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Recently, Hong Kong's Agriculture, Fisheries and Conservation Department (AFCD) said that a pet dog had been infected with the new coronavirus to a low degree, becoming the first case in the world.

The pet dog belongs to Zhou Qiao, who has been diagnosed with the new coronavirus pneumonia. The AFCD's tests found that its oral and nasal samples were weakly positive.

As soon as the news came out, many people were surprised: Is the new coronavirus "mutated" and able to spread in dogs?

Then a new coronavirus panic emerged: Many Australians choose to euthanize their pets, fearing that pets will contract the disease and infect themselves and their families.

The latest response from the World Health Organization is that there is no evidence that dogs are closely related to the transmission of new coronaviruses.

Li Gang, a researcher at the Beijing Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, said that according to previous research, no canine coronavirus has infected humans and human coronavirus-infected dogs, but the animal infection spectrum of the new coronavirus has not been known.

"In this regard, we must not panic first, and secondly, we must attach importance to and strengthen research on zoonotic diseases of pet origin and do a good job of prevention and control from the perspective of zoonotic diseases."

Zoonoses must conform to Koch's Law

Infectious diseases are diseases caused by pathogenic microorganisms such as viruses, bacteria or fungi. Zoonoses refer to diseases that are caused by the same pathogen and are epidemiologically interrelated and naturally spread between vertebrates and humans.

Li Gang pointed out that the condition for an infectious disease to become zoonotic is that pathogenic microorganisms must be able to spread between humans and animals and cause corresponding clinical symptoms.

"Most zoonotic infectious diseases are transmitted to humans through animals, such as rabies and cat scratch disease, and some zoonotic infectious diseases can be transmitted to animals, such as tuberculosis."

Li Gang said that the spread of infectious diseases between humans and beasts needs to meet three basic conditions necessary for the spread of infectious diseases: source of infection, route of transmission, and susceptible groups. Only when these three conditions exist and are linked to each other can zoonotic disease occur and spread.

Zoonoses usually have the characteristics of great harm, strong infectivity, high mass, wide area and obvious occupation.

Li Gang told China Science Daily that the detection of zoonotic diseases mainly uses laboratory methods such as pathogen isolation, molecular biology techniques (such as PCR, gene sequencing), and immunoserological techniques (such as ELISA, neutralization experiments). Whether humans and animals contain pathogens, specific nucleic acids, antigens and antibodies.

"The diagnosis of zoonotic diseases should be made based on clinical symptoms, epidemiological investigations, pathological changes, and laboratory diagnosis." Li Gang emphasized.

Cui Shangjin, a researcher at the Beijing Institute of Animal Husbandry and Veterinary Medicine of the Chinese Academy of Agricultural Sciences and chief scientist of the pet disease prevention and control innovation team believes that to determine whether an animal is infected with a disease, it first depends on whether it has the corresponding symptoms and whether it excretes the pathogen.

To determine whether it is contagious, it depends on whether the disease can cause disease in multiple animals or multiple individuals of one animal.

Li Gang told reporters that the determination of the relationship between pathogens and susceptible animals for new infectious diseases (including viral zoonotic diseases) must comply with Koch's law.

Koch's law is a set of scientific verification methods proposed by German bacteriologist Robert Koch to verify the relationship between bacteria and disease. It is regarded as the golden rule of infectious disease identification by future generations.

According to Koch's law, first, the same microorganisms appear in each case and do not exist in healthy people; second, such microorganisms must be isolated from the host for pure culture; third, the pure The culture is inoculated to a healthy and sensitive host, and the same disease will occur repeatedly. Fourth, the microorganism can be isolated and cultured again from the experimentally affected host.

Detection of new coronavirus in animals

Experts on animal disease prevention and control said that pet dogs like to use the nasal cavity and mouth to show their intimacy with their owners and to smell the ground objects. If the owner is infected with the new coronavirus and becomes ill, the virus can be transmitted to pets through close contact and contaminated items in the home, which is a contaminated virus.

"The new coronavirus is suitable for survival and reproduction in the human respiratory tract, and it is also possible to exist and survive in the upper respiratory tract of polluted dogs for a period of time," Cui Shangjin said.

Li Gang believes that the detection of new types of coronavirus nucleic acids on the above-mentioned pet dogs must first eliminate the possibility of external contamination. If the virus can be detected in the pet for several consecutive days, and the body also responds after a certain period of time (such as the detection of specific antibodies in the serum), then the animal can be considered infected with the new coronavirus.

So, why does this new coronavirus-positive pet dog have no symptoms? According to Cui Shangjin, one possibility is that many animals have antibodies that inhibit the virus, so they are less likely to develop symptoms.

"It is likely to be the same as previous research results: New coronaviruses detected in bats, civets, pangolins, etc., although very similar to human coronaviruses, do not cause disease in mammals, and pet dogs are only carriers of the virus. "He says.

Previously, the team of Shi Zhengli, a researcher at the Wuhan Institute of Virology, Chinese Academy of Sciences, did some research on the infectivity of the new coronavirus, and published an article in Nature stating that the new coronavirus may use angiotensin converting enzyme II (ACE2) as a cell The receptor invaded the host, and the researchers demonstrated that the new coronavirus can bind to ACE2 in humans other than mouse ACE2, Chinese horseshoe bats, civet cats and pigs.

The World Health Organization also said that due to the natural lack of ACE2 receptors in dogs and cats, the S-protein of the new coronavirus cannot invade cells in pets, so it cannot survive and reproduce in pets.

Therefore, most researchers believe that the greatest significance of the above pet dog test results is a warning, indicating that pets such as cats and dogs are at risk of transmitting the virus.

Nevertheless, Cui Shangjin said that the dog should be closely followed by the new coronavirus in the later period. "It is recommended that new types of coronaviruses be detected in animals such as dogs, cats, and minks to reduce the possible routes of transmission of new coronaviruses."

No need to be nervous

In the face of zoonotic diseases, the public is often prone to panic and make inappropriate actions. In this regard, Li Gang said that to deal with zoonotic diseases, traditional treatment methods for preventing infectious diseases can be used. "In simple terms, it is to control the source of infection, cut off the route of transmission, and protect vulnerable groups."

He believes that the public does not need to be overly nervous, as long as they pay attention to the following points, they will reduce the risk of illness: treat pets as family members; do good personal protection, isolate the source of infection, and go home to wash and clean in time; strictly control the feeding of pets to raw food Clean up pet cages and the environment in a timely manner; regular medical examinations; vaccination on schedule.

"At present, what the majority of pet-loving and pet-loving people need to do is to continue to do a good job of protecting themselves, their families and pets in accordance with the control requirements of government departments, and wait for the release of more authoritative scientific information. , Lethal pets, "said Cui Shangjin.

In a story published on FluentWoof, the author Dr. Libby Guise said if you’re already practicing good hygiene with your pooch, you may not need to change your behavior. Remember, even though it’s unlikely you could get this novel virus from your dog, there are other diseases that pass between canines and humans.

Affected by the new coronavirus pneumonia epidemic, since the Spring Festival, the vast majority of pet hospitals in Yangzhou City, Jiangsu Province have been closed, and the Animal Hospital of Yangzhou University has taken measures to stop services during the epidemic.

Physicians at the pet clinic of animal hospitals maintain close online contact with pet owners through telephone, QQ and WeChat, perform one-on-one online consultation services, solve common diseases at pet homes, and express delivery to pet owners. Pet medicine.

Liu Zongping, dean of the School of Veterinary Medicine at Yangzhou University, who has long been engaged in research on animal nutritional metabolism and poisoning diseases, urged veterinarians to use professional knowledge to help the people to alleviate the panic of the epidemic. The majority of pets treat pets scientifically and raise pets scientifically.

He said: "Animals and humans share the same ecosystem. Animal diseases are closely related to human health. The World Health Organization has put forward the concept of" One Health ". We must treat animal health, human health and ecological health as a whole. treat."

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