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Updated: Jun 23, 2026

A Luciferase-fluorescent Reporter Influenza Virus for Live Imaging and Quantification of Viral Infection
05:21

A Luciferase-fluorescent Reporter Influenza Virus for Live Imaging and Quantification of Viral Infection

Published on: August 14, 2019

Update: novel influenza A (H1N1) virus infections - worldwide, May 6, 2009

    MMWR. Morbidity and Mortality Weekly Report
    |May 16, 2009
    PubMed

    Insights

    A novel influenza A (H1N1) virus caused a global outbreak starting in Mexico and the US in 2009. Health organizations responded, and the World Health Organization (WHO) raised the pandemic alert to phase 5 due to human-to-human spread.

    Area of Science:

    • Public Health
    • Virology
    • Epidemiology

    Background:

    • An outbreak of novel influenza A (H1N1) virus emerged in Mexico and the United States in 2009.
    • The virus was confirmed by the CDC and Canadian health authorities.
    • Genetic analysis showed similarity between U.S. and Mexican influenza strains.

    Purpose of the Study:

    • To report on the initial investigations of the novel influenza A (H1N1) outbreak.
    • To provide an update on the global spread of the virus.
    • To document the public health response to the emerging pandemic.

    Main Methods:

    • Surveillance data compilation by WHO member states.
    • Case reporting and monitoring by the World Health Organization (WHO).
    • Genetic sequencing and comparison of influenza A (H1N1) strains.

    Main Results:

    • As of May 6, 2009, 1,882 confirmed cases were reported worldwide across 21 countries.
    • Human-to-human transmission was confirmed, leading to a WHO pandemic alert level increase to phase 5.
    • The novel influenza A (H1N1) virus demonstrated rapid international spread.

    Conclusions:

    • The novel influenza A (H1N1) virus represented a significant global public health threat in 2009.
    • International collaboration and surveillance were crucial for monitoring the outbreak.
    • The findings underscored the need for preparedness for novel influenza pandemics.

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