Strain Variation in Vector-borne Parasites

Recent work has been indicating that many species of parasites may actually occur as immunologically distinct strains. This has been recognized for some time in serotypes of viruses such as dengue, African horse sickness and bluetongue. These different strains may circulate in the vector and host populations completely independently, or they may interact in some way.

Interactions could be positive, where the infection of a host or vector by one strain increases the likelihood of the host being infected with another strain. Conversely, negative interactions are also known, where the presence of one strain prevents or reduces the chance of infection with another. These interactions are potentially very important in the control of disease, as the effort needed (such as vaccination) will depend on the independence of the strains.

By using data sets from different diseases, we are investigating whether the distribution of strains (which hosts have which strains, and in what combinations) can provide any information about the transmission of strains, and how this information can be used in the design of control strategies.

Contact: C. Lord