RAPD analysis of H. parasuis strains using primer 2 (panel A), primer 7 (panel B), and primer 12 (panel C). Reference strains A-O are described in Table 1. Reference strains were obtained between 1978 and 1990. Field strains 1–31 are described in Table 2. Field strains 1–24, 25–29, 30–31 were obtained in 2004, 1999, and 1984, respectively. Each lane was loaded with 10 μl of PCR amplification product containing approximately 30 ng of DNA. A DNA control (no cells) was included in lanes marked “No”. The Standard (Std) was a 1 kb DNA ladder.