Figure 3. Restriction fragment length polymorphism (RFLP) analysis of H2-products amplified with multiplex-nested primer set from seropositive sera. Ethidium bromide–stained polyacrylamide gels of AluI restriction endonuclease digestion of ≈230-bp rickettsial DNA amplified by using the nested primer H set WJ77/80 in the primary reactions and WJ79/83/78 in the nested reactions. Lanes: M, size marker DNA (25-bp DNA ladder); 1, H3-2; 2, H7-2; 3, H8-2; 4, H13-2; 5, H14-2; 6, H15-2; 7, H18-2; 8, H19; P, R. prowazekii; T, R. typhi. P and T; predicted fragments after digestion. The number on the left indicates the molecular size (in base pairs) of restriction fragments.