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Dreyer, G., Norões, J., Figueredo-Silva, J.

ELIMINATION OF LYMPHATIC FILARIASIS AS A PUBLIC HEALTH PROBLEM. NEW INSIGHTS INTO THE NATURAL HISTORY AND PATHOLOGY OF BANCROFTIAN FILARIASIS: IMPLICATIONS FOR CLINICAL MANAGEMENT AND FILARIASIS CONTROL PROGRAMS.

Transactions of the Royal Society of Tropical Medicine and Hygiene, 94:(6), 594-596, 2000.

ABSTRACT

Lymphatic filariasis caused by Wulchereria bancrofti occurs in individuais of all ages and both sexes, but prevails in those of low socioeconomic level. Endemic in countries of tropical and subtropical climates, lymphatic filariasis in currently targeted for a global elimination programme (OTTESEN et al., 1997). Early studies had recognized lymphangiectasia as a fundamental alteration in the natural history of lymphatic filariasis, but had attributed its cause to the down-stream obstruction of lymphatic vessels by the adult worms. This obstrucction would produce 2 outcomes: fistulization syndromes (chyluria and lymphscrotum), and interstitial fibrosis triggered by diffusible substancs released by live or dead worms. Traditionally, the natural history of lymphatic filariasis has been considered as a spectrum of clinical and evolutionary forms in a pre-established sequence–from uninfected individuals at one extreme, through disease-free microfilarial carriers, to patients with chronic pathology (M AIZELS et al ., 1991). Recent multidisciplinary studies, substantiated by clinical examination, ultrasonography, therapeutic trials, surgery and histopathology, have lent support to an alternative model of the natural history of the disease based in lymphangiectasia caused by a non-obstructive mechanism (D REYER et al ., 2000). Our observations of high-level lymphangiectasia in young adults (N ORÕES et al ., 1996a, 1996b) led us to strongly suspect that the genesis of this process occurred early in life. On the basis of these observations, we describe the natural history of lymphatic filariasis according to the different stages of human development: childhood, young adulthood, and later adulthood or maturity (Table).