Infectious Diseases Have A Great Impact On Morbidity And...

Infectious diseases have a great impact on morbidity and mortality of people living in long-term care facilities (LTCFs). It is reported that 1 to 3 million serious infections and several thousand outbreaks occur every year in LTCFs.1 Utsumi and colleagues showed in their review paper that influenza was the most reported outbreaks in LTCFs.2 The important source of influenza is infected person. An infected but asymptomatic person can shed the virus and be infectious as well.3 Influenza vaccination is the most effective way to prevent outbreaks. Older people, however, are less likely to be protected by vaccination because the antibody response in older people is considerably lower than in younger people.4 Older people living in LTCFs have†¦show more content†¦Contact tracing, for example, enables us to identify transmission of the disease from infected persons to uninfected persons, and thus to treat their contacts for reducing the spread of infection.6 The study of network s tructure is a first step to infer the disease spread as well as to build better predictive model for future outbreaks. In social network analysis, people within a network are referred to as nodes, and the relationships between people are referred to as edges.7 Each pair of nodes (i, j) is either connected or disconnected, that is, the contact direction is not taken into account in the analysis of the influenza transmission. In the simplest data generation, the connections are defined as ÃŽ ´_ij={ââ€"ˆ(0 if i ↛j@1 if i →j)â” ¤ For undirected edges (i.e., ignoring directionality), the contact matrix is symmetric, and its elements are ÃŽ ´_ij. Node color, shape and size, and edge weight in the social network diagram are conducive to presenting individual properties and connection frequencies. For example, in Figure 1 (the R code appears in APPENDIX), node colors in Figure 1(b) representing infectious status (light pink: infected and light blue: uninfected), and edge weights in Figure 1(c)