Scent dog identification of SARS-CoV-2 infections in different body fluids.

BACKGROUND: The main strategy to contain the current SARS-CoV-2 pandemic remains to implement a comprehensive testing, tracing and quarantining strategy until vaccination of the population is adequate. Scent dogs could support current testing strategies. METHODS: Ten dogs were trained for 8 days to detect SARS-CoV-2 infections in beta-propiolactone inactivated saliva samples. The subsequent cognitive transfer performance for the recognition of non-inactivated samples were tested on three different body fluids (saliva, urine, and sweat) in a randomised, double-blind controlled study. RESULTS: Dogs were tested on a total of 5242 randomised sample presentations. Dogs detected non-inactivated saliva samples with a diagnostic sensitivity of 84% (95% CI: 62.5-94.44%) and specificity of 95% (95% CI: 93.4-96%). In a subsequent experiment to compare the scent recognition between the three non-inactivated body fluids, diagnostic sensitivity and specificity were 95% (95% CI: 66.67-100%) and 98% (95% CI: 94.87-100%) for urine, 91% (95% CI: 71.43-100%) and 94% (95% CI: 90.91-97.78%) for sweat, 82% (95% CI: 64.29-95.24%), and 96% (95% CI: 94.95-98.9%) for saliva respectively. CONCLUSIONS: The scent cognitive transfer performance between inactivated and non-inactivated samples as well as between different sample materials indicates that global, specific SARS-CoV-2-associated volatile compounds are released across different body secretions, independently from the patient's symptoms. All tested body fluids appear to be similarly suited for reliable detection of SARS-CoV-2 infected individuals.

Serological screening in wild ruminants in Germany, 2021/2022: No evidence of SARS-CoV-2, bluetongue virus or pestivirus spread but high seroprevalences against Schmallenberg virus.

Wildlife animals may be susceptible to multiple infectious agents of public health or veterinary relevance, thereby potentially forming a reservoir that bears the constant risk of re-introduction into the human or livestock population. Here, we serologically investigated 493 wild ruminant samples collected in the 2021/2022 hunting season in Germany for the presence of antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and four viruses pathogenic to domestic ruminants, namely, the orthobunyavirus Schmallenberg virus (SBV), the reovirus bluetongue virus (BTV) and ruminant pestiviruses like bovine viral diarrhoea virus or border disease virus. The animal species comprised fallow deer, red deer, roe deer, mouflon and wisent. For coronavirus serology, additional 307 fallow, roe and red deer samples collected between 2017 and 2020 at three military training areas were included. While antibodies against SBV could be detected in about 13.6% of the samples collected in 2021/2022, only one fallow deer of unknown age tested positive for anti-BTV antibodies, and all samples reacted negative for antibodies against ruminant pestiviruses. In an ELISA based on the receptor-binding domain (RBD) of SARS-CoV-2, 25 out of 493 (5.1%) samples collected in autumn and winter 2021/2022 scored positive. This sero-reactivity could not be confirmed by the highly specific virus neutralisation test, occurred also in 2017, 2018 and 2019, that is, prior to the human SARS-CoV-2 pandemic, and was likewise observed against the RBD of the related SARS-CoV-1. Therefore, the SARS-CoV-2 sero-reactivity was most likely induced by another hitherto unknown deer virus belonging to the subgenus Sarbecovirus of betacoronaviruses.

Effect of cholinergic crisis on the potency of different emergency anaesthesia protocols in soman-poisoned rats.

BACKGROUND: In a military or terrorist scenario, combination of organophosphorus compounds (OP) poisoning with physical trauma requiring surgical treatment and thus general anaesthesia are possible. Previous in vitro studies showed an altered potency of relevant anaesthetics during cholinergic crisis. Hence, it is not clear, which anaesthetics are suitable to achieve the necessary stage of surgical anaesthesia in OP poisoning. METHODS: In the present study, different anaesthetic regimens (ketamine-midazolam, propofol-fentanyl, thiopental-fentanyl), relevant in military emergency medicine, were examined in soman-poisoned rats. Clinical signs and cardiovascular variables were recorded continuously. Blood samples for acetylcholinesterase (AChE) activity were drawn. After euthanasia or death of the animals, brain and diaphragm were collected for cholinesterase assays. RESULTS: Propofol-fentanyl and thiopental-fentanyl resulted in surgical anaesthesia throughout the experiments. With ketamine-midazolam, surgical anaesthesia without respiratory impairment could not be achieved in pilot experiments (no soman challenge) and was therefore not included in the study. Soman-poisoned and control animals required a comparable amount of propofol-fentanyl or thiopental-fentanyl. In combination with atropine, significantly less propofol was needed. Survival rate was higher with thiopental compared to propofol. Atropine improved survival in both groups. Blood and tissue AChE activities were strongly inhibited after soman administration with and without atropine treatment. DISCUSSION: The current in vivo study did not confirm concerns of altered potency of existing anaesthetic protocols for the application of propofol or thiopental with fentanyl due to soman poisoning. Despite severe cholinergic crisis, sufficient anaesthetic depth could be achieved in all animals. CONCLUSION: Further experiments in in vivo models closer to human pharmaco- and toxicokinetics (e.g., swine) are required for confirmation of the initial findings and for improving extrapolation to humans.

Human small bowel as model for poisoning with organophosphorus compounds.

In previous experiments, human and rat small bowel samples have been successfully used to study the spasmolytic effect of (potential) therapeutics in carbamate-constricted bowel specimens. Additionally, transferability from rat to human data was shown in the previous study. In the present study, the effects of atropine, scopolamine, MB327, HI-6 as well as obidoxime were examined in organophosphorus-poisoned human small bowel specimens. All substances were tested with at least seven concentrations in samples previously exposed to the nerve agent sarin. Furthermore, the cholinesterase reactivation potential of all substances was investigated. The test substances displayed a spasmolytic effect allowing the calculation of dose-response curves and EC50s. The parasympatholytic compound scopolamine had the strongest relaxing effect (EC50 = 0.05 µM) followed by atropine (EC50 = 0.07 µM). HI-6 and obidoxime were capable to reactivate the sarin-inhibited cholinesterase activity in small bowel samples. Both substances restored AChE activity in a dose-dependent way, with HI-6 being more potent (HI-6 EC50 = 3.8 µM vs obidoxime EC50 = 197.8 µM). Summarizing, our isolated human small bowel setup is a suitable tool to investigate the smooth muscle relaxing effect of (candidate) therapeutics for organophosphorus compound poisoning i.e. sarin exposure in a complex 3D tissue model.

Human small bowel as a useful tool to investigate smooth muscle effects of potential therapeutics in organophosphate poisoning.

Isolated organs proofed to be a robust tool to study effects of (potential) therapeutics in organophosphate poisoning. Small bowel samples have been successfully used to reveal smooth muscle relaxing effects. In the present study, the effects of obidoxime, TMB-4, HI-6 and MB 327 were investigated on human small bowel tissue and compared with rat data. Hereby, the substances were tested in at least seven different concentrations in the jejunum or ileum both pre-contracted with carbamoylcholine. Additionally, the cholinesterase activity of native tissue was determined. Human small intestine specimens showed classical dose response-curves, similar to rat tissue, with MB 327 exerting the most potent smooth muscle relaxant effect in both species (human EC50=0.7×10-5M and rat EC50=0.7×10-5M). The AChE activity for human and rat samples did not differ significantly (rat jejunum=1351±166 mU/mg wet weight; rat ileum=1078±123 mU/mg wet weight; human jejunum=1030±258 mU/mg wet weight; human ileum=1293±243 mU/mg wet weight). Summarizing, our isolated small bowel setup seems to be a solid tool to investigate the effects of (potential) therapeutics on pre-contracted smooth muscle, with data being transferable between rat and humans.