Fig 1.
Registered outbreaks of enzootic pneumonia in domestic pigs from 2010 to 2013.
The number of outbreaks (N) is indicated for each study area (units A-E) and colors indicate the source of infection. Dark blue: Domestic pig. Grey: Unknown, wild boar unlikely. Light blue: Unknown, wild boar suspected.
Fig 2.
Map of Switzerland depicting the location of the study areas.
The five study areas (units A-E) are indicated by shades of grey. Black lines correspond to canton borders, and blue areas are main lakes. The origin of wild boar (Sus scrofa) samples and their real-time PCR results are indicated by colored dots: Samples negative for Mycoplasma hyopneumoniae are green and positive samples are red.
Table 1.
Study areas (geographical units A-E) and their characteristics.
Fig 3.
Wild boar lungs with and without macroscopic enzootic pneumonia-like lesions (MaEPL).
A: Lung without MaEPL. B: Lung with early type MaEPL (red to dark red multilobular to coalescing consolidated areas affecting less than 50% of the lobe). C: Lung with late type MaEPL (multilobular to coalescing pale purple to grayish areas, showing signs of retraction of parenchyma and atelectasis). D: Lung with late type MaEPL (same as C but with more pronounced fibrosis). Measurement bars = 1cm.
Table 2.
Selected features for the histological assessment of wild boar lungs.
Fig 4.
Detected target groups of Mycoplasma hyopneumonia types in the five study areas.
Data refer to PCR-positive nasal swabs from wild boar. Study areas: units A-E. Dark blue: ABC/REP type. Light blue: ABC-only type. Grey: REP-only type.
Table 3.
Distribution patterns of 52 lungs with macroscopic lesions considered typical for enzootic pneumonia (“EP-like”, early and late types) and PCR results.
Table 4.
Frequency and distribution pattern of recorded histological features in wild boar lungs.
Table 5.
Histological characterization of wild boar lungs classified as early type, late type and without macroscopic EP-like lesions.
Fig 5.
Histological lesions associated with Mycoplasma hyopneumoniae infection and their distribution in wild boar lungs.
A: Lung without macroscopic enzootic pneumonia-like lesions (MaEPL) with moderate multifocal BALT hyperplasia along a bronchiole (measurement bar = 500nm). B: Lung with early type MaEPL and mild to moderate multifocal BALT hyperplasia (black arrow) and diffuse moderate thickening of the interalveolar septa (broncho-interstitial pneumonia). Marginal subpleural atelectasis is considered an artefact (measurement bar = 50mm). C: Lung with early type MaEPL and severe infiltration of mononuclear cells expanding the interlobular septum (thick black arrow) and compressing the regional airways. A discrete hyperplastic lymphoid follicle is also present (thin black arrow, measurement bar = 2mm). D: Lung with late type MaEPL and moderate to severe multifocal BALT hyperplasia (thick arrows), moderate infiltration of the submucosa of the airways (thin black arrow) and mild to moderate multifocal thickening of the interalveolar septa by infiltrating inflammatory cells (measurement bar = 500nm). E: Magnification (20x) of the framed area in D (inset). Intraluminal collection of neutrophils (thin black arrows, measurement bar = 20μm). F: Lung with late type MaEPL and diffuse intraalveolar collection of amorphous eosinophilic material (edema, black arrows) with mild to moderate multifocal lympho-plasmacytic clusters in the interstitium (black circles). Few numbers of mononuclear cells are also observed in the alveolar spaces along with free erythrocytes (hemorrhages, gunshot-related, measurement bar = 20μm).
Fig 6.
Relationship between PCR results and the absence/presence of macroscopic enzootic pneumonia-like lesions in wild boar.
PCR results refer to data obtained with nasal swabs. MaEPL: Macroscopic enzootic pneumonia-like lesions (of early and late type) detected in wild boar lungs. Dark blue: PCR-positive samples. Light blue: PCR-negative samples.
Table 6.
Identified risk factors for Mycoplasma hyopneumoniae infection in Swiss wild boar.