Most frequently, however, they are noted in the tissues about the region of the eyes and even under the conjunctivae, from which location they have been frequently extracted. It is this which has caused the name Filaria oculi to be given the worm.
Fig. 103.—L. loa above. Acanthocheilonema perstans below. (From Greene, after Fülleborn.)
The course of the wandering worm is usually marked by an oedematous track. In his own case, recently reported by a medical man, the first symptoms were transient painless swellings about the joints, associated with stiffness. Various diagnoses, such as rheumatism, erythema nodosum and angioneurotic oedema were made in his case. Although two adult filariae were removed at different times the blood examinations were negative for embryos.
As a rule the appearance of the worms in the subcutaneous tissues is characterized by itching sensations and a feeling of tension. Warmth causes them to appear in the superficial tissues while cold makes them confine themselves to the deeper structures. Eosinophilia is rather pronounced.
Calabar Swellings.—Although we have no absolute proof that these usually painless swellings, which occur rather suddenly on various parts of the body having only a thin layer of connective tissue, as forearms, face, ankles, hands, are connected with an infection with L. loa, yet such is the general view. These swellings are about the size of a hen’s egg, do not pit on pressure and last for about three days. There is marked tension over the swellings and they may itch greatly.
Fig. 104.—L. loa in the subcutaneous tissues, twice normal size. (From Greene, after Fülleborn.)
Rarely does one note more than one swelling at a time. Eosinophilia is quite marked during the attacks. Manson thinks the oedema results from the extrusion of embryos from the female at the site of the swelling. Ward considers the cause to be toxic material excreted by the worm.