Dogs Detecting COVID-19 From Sweat and Saliva of Positive People : A Field Experience in Mexico

ContextMolecular tests are useful in detecting COVID-19, but they are expensive in developing countries. COVID-19-sniffing dogs are an alternative due to their reported sensitivity (>80%) and specificity (>90%). However, most of the published evidence is experimental, and there is a need to determine the performance of the dogs in field conditions. Hence, we aimed to test the sensitivity and specificity of COVID-19-sniffing dogs in the field. MethodsWe trained four dogs with sweat and three dogs with saliva of COVID-19-positive patients, respectively, for 4.5 months. The samples were obtained from a health center in Hermosillo, Sonora, with the restriction to spend 5 min per patient. We calculated sensitivity, specificity, and their 95% confidence intervals (CI). ResultsTwo sweat-sniffing dogs reached 76 and 80% sensitivity, with the 95% CI not overlapping the random value of 50%, and 75 and 88% specificity, with the 95% CI not overlapping the 50% value. The 95% CI of the sensitivity and specificity of the other two sweat dogs overlapped the 50% value. Two saliva-sniffing dogs had 70 and 78% sensitivity, and the 95% CI of their sensitivity and specificity did not overlap the 50% value. The 95% CI of the third dog's sensitivity and specificity overlapped the 50% value. ConclusionFour of the six dogs were able to detect positive samples of patients with COVID-19, with sensitivity and specificity values significantly different from random in the field. We considered the performance of the dogs promising because it is reasonable to expect that with gauze exposed for a longer time to sweat and saliva of people with COVID-19, their detection capacity would improve. The target is to reach the sensitivity range requested by the World Health Organization for the performance of an antigen test (>= 80% sensitivity, >= 97% specificity). If so, dogs could become important allies for the control of the COVID-19 pandemic, especially in developing countries.Peer reviewe

Expert considerations and consensus for using dogs to detect human SARS-CoV-2-infections

Funding Information: This Open Access publication was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 491094227 “Open Access Publication Funding” and the University of Veterinary Medicine Hannover, Foundation.Peer reviewe

Scanning of homologous binding partner sequences with SPOT-derived PWMs reveals conservation of binding sites.

<p>(<b>A</b>) Sequence scanning of the <i>Sc</i>App1 and <i>Sc</i>Las17 homologs with a PWM of the Myo5 SH3 domains reveals that <i>Sp</i>App1 lost its Myo5 SH3 binding motif. The presence of multiple polyproline motifs in Las17 is conserved across all four yeasts. (<b>B</b>) Sequence scanning of the <i>Sc</i>Abp1 and <i>Sc</i>Gyp5 homologs shows that both <i>Sp</i>Gyp5-1 and SpGyp5-2 lost their Rvs167 SH3 binding motif. All significant hits are indicated by lollipops and colored according to the motif type (Type I, blue; Type II, red; TypeI/II, blue/red; Type III, green). Asterisks indicate previously reported interaction sites.</p

Approach used to characterize SH3 domain specificity conservation in four model yeasts.

<p>(<b>A</b>) Overview of the approach we used to characterize the SH3 domain specificity landscape in four yeast species that span an evolutionary distance of some 400 Ma. (<b>B</b>) Overview of all SH3 domain proteins in <i>S</i>. <i>cerevisiae</i> (<i>Sc</i>), <i>A</i>. <i>gossypii</i> (<i>Ag</i>), <i>C</i>. <i>albicans</i> (<i>Ca</i>) and <i>S</i>. <i>pombe</i> (<i>Sp</i>). The dendrogram derived from their full multiple sequence alignment illustrates the diverging sequence conservation of orthologs and paralogs, analogous to the evolutionary distance among the four different yeasts. Alternating colors of red and blue indicate conserved families. Previously non-described <u>S</u>H3 domain <u>c</u>ontaining <u>p</u>roteins (Scp) that could not be confidently assigned to a family are shown in grey.</p

Myo5 and Rvs167 binding validation.

<p>(<b>A</b>) Sepharose-bead bound GST or GST-tagged C-terminal myosin type I tails of <i>Sc</i>Myo5 (984–1219), <i>Sc</i>Myo3 (1010–1271), <i>Ag</i>Myo5 (1084–1292), <i>Ca</i>Myo5 (1004–1316) and <i>Sp</i>Myo1 (1967–1217) were incubated with a total protein extract of <i>S</i>. <i>cerevisiae</i> supplemented with TRITC-labeled actin. The fluorescent halos around the beads (sized 50–150 μm) show the ability of the myosin type I tails of the four different yeast species to recruit active actin polymerization machinery to the beads while the negative control GST does not. Addition of 10 μM Latrunculin A inhibits actin polymerization. (<b>B</b>) Yeast two-hybrid strains co-transformed with the indicated bait and prey constructs were spotted (~10⁴ cells) on minimal plates with histidine (His⁺), without histidine (His⁻), without histidine containing 2.5, 5, or 10 mM 3-amino-1,2,4-triazole (3AT), or without adenine (Ade^–). Weak interactors activate only the <i>HIS3</i> reporter and show growth on His⁻plates, while strong interactors activate both <i>HIS3</i> and <i>ADE2</i> reporters and show growth on His⁻plates containing 3AT or on Ade⁻plates. Note that <i>Ca</i>Rvs167-3 SH3 shows weak self-activation as revealed by growth on His⁻plates in the presence of an empty bait plasmid.</p

Within-family comparisons of specificity profiles highlight a novel diverged specificity class for <i>Ca</i>Rvs167-3.

<p>(<b>A</b>) Separately clustered heat maps of the Rvs167 and Myo5 families show that both families have a high degree of binding profile conservation among orthologs, with the exception of <i>Ca</i>Rvs167-3, whose binding profile does not correlate with any of the Rvs167 orthologs. (<b>B</b>) Specificity logos built from manual alignments of the top 10 binding peptides show that, with the exception of <i>Sp</i>Rv167, all Rvs167 binding peptides could be aligned as Type I and II profiles (left). The <i>Ca</i>Rvs167-3 binding profile forms a distinct Type I-like (Type I*) class, characterized by the presence of a hydrophobic residue instead of the first proline. All Myo5 ortholog binding profiles show a clear disposition for a poly-proline motif, devoid of charged residues (right).</p

Expert considerations and consensus for using dogs to detect human SARS-CoV-2-infections

Funding Information: This Open Access publication was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 491094227 “Open Access Publication Funding” and the University of Veterinary Medicine Hannover, Foundation.Peer reviewe

Image_1_Expert considerations and consensus for using dogs to detect human SARS-CoV-2-infections.PNG

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Evolution of the SH3 domain specificity landscape in yeasts

To explore the conservation of Src homology 3 (SH3) domain-mediated networks in evolution, we compared the specificity landscape of these domains among four yeast species, Saccharomyces cerevisiae, Ashbya gossypii, Candida albicans, and Schizosaccharomyces pombe, encompassing 400 million years of evolution. We first aligned and catalogued the families of SH3-containing proteins in these four species to determine the relationships between homologous domains. Then, we tagged and purified all soluble SH3 domains (82 in total) to perform a quantitative peptide assay (SPOT) for each SH3 domain. All SPOT readouts were hierarchically clustered and we observed that the organization of the SH3 specificity landscape in three distinct profile classes remains conserved across these four yeast species. We also produced a specificity profile for each SH3 domain from manually aligned top SPOT hits and compared the within-family binding motif consensus. This analysis revealed a striking example of binding motif divergence in a C. albicans Rvs167 paralog, which cannot be explained by overall SH3 sequence or interface residue divergence, and we validated this specificity change with a yeast two-hybrid (Y2H) assay. In addition, we show that position-weighted matrices (PWM) compiled from SPOT assays can be used for binding motif screening in potential binding partners and present cases where motifs are either conserved or lost among homologous SH3 interacting proteins. Finally, by comparing pairwise SH3 sequence identity to binding profile correlation we show that for 75% of all analyzed families the SH3 specificity profile was remarkably conserved over a large evolutionary distance. Thus, a high sequence identity within an SH3 domain family predicts conserved binding specificity, whereas divergence in sequence identity often coincided with a change in binding specificity within this family. As such, our results are important for future studies aimed at unraveling complex specificity networks of peptide recognition domains in higher eukaryotes, including mammals.LS, BW, FH and BD received funding from the European Union (Marie Curie Research Training Network Penelope; MRTN-CT-2006-036076)