| Infectious serositis in geese caused by Riemerella anatipestifer (R. anatipestifer) is an epizootic infection in goose industry resulting serious economical losses. Primarily outbreaks in young and growing goose aged 1-8 weeks was characterized by deposition of fibrin on the surface of liver and heart in gosling and fluid in the abnormal cavity and chest cavity, with the morbidity was 90% and the mortality 10%-40%. Septicemia anseru exsudative in geese was first described by Riemer in 1904 and the pathogen isolated was named as Pasteurella septicaemia. Latter, the bacteria was the same as pathogen of Infectious serositis in ducks, in memory of Riemer, and classified taxonomically Riemerella anatipestifer. Twenty-one serotypes of R.anatipestifer have been identified and no cross-protection has been reported in host infected by more than one serotype. R.anatipestifer is susceptibility to antibiotics such as gentamicin, enrofloxacin, Kanamycin. The problem of drug-resistance and residues were important safety problem in waterfowl industry recently because antibiotic are predominantly used for the therapy or prevent. As the goose feeding by grass developed quickly in Chongqing recent years, infectious serositis in geese was outbreaks seriously. Therefore, vaccination or passive protection was needed to prevent and control this disease.In this paper, we repoted the results of the diagnosing on the infectious serositis in geese in Chongqing. The infection was peracute, acute, or chronic in gosling aged 10-50 days old, as occulonasal discharges, poor growth, anorexia, watery diarrhea while nervous manifestation and ataxia. the morbidity was about 40%, followed by the therapy with antibiotics, the mortality was less than 18%.The typical pathologic lesion was found as pericarditis, perihepatitis, and airsacculitis. Bacterium were isolated from a total of six case by chocolate agar plate, and the XJY1,YC3 and XJY2 strains were identified as RA ,which were high sensitivity with gentamicin and neomycin . XJY1 and XJY2 were high sensitivity to cefatrizine, cefazolin and kanamycin. XJY1 and XJY2 strains caused morbidity by 80%, 100%, mortality 60%and 80% in experimental 12-day-old Sichuan White Goose inoculated 5 billions cell for 7 days post inoculation.On experimental infection in the same pet showed that ten-days-old healthy gosling had been infected from the ducks challenged by 0.4ml(8×10~9CPU /ml) of AF bacterium of R.anatipestifer isolated from field clinical ducks via subcutaneous route. The morbidity in the group of ducks challenged was 55 %( 4/8), and the mortality 40% for 7 PID. At necropsy, the other survival 4 ducks, lesions showed the typical pathological lesion of Infectious serositis in ducks. Gosling tested became ill at 1st PID and dead on the 3 PID, mortality was 75 %( 678). Pericarditis and perihepatitis were found in the survival two gosling and all dead gosling. In the group of gosling inoculated AF strain bacteria, the sick gosling was found at 1st PID, and mortality was 100%. All the 6 of ducks and goose each, the control groups, injected with physical solution (PS), grow well and healthly, and non pathological lesion founded at necropsy.The results showed that XJY1 and XJY2 strain bacteria caused infectious serositis for 12-days old duckling of Huabian duck, which were challenged subcutaneously 0.7 ml (8×10~9CPU /ml). The dairy diet of the ducks inoculated with XJY1 cell were decreased from 100% at 48 hours post inoculation, to 30% later, compared with the healthy control group. During 7 PID, the challenge group, 40%(2/5) of the ducks became clinical ill, but, no death. At necropsy, 80% (4/5) of ducks showed pericarditis and perihepatitis. At the XJY2 group, 60%(3/5) of ducks had clinical symptom,40%(2/5) of them were dead, and 2 of the survival 3 ducks showed pericarditis and perihepatitis in 2 ducks.The Microagglutination test (MAT)was developed to detect the antibodies against to R. anatipestifer in goose serum with excellence specific, fast, sensitivity, and the lower cost. R. anatipestifer bacterins inactivated by formalin, the A600 determined to 0.7 was prepared as the MAT antigen. The test was done in the V-type micro well plate and with total volume of 100μL. 5μL of goose serum was added to 95μL of PS and diluted double were reacted with 50μL of RA antigen for two hours at 37℃and overnight at 4℃. The white precipitation point of the bacterins at the centre of the well was a index of positive or negative result of the MAT. The well will be determined to the negative result if white precipitation point at the centre of the well was found and slide down to a line while the plate was vertically. The positive result showed none. Using MAT, XJY1 and XJY2 strain were identified as the same serotype, and the YC3 strain was typed another one. The agglutination will be observe and determined easily so the results tested by MAT showed good reproducibility. More than 10 serums sample can be detected in one microwell plate, so MAT was suitable for screening infection of RA in gosling.The results showed that, using MAT detection, the sera antibody titre against RA in goose immunized with XJY1 bacterins mixed with mineral oil adjuvant increased as gosling growing. All the serum from the gosling, Rongchang White goose, immunized at 6-days old, showed negative results. The average antibody titre of the serum from the gosling immunized at 16,22,30and 50 days old were 4.331og2,7.31og2,9.7 log2and 7.31og2 respectively at 14 PID. The antibody titre of the serum from the gosling immunized at 30-days old reached over 71og2,then, reduced to secondary high titre (over 61og2) retained for 35 days, and became negative. At the 42 PID, all the serum had been negative results.The antibody titer in the serum of the gosling detected by MAT correlated with immunoprotection, but not in a straight line correlation. Two goose serum which the antibody titer detected by MAT were respectively 1:80 and 1:160, collected from the gosling, Sichuan white goose, immunized at 30-day-old with mineral oil ajdvanted AF strain bacterins, were selected to do passive protection experiment. 14-day-old ducklings, Huabian duck, were challenged by 1ml (8×10~9CPU /ml) of AF strain via subcutaneous route, after30min, and injected the goose serum. In the PS injected control group, all the eight ducks were live well and normal at necropsy. At challenged control group, the mortality were 100 %( 8/8). In the group injected goose serum, titre of 1:80, survival rate were zero, 12.5 %( 1/8) and 62.5 %( 6/8) by the dosage of 0.25ml, 0.5ml, and lml. In the goose serum injection group, antibody titre were 1:160, however, survival rate were 0, 50 %( 4/8) by the dosage of 1ml and 2ml.
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