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Epifil: a dynamic model of infection and disease in lymphatic filariasis.

1998; American Society of Tropical Medicine and Hygiene; Volume: 59; Issue: 4 Linguagem: Inglês

10.4269/ajtmh.1998.59.606

1476-1645

M.S. Chan, Adinarayanan Srividya, Rachel Norman, S P Pani, K. D. Ramaiah, P. Vanamail, E Michael, Pradeep Das, Donald A. P. Bundy,

Parasite Biology and Host Interactions

The lack of a quantitative framework that describes the dynamic relationships between infection and morbidity has constrained efforts aimed at the community-level control of lymphatic filariasis. In this paper, we describe the development and validation of EPIFIL, a dynamic model of filariasis infection intensity and chronic disease. Infection dynamics are modeled using the well established immigration-death formulation, incorporating the acquisition of immunity to infective larvae over time. The dynamics of disease (lymphodema and hydrocele) are modeled as a catalytic function of a variety of factors, including worm load and the impact of immunopathological responses. The model was parameterized using age-stratified data collected from a Bancroftian filariasis endemic area in Pondicherry in southern India. The fitted parameters suggest that a relatively simple model including only acquired immunity to infection and irreversible progression to disease can satisfactorily explain the observed infection and disease patterns. Disease progression is assumed to be a consequence of worm induced damage and to occur at a high rate for hydrocele and a low rate for lymphodema. This suggests that immunopathology involvement may not be a necessary component of observed age-disease profiles. These findings support a central role for worm burden in the initiation and progression of chronic filarial disease.