The 6-year-old boys mother was diagnosed as a suspected case after his anal swab turned positive after discharge

 The 6-year-old boys mother was diagnosed as a suspected case after his anal swab turned positive after discharge

Recently, in Guangdong, Chongqing, Jiangsu, Hainan and other places, there have been cases of positive transfer of nucleic acid detection in discharged patients. Experts from the national health and Health Commission said that there was no further infection among these patients. In addition to the requirements of diagnosis and treatment plan, Shanghai has increased the requirements of anal swab detection.

A week after the boy left the hospital, his mother developed symptoms

On February 19, Liu, a 6-year-old boy, was cured and discharged from Qinhuangdao. Photo source: Qinhuangdao

Late on the night of February 29, Tianjin Municipal Health and Health Commission released a news that another case of confirmed discharge was found to be positive in nucleic acid test. It was a confirmed case in Qinhuangdao, Hebei Province, who returned to Tianjin after being cured and discharged from hospital. After 10 days, the anal swab samples were positive.

Liu, a boy, lives in liqizhuang street, Xiqing District, Tianjin. His parents worked in Wuhan from January 14 to 15 and returned to Tianjin on January 15. On January 21, the family drove a private car to Qinhuangdao, Hebei Province for the new year. From January 29 to February 6, the boy and his father were successively diagnosed as confirmed cases in Qinhuangdao third hospital and hospitalized for treatment. On February 19, the father and son were discharged from the hospital. On that day, a family of three returned to Tianjin by private car, and then they were isolated at home. The health departments of Tianjin and Hebei have been monitoring their health.

On February 26, the boys mother developed runny nose symptoms. On February 27, he drove to fever clinic to see a doctor. He was diagnosed as a suspected case, and the nucleic acid test result was negative. He was isolated for observation and treatment.

Subsequently, the CDC of Xiqing District collected specimens of the boy and his father. After testing, the boys throat swab samples were negative, the anal swab samples were positive, and the fathers throat swab and anal swab samples were negative.

On February 29, after the consultation of Tianjin municipal expert group, the boy was admitted to Haihe hospital for observation. The relevant departments have carried out final disinfection of their residences.

This is the third case of nucleic acid test positive in Tianjin. Previously, on February 27, Tianjin CDC reported that the 29th and 43th confirmed cases in Tianjin were positive in nucleic acid recheck on the 15th and 17th day during the centralized isolation observation after discharge, and had been transferred to Haihe hospital for observation and treatment.

In many places, anal swabs are positive, so far there are no cases of infection

Pharyngeal swab is to take secretions from nose, throat, tonsil and other parts for virus detection. The positive nucleic acid of throat swab indicates that there is a viral gene fragment or virus in throat or respiratory tract. Anal swab is to insert the swab into the anus 2 to 3 cm to take samples, or to wipe the folds around the anus for sampling. Beijing knows that there are many cases of negative throat swabs and positive anal swabs, and there are also cases of similar cases in children.

As early as February 5, the Chongqing municipal government announced at the epidemic prevention and control conference that there have been many cases in Chongqing where the throat swab test is negative, and finally confirmed as positive through the anal swab.

Similar cases have occurred in Guangdong and Zhejiang. On February 24, Gong Sitang, deputy director of Guangzhou women and childrens Medical Center, said in an interview with the media that the first child patient discharged from the hospital had negative throat swabs and anal swabs twice when leaving the hospital, but when returning home for isolation, relevant personnel found that the anal swabs were positive again when they came to the door for inspection.

Zhang Wenhong said that there are no cases about whether the nucleic acid test will spread in the patients with recurrent Yang. However, although there is no risk of transmission now, Shanghai will observe the recovered patients for another two weeks before they leave the hospital.

On February 29, Guo Yanhong, the supervision commissioner of the medical administration of the National Health Commission, said that some provinces reported that the patients who were cured and discharged were found to have positive nucleic acid test in the process of further consultation. Through monitoring, it was found that this part of patients did not infect others again, and another part of patients turned negative when they tested the new coronavirus nucleic acid again.

At present, the mother of the 6-year-old boy in Tianjin has been listed as a suspected case, but the nucleic acid test is negative and has not been confirmed.

Viral receptors are mainly distributed in the intestine, and detection has been required in Shanghai

The new coronavirus, similar to SARS virus, invades cells through the binding receptor ACE2.

Although the new coronavirus mainly causes respiratory symptoms, researchers found that ACE2 is mainly distributed in the intestine, and there will be some gastrointestinal symptoms. On February 9, medrxiv, a medical preprint website, published the papers of academician Zhong Nanshan and other experts online. In 1099 cases of covid-19 infection confirmed by the laboratory, nearly 10% of the patients had gastrointestinal symptoms, such as diarrhea, vomiting, etc.

According to the team of Professor Fang Jingyuan, Department of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University Medical College, ACE2 is mainly distributed in colonic epithelial cells. The team also analyzed two independent single cell sequencing data from the public database and found that ACE2 was expressed in human colorectal tissue, and its expression in colorectal cancer tissue was significantly higher than that in normal tissue.

Previously, experts have found a false-positive throat swab.

In a paper published in EMI, Shi Zhenglis team of researchers from Wuhan Institute of Virology, Chinese Academy of Sciences said that they found that the current strategy of detecting viral RNA in oral swabs was not perfect. When the oral swabs were negative, the virus might exist in patients anal swabs or blood. Patients infected with the new coronavirus may carry the virus in their intestines in the early or late stages of the disease.

However, according to the latest paper published in the New England Journal of medicine, the team of academicians Zhong Nanshan found that the clinical characteristics of the new coronavirus imitated the clinical characteristics of SARS, fever and cough were the main symptoms, and gastrointestinal symptoms were rare, which showed that compared with SARS, Middle East respiratory syndrome and seasonal influenza, the viruss preference difference.

The latest novel coronavirus pneumonia diagnosis and treatment plan (trial version sixth) has not yet included anal swab detection as a test standard. However, Guo Yanhong, the Ombudsman of the National Health Protection Commission, said that in order to keep abreast of the rehabilitation of patients after discharge, all patients were required to undergo medical observation for 14 days.

Zhang Wenhong said that Shanghai has made a preliminary plan, that is, after two times of negative nucleic acid test according to the diagnosis and treatment plan, patients will be given anal swabs at the same time. That is to say, if you swallow the nucleic acid, you may have the virus in your mouth, stool and intestines, so it should be all negative..

Fecal oral transmission + aerosol transmission deserves attention

The positive results of anal swabs indicate that the virus may remain in the stool, which brings the risk of fecal oral transmission + aerosol transmission.

During the SARS period, the spread of fecal oral aerosol had brought about great destruction. At the end of March 2003, a large number of SARS cases broke out in Taoda garden of Hong Kong. The reason is that after SARS patients used toilets, the virus leaked through the gap in the sewer and formed aerosol transmission.

At present, a team has detected the presence of new coronavirus in feces, and the fecal oral transmission of new coronavirus has been concerned.

Shis team said they observed a possible shift from oral positivity during early infection to anal swab positivity during late infection. The results showed that patients with negative swabs could not only be discharged from hospital, but also could transmit the virus through the oral fecal route. The latest paper of Zhong Nanshans team also shows that the new coronavirus is mainly transmitted through respiratory droplets and direct contact, similar to the conventional transmission routes of SARS virus, mers virus and highly pathogenic influenza. However, because new coronaviruses can be detected in the gastrointestinal tract, saliva and urine, it is necessary to study these potential routes of transmission.

However, Wu Yuanbin, director of the Department of social development and science and technology of the Ministry of science and technology, said at a recent press conference that the conclusion of the study so far shows that respiratory droplets and close contact transmission are still the main routes of transmission of the new coronavirus. There are some risks in fecal oral transmission, but the ability and conditions of transmission need to be further studied.

According to the problem of aerosol transmission, Wu Yuanbin also explained that the experimental animal Institute of China Medical College also carried out the corresponding transmission experiments, which also suggested that aerosol transmission should meet the three conditions of closed space, long time and high concentration of virus at the same time, and the possibility of aerosol transmission can only be found under extreme conditions. For ordinary people, in a well ventilated environment of daily life, the possibility of transmission is very small, and there is almost no risk of aerosol infection.

A case of positive nucleic acid test in Tianjin

The reporter learned from the city CDC that another case of confirmed discharge in our city was positive for nucleic acid test. This case is a confirmed case in Qinhuangdao City, Hebei Province. It returned to Tianjin after being cured and discharged from the hospital. Ten days later, the anal swab specimen was positive and was admitted to Haihe hospital for observation.

More than 99% homology between virus nucleic acid detected in saliva and fecal samples

The novel coronavirus infection diagnosis and treatment plan for children in Shenzhen Third Peoples Hospital (National Center for infectious diseases Clinical Research) was published in February 27th by the National Clinical Research Center for infectious diseases and the Third Affiliated Hospital of Shenzhen University of science and Technology (the Second Affiliated Hospital of Southern University of science and Technology). Meanwhile, the novel coronavirus pneumonia was detected in saliva of the new crown pneumonia patients, and the live virus was isolated from the patients anal swabs. The respiratory tract samples had more than 99% homology with the virus in stool samples.