Canine demodicosis

Canine demodicosis is also known as folliculosis or lipid mange. It is a common and stubborn skin disease caused by canine Demodex mites parasitizing sebaceous glands or hair follicles. It mostly occurs in puppies between 5 and 10 months old.

The pathogen of canine demodicosis and its life history

Canine Demodex is translucent and milky white, with a long and narrow body like a worm, with a body length of 0.25~0.3 mm and a width of 0.25 to 0.3 mm. About 0.04 mm, it can be divided into three parts: front, middle and rear. The mouthparts are located in the front part and are shoe-shaped; there are 4 pairs of very short legs in the middle, each leg consists of 5 segments; the rear part is slender and the surface is densely covered with horizontal stripes.
The entire development process of Demodex canis occurs on the dog body. It includes 4 stages: egg, larvae, nymph, and adult. The nymph has 3 stages. Most of the canine Demodex mites parasitize in the upper part of the hair follicles of the affected skin, and then move to the bottom, and rarely parasitize in the sebaceous glands. In addition to parasitizing inside and outside hair follicles, it can also live in the dog's tissues and lymph nodes, and some of them reproduce therein.

Key points for diagnosis of canine demodicosis

(1) Clinical symptoms can be divided into two types: Scaly type: mostly occurs in and around the eyelids, corners of the mouth, forehead, and nose The head, lower part of the neck, elbows, between toes, etc. There is hair loss in the affected area, accompanied by mild skin flushing and the occurrence of silvery-white sticky scurf. The skin appears slightly rough and cracked, or has small nodules. Later, the skin turned blue-gray white or red copper, and the affected area was almost not itchy. Some remained unchanged for a long time, and some turned into pus scar type.
Pus scar type: mostly occurs in the neck, chest, inner thigh and other parts, and later spreads to the whole body. There is large areas of hair loss on the body surface, large areas of erythema, and the skin is thick and often forms wrinkles. There is a diffuse pus scar rash in dogs from millet to wheat. The pus scar is blue-red, and pus is discharged when squeezed. It contains a large number of Demodex mites and insect eggs. After the pus scar ruptures, it forms ulcers, scabs, and smells bad. The stench.
There is almost no itching in the abscess type. If there is severe itching, it may be a mixed infection. Eventually death occurs from exhaustion, poisoning, or sepsis.
(2) Laboratory examination: Cut the nodules or pus scars on the skin, take the contents for smear microscopy, and the diagnosis can be confirmed if the parasites are found.

Measures for the prevention and control of canine demodicosis

Isolate and treat sick dogs, and use acaricides to disinfect contaminated places and utensils. The following drugs are used for treatment: dimethyl ether, the application concentration is 25Oppm, and the body surface is bathed. Ivermectin 200 micrograms/kg body weight, subcutaneous injection; Ivermectin is a broad-spectrum anthelmintic drug that kills nematodes and spider-loving insects, so it should be used with caution on dogs suspected of suffering from heartworm disease to avoid killing the cells in the heart. Heart meridian worms can cause blockage and cause accidents. 14% iodine tincture, apply to the affected area. In addition to local application of insecticides to severely ill dogs, antibacterial drugs should also be applied systemically to prevent secondary infections.