In addition to the typical respiratory response, new coronavirus disease 2019 (COVID-19) is also associated with very common gastrointestinal symptoms. Cases with gastrointestinal symptoms are more likely to be complicated by liver injury and acute respiratory distress syndrome (ARDS). If not treated in time, coma and circulatory failure may ensue. As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects the human body through the combination of angiotensin-converting enzyme 2 (ACE2) in the gastrointestinal tract, the mechanism underlying the gastrointestinal symptoms may involve damage to the intestinal mucosal barrier and promotion of the production of inflammatory factors. Indeed, after cells in the lungs become infected by SARS-CoV-2, effector CD4⁺ T cells reach the small intestine through the gut-lung axis, causing intestinal immune damage and diarrhea; early extensive use of antibacterial and antiviral drugs can also lead to diarrhea in patients. Thus, treatment options for COVID-19 patients should be promptly adjusted when they have gastrointestinal symptoms. As SARS-CoV-2 has been detected in the feces of COVID-19 patients, future prevention and control efforts must consider the possibility of fecal-oral transmission of the virus.

Background: Toll‐like receptor 4 (TLR4) is considered to be involved in the pathogenesis and progression of atopic dermatitis (AD). In the present study, we evaluated the relationship between TLR4 gene polymorphisms and the susceptibility or severity of AD among Chinese Han children.Methods: A total of 132 AD patients and 100 healthy controls were enrolled in this study. Four single‐nucleotide polymorphisms (rs19277914, rs11536891, rs7869402, and rs11536889) of the TLR4 gene were genotyped by multiplex PCR combined with next‐generation sequencing.Results: Our results showed that a significantly reduced risk for AD was associated with C allele [p = 0.008; odds ratio (OR) = 0.41, C vs. T], TC genotype (p = 0.022; OR = 0.41, TC vs. TT), and TC + CC genotype (p = 0.010; OR = 0.39, TC + CC vs. TT) of TLR4 rs11536891. The frequency of the haplotype GCCG (rs1927914–rs11536891–rs7869402–rs11536889) in AD patients was lower than that in the controls (p = 0.010; OR = 0.38). Moreover, the results indicated that a higher risk of severe AD was related to the T allele (p = 0.019; OR = 2.97, T vs. C) and the TC genotype (p = 0.021; OR = 3.34, TC vs. CC) of TLR4 rs7869402. A risk haplotype of TLR4 (GTTG) was found in severe AD patients (p = 0.010; OR = 5.26).Conclusions: Our data suggested that TLR4 rs11536891 polymorphism was associated with the susceptibility to AD in Chinese Han children. And TLR4 rs7869402 might confer the severity of pediatric AD patients.

Background: Early and accurate identification of infection viruses among children can benefit the personalized medical treatment and management, and reduce the future occurrence of serious symptoms. Thus, it is critical to develop a high-throughput multiplex real-time RT-PCR method to improve the accuracy and efficiency in routine clinical lab tests. Methods: We developed a real time RT-PCR combined with melting curve analysis (RRCMC) method for simultaneous detection of rotavirus A, B, C, norovirus GI and GII, adenovirus, astrovirus and sapovirus. Results: Stool samples were collected from 160 children with acute diarrhea and tested by RRCMC assay. A total of 71 patients were tested positive with norovirus, adenovirus or rotavirus. The RRCMC assay has high specificity. There is no internal cross-reaction among the 8 diarrhea viruses and no cross-reaction of other commonly intestinal pathogens and human genome. The limit detection was ranged from 1 × 10² to 1 × 10⁵ nucleic acid copies/ml for each diarrhea virus. Conclusion: The RRCMC method is a suitable rapid clinical test for infectious viruses, with the advantages of high-throughput, low cost, high sensitivity and specificity.