FILARIA LOA 301 



Filaria loa lives in the connective tissue of the conjunctive 

 between it and the bulbus oculi ; sometimes, however, it retires 

 into the depth of the orbit, to emerge nearer to the surface after 

 a longer or shorter time ; the wandering of the worm also from 

 one eye to the other beneath the skin of the bridge of the nose 

 has been observed, and occasionally the parasite has also been 

 known to appear in other parts of the body within the subcuta- 

 neous connective tissue, notably in the fingers. It is doubtful 

 whether it also occurs in the eye-ball. Several observations have 

 been reported, some relating to a comparatively long worm, which 

 may have been either Filaria loa or Filaria medinensis. 



FIG. 200. Filaria loa ; to the left is the posterior extremity of a male ; to the 

 right the anterior extremity of a female. Magnified. (After R. Blanchard.) 



The first accounts of Filaria loa long since forgotten were reported 

 by Pigafetta, and are contained in a book of travels on the Congo printed 

 in 1598. In an accompanying illustration is depicted, not only the ancient 

 method of extraction of the Medina worm, but also the operative removal 

 of the filaria from the conjunctiva. Subsequently the presence of the 

 worm in negroes was confirmed by Bajon in Guiana (1768) and by 

 Mongin in Mariborou (San Domingo) ; likewise in a negro (1770). At about 

 this time a French ship's doctor, Guyot, was cruising on the West Coast 

 of Africa ; he observed the parasite termed " loa " by the natives and 

 learned that it was frequent in the negroes of the Congo district. Since 

 that time numerous observations have been reported. It was formerly 

 common in South America, where the parasite was imported by slaves, but 

 it disappeared when the traffic ceased ; it is particularly prevalent in the 

 Congo, where it occurs not only in natives, but also in Europeans. During 



