key: cord-0254795-s9y7gsos
authors: Blázquez, Elena; Pujols, Joan; Segalés, Joaquim; Rodríguez, Carmen; Campbell, Joy; Russell, Louis; Polo, Javier
title: Estimated quantity of swine virus genomes based on quantitative PCR analysis in spray-dried porcine plasma samples collected from multiple manufacturing plants
date: 2021-10-25
journal: bioRxiv
DOI: 10.1101/2021.10.25.465711
sha: 1261a0722b4fc94b54cf4d865f362ed1f12b8a0a
doc_id: 254795
cord_uid: s9y7gsos

This survey was conducted to estimate the incidence and level of potential viral contamination in commercially collected porcine plasma. Samples of spray dried porcine plasma (SDPP) were collected over a 12-month period from eight spray drying facilities in Spain, England, Northern Ireland, Brazil, Canada, and the United States. In this survey, viral load for several porcine pathogens including SVA, TGEV, PRRSV (EU and US strains), PEDV, PCV2, SIV, SDCoV and PPV were determined by qPCR. Regression of Ct on TCID50 of serial diluted stock solution of each virus allowed the estimate of potential viral level in SDPP and unprocessed liquid plasma (using typical solids content of commercially collected porcine plasma). In this survey SVA, TGEV or SDCoV were not detected in any of the SDPP samples. Brazil SDPP samples were free of PRRSV and PEDV. Samples of SDPP from North America primarily contained the PRRSV-US strain while the European samples contained the PRRSV-EU strain (except for one sample from each region containing a low estimated level of the alternative PRRSV strain). Estimated viral level tended to be low ranging from <1.0 log10 TCID50 to <2.5 log10 TCID50. Estimated level of SIV was the exception with a very low incidence rate but higher estimated viral load <3.9 log10 TCID50. In summary, the incidence of potential viral contamination in commercially collected porcine plasma was variable and estimated virus level in samples containing viral DNA/RNA was low.

in the 25 cm 2 flask. If more than 25 positive cells were counted in a microscope 175 field, the 175 cm 2 flask was trypsinized and the cells were transferred to 3 new 175 cm 2 176 flasks. The virus stock was titrated in triplicate with a final titer of 10 5.5 TCID 50 /mL. between Ct and TCID 50 of serial diluted stock solutions were linear with a correlation 219 coefficient from 0.95 to 0.995 (Fig 1) . Similar correlation coefficients were found when 220 regressing Ct on log 10 GEC/g on the tested samples (Fig 1) . The slope of the lines for 221 either TCID50 or GEC/g were similar, while the intercepts were different (Fig 1) On the other hand, the inability to detect TGEV in these samples is also consistent with a multiple hurdles can inactivate more than 6 log 10 TCID 50 /g SDPP for spray drying and post 318 drying storage and > 10 log 10 TCID 50 /g SDPP if UV-C if also included (Table 1) .

In summary, the data from this survey allowed the calculation of potential viral 320 contamination in commercially collected porcine plasma. Estimated level of viral 321 contamination in commercially collected porcine plasma was very low ranging from <2 322 log 10 TCID 50 for most viruses with infrequent SIV levels as high as 4.5 log 10 TCID 50 /g 323 liquid plasma. Considering that the multiple hurdles in the manufacturing process (UV-C, 324 spray drying and post drying storage) are theoretically capable of inactivating much higher 325 levels of virus (11 to 20 log 10 TCID 50 ), it is safe to assume that SDPP is a product devoid of 

Risk 561 assessment of feed ingredients of porcine origin as vehicles for transmission of

Porcine Epidemic Diarrhea Virus (PEDv)

Effect of 564 spray-drying and ultraviolet C radiation as biosafety steps for CSFV and ASFV 565 inactivation in porcine plasma