PALUDISM IN DOGS. MALIGNANT PROTOZOAN JAUNDICE.
Distribution: Senegal, Lyons, E. Africa, Paris, Pas de Calais, Cape Colony. Microbiology: piroplasma: differentiation from that of Texas fever: pathogenesis: tick-borne. Symptoms: incubation 3 to 5 days; dulness, prostration, apathy, drowsiness, anorexia, thirst, hyperthermia, icterus, hæmoglobinuria, offensive odor, emaciation, protozoön in globules, loss of globules. Death in collapse. Lesions: body shrunken, emaciated, fœtid; dark tissues, mahogany yellow, petechiæ, enlarged congested liver and spleen; muco-enteritis; bloody urine. Treatment unsatisfactory. Prevention: keep from tick infested land; clear and cultivate land; smear dog with insecticide ointment when hunting.
In certain malarial districts dogs suffer severely and even fatally from a febrile affection in which violent shivering is followed by great hyperthermia and yellowish or brownish red discoloration of the visible mucosæ. It was frequently attributed to malaria, and even sought to be identified with intermittent fever in man. Marchoux in 1899 studied this disease on the malarious seaboard of Senegal, and recognized the existence of hæmoglobinuria and the presence in the red globules of a hæmatozoön. Leblanc, about the same date, found a protozoön in the blood of dogs at Lyons, suffering from “red water,” and Koch later found a double piroplasma in the red globules of suffering dogs in East Africa, both considering the disease analogous to Texas fever in cattle. Nocard and Almy in 1901, at Charenton, Paris, met with a similar affection in a dog which had just returned from a fox hunt, and was covered with ticks. Its urine was brownish red, like coffee-grounds, and highly charged with albumen and hæmoglobin. Many of the red globules were affected and contained minute, spherical refrangent bodies which, when stained with carbolized thionine, appeared like those of Texas fever. There were but 2,800,000 red globules in a cubic millimetre of blood.
The injection of 5 grammes of the blood into the jugular of an aged bitch caused in the 3d day hyperthermia (105° F.) and an extensive invasion of the red globules which still counted 6,100,000 per mm. On the 4th day the animal was thoroughly prostrated, refused to eat, had hæmoglobinuria, and many individual red globules enclosed from 4 to 8 hæmatozoa each. On the 5th day the count of the red globules was but 4,400,000 per mm. By the 6th day the urine was nearly normal, and appetite returned, but the red globules counted but 3,500,000 per mm. Menveux went to Pas de Calais with an Irish setter to hunt rabbits. The dog came in every night covered with ticks. In 5 days he sickened, with extreme prostration, diarrhœa and red urine and died on the 25th day.
Wm. Robertson describes the disease in Cape Colony. The piroplasma was first identified at Grahamstown by Purves and successfully inoculated by Spreul. By intravenous inoculation symptoms appeared on the fourth day and death followed about the sixth, while by subcutaneous inoculation the course was slower and the animal died about the eleventh day. Robertson inoculating from animal to animal carried it through a succession of thirteen dogs all of which perished. He found the blood to be infecting on the third day after inoculation subcutem, and the globules invaded on the fourth. They were especially numerous in blood taken from the spleen.
Microbiology. The protozoön resembles that of Texas fever, but is larger, longer, less pyriform, and more like an oat seed, staining slightly in the centre which shows one clear spot, and more deeply at two or three places in the margin. It stains well with carbol thionine blue or methylene blue, but not readily with hæmatoxylin. The dog’s blood, containing abundance of parasites, failed to infect horse, sheep, ox, cat, fowl, Guinea pig, rabbit, rat or mouse (Robertson).
Robertson found the ticks on every affected dog which had contracted the disease by simple exposure and which came under his observation. Specimens sent to Neumann were identified as Hæmaphysalis Leachi. Mature ticks from an infected dog were preserved and their eggs hatched in an incubator. The resultant six-legged larvæ, placed on susceptible puppies a month old proved harmless and no protozoa appeared in their blood. This was repeated when the same generation of ticks had reached the stage of nympha, and it was after two months from the hatching that the ticks, now mature, when placed on the same puppies conveyed the disease. On the thirteenth day the temperature reached 105° F., and the red globules swarmed with parasites, many single globules containing no fewer than eight. They were of various shapes, spherical, pyriform or cloveshaped many tapering finely toward the ends like an oat. The puppies died respectively 14 and 18 days after infection.
Experiments made on other dogs with the larval and mature ticks, fully confirmed the conclusion that the immature insect was harmless. A 14 days old puppy infected by mature ticks died on the 11th day so that the immunity of the other puppies cannot be due to a milk diet, as in the case of calves and Texas fever. Intravenous inoculation with the infected blood invariably conveyed the disease.
Symptoms. On the third day after inoculation the dog is dull, prostrate, apathetic and drowsy, refuses food and shows thirst. Temperature may reach 103° to 106° F. On the fourth day the mucosæ assume a yellowish tinge, and by the fifth this has encreased to a deep chrome yellow, which involves any white portions of the skin as well. Hæmoglobinuria is now well developed, the liquid being often as dark as claret, and the patient may lie perfectly prostrate, giving off an offensive odor from the skin, lungs, and especially from the mouth. The tongue is furred, the teeth dirty, and the gums may be congested or even ulcerated. Emaciation advances rapidly. The temperature may oscillate from day to day or it may rise steadily to a climax, and then descend suddenly when collapse occurs. In all cases the protozoön is found in the red globules, or free in the blood. In the worst cases the red globules may be so reduced in number that they can scarcely be found. Death comes usually by collapse. In some instances the hæmoglobinuria may be absent yet the disease advances to a fatal result.
Lesions. The carcass is usually shrunken and emaciated and exhales a fœtid odor. The mucosæ, white skin, and all naturally white structures (fat, connective tissue, fascia, tendons, ligaments, brain, spinal cord, etc.), are stained of a deep yellow. The muscles, liver and other darker tissues are of a mahogany yellow; petechiæ appear on the heart and serosæ; the liver is greatly enlarged and friable (10 lbs.) the spleen is swollen, gorged with blood and a soft, black, bloody pulp; the stomach and small intestines are empty, yellow and sometimes congested. The large intestines show muco-enteritis throughout with an abundant rusty red exudate. The kidneys are yellowish with cortex somewhat pale. The bladder also yellow contains dark colored urine. The red blood globules are greatly diminished in number, many are crenated, broken up and distorted and they contain the piroplasma in large numbers.
No system of treatment has proved successful. Essays would naturally be made with quinia and other antiperiodics.
Prevention would naturally be sought in keeping dogs off from the uncultivated land and brush during the tick season (summer, autumn), in clearing and cultivating the tick infested pastures, in drainage, or in smearing the coat of the dog with the oil of tar liniment or other insecticide when he goes hunting.