Comparison of serological tests for the detection of leptospira antibodies in immunised animals
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Date
1980
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Department of microbiology, College of veterinary and animal sciences, Mannuthy
Abstract
Leptospirosis is a widespread disease of man and animals and is of considerable economic importance besides being a public health problem. The leptospira infection in man and animals may be confirmed either by isolation of the organisms or by detection of specific antibodies in the serum and tissues of infected animals. Isolation of Leptospira is time consuming and beyond the scope of many diagnostic laboratories.
In the present study the sensitivity of passive haemagglutination test was compared with the established microscopic agglutination test utilizing rabbit hyperimmune serum as the source of antibody.
Leptospira serotypes were grown in Korthof’s medium enriched with 10% haemolysed rabbit serum. By 7 – 10 days satisfactory concentration of the organisms was obtained and was used for MA test. Passive haemagglutination test was carried out employing ethanol extracted antigen from concentrated leptospiral cultures. The PHA test was carried out after determining the optimum dilution of antigen required to sensitize sheep erythrocytes.
Hyper immune sera to both serotypes were raised in rabbits by a series of intravenous inoculations. Serum samples for antibody titration was collected at weekly intervals from seven days following the first injection till the 49th day.
Antibody titration by MA and PHA tests have shown that all the three animals inoculated with L. autumnalis had a uniform titre of 1:400 on the seventh day whereas the other three animals inoculated with L. pyrogenes showed a low titre of 1:100 by MA test. The PHA titre of both the groups remained the same ie 1:5. The maximum titre of 1:28000 for L. autumnalis was attained on the 21st day and remained unchanged until 35th day. The maximum PHA titre was attained only on 35th day (1:160). The rabbits inoculated with L. pyrogenes showed a maximum titre of 1:3200 by MA and 1:80 by PHA. The results obtained tend to show that PHA titres after reaching the maximum level remained detectable for longer period when compared to MA titres.
Erythrocyte sensitizing substance from both the serotypes and the sera samples collected periodically from immunized rabbits were preserved at – 200 C at varying length of time upto three months. There was no deterioration in the stability or potency of ESS or sera on storage.
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Citation
170085