Induction of mycoplasmal pneumonia in experimentally infected pigs by means of different inoculation routes

Abstract

The purpose of this study was to assess the effect of three different inoculation routes into mycoplasmal pneumonia (MP) in pigs challenged with Mycoplasma hyopneumoniae (M. hyopneumoniae). Thirty six-week-old M. hyopneumoniae seronegative piglets were randomly assigned to four groups: three challenged groups with experimentally inoculated pigs by either the endotracheal (ET; n = 8), intranasal (IN; n = 8) or aerosol (AE; n = 8) routes and one uninfected group (Control; n = 6). Blood samples were collected 1 day before challenge and at necropsy, 28 days post-inoculation (dpi), to assess seroconversion. Laryngeal swabs were collected at −1, 7, 14, 21 and 28 dpi in order to evaluate colonization. At necropsy, lung lesions were scored and lung tissue was collected for histopathological studies and M. hyopneumoniae DNA detection. Broncho-alveolar lavage fluid (BALF) was also obtained to detect M. hyopneumoniae DNA, specific IgA antibodies and cytokines. MP was observed in all inoculated groups, but the ET group displayed a significantly higher number of animals affected by MP as well as a higher mean lung lesion score. These results were paralleled with an earlier seroconversion and upper respiratory tract colonization of M. hyopneumoniae. Additionally, in the ET group, higher levels of pro-inflammatory cytokines and specific IgA antibodies in BALF were found. Under the conditions of the present study, MP was reproduced by the three evaluated inoculation routes. Obtained results suggest that the ET route is the most effective in order to induce MP in pigs experimentally challenged with M. hyopneumoniae.

Potential use of local and systemic humoral immune response parameters to forecast Mycoplasma hyopneumoniae associated lung lesions

“…For IgA antibody detection, an alkaline phosphatase-labelled goat anti-porcine IgA polyclonal antibody (Bethyl Laboratories, USA) was used as described previously [15]. Sample absorbance was obtained by reading at 405 nm and results expressed as OD values after subtraction of the mean OD value of BALF from the negative control animals.…”

Influence of pig gut microbiota on Mycoplasma hyopneumoniae susceptibility

“…However, variations in pneumonic lesions remain a challenge [9]. Several confounding variables, including possible maternal and paternal genetic effects have been suggested, which could influence the degree of mycoplasmal pneumonia [9, 11, 12]. A recursive partitioning analysis on determinants for experimental enzootic pneumonia reproduction identified study duration, M. hyopneumoniae strain, age at inoculation, co-infection with other pathogens, and animal source as the most important factors linked to the observed lung lesion score variability [9].…”

Evaluation of the clinical efficacy of a water soluble formulation of tylvalosin in the control of enzootic pneumonia associated with Mycoplasma hyopneumoniae and Pasteurella multocida in pigs

“…Both challenges through intranasal route and scored on Day 28. P values from least square means derived from statistical models route used in the Mhyop-only study [12]. Other factors that could explain this difference are the challenge strain and possibly the use of lung homogenate rather than pure culture as the challenge material [13].…”