Prevalence of Actinobacillus pleuropneumoniae infection in hunted wild boars (Sus scrofa) in Germany.

Actinobacillus pleuropneumoniae is an important pathogen of the porcine respiratory tract. Subclinically and chronically infected pigs may enter a permanent carrier state, harboring A. pleuropneumoniae in lungs or tonsils. Despite the enormous role of A. pleuropneumoniae in domestic swine production, no published data about prevalence and distribution of A. pleuropneumoniae infections in wild boars (Sus scrofa) are available. Antibodies against A. pleuropneumoniae have been detected in serum of wild boars from Slovenia. The aim of the present study was to evaluate A. pleuropneumoniae infection status in wild boars in Germany. Tissue samples from lungs and tonsils of 531 wild boars from 52 hunts during the hunting seasons 2004-05 to 2006-07 were examined for A. pleuropneumoniae by polymerase chain reaction (PCR). Although gross pathologic lesions typical for pleuropneumonia were not detected, 35.8% of the wild boars were PCR-positive. Tonsils were involved in 94.3% and lungs in 15.5%. Actinobacillus pleuropneumoniae infection prevalence increased with age and body weight. Further research is needed to understand the involvement of different A. pleuropneumoniae serotypes and to understand the interrelationship of A. pleuropneumoniae infection between wild boars and domestic pigs.

Qualitative and quantitative distribution of PCV2 in wild boars and domestic pigs in Germany.

Porcine circovirus 2 (PCV2), the causative agent of postweaning multisystemic wasting syndrome (PMWS), has been detected in North American and European wild boars at prevalences arguing for high circulation rates among populations. Systematic data on the qualitative distribution of PCV2 infections and on PCVD (PCV2 diseases) in wild boars are rare, however, and quantitative data about viral loads are missing. To be able to judge the PCV2/PCVD situation in wild boars, evaluation of the nationwide qualitative and quantitative distribution of PCV2 and PCVD in Germany was the objective of the present study. Wild boar samples were compared with domestic pig samples of the same greater areas, including tonsils, lungs, spleen, Lnn. bronchiales and Lnn. mesenterici of 349 wild boars and 348 domestic pigs. All of the wild boars and 308 of the domestic pigs have been apparently free of PCVD, 40 of the domestic pigs had been rejected from slaughter due to health problems (i.e. wasting). Tissues were examined by pathohistology, immunohistology (IHC), nested PCR (nPCR and quantitative PCR (qPCR). One wild boar (0.3%) and 8.7% of the domestic pigs were classified as PCVD-affected, based on pathohistology and IHC. PCV2 DNA was detected in 63.1% and 45.4% of the wild boars by nPCR and qPCR, respectively, and in 100% and 98.8% of the domestic pigs. PCV2 loads differed significantly between wild boars (average: 10(2.8) PCV2 genomes/microg extracted sample DNA) and domestic pigs (average: 10(4.2) PCV2 genomes/microg of sample DNA). The qualitative detection of PCV2 DNA in tissues of wild boars and domestic pigs was abundant and not of any pathological relevance. The overall load of PCV2 in domestic pigs was relatively high and borderline with respect to PCVD, and there was no difference between apparently healthy pigs and pigs rejected from slaughter in this respect. Most of the wild boars were infected with PCV2 at loads less relevant for PCVD.