The beginning was a foreign report. Hong Kong media reported that the South China Morning Post reported that "corona 19 confirmed dogs were" weak positive "in virus testing . The subject of the inspection was the Ministry of Agriculture, Forestry and Fisheries, Hong Kong, the Ministry of Agriculture, Food and Rural Affairs.

However, the South China Morning Post, which reported the issue, cited some important facts from Hong Kong authorities who conducted the inspection.

* "The dog did not show any clinical symptoms."
* "There is no evidence that a dog carries the Corona 19 virus."
* "Additional tests are being carried out to see if your dog is really infected with the virus or if the virus is simply in your mouth or nose."
* "WHO also found no evidence of infection between companion animals and humans of the Corona 19 virus."

Before being a reporter, as a veterinarian and a researcher who studied pathology, the cause and development of illness, I also curiously and interestingly read this article. Is this dog really infected with Corona 19? In conclusion, there seems to be little evidence for the dog to be infected with Corona 19 at this time.

How does a virus scan, including Corona19, work?

Basically, the virus test is basically done through a test equipment called 'Polymerase Chain Reaction'. It's complicated to explain in detail, but in simple terms, you can say, ' I 've cloned a lot of the virus genes I've got, increase the number, and analyze it.'

Let's take an example. There is a puppy named A. The Corona 19 virus is very seriously infected. For the sake of understanding, I will randomly say that I have been infected with 50 viruses. But let's say the inspector can't recognize at least 100 viruses, 'Oh, you're infected.' In this case, how many times more would a virus need to replicate to determine if it was infected? Yes, that's right. If you make 100 viruses of 50 animals, you only need to arithmetically double the number.

Conversely, this time there is a puppy named B. This B puppy is very mildly infected with the Corona 19 virus. In terms of numbers, it is said that there are two viruses in the body. In this case as well, the test would require 100 viruses, but the tester could say, "Oh, you're infected." To determine if you have a virus, you need to make two 100 eggs. In this case, you need to replicate 50 times or more viral genes. This means that PCR must be run much more times and repeatedly.

Now we come to this conclusion. "If you're infected with a lot of viruses, you can say that PCR is" infected, "or positive, even if you run less equipment." This is also true of the ongoing Corona19 Confirmation Test. If a person is infected with the Corona 19 virus (positive), you can get as many viral genes as you want by running less equipment called PCR. Of course, if you're not infected (negative), you'll have to run the test device many more times.

If so, another question arises here. How many times should you run a PCR device specifically to determine 'positive'? There is no correct answer. However, experimenters usually set '35' as the reference point. 1, 2, 3 times. By running the PCR equipment up to 34 and 35 , if you get as many genes as you want inside , it is judged as 'positive'. This may be interpreted as a high level of virus and a strong infection.

Conversely, if you run the equipment more than 36 times and still do not get the virus you want, then this means that you don't have enough viruses. In other words, it is judged as 'voice'. Corona19 prosecutors, who are currently passing through the media, are also confirmed in this way.
● Error possibility of virus scan

The description was long. Let's go back to the story of a dog with a corona 19 'weak bisexuality' in Hong Kong. This dog's decision is 'weak positive' . Positive is positive, and what is 'weak positive' ? Earlier, I said , "Usually, PCR is turned within 35 times and the result is 'positive' when the desired result is obtained ."

So how do you judge if you turn 34 times or 33 times as much as you want? It's less than 35, so positive is definitely positive. But there is also a steaming steam that is hard to shake off. It is difficult for the inspector to shout "Yes!" That is why testers usually conclude with the term ' weak positive '. It is presumed that this was the case for dogs in Hong Kong that were corona19 'weak positive'.

There is something to point out in this passage. Virus scanning is a reflection of the subjectivity of the scanner. During my previous military service, I did this virus test at a military medical research institute, a military research unit in the military, and I remember how I would judge every time a number on this border came out.

In other words, testing for viruses, the smallest microorganisms, is a difficult and difficult process.
0 or 1, not 'binary digital' which only describes two digits, but rather 'interpretation' by an experienced inspector. (Today, at this moment, I would like to express my deepest gratitude and respect to the inspectors who have given their full strength to the Corona 19 virus test all over the country.)

And, crucially, as with all tests, there is a limit that this PCR cannot be determined to be 100% accurate. In particular, it is very difficult, complicated, and sophisticated to isolate and test a virus that is completely invisible. This means that errors may occur during the experiment due to mechanical characteristics .

In fact, the Korean Veterinary Clinical Forum (KBVP), an academic veterinary clinic for treating animals, also said, "If you test 100 times with 99% accuracy, you can get false positives. I need to check because it came out. " In other words, it is difficult to conclude that 'weak positive' is positive and should be followed by additional tests. Anyway, from that point of view, the fact that the dog has been `` weak positive '' is "not to say that this dog is infected with Corona 19" .
● Is it 'infection' or 'contamination'? The possibility of simply 'burying'

So, if we assume that the dog is not actually infected with the corona virus, where did this trace of the virus that caused the 'weak positive' decision come from? If the virus didn't exist at all, it would have been voiced at all. However, the 'weak positive' decision can be said to have 'a little virus anyway'.

In this case, one of the hypotheses that can be deduced is that there was a simple contact. In other words, your dog may have been physically exposed to a contaminated house environment that is infected with a virus. To put it more simply, at one point, the Corona 19 virus was buried, and the dog squeaked and the virus could be 'buried' in the nose or mouth.

That's why the South China Morning Post also said, "If this was a result of environmental contamination of its, the authorities report that their dog may have had a mouth or nose in a virus-infected environment. mouth and nose. Oral, nasal and rectal samples were collected for testing. "

Another Hong Kong local journalist, Bin Guilbo , also reported that "the dog licked around the (master's mouth) and had a virus on his (dog) mouth and nose (可能 只是 因 狗隻 周圍 , 令 口 及 鼻 帶有 病毒)." I did it.

Han Ji-eun, Professor of Veterinary Medicine, College of Veterinary Medicine, Kyungpook National University. “Corona 19 is the most damaging to the lungs, but it is also known to reduce the function of other organs such as the heart, kidneys, and intestines. There may be limitations in judging whether or not there is a need for additional virus testing in dog feces or blood to see if the virus is physically buried in the dog. ”

In conclusion, I can summarize this. "The dog may have licked the owner of the corona confirmer, or was exposed to an environment with the corona virus. The virus may have been around the dog's mouth and nose."

● If you are inside your body but are hard to define an infection

Of course, the Corona 19 virus may actually have entered the dog's body. This cannot be ruled out either. Then, at another level, more fundamental questions arise. What is the definition of 'infected with a virus'?

Any virus, including the Corona 19 virus, can "physically" enter the human or animal body through the wounded mucous membrane. But that's not the end. What if you succeeded in getting into the body, but couldn't get inside the cell and stay outside? If so, it's virtually meaningless for a virus.

Basically, a virus must go inside a cell and continue to copy and make genes like itself. Like animals, including humans, give birth to children and preserve their species. If you don't, the virus will soon be caught by police and soldiers (immune cells) who have been reported and dispatched and will be killed and killed.

I don't know if the analogy is appropriate, but let's say someone from North Korea came down to our country.

① When a North Korean fisherman catches fish in the sea and his boat breaks down
② When a highly trained North Korean spy penetrates through the border network of our military

In both cases, it is the same that someone came down from North Korea. However, the phenomena and nature of what happens after you come to South Korea are completely different. In most cases, they are repatriated to North Korea. On the other hand, in case 2, if the spies are not caught on time, they will be actively engaged in domestic recruitment.

Infection is similar. It is necessary to distinguish whether the virus is simply physically inside the dog's body , or if it has penetrated deep into the cell and submerged in other cells . If you look closely at 'infection' from a medical point of view, the latter is the case that the virus enters the cell and is successful.

However, dogs that received this 'weak positive' luck were reported to have no clinical symptoms. Even if it is assumed that the virus has entered the dog's body, it can be seen that it did not actually enter the cell and multiply.

Park Jin-kyu, professor of pathology at Kyungpook National University, said, “Of course, we can't conclude that there are no clinical symptoms, but we haven't been infected. "It's hard to say that your dog is infected with the Corona 19 virus , given that it's a sample test." In other words, it's not the kind of “virus infection of pets” that viewers are worried about.
● "There is currently no evidence of pet infections or common infectious diseases."

The World Health Organization (WHO), as well as the Hong Kong Department of Agriculture, Forestry and Fisheries, says, "There is no evidence that pets can be infected at this time. The World Animal Organization (OIE) also announced that "the predominant transmission path of corona 19 is from human to human."

Choi Sung-kyun, senior researcher at the Daegu-Gyeongbuk Institute of Science and Technology (Dr. of Veterinary Medicine), said, “The data from this case is unlikely that the virus has been transferred from humans to animals. ” "It's hard to say that dogs are infected with the Corona virus because they don't have specific information on what kind of testing was done, how the virus gene sequence was detected," he said.

In a nutshell, given the information given so far, it's unlikely that your dog is infected with the Corona 19 virus. Kim Hyun-wook, chairman of the Korea Veterinary Clinical Forum, also advised that pets such as dogs and cats are very unlikely to be infected with Corona 19, and they do not need to quarantine or keep them away under realistic conditions.

However, experts advised that if a person infected with Corona 19 virus touches a pet, such as a hand that has been stained with the virus, the pet may be able to physically transfer the virus to a healthy person. After all, for the health of people, animals and all of us, it is best to thoroughly manage personal hygiene by wearing masks and washing your hands frequently and thoroughly.

※ Once again at this moment, I would like to express my deepest gratitude and respect to all the medical professionals who are fighting the war against viruses with their whole bodies. We also share words of encouragement and encouragement to all who suffer from Corona 19. Our media will do our best to fulfill our responsibilities as air as we wisely cope with these trials.

(Photo = Getty Images Korea)