インフルエンザの感染力が強い人がいる理由を科学者が解明(Scientists reveal why some people with the flu may be more contagious)

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2024-06-26 スイス連邦工科大学ローザンヌ校(EPFL)

EPFLの研究は、人間の体内に存在するウイルスと細菌の複雑な関係を明らかにしました。健康な人でも皮膚や腸、鼻、口には様々な細菌が存在します。インフルエンザのような呼吸器疾患にかかると、ウイルスは細菌と共存します。この研究では、くしゃみや咳、会話で飛散するウイルスが呼吸器細菌によりどのように影響を受けるかを調査しました。結果、細菌を含む飛沫では、ウイルスの感染力が長時間維持され、乾燥した環境でのウイルスの生存が延びることが分かりました。特に、黄色ブドウ球菌や肺炎球菌がウイルスを安定化させる効果が大きいことが示されました。この発見は、呼吸器疾患の伝播メカニズムを理解するための重要な情報を提供し、感染リスク評価に貢献する可能性があります。

<関連情報>

飛沫やエアロゾル中のA型インフルエンザウイルスの安定性は、呼吸器常在菌の存在によって高まる Stability of influenza A virus in droplets and aerosols is heightened by the presence of commensal respiratory bacteria

Shannon C. David, Aline Schaub, Céline Terrettaz, Ghislain Motos, Laura J. Costa, Daniel S. Nolan, Marta Augugliaro,…
Journal of Virology  Published:13 June 2024
DOI:https://doi.org/10.1128/jvi.00409-24

ABSTRACT

Aerosol transmission remains a major challenge for control of respiratory viruses, particularly those causing recurrent epidemics, like influenza A virus (IAV). These viruses are rarely expelled alone, but instead are embedded in a consortium of microorganisms that populate the respiratory tract. The impact of microbial communities and inter-pathogen interactions upon stability of transmitted viruses is well-characterized for enteric pathogens, but is under-studied in the respiratory niche. Here, we assessed whether the presence of five different species of commensal respiratory bacteria could influence the persistence of IAV within phosphate-buffered saline and artificial saliva droplets deposited on surfaces at typical indoor air humidity, and within airborne aerosol particles. In droplets, presence of individual species or a mixed bacterial community resulted in 10- to 100-fold more infectious IAV remaining after 1 h, due to bacterial-mediated flattening of drying droplets and early efflorescence. Even when no efflorescence occurred at high humidity or the bacteria-induced changes in droplet morphology were abolished by aerosolization instead of deposition on a well plate, the bacteria remained protective. Staphylococcus aureus and Streptococcus pneumoniae were the most stabilizing compared to other commensals at equivalent density, indicating the composition of an individual’s respiratory microbiota is a previously unconsidered factor influencing expelled virus persistence.

医療・健康
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