Ultrastructural pathology of nasal and tracheal mucosa of rabbits experimentally infected with Pasteurella multocida serotype D:1

Abstract

Sixteen 8- to 9-week-old Pasteurella multocida-free New Zealand White rabbits were divided into two equal groups. The first group was inoculated intranasally with P multocida serotype D:1 strain and the second group that was inoculated with phosphate-buffered saline (PBS) only was used as a control group. Pasteurella multocida was isolated from the nasal cavity of all infected rabbits in group 1 and from tracheal swabs of seven rabbits in this group. Four rabbits in group 1 died with clinical signs of septicaemia, two rabbits had mucopurulent nasal discharge and pneumonic lesions and the other two did not show any clinical signs or gross lesions. The ultrastructural changes detected were deciliation or clumping of cilia of ciliated epithelium, cellular swelling, vacuolation and sloughing. The subepithelial capillaries showed congestion, intravascular fibrin deposition, platelets aggregation and endothelial injury. Pasteurella multocida was observed attached to the injured endothelial cells. Heterophils, mast cells, vacuolated monocytes and macrophages infiltrated the lamina propria and between the degenerated epithelial cells.

Serological Response to Pasteurella multocida NanH Sialidase in Persistently Colonized Rabbits

“…In the challenge with isolate P-1059 described in this report, we observed a rapid infection phenomenon in which the rabbits were clinically ill within 30 h after intranasal exposure to a low bacterial dose. Similar results have been reported by others using P1059 and other virulent P. multocida isolates in rabbits (1,3,4). These infections might be detectable by PCR or culture because of the high replication rate of the bacteria in the host tissue (35).…”

“…Figure 2 illustrates the putative phases of P. multocida respiratory colonization and potential infection of rabbits. Exposure to virulent, invasive strains may result in rapid penetration of the respiratory mucosa, leading to peracute or acute disease (1,3,36,46). In the challenge with isolate P-1059 described in this report, we observed a rapid infection phenomenon in which the rabbits were clinically ill within 30 h after intranasal exposure to a low bacterial dose.…”

Pasteurella multocida: from Zoonosis to Cellular Microbiology

“…Symptoms of pasteurellosis in most animals range from mild to severe (44, 178,[189][190][191][192][193][194][195][196][197][198]. Mild symptoms include sneezing, copious mucous secretions, mild rhinitis, mild pneumonia with labored breathing, and fever but can progress to disseminated disease (hemorrhagic septicemia [further discussed in "Pasteurellosis and Hemorrhagic Septicemia" below]) and/or atrophic rhinitis (atrophy of nasal mucosa, seromucinous glands, and turbinate bones) associated with toxinogenic strains.…”

Signaling Cascades of Pasteurella multocida Toxin in Immune Evasion

“…While the original publications on the toxigenic infections or PMT treatment of animals provided no evidence of an inflammatory process, other animal models showed that PMT treatment causes inflammation [63,64]. In addition, our in vitro data using macrophage cell lines or primary bone marrow-derived immune cells show that PMT triggers the production of various pro-inflammatory cytokines [65,66].…”