Epidemiologic report and serologic findings for household contacts of three cases of influenza A (H7N9) virus infection

Qiu, Chao; Yuan, Songhua; Tian, Di; Yu, Yong; Zhang, Anli; Chen, Qingguo; Wan, Yanmin; Song, Zhigang; He, Jianhua; Li, Liangzhu; Sun, Jiao; Zhou, Mingzhe; Qiu, Changjian; Zhang, Zhiyong; Lu, Shuaiyao; Zhang, Xiaoyan; Hu, Yunwen; Xu, Jianqing

doi:10.1016/j.jcv.2013.12.004

Cited by 9 publications

(8 citation statements)

References 13 publications

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“…Non‐sustained human‐to‐human transmission is suspected to have also occurred for both viruses at similar rates (Hien et al., ; Olsen et al., ; Ungchusak et al., ; Yang et al., ; To et al., ; Li et al., ; Qiu et al., ). The viruses also appear to cause similar types of influenza‐like illness, along with diarrhoea, vomiting, and abdominal pain and bleeding in rare cases (Beigel et al., ; Kandeel et al., ).…”

Section: Resultsmentioning

confidence: 99%

A Systematic Review of the Comparative Epidemiology of Avian and Human Influenza A H5N1 and H7N9 - Lessons and Unanswered Questions

Bui

Bethmont

Chughtai

et al. 2015

Transbound Emerg Dis

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SummaryThe aim of this work was to explore the comparative epidemiology of influenza viruses, H5N1 and H7N9, in both bird and human populations. Specifically, the article examines similarities and differences between the two viruses in their genetic characteristics, distribution patterns in human and bird populations and postulated mechanisms of global spread. In summary, H5N1 is pathogenic in birds, while H7N9 is not. Yet both have caused sporadic human cases, without evidence of sustained, human-to-human spread. The number of H7N9 human cases in the first year following its emergence far exceeded that of H5N1 over the same time frame. Despite the higher incidence of H7N9, the spatial distribution of H5N1 within a comparable time frame is considerably greater than that of H7N9, both within China and globally. The pattern of spread of H5N1 in humans and birds around the world is consistent with spread through wild bird migration and poultry trade activities. In contrast, human cases of H7N9 and isolations of H7N9 in birds and the environment have largely occurred in a number of contiguous provinces in south-eastern China. Although rates of contact with birds appear to be similar in H5N1 and H7N9 cases, there is a predominance of incidental contact reported for H7N9 as opposed to close, high-risk contact for H5N1. Despite the high number of human cases of H7N9 and the assumed transmission being from birds, the corresponding level of H7N9 virus in birds in surveillance studies has been low, particularly in poultry farms. H7N9 viruses are also diversifying at a much greater rate than H5N1 viruses. Analyses of certain H7N9 strains demonstrate similarities with engineered transmissible H5N1 viruses which make it more adaptable to the human respiratory tract. These differences in the human and bird epidemiology of H5N1 and H7N9 raise unanswered questions as to how H7N9 has spread, which should be investigated further.

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Section: Resultsmentioning

confidence: 99%

A Systematic Review of the Comparative Epidemiology of Avian and Human Influenza A H5N1 and H7N9 - Lessons and Unanswered Questions

Bui

Bethmont

Chughtai

et al. 2015

Transbound Emerg Dis

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“…They found 19 cases of respiratory symptoms from these close contacts but all cases tested negative for the H7N9 virus [ 5 ]. Qiu et al reported that all family members of three patients infected by H7N9 showed negative reactions on H7N9 viral tests, although they all had close contact with the patients during the viral shedding period [ 17 ]. All of these previous reports indicated that the novel avian-origin H7N9 virus was not easily transmitted by close contact of H7N9 infected patient.…”

Section: Discussionmentioning

confidence: 99%

Serologic screenings for H7N9 from three sources among high-risk groups in the early stage of H7N9 circulation in Guangdong Province, China

Zou

et al. 2014

Virol J

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BackgroundThe aim of this study was to assess the prevalence of the novel avian influenza A virus (H7N9) in three high risk groups. The groups were divided into those exposed through infected individuals, those exposed through poultry and those individuals exposed through the external environment, in the early stage of the epidemic in Guangdong Province, which is located in the southern region of China.MethodsSerologic studies were conducted among samples collected from individuals who had close contact with the first H7N9 infected patient reported in Guangdong Province, those who were most likely exposed to the first group of H7N9 infected poultry, and those who might have been exposed to H7N9 in the environmental settings, namely hemagglutinin inhibition (HI) and microneutralizaiton(MN) assays using three viruses as antigens.ResultsThe alignment results of the viral sequences indicated the similarity of the HA gene sequence among viruses from exposure to infected poultry, infected humans and contaminated environments were highly conserved. Seven samples of individuals exposed to contaminated environments were positive in the HI assay and one sample among them was positive in the MN assay using poultry H7N9 virus as the antigen. One sample was positive against human H7N9 virus and 3 samples were positive against environmental H7N9 among those that were in contact with infected patients in HI assay. None of these were positive in MN assay. All HI titers of the 240 samples from those individuals in contact with infected poultry were less than 40 aganist the antigens from three viruses.ConclusionsThe results suggest that when the H7N9 virus was in the early stages of circulation in Guangdong Province, the antigenic sites of the HA proteins of the H7N9 strain isolated from different hosts were highly conserved. The risk of new infection is low in individuals who have contact with the infected patients, poultry or a contaminated environment in the early stages of the circulation of the H7N9 virus.

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“…Additionally, case‐ascertained household studies have sought to also answer similar questions about influenza by following the household contacts of a case series 65‐133 . To summarize the transmissibility of influenza, studies of both types often report the secondary attack rate (SAR), a descriptive statistic that quantifies the risk of an exposed person becoming ill from an infectious person living within the same household 1‐24,65‐72,73‐104,105‐124 . The SAR is the de facto measure of transmissibility of influenza, and trials of antivirals have used SAR to quantify changes in the transmissibility of influenza attributable to a therapeutic regimen given to infectious household members or a prophylactic regimen given to susceptible household members 13,14,21,66,71,72,111 .…”

Section: Introductionmentioning

confidence: 99%

Household transmission of influenza A and B within a prospective cohort during the 2013‐2014 and 2014‐2015 seasons

Dahlgren

Foppa

Stockwell

et al. 2021

Statistics in Medicine

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People living within the same household as someone ill with influenza are at increased risk of infection. Here, we use Markov chain Monte Carlo methods to partition the hazard of influenza illness within a cohort into the hazard from the community and the hazard from the household. During the 2013-2014 influenza season, 49 (4.7%) of the 1044 people enrolled in a community surveillance cohort had an acute respiratory illness (ARI) attributable to influenza. During the 2014-2015 influenza season, 50 (4.7%) of the 1063 people in the cohort had an ARI attributable to influenza. The secondary attack rate from a household member was 2.3% for influenza A (H1) during 2013-2014, 5.3% for influenza B during 2013-2014, and 7.6% for influenza A (H3) during 2014-2015. Living in a household with a person ill with influenza increased the risk of an ARI attributable to influenza up to 350%, depending on the season and the influenza virus circulating within the household.

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Epidemiologic report and serologic findings for household contacts of three cases of influenza A (H7N9) virus infection

Abstract: Despite ample unprotected exposures to case-patients during the virus shedding period, household members in this report were not infected by the H7N9 virus.

Cited by 9 publications

References 13 publications

A Systematic Review of the Comparative Epidemiology of Avian and Human Influenza A H5N1 and H7N9 - Lessons and Unanswered Questions

A Systematic Review of the Comparative Epidemiology of Avian and Human Influenza A H5N1 and H7N9 - Lessons and Unanswered Questions

Serologic screenings for H7N9 from three sources among high-risk groups in the early stage of H7N9 circulation in Guangdong Province, China

Household transmission of influenza A and B within a prospective cohort during the 2013‐2014 and 2014‐2015 seasons

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