PMID- 32402344 OWN - NLM STAT- MEDLINE DCOM- 20201230 LR - 20201230 IS - 1873-2542 (Electronic) IS - 0378-1135 (Linking) VI - 244 DP - 2020 May TI - PCV2 co-infection does not impact PRRSV MLV1 safety but enhances virulence of a PRRSV MLV1-like strain in infected SPF pigs. PG - 108656 LID - S0378-1135(20)30058-4 [pii] LID - 10.1016/j.vetmic.2020.108656 [doi] AB - Co-infection by a type 1 modified live vaccine-like strain (MLV1-like) of porcine reproductive and respiratory syndrome virus (PRRSV) and a type 2 porcine circovirus (PCV2) was identified on a French pig farm with post-weaning multisystemic wasting syndrome (PMWS). An in vivo experiment was set up to characterize the virulence level of the MLV1-like strain compared with the parental MLV1 strain, and to assess the impact of PCV2 co-infection on the pathogenicity of both PRRSV strains. Six groups of six pigs each were inoculated only with either one of the two PRRSV strains or with PCV2, or co-inoculated with PCV2 and MLV1 or PCV2 and MLV1-like strains. Six contact pigs were added to each inoculated group to assess viral transmission. The animals were monitored daily for 35 days post-inoculation for clinical symptoms. Blood and nasal swabs were sampled twice a week, and tissue samples were collected during necropsy for viral quantification. Compared to MLV1-infected pigs, animals infected with the MLV1-like strain had increased PRRSV viremia and nasal shedding, a higher viral load in the tonsils, and lymph node hypertrophy at microscopic level. PCV2 co-infection did not influence clinical, virologic or transmission parameters for MLV1, but co-infected MLV1-like/PCV2 pigs had the most severe lung lesions, the highest viremia in contact animals and the highest transmission rate. Our study demonstrated that the MLV1 strain tested was safe when co-inoculated with PCV2 in piglets. However, co-infection by the MLV1-like strain and PCV2 resulted in increased virulence compared with that due to a single infection. CI - Copyright (c) 2020 Elsevier B.V. All rights reserved. FAU - Eclercy, Julie AU - Eclercy J AD - Agence Nationale de Securite Sanitaire de l'Alimentation, de l'Environnement et du Travail (Anses), Laboratoire de Ploufragan-Plouzane-Niort, BP 53, 22440 Ploufragan, France. FAU - Larcher, Thibaut AU - Larcher T AD - Institut National de Recherche Agronomique (INRA), APEX, La Chantrerie, CS 40706, 44307 Nantes Cedex 3, France; Ecole Nationale Veterinaire, Agroalimentaire et de l'Alimentation Nantes Atlantique (Oniris), CS 40706, 44307 Nantes Cedex 3, France. FAU - Andraud, Mathieu AU - Andraud M AD - Agence Nationale de Securite Sanitaire de l'Alimentation, de l'Environnement et du Travail (Anses), Laboratoire de Ploufragan-Plouzane-Niort, BP 53, 22440 Ploufragan, France. FAU - Renson, Patricia AU - Renson P AD - Agence Nationale de Securite Sanitaire de l'Alimentation, de l'Environnement et du Travail (Anses), Laboratoire de Ploufragan-Plouzane-Niort, BP 53, 22440 Ploufragan, France. FAU - Bernard, Cecilia AU - Bernard C AD - Agence Nationale de Securite Sanitaire de l'Alimentation, de l'Environnement et du Travail (Anses), Laboratoire de Ploufragan-Plouzane-Niort, BP 53, 22440 Ploufragan, France. FAU - Bigault, Lionel AU - Bigault L AD - Agence Nationale de Securite Sanitaire de l'Alimentation, de l'Environnement et du Travail (Anses), Laboratoire de Ploufragan-Plouzane-Niort, BP 53, 22440 Ploufragan, France. FAU - Ledevin, Mireille AU - Ledevin M AD - Institut National de Recherche Agronomique (INRA), APEX, La Chantrerie, CS 40706, 44307 Nantes Cedex 3, France; Ecole Nationale Veterinaire, Agroalimentaire et de l'Alimentation Nantes Atlantique (Oniris), CS 40706, 44307 Nantes Cedex 3, France. FAU - Paboeuf, Frederic AU - Paboeuf F AD - Agence Nationale de Securite Sanitaire de l'Alimentation, de l'Environnement et du Travail (Anses), Laboratoire de Ploufragan-Plouzane-Niort, BP 53, 22440 Ploufragan, France. FAU - Grasland, Beatrice AU - Grasland B AD - Agence Nationale de Securite Sanitaire de l'Alimentation, de l'Environnement et du Travail (Anses), Laboratoire de Ploufragan-Plouzane-Niort, BP 53, 22440 Ploufragan, France. FAU - Rose, Nicolas AU - Rose N AD - Agence Nationale de Securite Sanitaire de l'Alimentation, de l'Environnement et du Travail (Anses), Laboratoire de Ploufragan-Plouzane-Niort, BP 53, 22440 Ploufragan, France. FAU - Bourry, Olivier AU - Bourry O AD - Agence Nationale de Securite Sanitaire de l'Alimentation, de l'Environnement et du Travail (Anses), Laboratoire de Ploufragan-Plouzane-Niort, BP 53, 22440 Ploufragan, France. Electronic address: olivier.bourry@anses.fr. LA - eng PT - Journal Article DEP - 20200324 PL - Netherlands TA - Vet Microbiol JT - Veterinary microbiology JID - 7705469 RN - 0 (DNA, Viral) SB - IM MH - Animals MH - Circoviridae Infections/pathology/*veterinary MH - Circovirus/*pathogenicity MH - Coinfection/*veterinary/*virology MH - DNA, Viral/blood MH - Farms MH - France MH - Genome, Viral MH - Porcine Reproductive and Respiratory Syndrome/blood/*pathology MH - Porcine respiratory and reproductive syndrome virus/classification/*pathogenicity MH - Specific Pathogen-Free Organisms MH - Swine MH - Viral Load MH - Viremia MH - Virulence MH - Virus Shedding OTO - NOTNLM OT - Co-infection OT - Modified-live vaccine OT - PCV2 OT - PRRSV OT - Safety COIS- Declaration of Competing Interest The authors declare that they have no conflict of interests. EDAT- 2020/05/14 06:00 MHDA- 2020/12/31 06:00 CRDT- 2020/05/14 06:00 PHST- 2020/01/14 00:00 [received] PHST- 2020/03/05 00:00 [revised] PHST- 2020/03/18 00:00 [accepted] PHST- 2020/05/14 06:00 [entrez] PHST- 2020/05/14 06:00 [pubmed] PHST- 2020/12/31 06:00 [medline] AID - S0378-1135(20)30058-4 [pii] AID - 10.1016/j.vetmic.2020.108656 [doi] PST - ppublish SO - Vet Microbiol. 2020 May;244:108656. doi: 10.1016/j.vetmic.2020.108656. Epub 2020 Mar 24.