Through the examination of co-infeCted bacteria in 245 pigs infected with PRRS virus in Bac Giang province, the results showed that: - The infection rate of Actinobacillus pleuropneumoniae was rather high (19.59 percent), in which the highest prevalence was found in 1.5 to 3 month old piglets (26.67 percent). - 35 isolated A. pleuropneumoniae species were belong to serotye 2 (72.92 percent)
10 species belong to serotye 5a (20.83 percent) and 3 species belong to serotye 5b (6.25 percent). - The A. pleuropneumoniae isolated species have all typical biological characteristics. - All A. pleuropneumoniae isolates had high toxicity, among them 9/12 species killed 100 percent experimental mice after 18-36 hours and 3/12 species killed 50 percent mice after 18-48 hours.