Hand-hygiene mitigation strategies against global disease spreading through the air transportation network

Christos Nicolaides; Demetris Avraam; Luis Cueto-Felgueroso; Marta C. González; Ruben Juanes

To get the infection, a healthy individual needs to touch to a contaminated surface or directly an infected person. If the individual is healthy and touch a contaminated surface -independent of how long ago he/she washed his/her hands -he/she will get the bacteria on hands. However, if he/she washes hands soon after he/she gets contaminated there is big probability of taking that bacteria out of hands before they are transmitted to body fluids. Therefore, the hand washing rate of healthy individuals affects the transmissibility of a disease as well. Our SIR WD model takes into account only the interdependence between disease transmission probability and the hand cleanliness of the infected individuals. To model the process where the hand washing behavior of susceptible/healthy individuals has a role in the infection process, we need to build a more sophisticated model based on SEIR reaction kinetics, where the extra epidemic compartment E indicates individuals that are Exposed to bacteria or viruses 36 . The SEIR epidemic model describes the following three processes: (a) a susceptible comes in contact with an infected individual and becomes exposed to the disease with some rate β (S + I β − → E + I), (b) an exposed becomes infected with some rate γ (E γ − → I), and (c) an infected recovers with rate µ (I µ − → R). Both rates β and γ are affected by the hand washing levels. Here, we keep our analysis simple by using the conventional SIR model with the assumption that if infected individuals wash hands frequently, there is smaller probability to contaminate surfaces or other healthy people directly.