Dog Diseases – Visceral Leishmaniasis
Visceral Leishmaniasis is a chronic zoonotic parasitic disease caused by Leishmania(L).donovani which is parasitic on internal organs. According to different sources of infection, Visceral Leishmaniasis is divided into 3 types: human-derived, canine-derived, and wild animal-derived.
Pathogen and life history
Leishmania(L).donovani is parasitic in the reticuloendothelial cells of the blood, bone marrow, liver, spleen, and lymph nodes of sick dogs. The worms in dogs are called amastigotes. It is round. The diameter is 2.4 to 5.2 microns, and some are elliptical, with a size of 2.9 to 5.7 microns × 1.8 to 4 microns. After staining with Wright’s solution, the cytoplasm is light blue and the nucleus is red round. Often leaning to one end of the worm body, the moving base is purple-red, small rod-shaped, located in the center of the worm body or slightly to the other end.
In the body of the transmission medium (sandflies). It is called promastigote (mastigote or droplet type), which is a slender and long spindle shape, 12-16 microns in length, with a free flagellum equivalent to the body length at the front end. In the fresh specimens, the flagella can be seen constantly swinging, and the body movement is very lively. When female sandflies suck the blood of sick dogs (humans) or other diseased animals, the amastigotes are ingested into the stomach of the sandflies. Then it develops into the promastigote in the digestive tract of the sandfly, and gradually concentrates in the mouth of the sandfly. When the sandfly sucks the blood of healthy dogs or other animals, the mature promastigote enters the healthy dog and then loses free flagella. Amastigotes, which follow the blood circulation to reach all parts of the body. After the amastigotes are engulfed by macrophages. Split and multiply in it.
(1) The incubation period of clinical symptoms is several weeks, several months or even more than 1 year. The sick dogs have no obvious symptoms in the early stage. Skin damage often occurs in the late stage. Manifested as hair loss, seborrhea, nodules and ulcers. The head, especially the ears, nose, face and around the eyes are most prominent. Accompanied by loss of appetite, depression, weight loss. Symptoms such as anemia and hoarse voice, and finally died.
(2) Laboratory examination The bone marrow can be extracted from the iliac bone of the sick dog or the diseased material from the ear lesions can be scraped for smear staining examination, and the diagnosis can be confirmed by finding the liduloid body.
First, in endemic areas, the management of dogs should be strengthened, and dogs should be inspected regularly. It is found that the sick dogs are treated in isolation except for particularly precious dog breeds (the treatment usually uses antimony preparations, such as sodium antimony gluconate). Other sick dogs should be culled.
Second, in the epidemic season, in conjunction with the patriotic sanitation campaign, the masses are mobilized to eliminate the breeding grounds of sandfly larvae, and pyrethroid insecticides are regularly sprayed on the kennels and dogs.