Adult filariae, either alive or dead and calcified, may be found in the lymphatic glands or in the contents of filarial abscesses.
The blood shows an eosinophilia.
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This filarial infection is at present only known for the West Coast of Africa. In the Cameroons and in Old Calabar the infection is quite common.
As noted in the table previously given, the adults which are a little more than an inch long have cuticular protuberances or bosses, about 12 to 15 microns in height. The sheathed embryo is very similar to that of F. bancrofti, but has a more twisted tail and shows a complete filling up of the tail end with rather elongated cells. The lines of the curves of the embryo show irregularities and are not the smooth lines characteristic of F. bancrofti embryos.
The periodicity is diurnal, for which reason the parasite was originally termed F. diurna.
Leiper has reported two species of Chrysops, one of the tabanid biting flies, as transmitting agents and considers that the embryos undergo development in the salivary glands of the fly.
The life history is not well understood but as a rule a period of several years elapses after infection before adult filariae or filarial embryos are found. Again, for some reason, adult filariae may be noted and when extracted be found full of embryos and yet embryos not be found in the peripheral circulation.
The adults are noted for their tendency to move about in the subcutaneous connective tissues having been found in such tissues in the region of scalp, trunk, penis and extremities.