Fig. 5From: Combination therapy of zinc and trimethoprim inhibits infection of influenza A virus in chick embryoIt shows haemagglutination inhibition test using chicken red blood cells. In A, convalescent serum was added to neutralise the virus, there was no agglutination (−). In B, Tri-Z was added at 5 mcq/ml, haemagglutination occurred but to less extent (++) than that of no treatment in C (++++). In D, no red cells were addedBack to article page