researchControl strategies
Overview
Much CIDD research is relevant to the design of strategies to control human and animal diseases — including zoonotic and other emerging diseases.
Drug development, drug treatment regimes
Drugs can slow or prevent disease agents from invading hosts, or from reproducing there. The drug can affect the disease agent directly, or indirectly via effects on the host. For example, Craig Cameron's work with positive-strand RNA viruses (e.g. poliovirus, hepatitis C) has yielded insights into how understanding the molecular details of genome replication can aid the development of antiviral drugs that disrupt pathogen replication.
Vaccination
Vaccination reduces disease transmission by reducing the pool of susceptible individuals. Much of CIDD's epidemiological work — on the spatiotemporal dynamics of disease and the effects of heterogeneity — can help inform strategies for distributing vaccine for:
- Human diseases such as measles, pertussis and influenza. For example, Bryan Grenfell and coworkers have used mathematical models to explore how potential loss of immunity to vaccine can affect long-term patterns of infection. Bryan Grenfell, Ottar Bjornstad and collaborators are currently extending work on measles in industrialized countries to model the epidemic consequences of novel vaccination strategies in developing countries, where measles is still a significant cause of mortality in children.
- Animal diseases such as equine influenza and Foot and Mouth Disease. In the latter case, Bryan Grenfell and collaborators are using data on the spatiotemporal spread of infection in the 2001 U.K. Foot and Mouth epidemic to examine the optimal balance of culling and vaccination in disease control.
CIDD research on immunodynamics, evolution of virulence and parasite interactions is also relevant to the development and distribution of effective vaccines.
Building design
The architectural design and spatial distribution of buildings can greatly affect disease transmission in humans and livestock — for example, by affecting contact rates between infected and susceptible individuals, duration of contacts, exposure of airborne pathogens to favorable or unfavorable conditions, and so on. Darla Lindberg and collaborators are combining empirical data with mathematical models to recommend how buliding design can reduce pathogen transmission. For example, we are exploring how airflow within and between poultry sheds can be optimized to reduce the spread of avian influenza.
Managing wildlife diseases
Our work on the ecology, evolution and epidemiology of disease has implications for:
- The design of disease containment and mitigation strategies in wildlife populations
- Strategies for reducing the probability of zoonoses emerging and persisting in human populations
For instance:
- Superspreaders are infectious individuals that infect a relatively large number of susceptible hosts. Hence, removing or vaccinating likely superspreaders could greatly aid disease control. Sarah Perkins, Isabella Cattadori, Peter Hudson and Jamie Lloyd-Smith are investigating the contribution of superspreaders to disease dynamics, and identifying factors that predispose individuals to become superspreaders.
» More about superspreading in our heterogeneities section - Anthropogenic and environmental change often increases the risk that humans are exposed to wildlife diseases, and vice versa. For example, removal of large mammals from ecosystems changes the range of hosts available for parasite vectors such as ticks. For instance, some large mammals are non-competent transmitters of tick-borne parasites, and so afford a dilution effect. Removal of these non-competent hosts may significantly increase the risk to humans of being bitten by ticks, and acquiring zoonotic infections such as Lyme Disease. A CIDD workshop has been convened to review the importance of the dilution effect in disease transmission.
- Management of one wildlife population can impact on disease dynamics in another. For example, modelling by Peter Hudson and collaborators has shown that predator removal can increase disease incidence in prey populations that are regulated by parasitic infections — particularly when the parasite is highly virulent, macroparasites are highly aggregated, hosts are long-lived and the predators select infected prey.