Standardisation of the haemagglutination test for peste des petits ruminants (PPR)

The different conditions which affect haemagglutination (HA) by peste des petits ruminants (PPR) virus were investigated. The conditions investigated include how sensitive red blood cells (RBCs) of different animal species are to the PPR haemagglutinin, the agglutination time for the chicken RBC, the temperature at which PPR virus gives the highest HA titre and the effect of temperature of the specimen containing the PPR virus on the HA titre. Human group “O” RBCs were found to give the highest HA titre when compared with chicken RBC, goat RBC, pig RBC and dog RBC using the same specimen (antigen) and under the same conditions. Following human group “O” in sensitivity were chicken RBC, goat RBC and pig RBC in descending order. Dog RBC was completely insensitive (i.e. gave no HA reaction). For chicken RBC, mean agglutination time was 25 min, when HA test was done at 25 ◦C (room temperature). When phosphate buffered saline (PBS) was used at different pH levels, highest HA titre was obtained at pH 6.8. Higher HA titre was obtained when the test was done at 4 ◦C than when it was performed at 25 ◦C. Temperature of the specimen just before the test was done, had no effect on the HA titre. So, it has been recommended that to make HA test for diagnosis of PPR standard, it should be performed with either human group “O’ or chicken RBCs. The diluent for the test should be PBS of pH 6.8 and the test should be performed at 4 ◦C. It should be read within 1 h of setting-up the test. © 2003 Published by Elsevier B.V.