Regeneration of toxigenic Pasteurella multocida induced severe turbinate atrophy in pigs detected by computed tomography

Abstract

BackgroundAtrophic rhinitis is a widely prevalent infectious disease of swine caused by Bordetella bronchiseptica and Pasteurella multocida. The course of the disease is considered to be different depending on the principal aetiological agents distinguishing B. bronchiseptica induced non-progressive and toxigenic P. multocida produced progressive forms. In order to compare the pathological events of the two forms of the disease, the development of nasal lesions has longitudinally been studied in pigs infected by either B. bronchiseptica alone or B. bronchiseptica and toxigenic P. multocida together using computed tomography to visualise the nasal structures.ResultsB. bronchiseptica infection alone caused moderately severe nasal turbinate atrophy and these lesions completely regenerated by the time of slaughter. Unexpectedly, complete regeneration of the bony structures of the nasal cavity was also observed in pigs infected by B. bronchiseptica and toxigenic P. multocida together in spite of seeing severe turbinate atrophy in most of the infected animals around the age of six weeks.ConclusionsB. bronchiseptica mono-infection has been confirmed to cause only mild to moderate and transient lesions, at least in high health status pigs. Even severe turbinate atrophy induced by B. bronchiseptica and toxigenic P. multocida combined infection is able to be reorganised to their normal anatomical structure. Computed tomography has further been verified to be a useful tool to examine the pathological events of atrophic rhinitis in a longitudinal manner.

Clinical and Economic Impacts of a Commercial Vaccine Containing Recombinant Antigen against Atrophic Rhinitis in Field Conditions

“…It is known that nontoxigenic P. multocida type D has relatively low relevance with turbinate atrophy (Ackermann et al, 1994;Magyar et al, 2013). A limitation of the current study was the absence of differentiation process between toxigenic and nontoxigenic strains of P. multocida type D. However, the correlation between the antigen detection rate (P. multocida type D; positive correlation and B. bronchiseptica; no significant correlation) and nasal lesion scores and significantly improved brachygnathia after vaccination in all three experimental farms indirectly reflects toxigenic clinical influence of P. multocida type D. Colostrum samples of non-vaccinated sows of farm B showed 0% of positive rate of PMT antibodies, which is the quite dissimilar results from farm A and C. This contradictory result could be attributed to the following facts; (i) Prior use of vaccine with an antigenic composition similar with RHINISENG ® has been identified in farm A and C but not in farm B (ii) Natural PMT is regarded as poor immunogen as described by others; PMT constitutes less than 0.6% of total cellular proteins (Liao et al, 2006.;Hsuan et al, 2009).…”

Pasteurella multocida toxin

“…On the other hand, infection with toxinogenic capsular serotype D and some serotype A strains of P. multocida is associated with moderate to severe progressive atrophic rhinitis in swine (see Figure 17.1), which is accompanied by growth retardation and can have a significant health and economic impact [9,14,15]. Furthermore, it has been found that prior exposure to or coinfection with B. bronchiseptica predisposes piglets to colonization by P. multocida and to enhanced severity and progression of atrophic rhinitis and growth retardation [16][17][18][19][20][21][22][23][24]. Other predisposing infections can also exacerbate atrophic rhinitis by P. multocida [25].…”

Comparison of Two Challenge Models of Atrophic Rhinitis in Piglets

“…The Bordetella bronchiseptica treatment followed by Toxigenic Pasteurella multocida infection used in group 1 had been tested on 4-day-old, 34-day-old, 2-month-old and 4-month-old piglets with varying degrees of turbinate lesions [2,7,15,16]. Inoculated the Bordetella bronchiseptica and Pasteurella multocida at the same time used in group 2 had been tested in 6-day-old, 3-week-old, and 6 to 8-week-old piglets with varying degrees of turbinate lesions [8][9][10].…”

“…There are two challenge models combined with Bordetella bronchiseptica and Pasteurella multocida. One model is to treat with Bordetella bronchiseptica followed by Toxigenic Pasteurella multocida infection [2][3][4][5][6][7]. Another model is to inoculate with Bordetella bronchiseptica and Pasteurella multocida at the same time [8][9][10].…”