Surface area calculation for Onchocerca volvulus microfilariae.

The pathogenesis of tissue damage in filarial infections involves the generation of inflammatory mediators by interaction of parasite surfaces with the host immune response. In the presence of a heavy parasite burden, the tremendous potential for development of adverse local or systemic inflammatory responses may be appreciated by knowledge of the cumulative surface area represented by circulating microfilariae. The approximate surface area of a single microfilariae of Onchocerca volvulus was calculated using mathematical formulae for standard geometrical shapes and values derived from serial measurements of electron micrographs. Numerical values for the surface area represented by large numbers of microfilariae are given and compared to surface areas of the host which can harbor many millions of microfilariae.