Synthetic biology of Vector-Borne disease*

The recent pandemic has taught us that the modern world is vulnerable to infectious diseases and demonstrated that we need to train ourselves to deal with future pandemics. One way to expand our knowledge of epidemics is to build laboratory systems that mimic aspects of disease spreading under safe conditions. To this end, we have developed a model system using a dimorphic bacteriophage that allowed us to recapitulate the spread of a vector-borne disease. The characteristic that renders a disease vector-borne is a life cycle that requires alternating types of host. Our "malaria in a petri dish" system is based on an engineered, nonhazardous, dimorphic bacteriophage with a life cycle that requires alternation between two host bacteria. We quantified the growth properties of the hosts and virus forms and examined the spread between independent bacterial microcolonies in an immobilized suspension. A mathematical model was able to describe the observed spread of the virus by treating the microcolonies as independent communities. The model correctly predicted both the efficiency of herd immunity and a reduced spread of infection when colonies are larger and more separated.