of membranes. Figure 1 shows the flow chart for the study. Results of T. cruzi PCR performed on tissues from the aborted fetus and the malformed neonate were negative. None of the remaining 45 neonates had signs or symptoms of congenital Chagas disease. Three cases of congenital infection were identified (figure 1). The 3 infected neonates were born at term by vaginal delivery, and none were small for their gestational age. All received treatment with benznidazole (7.5 mg/kg/day for 60 days), and no adverse effects were reported. Thus, among the 41 infants that were followed up, congenital transmission occurred in 3 (7.3%) of 41 (95% CI, 1.5%–19.9%). Discussion. The seroprevalence of T. cruzi infection among pregnant women in Latin America ranges from 2% to 51% [11], with higher rates in rural areas of Bolivia [7]. A previous study in the United States estimated a seroprevalence of 0.3% for T. cruzi infection among 2107 pregnant Latin American women, and no cases of congenital transmission were detected [8]. Our study demonstrates a rate of seroprevalence that is 10 times higher. This finding could be attributable to the high number of women coming to Barcelona from countries south of the equator, especially Bolivia. The rate of transplacental transmission was found to be 7.3%, which is consistent with the reported rates in countries where T. cruzi is endemic [7]. Moreover, there is a high variability, thus results are possibly influenced by the diagnostic methods used. The introduction of molecular techniques for the diagnosis of congenital disease in neonates favors detection and early treatment of the infection. Nevertheless, our observations indicate that perinatal transmission cannot always be ruled out, because in our study, 1 child had a false negative PCR assay result as a newborn but positive PCR and serologic test results at 8 months. Furthermore, the temporal presence of parasite DNA in neonate blood at birth may produce false positive
results; therefore, PCR tests should be repeated 1 month after birth. The presence of parasite DNA in blood detected during pregnancy or at delivery was notably higher among participants in our study (51.4%) than that detected among adult patients with Chagas disease who were Latin American immigrants in Barcelona during the same time period (26.7%; P ! .05) [12]. This finding may be attributable to some patients who present evidence of infection reactivity during pregnancy [13]. In our study, maternal infection did not affect the obstetrical outcome, because the incidences of premature delivery, small size for gestational age, and other obstetrical complications were similar to those in the overall population. In addition, all 3 T. cruzi– infected neonates were asymptomatic. Congenital transmission of T. cruzi cannot be prevented in established pregnancies. However, early detection and treatment of neonates soon after delivery demonstrates the best therapeutic results [4] and may prevent the establishment of the disease and the development of future complications in adulthood. Although Latin American populations have migrated throughout Europe and North America, currently, the main receptor countries of this migration are Australia, Canada, Spain, and the United States [1, 14]. However, the very recent population migration from Bolivia is of relevance for the emergence of Chagas disease in Europe and, particularly, Spain [15]. Given the results of our series, and the current demographic characteristics of the population in Spain, with 1700,000 Latin American women who are of childbearing age [15], we can expect ∼24,000 infected women in this age group in Spain. If we assume a vertical transmission rate of 7.3% and 1 pregnancy per woman during the next 10 years, we can expect to have ∼1750 infected neonates during this period. Although this figure is a rough extrapolation from a single study, these data demonstrate the potential prevalence of this emerging infectious disease in Spain. Population migration from Latin America is not confined to Spain. Europe clearly needs a more extensive assessment of this new phenomenon. Health authorities of countries where T. cruzi is not endemic but where there are many Latin American women may need to consider the introduction of screening programs at both blood banks and antenatal clinics. Acknowledgments We thank Mireia Sanllorente, Sara Herrero, Paulo Lo´pez-Chejade, and Silvia Tebar for their excellent technical assistance during the study. We would also like to thank the Departament de Salut de la Generalitat de Catalunya, and the Universitat de Barcelona for their support. Financial support. The Bayer Foundation and the Age`ncia d’Avaluacio´ de Tecnologies i Recerca Me`diques (AATRM; grant 024/13/2004). Potential conflicts of interest. All authors: no conflicts.
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