Page:Tropical Diseases.djvu/833

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XLII]
LOA LOA
777

had formerly been seen in his eye, I suggested that the new microfilaria, which I named F. diurna, was the hæmatozoal larval form of L. loa. This view was supported by the fact that in fragments of a loa which I received from Leuckart the contained embryos appeared to be identical in every respect with F. diurna. Nevertheless, I failed in several cases of L. loa infection to find mf. diurna in the blood.

In 1901 Dutton, Annett and Elliot had the opportunity of studying F. diurna in its own habitat in West Africa, and came to the conclusion that my hypothesis as regards the relationship of F. diurna and L. loa was erroneous, contending that F. diurna was none other than mf. bancrofti whose normal periodicity had been disturbed by the peculiar habits of those West African negroes who, they tell us, spent their nights in orgies.
Fig. 153.—Loa loa (nat. size).

Sambon, refuting the theory of the Liverpool Commission, again pointed out the similarity of mf. diurna to the larvæ still contained within the uterus of L. loa, and explained that the lack of contemporaneousness between mf. diurna and L. loa in the same patient is probably due to the fact that this long-lived parasite does not produce its young until after a long period of wanderings, when, having attained full maturity, it retires into deeper structures for parturition. He pointed out that the majority of filariæ removed whilst wandering beneath the skin of patients were more or less immature forms; that in young children L. loa is, as a rule, the only form found, whilst in adults mf. diurna is the commonest finding, with frequently the history of a previous loa and finally that F. equina of horses and asses, also found in or about the eyes of the host in its immature or barely mature stages, descends into the peritoneal cavity for parturition when fully mature.

Later, an association was discovered between