Page 3 of articles about Haemophilus parasuis - Glasser

It is important to be able to identify the distinct circulating strains and to differentiate between the strains that are merely colonisers and those that have the capacity to produce disease. With this aim various methods of classification of strains or “typing” of H. parasuis have been developed.

When the clinical signs on the farm and the lesions observed in the piglets lead us to suspect that there is a Haemophilus parasuis infection we have to confirm this diagnosis in the laboratory

Haemophilus parasuis is present in all swine producing countries and its prevalence is close to 100% on conventional farms. However, only a percentage of these farms present pathologies associated to the infection.

The factors of virulence allow the pathogenic strains to survive inside the animal and cause the infection, while the non-virulent strains lack these factors and can only survive in the upper respiratory tract as colonisers.

On a conventional farm with no problems with Glässer’s disease, it is possible to isolate various strains of Haemophilus parasuis which colonise piglets while being in balance with the animal’s immunity without producing pathology.

H. parasuis is a gram-negative bacillus of small size, which belongs to the Pasteurellaceae family. The group characterized by fibrinous polyserositis and fibrinous arthritis became known as Glässer’s disease.