key: cord-1037557-opltcnyi
authors: Yang, Xingyi; Xu, Quyi; Liu, Hong; Xu, Jichao; Yang, Dian; xiao, Cheng; Hu, Huiying; Liu, Yunyun; Liu, Chao
title: Collection and disinfection of forensic biological specimens in five cases concerning COVID-19 in Guangzhou, China
date: 2020-07-02
journal: Forensic Sci Int
DOI: 10.1016/j.fsisyn.2020.06.002
sha: 8dca83c00b713529afdbc2e701fdffd1e2761b7c
doc_id: 1037557
cord_uid: opltcnyi

There have been many cases of pneumonia caused by novel coronavirus infections in China and around the world. This will inevitably lead to a rise in the number of patients. At the present time, clinical and forensic autopsies have given guidance and explanations in relation to the problem of COVID-19 transmission and defense. However, less attention is paid to the handling of COVID-19 biological samples in forensic practice. Particularly, COVID-19 can survive on some surfaces for days. Since there were many cases involving COVID-19 during the epidemic, this article shares the methods and strategies for handling such inspection materials and the biological samples related specifically to COVID-19 cases.

acute respiratory syndrome (SARS) [1] . The pathogen of this particular outbreak is 26 COVID-19 and it is confirmed that the new coronavirus mainly infects human respiratory 27 epithelial cells [2] ，nectin-4+ epithelial cells, which can be spread through respiratory 28 droplets, aerosols, and contact with viral secretions [3] . Fever is usually the first symptom, 29 followed by respiratory symptoms. A high mortality is related to age and 30 immunosuppression [4] . The research presented here is based on the current 31 understanding of COVID-19 in June 2020 and is subject to change as more information is 32 released.

In forensic biology, we often have to use different biological samples, including 34 human saliva, blood, tears, vaginal secretions, organs and exfoliated cells. Studies have 35 shown that COVID-19 can be detected in pharyngeal swabs, perianal swabs, blood, 36 visceral slices, masks used by patients and elevator buttons [3, 5] . COVID-19 was 37 detected in the saliva samples of 91.7% (11/12) of patients [6] . Especially during the 38 epidemic, medical personnel cannot avoid being exposed to biological samples from 39 patients with confirmed or suspected COVID-19 infection. In addition to this, a major The collection process of these biological specimens requires close contact between 53 staff and patients, which causes a high risk of transmission of the virus to us. Therefore, 54 before biological sample collection, body temperatures and background of contact in the 55 epidemic area must be well known. Unless the case was urgent, we would wait for a few 56 days before we handled biological samples relating to COVID-19 suspected infected 57 patients that had a fever. If the body temperature is lower than 37.3 , we would choose 58 the level of protection according to whether the patient was within the epidemic area 

Case 2 concerns the COVID-19 old man in his house, who was assumed to commit 65 suicide by hanging. There were some suspicious bruises found on the arm that was brought 66 to our attention. To rule out homicide, his blood sample and exfoliated epithelial cell from 67 rope used to hang him were collected. Case 5 concerns the deceased that is suspected of having COVID-19 whose organ 76 was found in Pear River, China. To verify his identity, his viscera was collected.

Sample collection and preparation protocols 78 Before collecting biological samples on-site, 75% alcohol was sprayed on-site for 79 disinfection, and the specimens were subjected to ultraviolet radiation for 30 minutes. The 80 biological samples were then packaged in multi-layer bags.

The biological samples sent to the inspection laboratory were placed in a fume 82 hood first and then the thermostat was set to 56 for 30-40 minutes (Fig.2) . After this 83 process of disinfecting of the biological evidence, it was labeled as "sterilized".

The operator wore a scope, N-95 mask and ULTITEC 3000T protective clothing 85 and prepares tweezers and scissors. Upon entry of the ventilation room, 5% hypochlorous 86 acid was used to wipe the table. Every time a layer of a packaged bag was opened, 75% 87 alcohol was sprayed. The cotton swabs used were sprayed with 75% alcohol spray before 88 wiping the inspection materials. weighting was fix to 0.5.

After sample processing, the laboratory surfaces were wiped with 5% hypo-chloric 124 acid and 75% alcohol were sterilized further by ultraviolet light. All of the consumables 125 were discarded in a bucket marked with the COVID-19 logo for appropriate disposal. 17 STR profiles with the suspect and the LR ratio is 8.39×10 27 (Fig.3) . However, it is not COVID-19 will be provided, which will enable us to make more detailed decisions 192 concerning safe collection and disinfection procedures of forensic biological samples.

Conflict of interest 195 We declare that we do not have any interest that represents a conflict of interest in 196 connection with the work submitted. 

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We declare that we do not have any interest that represents a conflict of interest in connection with the work submitted