'The science of malaria eradication' Keystone Symposia
Monday Feb 3rd
From bioethical considerations, to mapping trends in malaria transmission with basic biology. From inspiring lessons in other eradication campaigns, to regulatory issues around tools which benefit populations, to novel genetic technologies which modify mosquitoes and the parasite life cycle. The first day of the Keystone Symposium on the science of malaria eradication set the scene for sharing and debating new discoveries and innovative approaches to malaria eradication.
Following the opening remarks, Frank O. Richards (Carter Center, USA) recounted elimination and eradication campaigns of three neglected tropical diseases. ‘Start in the hardest places first; by definition they will be the ones that take longer’, he suggested. Adding that, the need for surveillance and community-based approaches cannot be underestimated, and that only initiatives that address the problem from a regional perspective have any chance in achieving their goals.
Dyann Wirth (Harvard School of Public Health, USA) emphasized the need to understand the selective pressure at a biological level. Barcoding of Single Nucleotide Polymorphisms (SNPs) from parasite isolates was discussed as a key technology to evaluate trends in parasite evolution, and to assess trends in transmission, as well as the impact of interventions.
Vector biology was also addressed, with consensus that malaria eradication will not be successful without targeting the mosquito. The presentations focused on genetic tools with the potential to replace mosquito populations or to render them incapable of transmitting the parasite. Some examples involved genetic ‘scissors’ and others used bacteria symbionts through paratransgenesis.
Presentations were followed by lively Q&A and discussions at the poster sessions. In such a multidisciplinary environment, the importance of integrating strategies was highlighted. As an example, one participant suggested that we could start by reducing mosquito populations through genetic approaches, and then bring in Mass Drug Administration to finalize the job.
A number of questions remain open, however. What drives the parasite selection process, and which parasites or genomes persist over time? Are all parasite strains equally transmitted? What is the correlation between gametocytes and transmission and what are the determinants of infectiousness? How can vector biology strategies be implemented to sustainably reduce malaria transmission?
The good news is that malaria elimination and long-term eradication is not perceived as unachievable. Nelson Mandela was quoted to reinforce this message: “It always seems impossible until it is done”.