Home Economics American Trypanosomiasis Chagas Disease, Second Edition: One Hundred Years of Research
Prevention and control of congenital Trypanosoma cruzi infection
Primary prevention (prophylaxis) of fetal infection with T. cruzi aims to prevent infection of pregnant women. This can be obtained by limiting the risk of contamination through vector contacts (see Chapter 10, Control strategies against Triatominae and Chapter 22, Vector transmission: how it works, what transmits, where it occurs) or blood transfusion (see Chapter 24, Other forms of transmission: blood transfusion, organ transplantation, laboratory accidents, oral and sexual transmission). Another strategy which has now clearly shown its efficacy consists of treating infected girls before they enter into their child bearing years , (see Chapter 31, Treatment of Chagas disease).
Secondary prophylaxis would aim to avoid maternal—fetal parasite transmission from a previously infected pregnant woman using trypanocidal safe drugs. However, the potential teratogenic effects of both currently used trypanocidal drugs, benznida- zole and nifurtimox, are not known in humans. Moreover, the side effects of both drugs in adults are hardly acceptable during pregnancy and their curative efficacy is limited in the chronic phase of infection presented by most infected pregnant women (see Chapter 31, Treatment of Chagas disease). For all these reasons, the treatment of T. cruzi infection during pregnancy is currently not recommended.105 Moreover, a recent ex vivo study shows benznidazole and nifurtimox unable to impair parasite invasion of human placental chorionic villi explants and nifurtimox displaying toxic effects on such tissue.243 However, two other recent reports indicate the use of benz- nidazole during pregnancy to fight acute or reactivated infections, either because pregnancy was not known244 or the maternal life was threated.245 Such treatment prevented congenital transmission with no evidence of side effects either in the mother or the baby. Of course, more studies are necessary to validate these in vivo findings.
So, there is presently an international consensus to consider the best control strategy as associating the detection of congenital infection based on laboratory diagnosis (see section: Laboratory diagnosis of congenital infection with Trypanosoma cruzi) with the systematic treatment of positive neonates (see section: Treatment of congenital infection with Trypanosoma cruzi).105 The cost/benefit of this control strategy has been evaluated and shown to be much cheaper than the cumulative costs of managing chagasic patients over years.246,247 Obviously, its benefit remains fully effective if infants are reintegrated in areas where vector transmission has been controlled. Mathematical models have been proposed to estimate the time period it will take to eliminate congenital transmission in regions where vector transmission was reduced to close to zero.20 Such a control strategy has been applied successfully in different endemic countries. ,, ,,9 This
strategy is presently also recommended in some nonendemic countries, but currently only applied in Spain (Catalonia).250
Interestingly, the observation of an association between dwelling in areas of high vector density during pregnancy and the severity of congenital Chagas disease (see section: Trypanosoma cruzi infection and pregnancy outcomes)93 suggests that vector control programs in endemic Latin American areas might unexpectedly contribute to limit the mortality and morbidity of a nonvector-borne infection.
Restriction of breast-feeding in infected mothers has no rational base (see section: Possible transmission routes of Trypanosoma cruzi parasites). A recent case report and prospective study of lactating women with Chagas disease treated with benznidazole or nifurtimox showed the limited transference of such drugs into breast milk and the normal clinical evolution of the breastfed babies (with no adverse reactions), suggesting that maternal treatment for Chagas disease during breast feeding is unlikely to present a risk for the breastfed infant.251 —253
Although out of the scope of this chapter, it is important to mention that cord blood from neonates born to infected mothers should not be used for bone marrow transplantation, due to the risk of inducing an acute CD in an immunosuppressed
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