Part 90

In the advanced stages the picture is one of great anæmia, marasmus and general debility. When moved the animal will stumble over the slightest obstacle, even the litter, recovering himself with effort and difficulty. If he should fall he is liable to remain down indefinitely, the side next the ground becoming drenched with sweat though there is no general perspiration. The hair becomes encreasingly dry, withered and erect, the skin dry, powdery, rigid and more and more firmly adherent to the bones and muscles, losing all its natural pliancy and mellowness, and becoming like that of a dead animal. It is bloodless, and sloughs readily over the prominent bones, where compressed or bruised in lying, owing to the lack of nutritive and reparatory action. The visible mucosæ are absolutely bloodless. The muscles as a whole are wasted to an extreme degree, but this atrophy is most marked in the back and loins, along the longissimus dorsi and in the quarter in the gluteal muscles. The patient may remain recumbent, from sheer weakness, for a length of time at the last, or he may get up after a long recumbency and stand to the end.

Death may occur early with general anasarca and extreme hyperthermia (110° F.). In the great majority it appears to result largely from perforation of the stomach, clots in the heart, or general debility and heart failure.

Diagnosis. With symptoms such as are above described the discovery of the trypanosoma in the blood completes the diagnosis. Trypanosoma is found in dourine, nagana and other affections so that the discovery of it alone would not be conclusive as to the existence of surra. Nor can the discovery of the parasite always be made at the first or second attempt. The swarm of mature trypanosomata is found with the advent of a paroxysm, and as the veterinarian is often called during the decline of the attack the parasites have already retired and elude his investigation. It becomes needful to take the temperature and examine the blood daily sometimes for eight or ten days, and when with a sudden rise of temperature he finds also a swarming of the mature trypanosomata, the diagnosis is perfect. A drop of blood placed on a cover glass, pressed down upon the slide, and placed under the microscope, will show the parasite with eel-like movements among the blood globules. There may be very few during the first or second paroxysm, but they become numerous and very obvious as the disease gains its height. Evans recommends to use defibrinated blood.

They may be dried rapidly on a cover glass, fixed in absolute alcohol one or two minutes, then stained ten minutes in a mixture of the two following liquids united just before using:

A.—ONE PART OF THE MIXTURE.

Methylene blue 1 Grams. Borax 2.5 „ Distilled water 100 „

B.—FOUR PARTS OF THE MIXTURE.

Eosin .1 Grams. Water 100 „

The plasma of the trypanosoma appears blue, the flagellum red and the chromatin of a different shade of red. It may be permanently mounted in balsam.

Mortality. The disease is constantly fatal in horses, though the animal may survive for months.

SURRA IN CAMELS.

Haggar describes this as having remissions or intermissions as in the horse, the trypanosoma disappearing during the intervals to reappear with the hyperthermia. The temperature may rise to 106° F. and the animal wastes away to a veritable skeleton. A remarkable feature of the disease is the formation of immense abscesses containing a thick, cream-colored pus on the sides of the chest in the vicinity of the pad, and in the sheath and scrotum or udder near to the stifle pad. The mortality is nearly as great as in the horse or mule, yet the camel drivers say that a small percentage recover.

SURRA IN BOVINES.

The domestic ox, the sacred cow of India (Lingard) and the water buffalo (caribao) of the Philippines contract Surra. It is interesting to notice that in these animals the disease is relatively mild and recoveries are frequent.

In the Indian buffalo it causes dulness; advancing emaciation; slight temperature variations; muco-purulent inflammations of the conjunctiva, cornea, and pituita; and occasionally eruptions under the breast or belly.

Among lesions were atrophy, softening of lymph glands, enlarged liver and spleen (slight), petechiæ and blood extravasations on the pericardium, epicardium and other serosæ, and on the intestinal mucosa which sheds its epithelium in patches.

Stall enzoötics in cattle do not seem to affect horses casually. The disease is easily conveyed to rabbits, house rats and mice, dogs, cats and apes. Goats and ducks appeared to be immune (Penning).

TREATMENT OF SURRA.

In well established cases in the horse, ass or mule no treatment has succeeded in saving the patient. Almost every germicide has been called into requisition but without good effect. Among these may be named: mercuric chloride subcutem, iodine and potassium iodide intratracheally, iodoform subcutem and intravenously, oleum terebinthinæ subcutem and intravenously, potassæ bichromas by veins and stomach, cinchona alkaloids and arsenic, phenic acid and iodine, quinine, hydrargyri biniodidum, santonin, potash. The claims of different agents, notably arsenic and phenic acid, have been supported by the manifest improvement of condition under their use and the disappearance of the trypanosoma, but both these conditions may often appear during intermissions, without medication. The usual outcome is that the animal dies and the only claim that can be made is a slight extension of life. This is favored by dry, clean, airy stables, change of water, rich grain and succulent food (oats, rice, linseed, barley, gram sorghum, bran, middlings, salt, etc.), with iron, arsenic, and other tonics, yet the best that can be said for them is that they have deferred somewhat the inevitable death.

Prevention of Surra. The first consideration is to avoid placing equines and especially horses and mules, or camels in the infecting localities in the rainy season and just after it. Oxen and buffaloes can be used in such places with greater impunity. If they must be used in such localities, place the stables or pickets in dry locations well apart from marshes, and stagnant water. Keep the stables dark during the surra season, open to light on one side only and with screens in the windows. Make a deep pit for the manure, keep it well darkened and screened and turn every particle of manure into this several times a day so that the stable shall be perfectly clean. All rubbish heaps should be similarly dealt with. The flies breed in the manure and decaying organic matter. After each sweeping of the stable sprinkle the manure in the pit with some disinfectant, phenic acid, tar water, copperas, etc. Smear the skins of the animals with tar water, coal tar water, naphthalin, daily if necessary to prevent the attacks of the flies. Other suggestions in this line can be found under parasites.

An important consideration would be to seclude every animal attacked with surra. The flies can only carry and inoculate the poison when there is some source from which they can obtain it. Until we shall learn how many animals, tame and wild, casually contract the Trypanosoma Evansi we cannot speak of how effective this may be made, but it is at least a substantial advance in the line of restriction, since the infected horse or mule in the vicinity of healthy ones is a constant peril, and as given insects attack by preference, given favorite genera, the horse flies, coming from the diseased animal are much more likely than other flies to attack the sound horses. In a surra season it would be a wise economy to destroy the infected equine at once, as according to all past experience, sentence of death has already been passed upon him, and his preservation even for a hour is hopeless for him, but full of the gravest danger for others. The carcass and all pertaining to it, blood especially, should be promptly and deeply buried and the place thoroughly disinfected.

In the same way smudges made by burning green grass or other vegetation, tar, leather or other material producing empyreumatic products offensive to the fly may be employed.

Sanitary Police. The Department of Agriculture forbids the landing in the United States or its dependencies of any animal from the Phillipines. If the infection should by any accident be imported no cost should be considered too high to secure a prompt and thorough extinction of it.

NAGANA. TSETSE FLY DISEASE.

Trypanosoma Brucii: attacks horse, ass, mule, cattle, buffalo, antelope, camel, hyena, dogs, etc. Elephants and zebra, pigeon and hen immune. Tsétsé fly. Inoculation only certain channel; virulence in dead body 24 hours; in vitro 3 to 4 days, or when dried or heated (122° F.) Symptoms: hyperthermia; anæmia; leucocytosis; buffy coat; œdemas; catarrhs; wasting; debility. Lesions: as in surra; trypanosoma in blood at intervals, bone marrow, lymph glands, spleen. Immunizing unsuccessful. Prevention as in surra.

This is an infective disease caused by the Trypanosoma Brucii, which has been supposed to be identical with Trypanosoma Evansi but differs in its morphology and in its infectiveness toward a greater variety of animals. It is 25 to 30μ long by 1.5 to 2.5μ broad, less pointed at its posterior (nonflagellate) end, broader undulating membrane, more deeply staining protoplasm, and more sluggish movements. It invades the blood of horses, asses, mules, cattle, buffaloes, antelopes, camels, hyenas, and dogs, and can be inoculated on cats, rats, mice, rabbits, hedgehog, boshbok, zebra hybrids, Guinea pigs, goats, sheep, weasel, and monkey (Macacus rhesus). Elephants are immune though they suffer from T. Evansi, and the zebra is immune though a soliped.

The tsetse fly (glossina morsitans) is credited with being the main agent in transmitting the parasite to mammals, (see Diptera).

Kauthack, Durham and Blandford found that Guinea pigs were more resistant than rabbits, surviving the inoculation for a longer time. Bruce also found the native South African sheep and goats more refractory than others, yet their hæmatozoön was as deadly to other animals as that of horse or dog. Pigeons and South African hens proved refractory. Manifestly in Africa the present races of some animals are the products of the survival of the fittest.