Paratuberculosis
Paratuberculosis (paratuberculosis), also known as johne's disease; Mycobacterium tuberculosis by the Vice-ruminant animals due to chronic gastrointestinal disease, also known as paratuberculosis enteritis. To intractable diarrhea, progressive weight loss, thickening of intestinal mucosa and is characterized by the formation of folds. oie be classified as type b disease.
One. Etiology
Avian Mycobacterium paratuberculosis Mycobacterium paratuberculosis are sub-species, is a slender bacilli, and some were short stick, and some club-like, do not form spores, capsule and flagella, gram-positive.
Vice Mycobacterium tuberculosis resistant to heat and chemicals with the same M. tuberculosis, resistant to the external environment, the pollution of the pasture, manure can survive for several months to a year, and glycerol in milk can be stored in salt water months. Little resistance to moist heat, 60 ℃ 30 minutes or 80 ℃ 1 ~ 5 minutes to kill.
II. Epidemiology
Widely popular in the world of this disease to the dairy industry and beef industry developed countries suffer the most serious. The disease had no significant seasonal, but often occurs in spring and autumn. Was distributed mainly, and sometimes endemic.
The disease primarily in cattle (especially dairy) disease, young cattle most susceptible. Sheep, goats, deer and other animals can also be infected camels, horses, donkeys, pigs have a natural infections.
Sick animals is the main source of infection, symptoms, and the period of sick animals hidden in vitro can row to the bacteria, mainly excreted with the feces, polluting the surrounding environment. Can be excreted with the milk and urine. Animal feed was contaminated feed, water, the digestive tract infections. Young animals can be infected through breast milk or vertically through the placenta and infect the fetus.
III. Pathogenesis
Mycobacterium paratuberculosis after the intestines into the intestinal mucosa and submucosa, in which the breed, causing intestinal damage, initially in the small intestine, later spread to the large intestine, mucosa, submucosa, and epithelial cells produce a large number of classes, tissue , thickening, formation of wrinkles, while oppression Erzhi intestinal glands atrophy, affecting animals, the body digest and absorb other normal functions. Lead to sick animals the body weight loss.
IV. Clinical symptoms
Long incubation period, reaching 6 to 12 months, even years.
The disease is typically chronic diseases, the body temperature does not rise, intractable diarrhea, the clinical features of a high degree of weight loss. At first, intermittent diarrhea, after the development to recurrent intractable diarrhea. Thin fecal odor, with foam, mucus or blood clots. At first, normal appetite, good spirit, after the appetite has diminished, with the progression, sick animals weight loss, orbital subsidence, often lying down, decreased lactation, nutrition highly undesirable, rough skin, loose hair disorder, lower jaw and the hanging visible skin edema. Finally, death due to general weakness.
Five. Pathological changes
After the bacteria invade the intestinal mucosa and submucosa, reproduction, and cause intestinal damage. Main lesion in the digestive tract (jejunum, ileum, colon front) and mesenteric lymph nodes, intestinal mucosa to hypertrophy, characterized by mesenteric lymph nodes.
Mucosal thickening of 3 to 20 times, complicated by blunt curved folds, such as the brain back to the pattern. Mesenteric lymph nodes soft, wet section, there are yellow-white lesions.
VI. Diagnosis
According to typical clinical symptoms and pathological changes can make a preliminary diagnosis, laboratory diagnosis do need to be further confirmed.
Laboratory diagnosis: In international trade, there is no specified diagnosis, alternative diagnostic methods are complement fixation test, delayed type of allergy test and enzyme-linked immunosorbent assay.
Sample Collection: feces and intestinal tissue samples.
Pathogen check: smear microscopy (fecal smear with a Nissl staining luxuriant), bacterial culture.
Serological tests: complement fixation test (detection of suspected cases of clinical effect, but the survey group for screening, lack of specificity of the Act), enzyme-linked immunosorbent assay (check subclinical infection of carrier animals, more sensitive than complement combined test), agar gel diffusion test (can be used clinically suspicious cattle, sheep and goats, vice TB diagnosis), delayed type hypersensitivity (intradermal injection of tuberculin or deputy avian tuberculin-type).
VII. Control
Strengthen management on a regular basis and quarantine, isolation and out of sick animals, disinfection of contaminated barn was sick animals, utensils and so on. |