Coronavirus-sniffing dogs are putting their noses to work in airports -  Lonely Planet
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Dogs, being called the man’s best friend by Prussian King Fredrick William, are an epitome of trustworthiness in a world that some may call selfish or ‘ego-centric’. Whether it’s the audacious transport of diphtheria antitoxin by the Siberian Husky Balto to halt the epidemic or the World War II protagonist Terrier Smoky who lend a hand in setting up communications, or the mere canine that sleeps at your gate making sure no one harms you, these living beings and their colossal loyalty just never seems to cease. The unprecedented menace of COVID-19 caused a severe global stress in the 200,000 years of human history causing 3.35 million mortalities, the insidious collapse of healthcare systems, and the screeching scarcity of vaccines worldwide. In an ego-centric post COVID world, where a felony like unequal distribution of standard PCR diagnostics and vaccines dominates,. the man’s best comrade dogs shows up. The assignment highlights the story of how the sniffing ability of man’s best friend can detect COVID-19 and they are not charging a single penny for it.

The unfolding of Canine and COVID-19’s timeline

Canines combating the lockdown oppression  

It initially started with an article published in the journal ‘Frontiers in Veterinary Sciences’ in which the authors talked about the love of puppies in COVID-19 time and how the ownerships of these striking beings can protect against isolation during the lockdown 1. The pandemic had resulted in many countries imposing and enforcing a lockdown, where people were instructed to stay home. The governments all over the world expected people to remain steadfast during this time of adversity, but what they didn’t know of was the massive anxiety seclusion brings with an imposed lockdown. The clinicians of mental health posited the significance of social connections during the pandemic and how lockdown could bring melancholy, fretfulness and despair to the home, particularly affecting women 2. The research included 348 participants living unaccompanied, or accompanied by a dog or by a cat. They were provided with open ended questions asking how being a dog/cat owner impacted their lockdown experience and what were its effects on their pets. Astonishingly the findings reported were that owning a cat didn’t help the levels of mindfulness whereas owning a dog not only raised the levels of mindfulness, it also sheltered against oppression and stress. First thing first, in a world where threats of Disease-X are luring in, and can impose future lockdowns, one can vividly count on man’s best comrade to protect against the social havoc these potential pandemics can bring.

Can COVID-19 hurt the waging tail and pawns of these workaholics?

Before human beings ask these dogs to help them sniffing COVID-19, our responsibility is to make sure if COVID-19 can harm them? So let’s critique if dogs can actually be the detectors of the virus whilst at the same time saving itself from catching the virus. Despite trying for decades, human beings are yet to manufacture a machine that has as exquisite sensing and discerning ability as canines have. A completely trained canine that can sniff bombs is worth $ 0.15 million, in fact US government spend million dollars for utilizing these 220 million receptors (i.e. forty four times of human beings) for the cause. But whether canines could be used to sniff COVID-19, could only be dictated by adequate scientific evidence supporting the non-susceptibility of the canines towards COVID-19. 

If at this very moment, one scrolls through the website of CDC, it’s exhibited that these Dogs or Cats would rarely catch COVID-19 and still needs conclusive experimentation to decide if they are susceptible or not, and if they are, can their smelling abilities be compromised and whether the symptoms would be mild or too harsh. So far the amount of susceptibility studies published on canines is too inadequate. A study reporting the issue unfortunately, didn’t include any immunohistochemical staining or evaluation histopathology. It recorded little susceptibility and no support for replication of the virus though. This conundrum still persists since another report had contrary findings by amalgamating Real Time PCR (RT-PCR), Sanger sequencing and Plaque Reduction Neutralization Test (PRNT90) 5. Their findings suggested that despite having mild and reversible symptoms dogs were affected, and the owners should socially distant themselves from the dogs if the owners have caught the virus already. The study didn’t have condonable limitations though, like viral load detected from the samples was too stumpy.

This dilemma of dogs being or not being susceptible has led to abandoning many pets already, and if they are to be employed for a colossal task like sniffing viruses, decisive investigation is still the need of the hour. Fox 13 News did report about a Labrador Buffy with 300 million receptors in nose that was trained for around 9 months with blinded experiments, to detect COVID-19 with an efficacy of 95% at Sarasota hospital. This looked astonishing since they kind of provided an additional free diagnostic test, but when we read that it lies on patients’ feet too after sniffing COVID out, it surely did raise our eyebrow if Buffy was a hero for real or if it was being forced to become one. Since lying this close to infected patients could risk its own health too. If canines are to become the next big thing for sniffing COVID, we need to see if they are susceptible or not! If they are, then what length of distance with patients, needs to be ensured to safely sniff out COVID.

Scent of COVID-19 & Canines

The world has somehow mitigated the effects of COVID-19, at least a bit of it. Novel diagnostic techniques with swift and real-time detection are being developed to augment the diagnostic regimen. During respiratory infections, particular scent imprints can be caused by compounds that are volatile and organic. These compounds can be perceived by trained dogs that can detect with high precision. Researchers conducted a double-blinded study to identify SARS-CoV-2 patient’s tracheobronchial or salivary secretions. Canines, with high specificity and sensitivity, can detect viral or bacterial infections or cancers; they have astonishing olfactory acuity. Pathogen specific scent is identified by canines which may be made of VOCs (Volatile Organic Compounds). Viruses don’t have own metabolism, which is why host metabolic processes lead to release of VOCs. This method can be extremely efficacious in airport scenarios or country borders where real time and swift testing is mandatory.

Dog training and study design

Detection Dog Training System (DDTS) exhibited samples to the dogs without the intrusion of trainer in a randomized robotic way. Seven scent holes compose the device, with each hole connected to two metal containers via two tubes. The containers could rotate around a movable slide, displaying a single sniffing hole which would exhibit positive sample whilst the next six would be negative. There was grid protection on the containers, with L-shaped tubes being identical this affirmed that dog couldn’t physically contact the samples and no biasedness could come into play. For a right indication of positive sample, the treat was automatically given to the dog. While the treat was being consumed, the software would randomly allot next positions for the slides. The observer, the handler of the dog and the dog itself were blinded. The device automatically stored the length and amount of times each nose moved into the hole. Two weeks of training with the device and additional five days were required to eliminate any coincidental identification. After seven days of training 10,388 samples were presented to canines to sniff out the positive ones. The second day the detection rate was recorded 50%, which on fifth and seventh day escalated to 70% and 81% demonstrating fruitful process of generalization.

As described in Fig. 1, the dogs attained:

  • 94% (±3.4%) Detection Rate
  • Precise Positive Indications: 157
  • Accurate Negative Rejections: 792
  • Incorrect Positive Indications: 33
  • False Negative Rejections: 30
  • Sensitivity: 82.63%
  • Specificity:  96.35%
  • Sensitivity Range: 67.9 To 95.2%
  • Specificity Range: 92.4 To 98.9%
Fig. 1 Analytic sensitivity and specificity by single dog and all dogs. Whiskers display 95% confidence intervals

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