English dogs, most frequently in sporting dogs and those employed
on farms, owing to their eating the viscera of rabbits, &c., in which
the larval form (Cysticercus pisiformis) of this tapeworm dwells.
T. marginata is the largest cestode of the dog. It varies in length
from 5 to 8 ft., and is found in the small intestine of 30% of dogs in
Great Britain, its cystic form (C. tenuicollis) occurs in the peritoneum
of sheep. T. coenurus causes gid in sheep as previously stated. It
seldom exceeds 3 ft. in length. Dogs contract this parasite by eating
the heads of sheep infested with the bladder-worm (Coenurus
cerebralis). Dipylidium caninum, T. cucumerina, or melon seed
tapeworm, is a very common parasite of dogs. It varies in length
from 3 to 15 in.; its larval form (Cryplocystis trichodectis et pulicis)
is found in the abdomen of the dog-flea (Pulex serraticeps), the
dog-louse (Trichodectis latus) and in the flea (P. irritans) of the human
subject. The dog contracts this worm by swallowing fleas or lice
containing the cryptocysts. T. echinococcus may be distinguished
from the other tapeworms by its small size. It seldom exceeds
¼ in. in length, and consists of four segments including the head.
The fourth or terminal proglottis when ripe is larger than all the
rest. Its cystic form is Echinococcus veterinorum, which causes
hydatid disease of the liver, lungs, and other organs of cattle, pigs,
sheep, horses, and even man. This affection may not be discovered
during life. In well-marked cases the liver is much deformed,
greatly enlarged, and increased in weight; in the ox the hydatid
liver may weigh from 50 to 100 ℔ or more. Another tapeworm
(T. serialis) sometimes occurs in the small intestine. Its cystic
form is found in rodents. Bothriocephalus latus, or broad tapeworm,
about 25 ft. long and 1 in. broad, is found in the intestine of the dog
and sometimes in man. Its occurrence appears to be confined to
certain parts of the European continent. Its larval form is met
with in pike, turbot, tench, perch, and other fishes. The
heart-shaped bothriocephalus (B. cordatus) infests the dog and man in
Greenland. For the expulsion of tapeworm male fern extract has
been found the most effectual agent; areca powder in linseed oil,
and a combination of areca, colocynth and jalap, the dose varying
according to the age, size and condition of the dog, have also proved
beneficial.
The parasites which cause numerous skin affections in the domesticated animals may be arranged in two groups, viz. Dermatozoa. animal parasites or Dermatozoa, and vegetable parasites or Dermatophytes. The dermatozoa, or those which produce pruritus, mange, scab, &c., are lice, fleas, ticks, acari or mange mites, and the larvae of certain flies. The lice of the horse are Haematopinus macrocephalus, Trichodectes pilosus and T. pubescens; those of cattle, H. eurysternus, or large ox-louse, H. vituli, or calf-louse, and T. scalaris, or small ox-louse; and sheep may be attacked by T. sphaerocephalus, or sheep-louse, and by the louse-like ked or fag (Melophagus ovinus) which belongs to the pupiparous diptera. Dogs may be infested with two species of lice, H. piliferus and T. latus, and the pig with one, H. urius.
Ticks belong to the family Ixodidae of the order Acarina. A few species have been proved responsible for the transmission of diseases caused by blood parasites, and this knowledge has greatly increased the importance of ticks in veterinary practice. The best known ticks are Ixodes ricinus, or castor-bean tick, and I. hexagonus, which are found all over Europe, and which attack dogs, cattle, sheep, deer and horses. Rhipicephalus annulatus, or Texan fever-tick of the United States, Rh. decoloratus, or blue-tick of South Africa, and Rh. australis, or scrub-tick of Australia, transmit the parasite of red water or bovine piroplasmosis. Rh. appendiculatus carries the germs of East Coast fever, Rh. bursa is the bearer of the parasite of ovine piroplasmosis, and Rh. evertsi distributes the germs of equine biliary fever. Amblyomma hebraeum conveys the parasite of “heart-water” of cattle and sheep, and Haemaphysalis leachi transmits the parasite of canine piroplasmosis. Hyalomma aegyptium, or Egyptian tick, Rh. simus and Rh. capensis, are common in most parts of Africa.
The acari of itch, scab or mange are species of Sarcoptes, which burrow in the skin; Psoroptes, which puncture the skin and live on the surface sheltered by hairs and scurf; and Chorioptes, which live in colonies and simply pierce the epidermis. Representatives of these three genera have been found on the horse, ox and sheep; varieties of the first genus (Sarcoptes) cause mange in the dog and pig; and Chorioptes cynotis sometimes invades the ears of the dog and cat. These parasites live on the exudation produced by the irritation which they excite. Another acarus (Demodex folliculorum) invades the dog's skin and sometimes occurs in other animals. It inhabits the hair follicles and sebaceous glands, and causes a very intractable acariasis—the follicular or demodecic mange of the dog (see Mite). A useful remedy for mange in the horse is a mixture of sulphur, oil of tar and whale oil, applied daily for three days, then washed off and applied again. For the dog, sulphur, olive oil and potassium carbonate, or oil of tar and fish oil, may be tried. Various approved patent dips are employed for scab in sheep. A good remedy for destroying lice may be compounded from Stavesacre powder, soft soap and hot water, applied warm to the skin. Follicular mange is nearly incurable, but recent cases should be treated by daily rubbing with an ointment of 5 parts cyllin and 100 parts of lanoline.
The vegetable parasites, or Dermatophytes, which cause tinea or ringworm in horses, cattle and dogs, belong to five distinct Dermatophytes. genera: Trichophyton, Microsporum, Eidamella, Achorion and Oospora. Ringworm of the horse is either a Trichophytosis produced by one of four species of fungi (Trichophyton mentagrophytes, T. flavum, T. equinum and T. verrucosum), or a Microsporosis caused by Microsporum audouini. Ringworm of cattle is always a Trichophytosis, and due to T. mentagrophytes. Four different dermatophytes (T. caninum, M. audouini var. caninum, Eidamella spinosa and Oospora canina) affect the dog, producing Trichophytic, Microsporous and Eidamellian ringworm and favus. Little is known of ringworm in sheep and swine. The fungi attack the roots of the hairs, which after a time lose their elasticity and break off, leaving a greyish-yellow, bran-like crust of epidermic products, dried blood and sometimes pus. In favus the crusts are yellow, cupped, almost entirely composed of fungi, and have an odour like that of mouldy cheese. Ringworm may affect any part of the skin, but occurs principally on the head, face, neck, back and hind quarters. It is very contagious, and it may be communicated from one species to another, and from animals to man. The affected parts should be carefully scraped and the crusts destroyed by burning; then the patches should be dressed with iodine tincture, solution of copper sulphate or carbolic acid, or with oil of tar.
Bibliography.—Modern veterinary literature affords striking evidence of the progress made by the science: excellent text-books, manuals and treatises on every subject belonging to it are numerous, and are published in every European language, while the abundant periodical press, with marked ability and discrimination, records and distributes the ever-increasing knowledge. The substantial advances in veterinary pathology, bacteriology, hygiene, surgery and preventive medicine point to a still greater rate of progress. The schools in every way are better equipped, the education and training—general and technical—of students of veterinary medicine are more comprehensive and thorough, and the appliances for observation and investigation of disease have been greatly improved. Among the numerous modern works in English on the various branches of veterinary science, the following may be mentioned: McFadyean, Anatomy of the Horse: a Dissection Guide (London, 1902); Chauveau, Comparative Anatomy of the Domesticated Animals (London, 1891); Cuyer, Artistic Anatomy of Animals (London, 1905); Share-Jones, Surgical Anatomy of the Horse (London, 1907); Jowett, Blood-Serum Therapy and Preventive Inoculation (London, 1906); Swithinbank and Newman, The Bacteriology of Milk (London, 1905); Fleming, Animal Plagues (London, 1882); Merillat, Animal Dentistry (London, 1905); Liautard, Animal Castration (9th ed., London, 1902); Moussu and Dollar, Diseases of Cattle, Sheep, Goats and Swine (London, 1905); Reeks, Common Colics of the Horse (London, 1905); Sessions, Cattle Tuberculosis (London, 1905); Sewell, Dogs: their Management (London, 1897); Hobday, Surgical Diseases of the Dog and Cat (London, 1906); Hill, Management and Diseases of the Dog (London, 1905); Sewell, The Dog's Medical Dictionary (London, 1907); Goubaux and Barrier, Exterior of the Horse (London, 1904); Reeks, Diseases of the Foot of the Horse (London, 1906); Roberge, The Foot of the Horse (London, 1894); Jensen, Milk Hygiene: a Treatise on Dairy and Milk Inspection, &c. (London, 1907); Smith, Manual of Veterinary Hygiene (London, 1905); Fleming, Human and Animal Variolae (London, 1881); Hunting, The Art of Horse-shoeing (London, 1899); Fleming, Horse-shoeing (London, 1900); Dollar and Wheatley, Handbook of Horse-shoeing (London, 1898); Lungwitz, Text-Book of Horse-shoeing (London, 1904); Axe, The Horse: its Treatment in Health and Disease (9 vols., London, 1905); Hayes, The Points of the Horse (London, 1904); Robertson, Equine Medicine (London, 1883); Hayes, Horses on Board Ship (London, 1902); FitzWygram, Horses and Stables (London, 1901); Liautard, Lameness of Horses (London, 1888); Walley, Meat Inspection (2nd ed., London, 1901); Ostertag, Handbook of Meat Inspection (London, 1907); Courtenay, Practice of Veterinary Medicine and Surgery (London, 1902); Williams, Principles and Practice of Veterinary Medicine (8th ed., London, 1897); J. Law, Text-book of Veterinary Medicine (5 vols., New York, 1905); Cadiot and Dollar, Clinical Veterinary Medicine and Surgery (London, 1900); Steel, Diseases of the Ox (London, 1881); Leblanc, Diseases of the Mammary Gland (London, 1904); De Bruin, Bovine Obstetrics (London, 1901); Fleming, Veterinary Obstetrics (London, 1896); Dalrymple, Veterinary Obstetrics (London, 1898); Neumann, Parasites and Parasitic Diseases of the Domesticated Animals (London, 1905); F. Smith, Veterinary Physiology (3rd ed., London, 1907); Meade Smith, Physiology of the Domestic Animals (London, 1889); Kitt, Comparative General Pathology (London, 1907); Friedberger and Fröhner, Veterinary Pathology (London, 1905); Brown, Atlas of the Pig (London, 1900); Rushworth, Sheep and their Diseases (London, 1903); Fleming, Operative Veterinary Surgery (London, 1903); Williams, Principles and Practice of Veterinary Surgery (10th ed., London, 1903); Moller and Dollar, Practice of Veterinary Surgery (London, 1904); Fröhner, General Veterinary Surgery (New York, 1906); Merillat, Principles of Veterinary Surgery and Surgical Pathology (London, 1907); Cadiot and Almy, Surgical
