More than one genotype of ABV is circulating in North American waterfowl. While the infected ducks were not observed to be suffering from overt disease, based on the immunohistochemistry, we speculate that they may have suffered some visual impairment.

Background: Porcine circovirus type 2 (PCV2) is an important DNA pathogen commonly in pig farms, which can cause immunosuppression and induce apoptosis. To evade clearance by the host immune system, PCV2 constantly builds up complex mechanisms or mutates genes, it is difficult to eradicate complex PCV2 infection by relying on vaccine immunity and one compound. At present, there is no literature report on the effective prevention and treatment of PCV2 infection by the combined a of two or more compounds through multiple pathways and multiple targets. We have previously demonstrated the anti-PCV2 effect of Matrine in vitro, but its mechanism has not been further studied. Many literatures have proved that Osthole has a variety of pharmacological activities. Therefore, this study explored the synergistic antiviral effect of Matrine combined with Osthole and the synergistic anti-apoptosis mechanism in the same pathway and targets.Results: It was first demonstrated that Osthole alone had anti-PCV2 effect and the synergistic anti-PCV2 effect combined with Matrine was better than Matrine and Osthole alone by qPCR, IFA and Western blot results. Subsequently, demonstrated that the reduction of endoplasmic reticulum PERK apoptosis induced by PCV2 was mainly contributed the mechanism of anti-PCV2 using these two extracts by Annexin V-FITC/PI, JC-1 and Western blot results. Finally, it was further demonstrated that Matrine combined with Osthole could inhibit the expression of Cap in cap-transfected PK-15 cells, thus inhibiting Cap-induced PERK apoptosis. In this study, Ribavirin was used as the positive control.Conclusions: It was proved that the synergistic anti-PCV2 effect of Matrine combined with Osthole was significantly better than that of Matrine and Osthole alone. And the two ombined, with Cap and GRP78 as potential targets of anti-PCV2, further inhibited PERK apoptosis induced by PCV2 infection by directly inhibiting the expression of PCV2 Cap protein. The results formed a basis for further studies on the mechanism of anti-PCV2 in vivo using Matrine combined with Osthole and developing new anti-PCV2 compounds with Cap and GRP78 as therapeutic targets.

The identification of Parrot bornaviruses in psittacine birds with proventricular dilatation disease (PDD) has not been sufficient to explain the pathogenesis of this fatal disease since not all infected birds develop clinical signs. One hypothesis suggests that PaBV could trigger the production of autoantibodies targeting neuronal gangliosides. These are major neuronal antigens, and PDD might therefore resemble Guillain-Barré Syndrome (GBS) in its pathogenesis. Experimental inoculation of pure gangliosides and brain-derived ganglioside extracts were used in two different immunization studies. A preliminary study on seven healthy chickens (Gallus gallus domesticus) was performed using a group of four chickens inoculated with a brain ganglioside extract in Freund's complete adjuvant (FCA) and a control group comprised by three chickens inoculated only with phosphate-buffered saline (PBS). A second study with five healthy quaker parrots (Myiopsitta monachus) was comprised of three groups. Two quaker parrots received purified gangliosides in FCA, two received a crude brain extract in FCA, and one control quaker parrot received FCA alone. In the preliminary study, one chicken developed ataxia and weakness. None of the quaker parrots had any clinical signs that could resemble PDD or GBS. None of the chickens or quaker parrots presented any gross lesions. The chicken with clinical signs had a perivascular and perineural lymphocytic infiltrate in the proventriculus. Two of the quaker parrots (one from each treatment group) developed mild lymphoplasmacytic encephalitis and myelitis. Our results suggest that autoantibodies against gangliosides in birds are not associated with a condition resembling PDD.PeerJ Preprints | https://doi.org/10.7287/peerj.preprints.2852v1 | CC BY 4.0 Open Access | rec:

Background: Porcine circovirus type 2 (PCV2) is an important and common DNA virus that infect pig and can cause immunosuppression and induce apoptosis in the infected cells. To escape the host immune system, PCV2 constantly builds up complex mechanisms or mutates genes, and that is why it is difficult to eradicate complex PCV2 infection by relying on vaccines and single compound. At present, there is few literature reports on the effective prevention and treatment of PCV2 infection by a combination of two or more compounds. Previously, we have demonstrated the anti-PCV2 effect of Matrine in vitro, but its mechanism has not been further evaluated. Literatures have proven that Osthole has a variety of pharmacological activities, and we tested the ability of Osthole to inhibit PCV2 replication in cell culture. Therefore, this study explored the synergistic antiviral effect of Matrine combined with Osthole and their synergistic anti-apoptotic mechanism.Results: Osthole alone had an anti-PCV2 effect, and then its synergistic anti-PCV2 effect of Osthole and Matrine was better than that of Matrine or Osthole alone as demonstrated by qRT-PCR, IFA and Western blotting results. The anti-apoptotic mechanism of these two compounds by inducing the PERK pathway by PCV2 was elucidated through Annexin V-FITC/PI, JC-1 and Western blotting. Matrine and Osthole combination could inhibit the expression of Cap in Cap-transfected PK-15 cells, thus inhibiting Cap-induced PERK apoptosis. Ribavirin was used as a positive control.Conclusions: The combination of Osthole and Matrine had the synergistic effect of anti-PCV2 infection by directly inhibiting the expression of PCV2 Cap protein. The combination of these two compounds also inhibited PERK apoptosis induced by PCV2 Cap protein, possibly by regulating the level of GRP78. The results formed a base for further studies on the mechanism of anti-PCV2 in vivo using Matrine and Osthole combination and developing new anti-PCV2 compounds with Cap and GRP78 as therapeutic targets.

BackgroundPRRSV and PCV2 co-infection is very common in swine industry which results in huge economic losses worldwide. Although vaccination is used to prevent viral diseases, immunosuppression induced by PRRSV and PCV2 leads to vaccine failure. Our previous results have demonstrated that Matrine possessed antiviral activities against PRRSV/PCV2 co-infection in vitro. To establish a PRRSV/PCV2 co-infected KM mouse model and evaluate the antiviral activities of Matrine against PRRSV/PCV2 co-infection. A total of 144 KM mice were randomly divided into six groups with 24 mice in each group, named as: normal control, PRRSV/PCV2 co-infected group (PRRSV/PCV2 group), Ribavirin treatment positive control (Ribavirin control) and Matrine treatment groups (Matrine 40 mg/kg, Matrine 20 mg/kg and Matrine 10 mg/kg). Except normal control group, all mice in other five groups were inoculated with PRRSV, followed by PCV2 at 2 h later. At 7 days post-infection (dpi), mice in the treatment groups were intraperitoneally administered with various doses of Matrine and Ribavirin, twice a day for 5 consecutive days. ResultsPRRSV N and PCV2 CAP genes were detected by PCR in multiple tissues including heart, liver, spleen, lungs, kidneys, thymus and inguinal lymph nodes. The viral load of PCV2 was the highest in liver followed by thymus and spleen. Although PRRSV were detected in most of the tissues, but the replication of PRRSV was not significantly increased, as shown by qPCR analysis. Comparing with PCV2 infection alone, PRRSV infection significantly elevated PCV2 replication and also exacerbated PCV2 induced interstitial pneumonia. qPCR analysis demonstrated that 40 mg/ml Matrine significantly attenuated PCV2 replication in liver and alleviated virus induced interstitial pneumonia, suggesting that Matrine could directly inhibit virus replication. In addition, Matrine treatment enhanced peritoneal macrophages phagocytosis at 13 and 16 dpi, and 40 mg/kg of Matrine increased the proliferation activity of lymphocytes. Body weight gain was continuously promoted by administrating Matrine at 10 mg/kg.ConclusionMatrine possessed antiviral activities via inhibiting virus replication and regulating immune functions in mice co-infected by PRRSV/PCV2. These data provide new insight into controlling PRRSV and PCV2 infection and support further the research for developing Matrine as a new possible veterinary medicine.