Distribution of Avian Influenza A Viruses in Poultry-Related Environment and Its Association with Human Infection in Henan, 2016 to 2017

Objective To survey avian influenza A viruses(AIVs) in the environment and explore the reasons for the surge in human H7 N9 cases.Methods A total of 1,045 samples were collected from routine surveillance on poultry-related environments and 307 samples from human H7 N9 cases-exposed environments in Henan from 2016 to2017. The nucleic acids of influenza A(Flu A), H5, H7, and H9 subtypes were detected by real-time polymerase chain reaction.Results A total of 27 H7 N9 cases were confirmed in Henan from 2016 to 2017, 24 had a history of live poultry exposure, and 15 had H7 N9 virus detected in the related live poultry markets(LPMs). About 96%(264/275) Flu A positive-environmental samples were from LPMs. H9 was the main AIV subtype(10.05%) from routine surveillance sites with only 1 H7-positive sample, whereas 21.17% samples were H7-positive in H7 N9 cases-exposed environments. Samples from H7 N9 cases-exposed LPMs(47.56%)had much higher AIVs positive rates than those from routine surveillance sites(12.34%). The H7+H9 combination of mixed infection was 78.18%(43/55) of H7-positive samples and 41.34%(43/104) of H9-positive samples.Conclusion The contamination status of AIVs in poultry-related environments is closely associated with the incidence of human infection caused by AIVs. Therefore, systematic surveillance of AIVs in LPMs in China is essential for the detection of novel reassortant viruses and their potential for interspecies transmission.

First outbreak of human infection with avian influenza A(H7N9) virus in Guangxi, China, 2016 to 2017

To the Editor: Since avian influenza A(H7N9) was first identified in Shanghai, China, in March 2013, there have been a total of five epidemics. These have amounted to 1564 laboratory-confirmed cases up to September 2017, with a fatality rate of about 40%.[1] In the fifth wave, 4.09% of cases (31/758) were infected with the highly pathogenic avian influenza (HPAI) A(H7N9). This indicated that the pathotype of the A(H7N9) had switched from low pathogenic avian influenza (LPAI) to HPAI.

Vaccination of poultry successfully eliminated human infection with H7N9 virus in China

The H7 N9 viruses that emerged in China in 2013 were nonpathogenic in chickens but mutated to a highly pathogenic form in early 2017 and caused severe disease outbreaks in chickens. The H7 N9 influenza viruses have caused five waves of human infection, with almost half of the total number of human cases(766 of 1,567) being reported in the fifth wave, raising concerns that even more human infections could occur in the sixth wave. In September 2017, an H5/H7 bivalent inactivated vaccine for chickens was introduced, and the H7 N9 virus isolation rate in poultry dropped by 93.3% after vaccination. More importantly,only three H7 N9 human cases were reported between October 1, 2017 and September 30, 2018, indicating that vaccination of poultry successfully eliminated human infection with H7 N9 virus. These facts emphasize that active control of animal disease is extremely important for zoonosis control and human health protection.

Environmental connections of novel avian-origin H7N9 influenza virus infection and virus adaptation to the human

A novel H7N9 influenza A virus has been discovered as the causative identity of the emerging acute respiratory infection cases in Shanghai,China.This virus has also been identified in cases of infection in the neighboring area Hangzhou City in Zhejiang Province.In this study,epidemiologic,clinical,and virological data from three patients in Hangzhou who were confirmed to be infected by the novel H7N9 influenza A virus were collected and analyzed.Human respiratory specimens and chicken feces from a contacted free market were tested for influenza virus by real-time reverse transcription PCR(RT-PCR) and sequencing.The clinical features of the three cases were similar featured with high fever and severe respiratory symptoms;however,only one of the patients died.A certain degree of diversity was observed among the three Hangzhou viruses sequenced from human samples compared with other reported H7N9 influenza A viruses.The sequences of the novel avian-origin H7N9 influenza viruses from Hangzhou City contained important amino acid substitutions related to human adaptation.One of the Hangzhou viruses had gained a novel amino acid substitution(Q226I) in the receptor binding region of hemagglutinin.More importantly,the virus sequenced from the chicken feces had a 627E substitution in the PB2 protein instead of the mammalian-adapted 627K substitution that was found in the PB2 proteins from the Hangzhou viruses from the three patients.Therefore,the newly-emerging H7N9 virus might be under adaptation pressure that will help it "jump" from avian to human hosts.The significance of these substitutions needs further exploration,with both laboratory experiments and extensive field surveillance.

Novel human H7N9 influenza virus in China

Outbreaks of H7N9 avian influenza in humans in 5 provinces and 2 municipalities of China have reawakened concern that avian influenza viruses may again cross species barriers to infect the human population and thereby initiate a new influenza pandemic.Evolutionary analysis shows that human H7N9 influenza viruses originated from the H9N2,H7N3 and H11N9 avian viruses,and that it is as a novel reassortment influenza virus.This ar­ticle reviews current knowledge on 11 subtypes of influenza A virus from human which can cause human infec­tions.

Fungal spondylodiscitis in a patient recovered from H7N9 virus infection:a case study and a literature review of the differences between Candida and Aspergillus spondylodiscitis

To report a rare case of fungal spondylodiscitis in a patient recovered from H7N9 virus infection and perform a literature review of the different characteristics of Candida and Aspergillus spondylodiscitis, we reviewed cases of spondylodiscitis caused by Candida and Aspergillus species. Data, including patients＇ information, patho- genic species, treatment strategy, outcomes, and relapses, were collected and summarized. The characteristics of Canclida and Aspergillus spondylodiscitis were compared to see if any differences in clinical features, management, or consequences could be detected. The subject of the case study was first misdiagnosed as having a vertebral tumor, and then, following open biopsy, was diagnosed as having fungal spondylodiscitis. The patient made a good recovery following radical debridement. Seventy-seven additional cases of Candida spondylodiscitis and 94 cases of Asper- gillus spondylodiscitis were identified in the literature. Patients with Candida spondylodiscitis tended to have a better outcome than patients with Aspergillus spondylodiscitis （cure rate 92.3% vs. 70.2%）. Candida was found more fre- quently （47.8%） than Aspergillus （26.7%） in blood cultures, while neurological deficits were observed more often in patients with Aspergillus spondylodiscitis （43.6% vs. 25.6%）. Candida spinal infections were more often treated by radical debridement （60.5% vs. 39.6%）. Patients with Candida spondylodiscitis have better outcomes, which may be associated with prompt recognition, radical surgical debridement, and azoles therapy. A good outcome can be ex- pected in fungal spondylodiscitis with appropriate operations and anti-fungal drugs.

Economic burden and its associated factors of hospitalized patients infected with A (H7N9) virus: a retrospective study in Eastern China, 2013–2014

Background:H7N9 continues to cause human infections and remains a pandemic concern.Understanding the economic impacts of this novel disease is important for making decisions on health resource allocation,including infectious disease prevention and control investment.However,there are limited data on such impacts.Methods:Hospitalized laboratory-confirmed H7N9 patients or their families in Jiangsu Province of China were interviewed.Patients’direct medical costs of hospitalization were derived from their hospital bills.A generalized linear model was employed to estimate the mean direct medical costs of patients with different characteristics.Results:The mean direct cost of hospitalization for H7N9 was estimated to be¥71060(95%CI,48180–104820),i.e.,US$10996(95%CI,7455–16220),and was¥12060(US$1861),¥136120(US$21001)and¥218610(US$33728)for those who had mild or severe symptoms or who died,respectively.The principal components of the total fees differed among patients with different disease severity,although medication fees were always the largest contributors.Disease severity,proportion of reimbursement and family member monthly average income were identified as the key factors that contributed to a patient’s direct medical cost of hospitalization.Conclusions:The direct medical costs of hospitalized patients with H7N9 are significant,and far surpass the annual per capita income of Jiangsu Province,China.The influencing factors identified should be taken into account when developing related health insurance policies and making health resource allocation.Trial registration:Not applicable.This is a survey study with no health care intervention implemented on human participants.

人感染H7N9禽流感引发的传染病学教学思考

人感染H7N9禽流感疫情引发教学者对传染病学教学的思考，分析当前传染病学教学面临的挑战：传染病疾病谱发生巨大变化，但教学课时有限；传染病发病率下降，而适宜的教学病例有限；医学生对传染病学学习存在畏惧心理；教学师资缺乏；公众对传染病防控要求越来越高等。由此提出以下应对策略：调整课程设置；注重教学病例积累，使用多媒体教学，利用专科医院的教学资源；教育学生学会自身防护；注重青年教师培养；强调学科特征及公共卫生的重要性；改进教学方法，提高教学效率。