Myiasis.
This is the name applied to the condition in which the larvæ of flies are found parasitic in the body. It may be cutaneous, nasal or intestinal. The last named is not of great importance. Different species of flies may be concerned; thus in Africa, one of the best known flies producing this condition is called on the West Coast the Tumbu fly. The fly itself is about the size of a small blue-bottle, and is yellowish-grey in colour. It has a fat white larva, which burrows under the skin and produces a small boil or wheal, in the centre of which there is an opening which, unless blocked up by discharge, looks black owing to the presence of excrement from the posterior end of the larva. The skin round the hole becomes inflamed and very itchy. The commonest site is the forearm, but in Europeans various parts of the body may be attacked.
Treatment.—When small the larvæ can easily be squeezed out. They are, however, best extracted with forceps, and this is more readily done if a little chloroform is injected into the maggot before it is removed. Apply local sedatives, such as lead and opium and, after removal of the maggot, paint the skin with iodine. Indeed, if there is some delay in getting the maggot removed, it is well to apply tincture of iodine to the skin to prevent the occurrence of suppuration.
In Central and South America we meet with the so-called Ver macaque, which is the larva of another species of fly, and which gets under the skin in much the same way as does that of the Tumbu fly. It causes a great deal of pain, especially when it is moving about. It should be treated on the same lines as above.
The Screw-worm is also met with in America, and is the maggot of a fly which lays its eggs on the surface of wounds and in the ears and nose of persons sleeping in the open air. The maggots burrow into the tissues and may bring about a very serious condition if not detected at an early date and removed.
Treatment.—Injections of chloroform are one of the best ways of getting rid of maggots in the ear or nose, but medical attention is required. Wounds should be protected and kept clean. If infected they may be treated with turpentine, a painful but effective method.
Ophthalmia, Simple.
Simple ophthalmia, conjunctivitis, or inflammation of the membrane covering the eye and the inner side of the eyelids, is usually due to cold or dust.
Symptoms.—The affected eye is bloodshot and painful, waters freely, and cannot bear a bright light; there is a feeling of grittiness, as if the trouble were due to something between the eye and eyelid.