Читать книгу Principles of Virology, Volume 2 - Jane Flint, S. Jane Flint - Страница 45

How many people do you encounter each day in conversation, in the classroom, or passing on the street? Dozens to hundreds of interactions—some long-lasting, others fleeting—can occur in a day, and each of these individuals has a personal “network” as well. The science of social networks as a tool to understanding spread of pathogens within communities has revolutionized epidemiology. Such networks define potential transmission routes; for example, contact tracing identifies likely transmission network connections from known infected cases and then applies this information to treat or contain their contacts, thereby reducing the spread of infection. Contact tracing is a highly effective public health tool, as it uses the underlying transmission dynamics to target control efforts and does not rely on a detailed understanding of the etiology of the infection.

Network analysis has been used most effectively when considering viruses that are spread via sexual activity. In contrast to airborne infections, sexually transmitted viruses, such as human immunodeficiency virus type 1 and some herpesviruses, have transmission routes that should be easily identified, provided one can recall recent sexual partners. In these cases, an individual identifies their sexual partners over a given period, these partners are then contacted and asked for their partners, and so on; this process is known as snowball sampling, and is used by many public health officials to contact individuals who may be at risk for infection.

Developing methods to trace viruses’ spread via aerosols is far more challenging. One successful strategy took advantage of the fact that most people carry mobile phones; in this study, data were collected using Bluetooth to sense other mobile phones in the vicinity. These data gave a highly detailed account of an individual’s behavior and contact patterns, and allowed highly detailed interaction maps to be developed.