How to prevent and treat Klebsiella infection in nutria (coypu) farming?

Klebsiella infection (Klebsiellosis), also known as multiple abscesses, is a sporadic or enzootic chronic infectious disease caused by Klebsiella pneumoniae. (Pathogen and epidemiology) The bacterium is widely distributed in soil, water, and the respiratory and digestive tracts of humans and animals, and can cause disease in humans as well as fur-bearing animals, livestock, poultry and many other animals. The disease occurs mostly in summer and autumn, and young nutria are especially susceptible. In culture media the bacterium is highly pleomorphic, but in infected material it mostly appears as short, thick, oval-shaped bacilli (1—2 micrometers long, 0.5—0.8 micrometers wide), scattered or in pairs, without flagella, non-motile, and able to form a thick, large capsule that is 2—3 times the size of the bacterial body. However, after prolonged culture it loses its viscous large capsule and develops pili. It is Gram-negative and often shows bipolar staining. On ordinary agar medium it forms milky-white, moist, glistening, semi-transparent, mucoid, perfectly round colonies. With continued culture, some colonies fuse into a mucoid mass that can be drawn into threads with an inoculating loop; after 3—4 days on slant agar, the bacterial growth flows down to the lower part of the slant like honey; after several days in broth, it grows into a mucoid mass. (Clinical symptoms) The disease usually takes a chronic course, and early clinical symptoms are not obvious; only localized round or oval abscesses appear on the body, mostly on the hind limbs, tail, under the jaw, forelimbs and back, and occasionally on the tip of the nose. Some abscesses rupture and discharge thick, grayish-white pus with a foul, fishy odor. Necropsy reveals abscesses ranging in size from a soybean to an egg and of varying hardness; when cut open, the center contains grayish-white viscous pus surrounded by connective tissue. Affected nutria gradually become emaciated; in the middle and late stages of the disease, appetite decreases or is completely lost, and young nutria often develop hind limb paralysis. (Diagnosis) A preliminary diagnosis can be made based on the typical symptoms, but confirmation requires further bacteriological examination and biochemical tests.

(Prevention and control measures) At present there is no effective Klebsiella pneumoniae vaccine. Strictly implementing veterinary hygiene regulations, strengthening sanitation and disinfection of the nutria house, and especially ensuring clean bath water and preventing external injuries to the nutria's body, along with strict quarantine when introducing breeding stock, are important measures for preventing this disease. If Klebsiella infection has already occurred, both local and systemic treatments should be used simultaneously.

① Local treatment: Incise the abscess in the affected nutria, drain the pus, clean with 3% hydrogen peroxide and 0.1% Rivanol, then apply 3% iodine tincture, and finally dust with anti-inflammatory powder. The tail and hind limbs can be bandaged. Drain the pus and clean once daily in this way, and take care not to let the affected nutria enter the water pool.

② Systemic treatment: Mix furazolidone into concentrated feed at a dose of 0.5 tablet per animal and feed it, twice a day; at the same time, inject chloramphenicol intramuscularly at 0.5 mL per animal, twice daily, for a 6-day course of treatment.