Where aldehydes are used for disinfection we consider 30 minutes contact time for difficult viruses like African Swine Fever (ASF) virus to be adequate. Coronaviruses like PEDv TGE IBV and the SARS virus are much easier to inactivate than ASF virus. I'd consider the SARS virus to be similar to Infectious Bronchitis Virus which is systemic and affects a wide variety of tissues.
Inactivating a virus in a chunk of tissue is more challenging than disinfection of contaminated fomites but I see no reason to think that routine fixation times would not completely inactivate the SARS coronavirus. The concentrations of aldehyde for fixation are at least 10 times higher than the highest concentrations used when aldehydes are employed for disinfection. I'd be more concerned about the container than the contents. For necropsy samples from your human specimens there is not generally any rush to get the results so the CDC's C.Y.A. time doesn't cause trouble but waiting 72 hours for a surgical path result would seem to be just wasting time. E. Wayne Johnson DVM Enable AgTech Beijing Tony Henwood (SCHN) via Histonet wrote:
Hi Richard, It will depend on the size of the tissue and the source. Lung tissue is the major concern. Other tissues not affected as much (based on the burgeoning literature on Covid-19). Routine fixation time are applicable, remembering that the alcohols and heated wax will also inactivate the virus (triple whammy). I suppose that I better add a reference: https://www.tandfonline.com/doi/full/10.1080/01478885.2020.1734718 -----Original Message----- From: Cartun, Richard via Histonet [mailto:histonet@lists.utsouthwestern.edu] Sent: Tuesday, 21 April 2020 6:51 AM To: histonet@lists.utsouthwestern.edu Subject: [Histonet] Formalin fixation for COVID-19 positive tissues ..... How long are you fixing surgical tissue specimens from COVID-19 positive patient's before tissue processing? I know that the CDC is recommending "72" hours for autopsy tissues, but, to me, that seems excessive for surgical pathology specimens. Any information that you can share on this subject would be appreciated. Thank you and stay safe. Richard Richard W. Cartun, MS, PhD Director, Histology & The Martin M. Berman, MD Immunopathology/Morphologic Proteomics Laboratory Director, Biospecimen Collection Programs Assistant Director, Anatomic Pathology Hartford Hospital 80 Seymour Street Hartford, CT 06102 (860) 972-1596 (Office) (860) 545-2204 (Fax) richard.car...@hhchealth.org<mailto:richard.car...@hhchealth.org> This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure, or distribution is prohibited. If you are not the intended recipient, or an employee or agent responsible for delivering the message to the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message, including any attachments. _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet This message is intended for the addressee named and may contain confidential information. If you are not the intended recipient, please delete it and notify the sender. Views expressed in this message are those of the individual sender, and are not necessarily the views of NSW Health or any of its entities. _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet
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