Circoviruses

A randomized controlled study on the efficacy of a novel combination vaccine against enzootic pneumonia (Mycoplasma hyopneumoniae) and porcine Circovirus type 2 (PCV2) in the presence of strong maternally derived PCV2 immunity in pigs

“…In contrast, weaker immune responses have been associated with PCV2-SD clinical cases [28–30]. The trial farm was a subclinical PCV2 infected farm and a probable enhancement of PCV2 replication around the 12th week of age occurred possibly due to animal movement and/or introduction of a different PCV2 genotype [20, 31]. PCV2 serology results suggested an increased antibody response in vaccinated pigs in comparison with controls, throughout the course of the study.…”

“…The lungs of trial animals were examined individually by the same pathologist at slaughter to score the severity of typical M. hyo lesions according to the same methodology as in the pre-trial screening [18]. The lesions of cranio-ventral pulmonary consolidation (expressed as lung lesions score - LLS) of each tested lung was the addition of the proportion of each lobe surface with signs of typical M. hyo associated inflammation (consolidated, grey to purple coloured), multiplied with the weighting factor of each lobe [20]. The LLS score ranged from 0 to 55 at maximum.…”

Mycoplasma hyopneumoniaevaccination at or shortly before weaning under field conditions: a randomised efficacy trial

“…It is generally acknowledged that most PRRS(V) and PCV-2 infections occurring at the end of the fattening period are subclinical and thus, this is the reason why in many cases no gross IPn lesions are detected at slaughter (Segalés and others 2012, Pileri and Mateu 2016). Nevertheless, the potentiating effect of the combination of viral pathogens with a M hyopneumoniae infection on the severity of Mycoplasma -like lung lesions induced has already been experimentally described by Thacker and others (1999, 2001), Opriessnig and others (2004) and Dorr and others (2007), and demonstrated under field conditions by Del Pozo Sacristán and others (2014).…”

Pathogen elimination and prevention within a regulated, Designated Pathogen Free, closed pig herd for long‐term breeding and production of xenotransplantation materials

“…The hallmark lesion of PCV2 infection is lymphopenia in the blood circulation and lymphodepletion in lymphoid organs in which lymphoid cells are replaced by histiocytes with intracytoplasmic inclusion bodies. Cofactors in disease progression are multifold as PCV2 is immunosuppressive and include the composition of the virus itself; coinfection by viruses such as porcine parvovirus and porcine reproductive and respiratory syndrome virus, and bacteria such as Mycoplasma hyopneumoniae and host factors such as the breed of pigs, for example, purebred Landrace pigs being more susceptible than Duroc or Large White pigs . Both types of PCV have a widespread global presence in swineherds: Antibodies to PCV1 and PCV2 were detected in archived pig sera taken as early as the 1970s, although the first clinical disease outbreaks of PCV2 were first reported in the second half of the 1990s .…”

“…Importantly, PCV is extremely robust and resistant to disinfection procedures. It is stable at pH 3 and resistant to heat inactivation even up to 120°C for 30 minutes . It is also resistant to inactivation by chloroform .…”