Dog Diseases – Canine Demodicosis
Canine demodicosis is also called trichomoniasis or lipoidosis. It is a common and stubborn skin disease caused by demodex canine parasites on sebaceous glands or hair follicles. It usually occurs in puppies between 5 and 10 months of age.
Pathogen and life history
Demodex canine is translucent and milky white. The body is narrow and long like a worm, with a body length of 0.25～O. 3 mm. It is about 0.04 mm wide and can be divided into three parts: front, middle, and back from the appearance. The mouthparts are in the shape of a shoe in the front. There are 4 pairs of very short feet in the middle. Each foot is composed of 5 segments. The back part is slender and the surface is densely covered with horizontal stripes.
All the developmental process of Demodex canine is carried out on the dog’s body. Including 4 stages of egg, larva, nymph, and adult, nymph has 3 stages. Demodex canine is mostly parasitic on the upper part of the affected skin hair follicles. Then turn to the bottom. It is rarely parasitic in the sebaceous glands. In addition to being parasitic in the hair follicles, it can also live in the tissues and lymph nodes of the dog. And some breed in it.
(1) Clinical symptoms
① Scaly type mostly occurs in the eyelids and their surroundings, corners of mouth, forehead, nose and lower neck, elbows, and between toes. Hair removal on the affected area. Accompanied by mild flushing of the skin and silvery white sticky dander, the skin appears slightly rough and cracked, or with small nodules. Later, the skin was blue-gray-white or copper-red, the affected area was hardly itchy, some remained unchanged for a long time, and some became pustular.
②Pustular type usually occurs in the neck, chest, inner thigh and other parts, and spread to the whole body in the later stage. Large areas of hair loss on the body surface, large areas of erythema, and thick skin, often forming wrinkles. There are diffuse pustules from millet to wheat grains, the pustules are blue-red, pus is discharged when squeezed, and contains a large number of demodex mites and eggs. After the pustules rupture, they form ulcers, scabs, and have unpleasant smells. stench. Pustular type has almost no itching. If there is a severe itching, it may be a mixed infection. The sick dog eventually died of exhaustion, poisoning or sepsis.
(2) Laboratory examination: Cut through the nodules or pustules on the skin, and take the contents for smear microscopy. If the parasites are found, the diagnosis can be confirmed.
Isolate and treat sick dogs, and disinfect contaminated places and utensils with acaricides. The following drugs are selected for treatment: Dimethyl ether, the application concentration is 250 ppm, and the body surface is bathed. Ivermectin 200 micrograms/kg body weight, subcutaneously injected. Ivermectin is a broad-spectrum anthelmintic for killing nematodes and arachnid insects, so it should be used with caution in dogs suspected of having heartworm disease to avoid accidents caused by killing heartworms in the heart and causing blockage. 14% iodine tincture, apply to the affected area. In addition to topical application of pesticides to severely ill dogs, antibacterial drugs should also be applied systemically to prevent secondary infections.