Focus Group 2010/2011

Limits to Disease Control – Failures in Disease

Parasitic diseases are among the most important elements for human medicine and agriculture as well as for natural ecosystems. Vast resources are devoted to combating infectious diseases, and large sections of the professional fields of medicine, plant pathology and veterinary science are actively researching and implementing this goal. Within the past decade, ecologists and evolutionary biologists, too, have entered the field of infectious disease biology. Their work has already led to an enormous increase in our understanding of the disease process – but there are still huge gaps in our knowledge and understanding of disease evolution. There is a tendency in evolutionary biology to focus on the success of evolution, rather than its failures. From a simple viewpoint, the mere occurrence of disease in a species represents an evolutionary failure: the failure of the host to evolve disease resistance. However in disease biology, evolutionary failure is a two-edged sword: Pathogens themselves may be evolving, or indeed failing to evolve. For example, why has Treponema pallidum, the bacterium that causes syphilis, never evolved resistance to penicillin? Why are there no vaccine-escape mutants in the measles virus? Hosts and pathogens are continuously co-evolving, and it is important to understand what limits or facilitates this process. 

On a more general level, we still lack theories and that would help explain the diversity of these phenomena, and which might also better guide empirical and applied approaches to disease biology. For example, what theory would be needed to really understand the ecology and evolution of diseases? Why do certain pathogens escape control, whilst others do not? Are there general rules that explain the variation that we see among disease systems? 

The focus group assembles leading researchers in the field of disease evolution with an interest in exploring the boundaries of the current approaches to disease evolution and control.