Key Technical Points for the Prevention and Control of Pseudomonas Infection in Mink

Pseudomonas infection in mink, also known as mink Pseudomonas aeruginosa infection or mink hemorrhagic pneumonia, is an acute infectious disease of mink caused by Pseudomonas aeruginosa of the genus Pseudomonas. The disease is characterized by difficulty breathing, hemorrhagic pneumonia changes and pulmonary edema, and hemorrhagic pathological changes in organ tissues, and often occurs as an endemic.

1. Pathogen

The pathogen of this disease is Pseudomonas aeruginosa, also known as Pseudomonas aeruginosa, which is widely present in nature, and exists in animal feces, water and sewage. Gram-stain negative. Cultured on ordinary medium, it can produce yellow-green pigment, hence the name Pseudomonas aeruginosa.

2. Epidemiological characteristics

Mink is the most susceptible fur-bearing animal. Laboratory animals such as rabbits, guinea pigs and mice are all susceptible. The main sources of infection are contaminated meat feed, diseased mink and carrier mink. In addition, due to irrational use of antibiotics, bacteria resistant to Pseudomonas aeruginosa are suppressed, causing Pseudomonas aeruginosa to multiply in large numbers and resulting in the disease. The main routes of infection are the oral cavity and respiratory tract. This disease mostly occurs in autumn, most commonly in October. High-contact transmission is the epidemiological characteristic of this disease, because October is the molting season, and the flying down is easily transmitted to healthy mink.

3. Clinical symptoms

In natural infection, the incubation period of this disease is 1 to 2 days, or as long as 4 to 5 days. According to the course of disease and pathological changes, it can be divided into acute type and hyperacute type. Most infected mink often die without obvious symptoms; on careful observation, only lethargy, anorexia, short and difficult breathing, convulsions and blood-colored fluid flowing from the mouth and nose are seen. Acute cases often show abdominal breathing, abnormal sounds, blood-like fluid flowing from the nostrils, blood-like contaminants around the mouth and nose, and blood stains are often seen under the cage. The course of disease is as short as a few hours and as long as 1 to 2 days, and the mortality rate is almost 100%.

4. Anatomical and pathological changes

Hemorrhagic lesions in the lungs are the main feature. The lungs are enlarged and hemorrhagic, dark red, with dense lung tissue and liver-like hardness; when cut open, a large amount of blood-like foam flows out. The trachea and bronchi are pink. The affected lungs sink when placed in water. Gray small nodules are often present in the affected areas, with pleural effusion and enlargement of the hilar lymph nodes. The spleen is enlarged and red-purple. The liver is pale and dry. The stomach and duodenum often contain blood-like fluid; the blood flows in from the nose before death.

5. Diagnosis

A preliminary diagnosis can be established based on epidemiology, symptoms and pathological necropsy. Pulmonary hemorrhage and pulmonary edema are the main features that distinguish this disease from other diseases. Confirmation requires bacteriological examination: first, culture examination for the presence of pigment; second, animal inoculation to see whether toxicity is present. If green pigment can be produced, inoculation kills mice, and a pure culture of Pseudomonas aeruginosa is isolated, then a confirmed diagnosis can be made.

6. Prevention and control

(1) Prevention: Vaccination can be used to prevent this disease, but a successful vaccine has not yet been developed. When the disease occurs, immediately isolate diseased mink and treat with antibiotics until the pelt-taking period for pelting. Thoroughly and repeatedly disinfect contaminated cages, floors and utensils. Burn cages with a flame torch, taking care to burn off all down. Scrub the small chambers with 2% alkali solution. Prevent mink from escaping and contact between personnel.

(2) Treatment: Streptomycin 100,000 units, intramuscular injection, twice a day, for 7 consecutive days; gentamicin 20,000 units, intramuscular injection, twice a day, for 7 consecutive days; administer sulfamethoxazole to the whole group, 0.3 to 0.5 grams per mink, mixed into the feed for feeding. In addition, polymyxin and neomycin also have good effects.