Each year 500 000 new infections with visceral leish-maniasis occur. According to WHO, the ratio of subclinical to clinical infections is 5:1.14. A study from Kenya suggested that asymptomatic persons can be a reservoir of leishmaniasis for extended periods. People can develop the disease even decades after traveling to endemic areas.
Women become immunosupressed during pregnancy, with a shift from cell-mediated to humoral immunity, which has been described in mice as well as humans. Therefore, women may also have a higher susceptibility to leishmanisis during pregnancy, as has been shown in mice. Pregnancy may trigger the (re)activation of disease. A recent report describes a leishmaniasis infection of an infant determined to have been infected by his mother, who had must have had a subclinical infection that was reactivated by pregnancy (Meinecke et al., 1999). The mother had traveled to the Mediterranean areas of Portugal, Malta and Corsica years previously. Thus leish-maniasis can be transmitted congenitally from asymptomatic mother to child. Women who have lived in endemic areas for extended periods of time should be evaluated for asymptomatic disease. Asymptomatic leishmanaisis should be considered in the prenatal evaluation of women who have lived in endemic countries and may not be symptomatic.
Visceral leishmaniasis is endemic to several tropical and subtropical countries, but also to the Mediterranean region. It is transmitted by the sand fly (Phlebotomus and Lutzomyia spp). Occasional nonvector transmissions have also been reported, through blood transfusions, sexual intercourse, organ transplants and dog excrements, and sporadically outside endemic areas.
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