A number of monkeys (Macacus rhesus) were found to be infected with a nematode which gave rise to several types of skin lesions, subcutaneous nodules, edema about the joints, and elongated serpiginous blisters of the palms and soles.
In the subcutaneous nodules were found larval forms of the nematode and possibly adult male forms.
The reaction about these worms consisted of proliferation of fixed cells, and invasion of eosinophils, with subsequent presence of giant cells, young blood vessels, and finally capsule formation; eventually the worms were killed, eliminated, and the nodule disappeared.
In the skin of the palms and soles the adult female worm burrowed in the epidermis, producing an elongated serpiginous blood blister that eventually became purulent. In this blister the worm laid her eggs; and by the bursting of the blister the eggs were discharged into the outer world and placed in a position to infect new hosts. The reaction in the epidermis was evidently not severe enough to interfere seriously with the health of the host or with the continuation of the egg-bearing period of the female parasite. This condition of almost perfect parasitism is an ideal one for the continuation of the life of this species of nematode. In so far as we are able to determine this is the first description of a nematode that lays its eggs in the epidermis.
The provisional name of the parasite is Trichosoma cutaneum, 1922.