The Serum Value of NO and IL-17 were Increased in Children with Influenza A Viral Pneumonia.

BACKGROUND: Influenza A virus can cause severe respiratory infection in children and even result in immune system dysfunction. The aim of this study is to examine the clinical value of peripheral blood lymphocytes and serum nitric oxide (NO) and cytokines in children with influenza A viral pneumonia. METHODS: Thirty children hospitalized with confirmed influenza A viral pneumonia and 30 healthy controls were enrolled in this study. The blood samples were collected from all the children and anti-coagulated with EDTA. The peripheral blood lymphocyte subsets were analyzed by flow cytometry. Griess assay were performed to calculate serum NO and nitrite (NO2-) levels. The serum concentrations of IFN-γ and IL-17 were measured by ELISA. RESULTS: The serum levels of NO, NO2-, and IL-17 were significantly higher in children with influenza A viral pneumonia than controls (p < 0.01), while the level of IFN-γ had no significant difference (p = 0.515). Additionally, the patients had significantly lower percentages of peripheral blood CD3+, CD3+CD4+ T lymphocytes, and CD56+CD16+ natural killer (NK) cells than controls (p < 0.05), while CD3+CD8+ and CD4-CD8- (double negative, DN) T lymphocytes did not differ significantly (p > 0.05). Correlation analysis suggests that the serum NO level is positively correlated with IL-17 (p < 0.05). Conclusions: The increased levels of NO and IL-17 may be related to dysregulated lymphocytes' immune response in children with influenza A viral pneumonia. These abnormalities may be the main cause of inflammatory lung damage, and thus have significant prognostic value.

Human adenovirus (HAdV) infection in children with acute respiratory tract infections in Guangzhou, China, 2010-2021: a molecular epidemiology study.

BACKGROUND: Human adenovirus (HAdV) infection can cause a variety of diseases. It is a major pathogen of pediatric acute respiratory tract infections (ARIs) and can be life-threatening in younger children. We described the epidemiology and subtypes shifting of HAdV among children with ARI in Guangzhou, China. METHODS: We conducted a retrospective study of 161,079 children diagnosed with acute respiratory illness at the Guangzhou Women and Children's Medical Center between 2010 and 2021. HAdV specimens were detected by real-time PCR and the hexon gene was used for phylogenetic analysis. RESULTS: Before the COVID-19 outbreak in Guangzhou, the annual frequency of adenovirus infection detected during this period ranged from 3.92% to 13.58%, with an epidemic peak every four to five years. HAdV demonstrated a clear seasonal distribution, with the lowest positivity in March and peaking during summer (July or August) every year. A significant increase in HAdV cases was recorded for 2018 and 2019, which coincided with a shift in the dominant HAdV subtype from HAdV-3 to HAdV-7. The latter was associated with a more severe disease compared to HAdV-3. The average mortality proportion for children infected with HAdV from 2016 to 2019 was 0.38% but increased to 20% in severe cases. After COVID-19 emerged, HAdV cases dropped to 2.68%, suggesting that non-pharmaceutical interventions probably reduced the transmission of HAdV in the community. CONCLUSION: Our study provides the foundation for the understanding of the epidemiology of HAdV and its associated risks in children in Southern China.

Lack of gene flow between Phytophthora infestans populations of two neighboring countries with the largest potato production.

Gene flow is an important evolutionary force that enables adaptive responses of plant pathogens in response to changes in the environment and plant disease management strategies. In this study, we made a direct inference concerning gene flow in the Irish famine pathogen Phytophthora infestans between two of its hosts (potato and tomato) as well as between China and India. This was done by comparing sequence characteristics of the eukaryotic translation elongation factor 1 alpha (eEF-1α) gene, generated from 245 P. infestans isolates sampled from two countries and hosts. Consistent with previous results, we found that eEF-1α gene was highly conserved and point mutation was the only mechanism generating any sequence variation. Higher genetic variation was found in the eEF-1α sequences in the P. infestans populations sampled from tomato compared to those sampled from potato. We also found the P. infestans population from India displayed a higher genetic variation in the eEF-1α sequences compared to China. No gene flow was detected between the pathogen populations from the two countries, which is possibly attributed to the geographic barrier caused by Himalaya Plateau and the minimum cross-border trade of potato and tomato products. The implications of these results for a sustainable management of late blight diseases are discussed.

Human-Mediated Gene Flow Contributes to Metapopulation Genetic Structure of the Pathogenic Fungus Alternaria alternata from Potato.

Metapopulation structure generated by recurrent extinctions and recolonizations plays an important role in the evolution of species but is rarely considered in agricultural systems. In this study, generation and mechanism of metapopulation structure were investigated by microsatellite assaying 725 isolates of Alternaria alternata sampled from potato hosts at 16 locations across China. We found a single major cluster, no isolate-geography associations and no bottlenecks in the A. alternata isolates, suggesting a metapopulation genetic structure of the pathogen. We also found weak isolation-by-distance, lower among than within cropping region population differentiation, concordant moving directions of potato products and net gene flow and the highest gene diversity in the region with the most potato imports. These results indicate that in addition to natural dispersal, human-mediated gene flow also contributes to the generation and dynamics of the metapopulation genetic structure of A. alternata in China. Metapopulation structure increases the adaptive capacity of the plant pathogen as a result of enhanced genetic variation and reduced population fragmentation. Consequently, rigid quarantine regulations may be required to reduce population connectivity and the evolutionary potential of A. alternata and other pathogens with a similar population dynamics for a sustainable plant disease management.

[Complete genomic sequence analysis on human enterovirus 71 strain in Guangzhou, in 2008 and 2010].

OBJECTIVE: To study the genomic genotypes and variation of human enterovirus 71 (EV71) infected infants in Guangzhou city, in 2008 and 2010. METHODS: Primers were designed on the basis of the genomic sequence of EV71 SHZH03 strain (AY465356) in the GenBank, and EV71 genome amplified by RT-PCR. PCR-products were directly sequenced and the genomic nucleotide sequences were analyzed with the programs of Clustal W/X, DNASTAR and MEGA 4.1. RESULTS: 9 strains of EV71 genome appeared to be 7405 bp in length. The genomic sequences of EV71 Guangzhou strains were compared with those of EV71 in GenBank, which revealed that the homology with EV71 genotype C4a Fuyang strains ranged between 98% - 99%. Homology with genotype C4b were 92% - 94%, with genotypes C1, C2, C3 as 82% - 83%, with genotypes B3, B4, B5 as 81% - 83% and the homology with genotype A was 80%. When compared the VP1 genes of EV71 Guangzhou strains with genotypes A, B, C virus, we revealed that the highest homology was also with genotype C4a. When compared the VP1 amino acid sequences of EV71 Guangzhou strains with genotype A, B, C virus by Clustal W program, the results revealed that the amino acid residue Q at position 22 in VP1 gene was transformed to H, while 213 (S→T) and 1764 (V→I) mutations in polyprotein were discovered. CONCLUSION: Data from the sequences and phylogenetics analysis on those Guangzhou strains in 2008 and 2010 revealed that those isolates belong to genotype C4a, with the homology with Fuyang strains as 98%-99%. Mutation of amino acid residue H at position 22 in VP1 gene was discovered and the neutralizing antibody of EV71 might have been conversed by this residue. 213 (S→T) and 1764 (V→I) mutations in polyprotein were also discovered.

[Etiology of hand, foot and mouth disease in Guangzhou in 2008].

OBJECTIVE: To understand the etiology of hand, foot and mouth disease (HFMD) in Guangzhou area in 2008. METHOD: Totally 1023 clinical specimens were collected from pediatric patients suspected of HFMD in 2008. TaqMan real-time RT-PCR were used for detection of enterovirus 71 (EV71), Coxsackievirus A16 (CA16) and other enteroviruses. The specimens which were enterovirus positive by RT-PCR method with universal primer but EV71 and CA16 negative, were amplified and sequenced for 5'untranslated region. RESULT: Enterovirus was identified from 434 of 1023 samples and detection rate of enterovirus was 42.42%; of the 434 samples, 276 were positive for EV71 (63.6%), 126 for CA16 (29%), 4 samples for enterovirus 84, 3 for Echovirus 11, 2 for Echovirus 9, 3 for Coxsackievirus B3, 4 for Coxsackievirus A10, 3 for Coxsackievirus A6, 6 for Coxsackievirus A12 or A5, and for 7 samples typing was difficult. CONCLUSION: The major causative agents of HFMD in Guangzhou were EV71 and CA16 in 2008, and EV84, CA10, CA12, CA6, COSB3, ECHV11, ECHV9 were also the pathogens for smaller proportions of patients.