Robert Webster is primarily associated with work on Option 2: Influenza virus.

Robert G. Webster is a renowned virologist who has made significant contributions to the field of influenza research. He is widely recognized for his expertise in studying the influenza virus and its impact on human health. Here are some key points that support the selection of Option 2:

1. Expertise and Research Focus: Robert Webster has dedicated a significant portion of his career to studying the influenza virus. His research has focused on various aspects of influenza, including its ecology, evolution, transmission, and the development of vaccines. He has conducted extensive studies on the molecular biology and pathogenesis of influenza viruses.

2. Pioneering Work on Avian Influenza: Webster is particularly renowned for his groundbreaking research on avian influenza viruses, also known as bird flu. He played a crucial role in identifying and understanding the H5N1 strain of avian influenza, which poses a potential pandemic threat to humans. Webster`s work shed light on the transmission dynamics of avian influenza and helped in devising strategies for prevention and control.

3. Collaboration with WHO and CDC: Webster has collaborated closely with organizations such as the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) in the United States. His expertise has been instrumental in guiding global efforts to monitor and respond to influenza outbreaks, including the development of effective vaccines.

4. International Recognition and Awards: Robert Webster`s contributions to influenza research have garnered international recognition. He has received numerous prestigious awards for his work, including the Prince Mahidol Award for his exceptional contributions to public health, particularly in the field of avian influenza.

While Robert Webster is a highly accomplished scientist, it`s important to note that he may have made contributions to other areas of research as well. However, his significant and groundbreaking work on the influenza virus makes Option 2, Influenza virus, the most appropriate choice.