There is very little of importance in connection with treatment. When the worms, which travel in the tissues about the eye, at the rate of about ½ inch per minute, are noted, some local anaesthetic may be used and the worm seized with forceps and extracted through a small incision. Elliot recommends the application of hot fomentations to the eye and upon the appearance of the worm under the conjunctiva to instill cocaine solution, seize the worm with forceps and then pass a silk ligature through the conjunctival fold taking in the worm. The ligature is tied and an incision made through which the worm is extracted. Cooling local applications, or an ichthyol ointment, may be applied to the Calabar swellings.
ONCHOCERCA VOLVULUS
This name is given to a filarial worm, found principally on the West Coast of Africa, which causes the formation of subcutaneous tumors. In certain localities as many as 10% of the population may be infected. More recently the parasite has been reported from Guatemala.
It is supposed that the adult worms cause an inflammation of the lymphatic vessel in which they may lie and that a formation of new connective tissue results, giving rise to a tumor-like mass, which is most often found in the axilla or about the sides of the thorax. This tissue stroma encompasses the worms except for the anterior extremity of the female, with its uterine opening, and the posterior extremity of the male carrying the spicules, which ends lie loose in a sort of cyst-like dilatation, which is filled with a viscid fluid swarming with unsheathed embryos. These tumor-like masses cause very little discomfort, last indefinitely and do not tend to ulcerate.
It was formerly thought that these larvae were absent from the peripheral circulation but more recent investigations in cases of onchocerciasis have shown sheathless larvae in the blood, which had the characteristics of those in the contents of the tumors. Such findings, however, are of extreme rarity, the blood examination being almost invariably negative.
The cysts are usually found on the sides of the chest and are quite superficial, with the skin freely movable over them. They may be as large as a hen’s egg but usually are smaller. They are also found over trochanters or along the crests of the ilium.
Dubois states that the embryos may be found in juice from puncture of groin glands.
The tumors are easily enucleated.
In the American infections the tumours are more common in the regions near the eye and it has been thought that certain cases of keratitis may be due to onchocerciasis.