Contagious Diseases and Social Networks
In the past decade, there has been an outbreak of contagious diseases all around the world. Quite recently, there has been an outbreak of Zika virus, which has made it way even to the states. Although the virus originated in the continent of Africa, the first reported case of the Zika virus has been confirmed in Florida by CDC. Like most other contagious diseases, spread of the Zika virus depends on direct contact – modes of contact include transmission of body fluids, mosquitoes etc
You might be wondering why my blog in a class for networks is about contagious disease. Did you know that quite interestingly contagious diseases can be represented and analyzed by graph theory? Let’s take a look at it. In a visual representation of contagious diseases, the nodes represent infected humans while the people who they are infected by and the people who they would infect are represented by edges. Essentially, we have a digraph since transmission of contagious diseases is usually unidirectional. Like any other digraphs, graph theories can be used to analyzed and predict graph behavior.
Since spread of contagious diseases depends on direct contact, the people who will be infected are family and friends of the infected. If someone has strong ties with the infected, he/she is more likely to contract the disease. On the other hand, if someone has weak ties with the infected, he/she is less likely to contract the disease. Often, people connecting two different communities can act as local bridges. For example, the man who was infected with the Zika virus in Florida had recently been to Africa and he acted as a local bridge between the community he visited in Africa and the community in Florida.
Graph theory can be a useful tool for intervention in the case of an outbreak of a contagious disease. It can be a tool for CDC to determine who the infected has interacted with in the recent past so that the spread of disease can be regulated.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.524.5507&rep=rep1&type=pdf
http://cabtes55.cnea.gov.ar/estadistica/abramson/notes/Epidemics-Lectures-PANDA.pdf