DIAGNOSTIC ACCURACY OF NON-INVASIVE DETECTION OF SARS-COV-2 INFECTION BY CANINE OLFACTION

BACKGROUNDThroughout the COVID-19 pandemic, testing individuals remains a key action. One approach to rapid testing is to consider the olfactory capacities of trained detection dogs. METHODSProspective cohort study in two community COVID-19 screening centers. Two nasopharyngeal swabs (NPS), one saliva and one sweat samples were simultaneously collected. The dog handlers (and the dogs...) were blinded with regards to the Covid status. The diagnostic accuracy of non-invasive detection of SARS-CoV-2 infection by canine olfaction was assessed as compared to nasopharyngeal RT-PCR as the reference standard, saliva RT-PCR and nasopharyngeal antigen testing. RESULTS335 ambulatory adults (143 symptomatic and 192 asymptomatic) were included. Overall, 109/335 participants tested positive on nasopharyngeal RT-PCR either in symptomatic (78/143) or in asymptomatic participants (31/192). The overall sensitivity of canine detection was 97% (95% CI, 92 to 99) and even reached 100% (95% CI, 89 to 100) in asymptomatic individuals compared to NPS RT-PCR. The specificity was 91% (95% CI, 72 to 91), reaching 94% (95% CI, 90 to 97) for asymptomatic individuals. The sensitivity of canine detection was higher than that of nasopharyngeal antigen testing (97% CI: 91 to 99 versus 84% CI: 74 to 90, p=0.006), but the specificity was lower (90% CI: 84 to 95 versus 97% CI: 93 to 99, p=0.016). CONCLUSIONSNon-invasive detection of SARS-CoV-2 infection by canine olfaction could be one alternative to NPS RT-PCR when it is necessary to obtain a result very quickly according to the same indications as antigenic tests in the context of mass screening.

SARS-COV-2 VIRUS INFECTED PATIENT IDENTIFICATION THROUGH CANINE OLFACTIVE DETECTION ON AXILLARY SWEAT SAMPLES

Facing the COVID-19 pandemic, testing individuals in order to promptly isolate positive people is one of the key actions. One approach to rapid testing might be to consider the olfactory capacities of trained detection dogs in order to develop a non-invasive, rapid and cheap mass detection approach, through the Volatile Organic Compounds (VOCs) signature of SARS-CoV-2 infection. The goal of this study was to determine the individual values of sensitivity and specificity of trained dogs when performing olfactory detection of COVID-19 on axillary sweat samples. Seven dogs were used to sniff a total of 218 samples (62 COVID-19 positive and 156 COVID-19 negative samples), based on a randomised and double-blinded protocol carried out on olfaction cone line-ups. To ensure a wide olfactory range as close as possible to operational conditions, the samples were retrieved from 13 different sites. Sensitivities varied from 87% to 94% for 6 dogs, and were above 90% for 3 of them. Only one dog, whose sensitivity was 60%, was not selected to subsequently enter the operational stage. Specificities varied from 78% to 92%, with 6 dogs over 85% and 4 dogs over 90%. Based on the calculated sensitivity and specificity for each dog, positive and negative predictive values (PPV and NPV) were calculated according to several prevalence rates of SARS-CoV-2 scenarii, and were compared to PPV and NPV of an "almost perfect" diagnostic tool. For 6 out of the 7 dogs, and for a prevalence rate of SARS-CoV-2 lower or equal than 40%, the NPV of the dogs were virtually the same as the one of the "almost perfect" tool. Along with other studies on olfactory detection of COVID-19 by dogs these positive and encouraging results suggest that olfactory dogs may play an important part in mass COVID-19 pre-testing situations.

Use Of Canine Olfactory Detection For COVID-19 Testing Study On U.A.E. Trained Detection Dog Sensitivity

This study aimed to evaluate the sensitivity of 21 dogs belonging to different United Arab Emirates (UAE) Ministry of Interior (MOI), trained for COVID-19 olfactory detection. The study involved 17 explosives detection dogs, two cadaver detection dogs and two dogs with no previous detection training. Training lasted two weeks before starting the validation protocol. Sequential five and seven-cone line-ups were used with axillary sweat samples from symptomatic COVID-19 individuals (SARS-CoV-2 PCR positive) and from asymptomatic COVID-19 negative individuals (SARS-CoV-2 PCR negative). A total of 1368 trials were performed during validation, including 151 positive and 110 negative samples. Each line-up had one positive sample and at least one negative sample. The dog had to mark the positive sample, randomly positioned behind one of the cones. The dog, handler and data recorder were blinded to the positive sample location. The calculated overall sensitivities were between 71% and 79% for three dogs, between83% and 87% for three other dogs, and equal to or higher than 90% for the remaining 15 dogs (more than two thirds of the 21 dogs). After calculating the overall sensitivity for each dog using all line-ups, "matched" sensitivities were calculated only including line-ups containing COVID-19 positive and negative samples strictly comparable on confounding factors such as diabetes, anosmia, asthma, fever, body pain, diarrhoea, sex, hospital, method of sweat collection and sampling duration. Most of the time, the sensitivities increased after matching. Pandemic conditions in the U.A.E., associated with the desire to use dogs as an efficient mass-pretesting tool has already led to the operational deployment of the study dogs. Future studies will focus on comparatives fields-test results including the impact of the main COVID-19 comorbidities and other respiratory tract infections.

Quantitative assessment of systolic and diastolic right ventricular function by echocardiography and speckle-tracking imaging: a prospective study in 104 dogs

Our aim was (1) to determine the within-day and between-day variability of several indices of systolic and diastolic right ventricular (RV) function by using conventional echocardiography and speckle-tracking echocardiography (STE) (Study 1), (2) to quantify these variables in a large healthy canine population (n = 104) with Doppler-derived estimated systolic pulmonary arterial pressure (SPAP) and left ventricular (LV) function, and (3) to establish the corresponding reference intervals (Study 2). For both studies, RV variables included tricuspid annular plane systolic excursion (TAPSE), right fractional area change (RFAC), STE longitudinal systolic strain (StS) of the RV free wall (RVFW) and of the entire RV (i.e., global RV StS), STE longitudinal systolic RVFW strain rate (SRS), and the diastolic early:late strain rate ratio. All but one within- and between-day coefficients of variation (13/14) were < 15%, the lowest being observed for TAPSE (3.6–9.8%), global RV StS (3.8–9.9%), and RVFW StS (3.7–7.3%). SPAP was weakly and negatively correlated with the TAPSE:body weight ratio (r(s) = −0.26, p = 0.01) and RVFW SRS (r(s) = −0.23, p < 0.05). Reference intervals (lower and upper limits with 90% confidence intervals) were provided for all variables. STE provides a non-invasive evaluation of RV function that may be used for clinical investigations in canine cardiology.