Abstract: Haemophilus parasuis disease is known as leather Las disease (Glasser’s disease), which is a bacterial pig disease, causing pigs serositis, arthritis and meningoencephalitis. Recent years,it shows a worldwide distribution and the existence in most farmsand of China has been confirmed, bringing serious damages to swine industry. There are many serotypes of Haemophilus parasuis, virulences of different serotypes are not same, people know very little of its virulence factors, and less of the pathogenic mechanism, the pathogenic potential virulence factors associated with capsule, pili, lipopolysaccharide, outer membrane proteins, enzymes and so on .In this paper, these virulence factors and pathogenesis of the disease were reviewed in order to provide the scientific basis for prevention and control of the disease.

Key words: Hps; virulence factors; pathogenesis