Little Evidence of Subclinical Avian Influenza Virus Infections among Rural Villagers in Cambodia

Gray, Gregory C.; Krueger, Whitney S.; Chum, Channimol; Putnam, Shannon D.; Wierzba, Thomas F.; Heil, Gary L.; Anderson, Benjamin D.; Yasuda, Chadwick Y.; Williams, M. C.; Kasper, Matthew R.; Saphonn, Vonthanak; Blair, Patrick J.

doi:10.1371/journal.pone.0097097

Cited by 8 publications

(5 citation statements)

References 29 publications

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“…On the other hand, a population of antibodies reducing the replication of H5 virus, but not clearing it, was induced after the repeated infection with this mouse-adapted avian IAV (results not shown). These results correspond to the observation of Gray et al (2014), who showed that many infections of humans with avian IAV (of subtypes H4, H5, H6, H9 or H12) were subclinical with generally none or only very low titers of VN antibodies having been detected. This phenomenon might influence the process of adaptation of avian viruses to mammalian hosts, including humans.…”

Section: Discussionsupporting

confidence: 91%

Virus-neutralizing antibody response of mice to consecutive infection with human and avian influenza A viruses

Janulíková¹,

Stropkovská²,

Bobišová³

et al. 2015

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Summary. -In this work we simulated in a mouse model a naturally occurring situation of humans, who overcame an infection with epidemic strains of influenza A, and were subsequently exposed to avian influenza A viruses (IAV). The antibody response to avian IAV in mice previously infected with human IAV was analyzed. We used two avian IAV (A/Duck/Czechoslovakia/1956 (H4N6) and the attenuated virus rA/Viet Nam/1203-2004 (H5N1)) as well as two human IAV isolates (virus A/Mississippi/1/1985 (H3N2) of medium virulence and A/Puerto Rico/8/1934 (H1N1) of high virulence). Two repeated doses of IAV of H4 or of H5 virus elicited virus-specific neutralizing antibodies in mice. Exposure of animals previously infected with human IAV (of H3 or H1 subtype) to IAV of H4 subtype led to the production of antibodies neutralizing H4 virus in a level comparable with the level of antibodies against the human IAV used for primary infection. In contrast, no measurable levels of virus-neutralizing (VN) antibodies specific to H5 virus were detected in mice infected with H5 virus following a previous infection with human IAV. In both cases the secondary infection with avian IAV led to a significant increase of the titer of VN antibodies specific to the corresponding human virus used for primary infection. Moreover, cross-reactive HA2-specific antibodies were also induced by sequential infection. By virtue of these results we suggest that the differences in the ability of avian IAV to induce specific antibodies inhibiting virus replication after previous infection of mice with human viruses can have an impact on the interspecies transmission and spread of avian IAV in the human population.Keywords: avian influenza A viruses; sequential influenza A infection; antibody response; virus-neutralizing antibodies; HA2-specific antibodies; original antigenic sin * Corresponding author. E-mail: viruevar@savba.sk; phone: +421-2-59302427. Abbreviations: HA = hemagglutinin; IAV = influenza A virus; MAb = monoclonal antibody; OAS = original antigenic sin; VN = virus-neutralizing

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Section: Discussionsupporting

confidence: 91%

Virus-neutralizing antibody response of mice to consecutive infection with human and avian influenza A viruses

Janulíková¹,

Stropkovská²,

Bobišová³

et al. 2015

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“…We excluded three studies [ 55 , 57 , 60 ] that presented data previously reported in three other included studies [ 54 , 56 , 59 ]. Of the remaining 63 studies, 27 were conducted among a total of 19,320 participants during 1997 to 2016 in five countries and utilized the WHO-recommended seropositive antibody titer threshold (Fig.…”

Section: Resultsmentioning

confidence: 99%

Serological evidence of human infections with highly pathogenic avian influenza A(H5N1) virus: a systematic review and meta-analysis

Chen

Wang

et al. 2020

BMC Med

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Background Highly pathogenic avian influenza A(H5N1) virus poses a global public health threat given severe and fatal zoonotic infections since 1997 and ongoing A(H5N1) virus circulation among poultry in several countries. A comprehensive assessment of the seroprevalence of A(H5N1) virus antibodies remains a gap and limits understanding of the true risk of A(H5N1) virus infection. Methods We conducted a systematic review and meta-analysis of published serosurveys to assess the risk of subclinical and clinically mild A(H5N1) virus infections. We assessed A(H5N1) virus antibody titers and changes in titers among populations with variable exposures to different A(H5N1) viruses. Results Across studies using the World Health Organization-recommended seropositive definition, the point estimates of the seroprevalence of A(H5N1) virus-specific antibodies were higher in poultry-exposed populations (range 0–0.6%) and persons exposed to both human A(H5N1) cases and infected birds (range 0.4–1.8%) than in close contacts of A(H5N1) cases or the general population (none to very low frequencies). Seroprevalence was higher in persons exposed to A(H5N1) clade 0 virus (1.9%, range 0.7–3.2%) than in participants exposed to other clades of A(H5N1) virus (range 0–0.5%) (p < 0.05). Seroprevalence was higher in poultry-exposed populations (range 0–1.9%) if such studies utilized antigenically similar A(H5N1) virus antigens in assays to A(H5N1) viruses circulating among poultry. Conclusions These low seroprevalences suggest that subclinical and clinically mild human A(H5N1) virus infections are uncommon. Standardized serological survey and laboratory methods are needed to fully understand the extent and risk of human A(H5N1) virus infections.

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“…Slightly lower rates were found for H1N2v, for which 5% (fourfold antibody titre increase, rural residents) and 8% (antibody titre rise, farm workers and abattoir workers) of study participants had evidence of exposure over two years [58,74]. In the period from 2008 to 2011, both Coman et al and Gray et al found a high percentage of seroconversions for H1N1v and H1N2v, which were most likely due to cross-reactions with influenza A(H1N1)pdm09 [117,118]. Both Coman et al and Terebuh et al investigated serological evidence of H3N2v exposure during a time-period of two years, concluding that the number of titre increases for different types of H3N2v in the swine-exposed group were not significantly higher than in control groups [74,117].…”

Section: Resultsmentioning

confidence: 99%

“…Four cohort studies found antibodies to H6N1 during their two-year study periods. The percentage of the study populations that experienced an increase in antibody titres ranged between 0.1% and 2% [101,108,117,118]. Two of the four studies could not find an association with animal exposure.…”

Section: Resultsmentioning

confidence: 99%

Weighing serological evidence of human exposure to animal influenza viruses − a literature review

2016

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Assessing influenza A virus strains circulating in animals and their potential to cross the species barrier and cause human infections is important to improve human influenza surveillance and preparedness. We reviewed studies describing serological evidence of human exposure to animal influenza viruses. Comparing serological data is difficult due to a lack of standardisation in study designs and in laboratory methods used in published reports. Therefore, we designed a scoring system to assess and weigh specificity of obtained serology results in the selected articles. Many studies report reliable evidence of antibodies to swine influenza viruses among persons occupationally exposed to pigs. Most avian influenza studies target H5, H7 and H9 subtypes and most serological evidence of human exposure to avian influenza viruses is reported for these subtypes. Avian influenza studies receiving a low grade in this review often reported higher seroprevalences in humans compared with studies with a high grade. Official surveillance systems mainly focus on avian H5 and H7 viruses. Swine influenza viruses and avian subtypes other than H5 and H7 (emphasising H9) should be additionally included in official surveillance systems. Surveillance efforts should also be directed towards understudied geographical areas, such as Africa and South America.

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Little Evidence of Subclinical Avian Influenza Virus Infections among Rural Villagers in Cambodia

Cited by 8 publications

References 29 publications

Virus-neutralizing antibody response of mice to consecutive infection with human and avian influenza A viruses

Virus-neutralizing antibody response of mice to consecutive infection with human and avian influenza A viruses

Serological evidence of human infections with highly pathogenic avian influenza A(H5N1) virus: a systematic review and meta-analysis

Weighing serological evidence of human exposure to animal influenza viruses − a literature review

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