Diagnosis and control of leptospirosis in pigs

An outbreak of diseases characterized by jaundice, hemoglobinuria and subcutaneous edema in a pig farm in Shuimogou District of Urumqi was diagnosed as porcine leptospirosis according to epidemiology, autopsy, bacteriological examination and animal experiments. The report is as follows.

1 morbidity

Wang Mou, a farmer in Shuimogou District, Urumqi City, raised 147medium pigs with average weight of 40~50kg, one died suddenly, 3 died 2 days later, 2 died 3 days later, and a total of 34 pigs died 12 days later, with a mortality rate of 23.2%. The livestock owner claimed that due to the newly built enclosure, the ground was wet and the temperature was 20: 22 ℃. When the temperature outside the house drops, the number of rats increases obviously and often goes in and out of the feeding trough.

2 clinical symptoms

The body temperature of diseased pigs increased by about 40.5 to 41.5 ℃, stuttering, refusing to eat, convulsing, convulsing, shaking, standing unsteadily; individual constipation, partial diarrhea; brown or blood-colored urine; yellowish skin; yellow staining of eye conjunctiva and sclera; 4 dead pigs had edema of face, subjaw and neck; 6 pigs died of acute death, and the others all died within 2-3 days after the occurrence of elevated body temperature.

3The change of dissection.

The skin is yellowish, muscle anemia, neck subcutaneous edema, subcutaneous fat yellow staining; pleural and pericardial effusion, occasional bleeding in the endocardium of the heart; thin blood; enlarged lungs, yellowish yellow; gallbladder filling; mesenteric lymph node enlargement; kidney occasionally spot gray-white necrotic focus; gastric wall edema; bladder urination, showing brown or blood color.

4 laboratory inspection

The main results were as follows: (1) the cardiac blood, pleural effusion, liver and kidney tissues were aseptically collected and examined by dark field microscope, and various rod-shaped Leptospira were found with different shapes, active movements and hooks at both ends or one end. The smears of heart blood, liver, spleen and kidney of dying pigs were collected aseptically, stained with silver plating and examined by dark field microscope, and a large number of filamentous, brown-black, hook-shaped and round rods were found.

(2) Heart blood, liver, kidney and spleen tissues were aseptically collected and inoculated with Schiffner's medium and cultured for 25 ℃. Every 5 days, mild opacification was observed on the 15th day, followed by dark field microscopic examination, and the results were the same as the disease material pressing tablets.

(3) under the condition of strict isolation, 5 guinea pigs weighing about 150 ~ 200g were injected intraperitoneally, and 5 control guinea pigs with the same weight were injected intraperitoneally with Schiffner's culture medium 0.25ml. Results the control group was still alive after 7 days, while in the experimental group, the body temperature increased gradually 24 hours after inoculation, which was 0.5-1.0 ℃ higher than normal, stuttering, anorexia, yellow staining of conjunctiva, yellowish skin, hemoglobinuria, and all died within 120 hours. The autopsy showed typical subcutaneous tissue, yellow skin, enlarged liver, kidney swelling scattered in the necrotic focus, pleural effusion, ascites and urinary bladder were brown or blood.

(4) Heart blood, liver, spleen and kidney tissues were aseptically collected, and the dark field was pressed for direct microscopic examination, and a large number of fine filamentous, athletic, hook-shaped rods were found at one or both ends. According to the comprehensive analysis of epidemiology, clinical symptoms, changes of autopsy, etiological examination and animal experiments, leptospirosis was diagnosed.

5 Prevention and control measures

(1) doxycycline, 20mg/kg weight day, mixing for 7 days.

(2) Bizhi (gentamicin sulfate + TMP) 10mg/kg weight per day, twice a day, intramuscular injection for 5 days.

(3) 295g oral rehydration salt, 10 bags a day, drinking water for 7 days.

(4) the enclosure was thoroughly cleaned, 0.1% sodium hydroxide was disinfected for 7 days, and the cinder was sprayed to absorb moisture.

(5) put rat poison "Quick Arrow" in an all-round way. After the above treatment, the death of pigs stopped after 12 days.