Tsetse flies (Diptera: Glossinidae) are the sole vectors of pathogenic trypanosomes that cause Human African trypanosomiasis (HAT) in sub-Saharan Africa. Current methods to control his devastating disease include the use of pesticides to eliminate the tsetse vector and chemotherapeutic agents to treat already infected individuals. Both of these methods have drawbacks that severely limit their effectiveness.
A novel method, called ‘paratransgenesis’, is being developed that would employ tsetse’s symbiotic bacteria to express trypanocidal compounds in vivo. Tsetse’s facultative mutualist, Sodalis glossinidius, lives in close proximity to pathogenic trypanosomes in the host’s gut. This bacterium can be cultured in vitro, genetically modified and reintroduced back into female flies. These ‘paratransgenic’ females subsequently maintain infections with recombinant Sodalis that continuously express their transgene throughout the life of the fly. Current and future studies include developing methods to increase the stability of transgene expression over time, and identifying novel and effective effector molecules to use in the system.