The Animal Parasites of Man

by Harold Benjamin Fantham; Max Braun; J. W. W. Stephens; Fred. V. Theobald

During the day the resort of bird mites is in the droppings and in the woodwork, etc., of cages in which canaries, crossbills and parrots are kept; in the crevices of doors, in the chinks between the board planks of bedsteads, so that at night they may seek some domestic animal to suck the blood and so satisfy their hunger. It is by no means rare for young animals, chickens and unfledged pigeons, etc., to perish in consequence of the great loss of blood. This nocturnal habit of life explains why no mites can be found during the day in spite of the most careful examination of the human body, to which they may be transmitted. On the uncovered parts of the body they not only cause severe irritation, but also severe diffuse itching erythema and eczema. Thorough disinfection of the cages by hot solution of caustic potash, in addition, sprinkling over with tar, red carbolic acid or petroleum, thoroughly powdering over the birds with flores pyrethræ, washing with water containing oleum anisi, washing the walls, doors and bedsteads with soap, disinfection of the mattresses, linen and clothes, will protect against further infection. In the case of man the disease needs no special treatment, as the eruptions generally disappear after some days. Heinecke[1024] recommends lavages with 1 per cent. carbolic acid solution. [Vide also p. 492 in body of this work.—F. V. T.]

[Dermanyssus hirundinis, Hermann, is identical with this species. By far the best treatment is with paraffin or kerosene oil applied to the places where they pass the day.—F. V. T.]

Ixodes reduvius (ricinus).

The female is occasionally transmitted to the human skin, and bores its proboscis deep into it and sucks itself full of blood. At sensitive points of the cutaneous surface—for example over the skin of the penis—a feeling of severe pain is produced. Buy’s[1025] observations as to the geographical distribution of the Ixodinæ show that in all lands in which cattle, horses, sheep and dogs exist, Ixodinæ are to be found. Recent observations show that the Ixodinæ play an important part in the transmission of Hæmosporidia (vide body of work, pp. 493, 494). Sprinkling with oil, vaseline, benzine, ether, petroleum, naphtha, turpentine (Jelgenum[1026]), will easily lead to the removal of the parasite; if the body is torn away with violence and the proboscis is left sticking in the skin, the presence of the latter will give rise to inflammation and suppuration.

Sarcoptes scabiei (Scabies).

The disease produced by Sarcoptes scabiei shows itself in polymorphous areas, such as accompany eczema, and are produced on the one hand by the Sarcoptes alone and on the other hand by the scratching with the nails. The localization of both kinds of efflorescences is different from those which are produced by the Sarcoptes; they occur as papules, vesicles, pustules and mite-tracks, and their usual situation is between the fingers, on the ulnar border of the hand, on the wrist, on the palm of the hand, on the anterior border of the axilla, on the penis and at the base of the thorax. The excoriations are situated on the forearm, over the thigh, over the abdomen, and may be distributed in greater or less degree over the whole body; the back and the face only remain free. The symptoms consist in violent itching, the onset of which specially takes place at night.

The mite-tracks are fine curving lines, curved like a, u, c, or s, which appear as if they had been scratched with a fine needle. Upon closer examination with the magnifying glass one sees in their course small openings. These openings, in persons who keep themselves clean, are scarcely coloured; but in patients whose occupations necessitate their being associated with coloured or dirty substances, they are dark. The length of the tracks varies from some millimetres to 1 1/2 to 2 cm. They are at the one end, where the Sarcoptes is embedded in the epidermis, widened like a funnel and slightly exfoliated. The track at this point is sharply defined; the mite shows through the epidermis as a yellowish round point. In the course of the track there develop papulæ, vesicles or pustules, which raise the level of the track. The intensity of these inflammatory appearances depends upon the susceptibility of the human individual and upon the capability of the reaction of the skin. There are people in whom scarcely any inflammatory symptoms make their appearance; on the other hand there are some, especially children and lymphatic individuals, in whom severe impetiginous ecthymatous pustules, together with their sequelæ, are set up.

The results produced by scratching consist in papules, which usually bear a small scab of blood, and are arranged in the form of striæ, in eczematous surfaces, weeping or sanguineous scabs, vesicles, pustules, etc. The complications that set in are frequently urticaria and even furuncles, lymphangitis and inflammation of the glands, which now and then is followed by the formation of abscesses in the glands.

The duration of the disease is unlimited; when untreated it leads to a form of rare occurrence, that of scabies norvegica[1027]; in this the collection of crusts and scales, in which a quantity of dead mites, larvæ and ova are present, may become colossal.

The symptoms of scabies abate in the presence of intercurrent acute diseases and reappear after the malady is over. The fact has for long contributed to the idea of scabies being regarded as a disease capable of being “driven in” upon the internal organs and forming metastases.