A patient with sore throat has a positive Paul Bunnel test. The causative organism is:
High-Yield Explanation
Ans. (a) EBV Paul Bunell test is the standard diagnostic procedure of infectious mononucleosis which is caused by EBV. Paul Bunell test detects heterophile antibody. I'aul buneii lest Heterophile agglutination test: In this test inactivated serum (56degC for 30 minutes) in doubling dilutions is mixed with equal volumes of a 1% suspen- sion of sheep erythrocytes. An agglutination titre of 100 or above is suggestive of infectious mononucleosis. For ti confirmation, differential absorption of agglutinins with guinea pig kidney and ox red cells is necessary Infectious monoucleosis antibody is removed by ox red cell but not guinea pig kidney. The Paul Bunell antibody develops early during the course of infectious mononucleosis, and disappears within two months. False-positive: In patient with lymphoma, hepatitis, malaria, connective tissue disease. Differential absorption test for Paul-Bunnell antibody Guinea pig kidney Ox red cells Normal serum Absorbed Not absorbed Antibody after serum therapy Absorbed Not absorbed Infectious mononucleosis Not absorbed Absorbed Remembe! - MC cause of heterophile antibody (+)ve infectious mononucleosis is EBV. MC cause of heterophile antibody (-) ye infectious mononucleosis is CMV. Heterophile (-) ve IM is also caused by toxoplasmosis, Listeria, non-infectious stimuli.