Glasserella parasuis: The Causal Agent of Glasser's Disease
Publish Date: May 5, 2022
Glässer’s disease is an important cause of post-weaning morbidity and mortality in swine populations worldwide. The disease was first described in 1910, but the etiological agent was not isolated until 1922. It is a gram-negative bacterium Glaesserella parasuis (G. parasuis), formerly known as Haemophilus parasuis, that belongs to the Pasteurellaceae family (Dickerman et al., 2019). G. parasuis is part of the normal microbiota of pigs and is an early colonizer of piglets. The bacterium can be detected in the trachea, nasal passages or tonsils of piglets as early as two days after birth. Pigs can be colonized by both virulent and non-virulent strains. Although it is normally found in the upper respiratory tract (URT) of pigs, upon disruption of pig’s immune system, it causes Glässer’s disease. The disease is normally observed in 4 through 8-week-old pigs (nursery pigs) but it can sporadically occur in older pigs (Aragon et al., 2019). Weaned piglets are more susceptible because of waning maternal antibodies. Proper diagnosis and typing of isolates is crucial to understand the molecular epidemiology of strains involved and to design better herd-specific autogenous vaccines to control the disease. Knowledge of the circulating strains within or between farms is crucial. Traditionally, serotyping has been the most common typing method, with 15 known serotypes (Kielstein and Rapp-Gabrielson, 1992).
Streptococcus Suis Disease in Pigs
Publish Date: December 6, 2021
The bacteria, Streptococcus suis (S. suis) causes significant disease in swine operations worldwide. In fact, it is now the most common cause of systemic disease in nursery piglets. Furthermore, there has been a marked increase in S. suis cases recently, mainly in herds who have reduced and/or eliminated the use of preventive medications (Poeta Silva, 2021). S. suis colonizes the tonsils of most pigs and is capable of causing disease in the brain via meningitis (brain barrier inflammation) and through septicemia (bloodstream infection), thus reaching other organs. While S. suis is most often associated with meningitis, other manifestations include arthritis, polyserositis (widespread membrane inflammation), endocarditis (heart valve inflammation) and, as a secondary cause, pneumonia (lung inflammation). S. suis is also a zoonotic agent able to cause serious disease (mostly meningitis) in people working with pigs or pork-derived products.