Infection of cesarean-derived colostrum-deprived pigs with porcine circovirus type 2 and Swine influenza virus.
ABSTRACT Porcine circovirus type 2 (PCV2) and swine influenza virus (SIV) are important pathogens for porcine respiratory disease complex, which is economically significant worldwide. The pathogenesis of PCV2-SIV coinfection is unknown. In this study, we focused on establishing a challenge model for PCV2 to determine whether SIV influences PCV2 replication and increases the severity of PCV2-associated disease. Cesarean-derived colostrum-deprived pigs were inoculated intratracheally with cell culture medium only (negative control group), PCV2 only, or PCV2 followed 1 wk later with SIV H1N1. Two pigs from each group were necropsied at 12, 21, 28, and 35 d after inoculation. Coinfection with SIV did not increase the number of PCV2 genomic copies in serum or target tissues or the severity of microscopic lesions associated with PCV2 in lung or lymph node. The antibody titer to PCV2 did not differ significantly between PCV2-SIV- and PCV2-infected groups. In conclusion, SIV H1N1 did not influence PCV2 replication in dually infected pigs in this study.
SourceAvailable from: Małgorzata Pomorska-Mól[Show abstract] [Hide abstract]
ABSTRACT: This paper aims at the presentation of infectious agents related swine respiratory system pathology. Currently, infectious diseases of multifactorial etiolo- gy dominate in pigs. Among them porcine respirato- ry disease complex (PRDC), is of the most importance due to substantial economic losses and the reduced welfare level in the pig industry. There is a variety of viral and bacterial pathogens commonly associated with PRDC, including porcine reproductive and respir- atory syndrome virus, swine influenza virus, porcine circovirus type 2, Mycoplasma hyopneumoniae, Act- inobacillus pleuropneumoniae and Pasteurella multo- cida. The pathogenesis of the PRDC is complex and depends directly on participating pathogens what makes generalizations about PRDC treatment and control quite difficult. Interactions between viral and bacterial pathogens play an important role in the de- velopment and outcome of PRDC. Simultaneous in- fection with two or more pathogens commonly re- sults in more severe clinical signs and pathological lesions. Data on simultaneous bacterial-bacterial in- teractions, viral-viral interactions, and bacterial-viral interactions are presented in this paper.
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ABSTRACT: Porcine circovirus associated disease (PCVAD) has made an economic impact in global swine production, is caused by porcine circovirus type 2 (PCV2) and manifests in forms of multisystemic disease, wasting, pneumonia, diarrhea in growing pigs and reproductive failure in gilts and sows. PCVAD is enhanced by PRRSV co-infection alongside PCV2 infection in pigs and is not very well understood except that PRRSV potentiates PCV2 replication in the host. We characterized apoptosis in gnotobiotic pigs caused by both PCV2a and PCV2b and for the first time established that both PCV2a and PCV2b are able to promote cell death in the hepatocytes of gnotobiotes of clinically affected pigs leading to hepatic failure. We further delineated the role of PRRSV in affecting PCV2a and PCV2b apoptosis in specific pathogen free (SPF) pigs and demonstrated that PRRSV does not cause apoptosis induction in PCV2a and PCV2b infected pigs. We compared and demonstrated that in vitro differences in PCV2 or PRRSV replication or IFN gamma; and IL-10 release in porcine alveolar macrophages (PAMs) inoculated with several PCV2-PRRSV combinations are small and not dependent on ORF1 or ORF2 origin. We analyzed the shedding of both PCV2a and PCV2b in piglets co-infected with PRRSV and ascertained that PRRSV is capable of prolonging PCV2 viremia and subsequent shedding in the nasal, oral secretions and fecal excretion that can increase horizontal transmission of PCV2a and PCV2b in nayve herds. Finally we also verified if prior PRRSV exposure had any detrimental effect on PCV2 vaccines currently available in the US market. We were able to establish that the PCV2 vaccines are able to provide protective immunity to piglets that had prior PRRSV infection.
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ABSTRACT: Porcine respiratory disease complex (PRDC) is a serious health problem that mainly affects growing and finishing pigs. PRDC is caused by a combination of viral and bacterial agents, such as porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV), Mycoplasma hyopneumoniae (Myh), Actinobacillus pleuropneumoniae (APP), Pasteurella multocida and Porcine circovirus 2 (PCV2). To characterize the specific role of swine influenza virus in PRDC presentation in Colombia, 11 farms from three major production regions in Colombia were examined in this study. Nasal swabs, bronchial lavage and lung tissue samples were obtained from animals displaying symptoms compatible with SIV. Isolation of SIV was performed in 9-day embryonated chicken eggs or Madin-Darby Canine Kidney (MDCK) cells. Positive isolates, identified via the hemagglutination inhibition test, were further analyzed using PCR. Overall, 7 of the 11 farms were positive for SIV. Notably, sequencing of the gene encoding the hemagglutinin (HA) protein led to grouping of strains into circulating viruses identified during the human outbreak of 2009, classified as pandemic H1N1-2009. Serum samples from 198 gilts and multiparous sows between 2008 and 2009 were obtained to determine antibody presence of APP, Myh, PCV2 and PRRSV in both SIV-H1N1p-negative and -positive farms, but higher levels were recorded for SIV-H1N1p-positive farms. Odds ratio (OR) and P values revealed statistically significant differences (p<0.05) in PRDC presentation in gilts and multiparous sows of farms positive for SIV-H1N1p. Our findings indicate that positive farms have increased risk of PRDC presentation, in particular, PCV2, APP and Myh.Virologica Sinica 08/2014; 29(4):242-249. DOI:10.1007/s12250-014-3471-5