Human Cases Of Avian Influenza Research Articles

H5 and H9 Avian Influenza - potential re-emergent zoonotic threats to humans.

This review aims to discuss the current state of human infections with Avian Influenza A (H5) and (H9) viruses, to support awareness of the global epidemiology among clinicians and public health professionals interested in emerging respiratory infections. Among increasing numbers of detections in avian species of Avian Influenza A(H5N1) clade 2.3.4.4b globally, reported human cases of severe infection have been rare.Enhanced surveillance of persons exposed to avian species infected with Influenza A(H5N1) clade 2.3.4.4b in different countries has identified small numbers of asymptomatic individuals with Avian Influenza A(H5N1) detected by PCR from the upper respiratory tract; some of these instances have been considered to represent contamination rather than infection.There have also been recent sporadic human cases of Avian Influenza A(H9N2) internationally, including in China and Cambodia. Human infections with Avian Influenza A(H5) and (H9) viruses remain of interest as an emerging infection both to clinicians and public health professionals. While maintaining effective surveillance is essential, One health strategies to control infection in avian species will be key to mitigating these risks.

Analysis of avian influenza A (H3N8) viruses in poultry and their zoonotic potential, China, September 2021 to May 2022.

BackgroundTwo human cases of avian influenza A (H3N8) virus infection were reported in China in 2022.AimTo characterise H3N8 viruses circulating in China in September 2021-May 2022.MethodsWe sampled poultry and poultry-related environments in 25 Chinese provinces. After isolating H3N8 viruses, whole genome sequences were obtained for molecular and phylogenetic analyses. The specificity of H3N8 viruses towards human or avian receptors was assessed in vitro. Their ability to replicate in chicken and mice, and to transmit between guinea pigs was also investigated.ResultsIn total, 98 H3N8 avian influenza virus isolates were retrieved from 38,639 samples; genetic analysis of 31 representative isolates revealed 17 genotypes. Viruses belonging to 10 of these genotypes had six internal genes originating from influenza A (H9N2) viruses. These reassorted viruses could be found in live poultry markets and comprised the strains responsible for the two human infections. A subset of nine H3N8 viruses (including six reassorted) that replicated efficiently in mice bound to both avian-type and human-type receptors in vitro. Three reassorted viruses were shed by chickens for up to 9 days, replicating efficiently in their upper respiratory tract. Five reassorted viruses tested on guinea pigs were transmissible among these by respiratory droplets.ConclusionAvian H3N8 viruses with H9N2 virus internal genes, causing two human infections, occurred in live poultry markets in China. The low pathogenicity of H3N8 viruses in poultry allows their continuous circulation with potential for reassortment. Careful monitoring of spill-over infections in humans is important to strengthen early-warning systems and maintain influenza pandemic preparedness.

Human death due to H5N1 amid the COVID-19 pandemic and Mpox outbreak: A call for action.

Human death due to H5N1 amid the COVID-19 pandemic and Mpox outbreak: A call for action.

Highly pathogenic avian influenza virus of the A/H5N8 subtype, clade 2.3.4.4b, caused outbreaks in Kazakhstan in 2020.

BackgroundLarge poultry die-offs happened in Kazakhstan during autumn of 2020. The birds’ disease appeared to be avian influenza. Northern Kazakhstan was hit first and then the disease propagated across the country affecting eleven provinces. This study reports the results of full-genome sequencing of viruses collected during the outbreaks and investigation of their relationship to avian influenza virus isolates in the contemporary circulation in Eurasia.MethodsSamples were collected from diseased birds during the 2020 outbreaks in Kazakhstan. Initial virus detection and subtyping was done using RT-PCR. Ten samples collected during expeditions to Northern and Southern Kazakhstan were used for full-genome sequencing of avian influenza viruses. Phylogenetic analysis was used to compare viruses from Kazakhstan to viral isolates from other world regions.ResultsPhylogenetic trees for hemagglutinin and neuraminidase show that viruses from Kazakhstan belong to the A/H5N8 subtype and to the hemagglutinin H5 clade 2.3.4.4b. Deduced hemagglutinin amino acid sequences in all Kazakhstan’s viruses in this study contain the polybasic cleavage site (KRRKR-G) indicative of the highly pathogenic phenotype. Building phylogenetic trees with the Bayesian phylogenetics results in higher statistical support for clusters than using distance methods. The Kazakhstan’s viruses cluster with isolates from Southern Russia, the Russian Caucasus, the Ural region, and southwestern Siberia. Other closely related prototypes are from Eastern Europe. The Central Asia Migratory Flyway passes over Kazakhstan and birds have intermediate stops in Northern Kazakhstan. It is postulated that the A/H5N8 subtype was introduced with migrating birds.ConclusionThe findings confirm the introduction of the highly pathogenic avian influenza viruses of the A/Goose/Guangdong/96 (Gs/GD) H5 lineage in Kazakhstan. This virus poses a tangible threat to public health. Considering the results of this study, it looks justifiable to undertake measures in preparation, such as install sentinel surveillance for human cases of avian influenza in the largest pulmonary units, develop a human A/H5N8 vaccine and human diagnostics capable of HPAI discrimination.

INFLUENZA A/H10 VIRUSES OF WILD BIRDS, MAMMALS AND HUMANS

Emerging infectious diseases pose a serious threat to wildlife, domestic animals, and public health. Of the more than 335 human infectious diseases that have emerged over the past six decades, influenza is one of the most common infection, causing up to 650,000 deaths per year. In addition to the annual seasonal influenza A, the emergence of its new, pandemic, and highly pathogenic variant is even more dangerous. This review describes the classification of influenza pathogens, their structural features, and sources of isolation. The latest published data on the structure, ecology, phylogenesis and pathogenicity of influenza A subtype H10 viruses from various host species are summarized. It is noted that the avifauna is not the only possible reservoir for H10 influenza viruses; avian H10N8 infected dogs in China and mink in Scandinavia, and H10N7 caused widespread mortality of seals in the Baltic Sea in 2014. The first three human cases of avian influenza A H10N8 were reported in 2013-2014 in China, one of which lead to mortality. Information is provided on the genetic variability and evolution of influenza A subtype H10 strains circulating in avifaunal, mammalian, and human populations. Influenza A subtype H10 virus is actively evolving by exchange of genetic information. The potential epidemiological hazard of influenza A virus (H10N8) is as a causative agent of a pandemic, and the need to control its circulation in populations of birds, mammals and among the people is emphasized.

Long-term clinical prognosis of human infections with avian influenza A(H7N9) viruses in China after hospitalization

BackgroundMainland China has experienced five epidemics of human cases of avian influenza A(H7N9) virus infection since 2013. We conducted a prospective study to assess long-term clinical, pulmonary function testing, and chest computed tomography (CT) imaging findings after patients were discharged from hospital.MethodsA(H7N9) survivors in five provinces and one municipality underwent follow-up visits from August 2013 to September 2018, at three, six, and 12 months after illness onset, and a subset was also assessed at 18 and 64 months after onset. Thirteen patients were enrolled from the first A(H7N9) epidemic in 2013, 36 from the 2013-2014 second epidemic, and 12 from the 2016-2017 fifth epidemic. At each visit, A(H7N9) survivors received a medical examination, including the mMRC (modified Medical Research Council) dyspnea scale assessment, chest auscultation, pulmonary function testing and chest CT scans.FindingsThe median age of 61 A(H7N9) survivors was 50 years. The cumulative rate of pulmonary dysfunction was 38·5% and 78·2% for chest CT scan abnormalities at the end of follow-up. Restrictive ventilation dysfunction was common during follow-up. Mild dyspnea was documented at three to 12-month follow-up visits.InterpretationPatients who survived severe illness from A(H7N9) virus infection had evidence of persistent lung damage and long-term pulmonary dysfunction.FundingNational Science Fund for Distinguished Young Scholars (grant number 81525023); Program of Shanghai Academic/Technology Research Leader (grant number 18XD1400300); National Science and Technology Major Project of China (grant numbers 2017ZX10103009-005, 2018ZX10201001-010).

Genetic characterization of the first detected human case of avian influenza A (H5N6) in Anhui Province, East China

We compared complete genome sequences of two strains of an avian influenza A (H5N6) virus isolated from a patient in Anhui Province with those of other strains from GenBank and Global initiative on sharing all influenza data (GISAID). The HA gene of the isolated virus shared homology with that of A/chicken/Zhejiang/727155/2014 (H5N6) at the level of similarity of 98%. The six internal genes of the Anhui strains were close to those of H9N2 viruses from Zhejiang, Shandong, and Guangdong provinces, with a similarity of 99%. In addition, the similarity between the internal antigens (NP and MP) of the isolated H5N6 virus and H7N9 and H10N8 viruses was 99%. Based on the data of phylogenetic analysis, the H5N6 influenza virus isolated in Anhui Province belonged to clade 2.3.4.4. The virus was shown to have molecular characteristics of highly pathogenic avian influenza viruses, including eight glycosylation sites and an amino acid sequence of the HA protein cleavage site, PLRERRRKKR/GLF, containing multiple basic amino acids. Additionally, the stalk domain of the NA protein was found to have a deletion in NA stalk region (11 amino acids in N6, positions 58–68). Our study demonstrated that the H5N6 virus from Anhui Province represented a triple-reassortant virus and could be highly pathogenic to humans. The prevalence of this virus should be closely monitored.

Zoonotic Influenza and Human Health-Part 2: Clinical Features, Diagnosis, Treatment, and Prevention Strategies.

Purpose of ReviewZoonotic influenza viruses are those influenza viruses that cross the animal-human barrier and can cause disease in humans, manifesting from minor respiratory illnesses to multiorgan dysfunction. The increasing incidence of infections caused by these viruses worldwide has necessitated focused attention to improve both diagnostic as well as treatment modalities. In this second part of a two-part review, we discuss the clinical features, diagnostic modalities, and treatment of zoonotic influenza, and provide an overview of prevention strategies.Recent FindingsIllnesses caused by novel reassortant avian influenza viruses continue to be detected and described; most recently, a human case of avian influenza A(H7N4) has been described from China. We continue to witness increasing rates of A(H7N9) infections, with the latest (fifth) wave, from late 2016 to 2017, being the largest to date. The case fatality rate for A(H7N9) and A(H5N1) infections among humans is much higher than that of seasonal influenza infections. Since the emergence of the A(H1N1) 2009 pandemic, and subsequently A(H7N9), testing and surveillance for novel influenzas have become more effective. Various newer treatment options, including peramivir, favipiravir (T-705), and DAS181, and human or murine monoclonal antibodies have been evaluated in vitro and in animal models.SummaryArmed with robust diagnostic modalities, antiviral medications, vaccines, and advanced surveillance systems, we are today better prepared to face a new influenza pandemic and to limit the burden of zoonotic influenza than ever before. Sustained efforts and robust research are necessary to efficiently deal with the highly mutagenic zoonotic influenza viruses.

Zoonotic Influenza and Human Health-Part 1: Virology and Epidemiology of Zoonotic Influenzas.

Zoonotic influenza viruses are those that cross the animal-human barrier and can cause disease in humans, manifesting from minor respiratory illnesses to multiorgan dysfunction. They have also been implicated in the causation of deadly pandemics in recent history. The increasing incidence of infections caused by these viruses worldwide has necessitated focused attention to improve both diagnostic as well as treatment modalities. In this first part of a two-part review, we describe the structure of zoonotic influenza viruses, the relationship between mutation and pandemic capacity, pathogenesis of infection, and also discuss history and epidemiology. We are currently witnessing the fifth and the largest wave of the avian influenza A(H7N9) epidemic. Also in circulation are a number of other zoonotic influenza viruses, including avian influenza A(H5N1) and A(H5N6); avian influenza A(H7N2); and swine influenza A(H1N1)v, A(H1N2)v, and A(H3N2)v viruses. Most recently, the first human case of avian influenza A(H7N4) infection has been documented. By understanding the virology and epidemiology of emerging zoonotic influenzas, we are better prepared to face a new pandemic. However, continued effort is warranted to build on this knowledge in order to efficiently combat the constant threat posed by the zoonotic influenza viruses.

Clinical, epidemiological and virological characteristics of the first detected human case of avian influenza A(H5N6) virus

A human infection with novel avian influenza A H5N6 virus emerged in Changsha city, China in February, 2014. This is the first detected human case among all human cases identified from 2014 to early 2016. We obtained and summarized clinical, epidemiological, and virological data from this patient. Complete genome of the virus was determined and compared to other avian influenza viruses via the construction of phylogenetic trees using the neighbor-joining approach. A girl aged five and half years developed fever and mild respiratory symptoms on Feb. 16, 2014 and visited hospital on Feb. 17. Throat swab specimens were obtained from the patient and a novel reassortant avian influenza A H5N6 virus was detected. All eight viral gene segments were of avian origin. The hemagglutinin (HA) and neuraminidase (NA) gene segments were closely related to A/duck/Sichuan/NCXN11/2014(H5N1) and A/chicken/Jiangxi/12782/2014(H10N6) viruses, respectively. The six internal genes were homologous to avian influenza A (H5N2) viruses isolated in duck from Jiangxi in China. This H5N6 virus has not gained genetic mutations necessary for human infection and was suggested to be sensitive to neuraminidase inhibitors, but resistant to adamantanes. Epidemiological investigation of the exposure history of the patient found that a live poultry market could be the source place of infection and the incubation period was 2–5days. This novel reassortant Avian influenza A(H5N6) virus could be low pathogenic in humans. The prevalence and genetic evolution of this virus should be closely monitored.

Chronological, geographical, and seasonal trends of human cases of avian influenza A (H5N1) in Vietnam, 2003-2014: a spatial analysis.

BackgroundHuman cases of highly pathogenic avian influenza A (H5N1) virus infection continue to occur in Southeast Asia. The objective of this study was to identify when and where human H5N1 cases have occurred in Vietnam and how the situation has changed from the beginning of the H5N1 outbreaks in 2003 through 2014, to assist with implementing methods of targeted disease management.MethodsWe assessed the disease clustering and seasonal variation of human H5N1 cases in Vietnam to evaluate the geographical and monthly timing trends. The clustering of H5N1 cases and associated mortality were examined over three time periods: the outbreak period (2003–2005), the post-outbreak (2006–2009), and the recent period (2010–2014) using the flexibly shaped space-time scan statistic. The most likely cases to co-cluster and the elevated risks for incidence and mortality were assessed via calculation of the relative risk (RR). The H5N1 case seasonal variation was analysed as the cyclic trend in incidence data using Roger’s statistical test.ResultsBetween 2003 and 2005, H5N1 cases (RR: 2.15, p = 0.001) and mortality (RR: 2.49, p = 0.021) were significantly clustered in northern Vietnam. After 2010, H5N1 cases tended to occur on the border with Cambodia in the south, while H5N1 mortality clustered significantly in the Mekong delta area (RR: 6.62, p = 0.002). A significant seasonal variation was observed (p < 0.001), with a higher incidence of morbidity in December through April.ConclusionsThese findings indicate that clinical preparedness for H5N1 in Vietnam needs to be strengthened in southern Vietnam in December–April.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-1391-8) contains supplementary material, which is available to authorized users.

A modeling study of human infections with avian influenza A H7N9 virus in mainland China.

Since February 2013, more than 400 laboratory-confirmed human cases of avian influenza A H7N9 infection have been reported in mainland China. Little is known of the dynamics of this novel virus in poultry and human populations, which is essential for developing effective long-term control strategies for this zoonosis. The aim of this study was to evaluate the impact of screening and culling of infected poultry on the evolution of the H7N9 epidemic. A mathematical model for transmission dynamics of avian influenza A H7N9 virus in human and poultry populations was constructed. Parameters in the model were estimated using publicly available nationwide surveillance data on animal and human infections. By fitting a two-host model, it was shown that screening for H7N9 in poultry and culling could effectively decrease the number of new human H7N9 cases. Furthermore, the elimination of circulating H7N9 virus is possible if an intensive, but technically feasible, poultry screening and culling policy is adopted. Screening and culling infected poultry is a critical measure for preventing human H7N9 infections in the long term. This model may provide important insights for decision-making on a national intervention strategy for the long-term control of the H7N9 virus epidemic.

First human case of avian influenza A (H5N6) in Yunnan province, China

Objective:To report clinical, virological, and epidemiological features of the first death caused by a H5N6 avian influenza virus in Yunnan Province, China.Method:The case was described in clinical expression, chest radiography, blood test and treatment. Real-time RT-PCR was used to detect H5N6 virus RNA in clinical and environment samples. Epidemiological investigation was performed including case exposure history determinant, close contacts follow up, and environment sample collection.Results:The patient initially developed sore throat and coughs on 27 January 2015. The disease progressed to severe pneumonia, multiple organ dysfunction syndrome, and acute respiratory distress syndrome. And the patient died on 6 February. A highly pathogenic avian influenza A H5N6 virus was isolated from the tracheal aspirate specimen of the patient. The viral genome analyses revealed that the H5 hemmagglutinin gene belongs to 2.3.4.4 clade. Epidemiological investigation showed that the patient had exposure to wild bird. All close contacts of the patient did not present the same disease in seven consecutive days. A high H5 positive rate was detected in environmental samples from local live poultry markets.Conclusion:The findings suggest that studies on the source of the virus, transmission models, serologic investigations, vaccines, and enhancing surveillance in both humans and birds are necessary.

Attitudinal changes toward control measures in live poultry markets among the general public and live poultry traders, Guangzhou, China, January-February, 2014

Two sets of cross-sectional surveys were conducted among the general public and live poultry traders (LPTs) during January-February, 2014, to monitor attitudes toward human cases of avian influenza A(H7N9)-related control measures among these 2 parties in Guangzhou, China. We found generally high support for regular market rest days among the general public and LPTs, but only limited support for permanent central slaughtering of poultry. LPTs' support for relevant control measures declined after the citywide wet market closure.

Correlation between reported human infection with avian influenza A H7N9 virus and cyber user awareness: what can we learn from digital epidemiology?

Data on the topic of novel avian influenza A (H7N9) were collected based on the web analysis tool 'Baidu Index', a major Chinese search engine. We found a positive correlation between the volume of H7N9-related 'cyber user awareness' and the epidemic situation during the H7N9 outbreak in China (r=0.98, p<0.01, cumulative; r=0.43, p=0.018, daily) except in the early stage; the ranks of H7N9-related topics changed at different epidemic stages. This study may improve our understanding of the role of web-based media in infectious disease surveillance in China.

Effect of closure of live poultry markets on poultry-to-person transmission of avian influenza A H7N9 virus: an ecological study

Transmission of the novel avian influenza A H7N9 virus seems to be predominantly between poultry and people. In the major Chinese cities of Shanghai, Hangzhou, Huzhou, and Nanjing--where most human cases of infection have occurred--live poultry markets (LPMs) were closed in April, 2013, soon after the initial outbreak, as a precautionary public health measure. Our objective was to quantify the effect of LPM closure in these cities on poultry-to-person transmission of avian influenza A H7N9 virus. We obtained information about every laboratory-confirmed human case of avian influenza A H7N9 virus infection reported in the four cities by June 7, 2013, from a database built by the Chinese Center for Disease Control and Prevention. We used data for age, sex, location, residence type (rural or urban area), and dates of illness onset. We obtained information about LPMs from official sources. We constructed a statistical model to explain the patterns in incidence of cases reported in each city on the basis of the assumption of a constant force of infection before LPM closure, and a different constant force of infection after closure. We fitted the model with Markov chain Monte Carlo methods. 85 human cases of avian influenza A H7N9 virus infection were reported in Shanghai, Hangzhou, Huzhou, and Nanjing by June 7, 2013, of which 60 were included in our main analysis. Closure of LPMs reduced the mean daily number of infections by 99% (95% credibility interval 93-100%) in Shanghai, by 99% (92-100%) in Hangzhou, by 97% (68-100%) in Huzhou, and by 97% (81-100%) in Nanjing. Because LPMs were the predominant source of exposure to avian influenza A H7N9 virus for confirmed cases in these cities, we estimated that the mean incubation period was 3·3 days (1·4-5·7). LPM closures were effective in the control of human risk of avian influenza A H7N9 virus infection in the spring of 2013. In the short term, LPM closure should be rapidly implemented in areas where the virus is identified in live poultry or people. In the long term, evidence-based discussions and deliberations about the role of market rest days and central slaughtering of all live poultry should be renewed. Ministry of Science and Technology, China; Research Fund for the Control of Infectious Disease; Hong Kong University Grants Committee; China-US Collaborative Program on Emerging and Re-emerging Infectious Diseases; Harvard Center for Communicable Disease Dynamics; and the US National Institutes of Health.

One World, One Health, One Medicine: An Assessment of Intersectoral Collaboration in Avian Influenza Control in Lagos State

Avian influenza (bird flu) is an infectious disease of birds caused by type A strains of the influenza virus. The infection is known to cross species barrier to infect humans. Between March 2006 and September 2007 Avian influenza (AI) outbreaks occurred in 99 poultry farms in Lagos State. The only human case of AI in Nigeria was detected at a health facility in Lagos in Jan 2007. The outbreak was curbed in the State by the end of year 2007. The collaboration between Veterinary, Health, and Information departments following the AI outbreaks aided the early control of the disease.

Improving global influenza surveillance: trends of A(H5N1) virus in Africa and Asia

BackgroundHighly pathogenic avian influenza A(H5N1) viruses are an important health problem in many Asian and African countries. The current increase in human cases demonstrates that influenza A(H5N1) is still a significant global pandemic threat. Many health organizations have recognized the need for new strategies to improve influenza global surveillance. Specifically, the World Health Organization through the global technical consultation for influenza surveillance have called for a detailed picture of the current limitations, especially at the nation level, to evaluate, standardize and strength reporting systems. The main goal of our study is to demonstrate the value of genetic surveillance as part of a strategic surveillance plan. As a proof of concept, we evaluated the current situation of influenza A(H5N1) in Asian and Africa.ResultsOur analysis revealed a power-law distribution in the number of sequences of A(H5N1) viruses analyzed and/or reported to influenza surveillance networks. The majority of the Asian and African countries at great risk of A(H5N1) infections have very few (approximately three orders of magnitude) sequenced A(H5N1) viruses (e.g. hemagglutinin genes). This suggests that countries under pandemic alert for avian influenza A(H5N1) have very limited participation (e.g. data generation, genetic analysis and data share) in avian influenza A(H5N1) surveillance. More important, this study demonstrates the usefulness of influenza genetic surveillance to detect emerging pandemic threat viruses.ConclusionsOur study reveals that some countries suffering from human cases of avian influenza have limited participation (e.g. genetic surveillance or data share) with global surveillance networks. Also, we demonstrate that the implementation of genetic surveillance programs could increase and strengthen worldwide epidemic and pandemic preparedness. We hope that this work promotes new discussions between policy makers and health surveillance organizations to improve current methodologies and regulations.

Avian influenza (H5N1) expert system using Dempster-Shafer theory

Based on cumulative number of confirmed human cases of avian influenza (H5N1) reported to World Health Organization (WHO) in 2011 from 15 countries, Indonesia has the largest number of deaths because of avian influenza which 146 deaths. In this research, the researcher built an avian influenza (H5N1) expert system for identifying avian influenza disease and displaying the result of identification process. In this paper, we describe five symptoms as major symptoms which include depression, combs, wattle, bluish face region, swollen face region, narrowness of eyes, and balance disorders. We use chicken as research object. Dempster-Shafer theory is to quantify the degree of belief as inference engine in expert system, our approach uses Dempster-Shafer theory to combine beliefs under conditions of uncertainty and ignorance, and allows quantitative measurement of the belief and plausibility in our identification result. The result reveals that avian influenza (H5N1) expert system has successfully identified the existence of avian influenza and displaying the result of identification process.

Comprehensive therapy for human H5N1

The mortality of human H5N1 (pneumonia) is very high. The cumulative number of confirmed human cases of avian influenza A(H5N1) reported is 504, and 59.3% of them have been dead (situation on 12, August 2010). Early intervention could improve the prognosis of this disease.