robert_kurzban's picture
Psychologist, UPenn; Director, Penn Laboratory for Experimental Evolutionary Psychology (PLEEP); Author, Why Everyone (Else) is a Hypocrite
The Ongoing Battles With Pathogens

The end of the year saw two stories about pathogens, one hopeful and the other less so. The hopeful one is the advancing ability to insert genes that are desirable (from humans’ point of view) into organisms and facilitating that gene’s spread through the population.

Consider the case of malaria, a focus of current efforts. Inserting a gene that inhibits the spread of malaria into a mosquito genome is helpful, but to only a limited degree: if the gene doesn’t spread in wild populations, then its effects will be fleeting. If, however, mosquitoes are released that have the gene in question as well as genes that facilitate the spread of the gene, then the effects can be long-lasting.

The less hopeful case is so-called “super-gonorrhea,” strains of the pathogen that are resistant to the antibiotics currently in use. As is well known, the use of antibiotics gives an advantage to strains of pathogens that are resistant. The tools we use to treat disease become the means by which we make the diseases harder to treat. Cases of super-gonorrhea have appeared in England, leading to a certain amount of concern.

Malaria still infects tens of millions of people and causes hundreds of thousands of deaths. Of course global climate change and political strife are important issues, but pathogens still account for millions of lives lost around the world.

Historically, as illustrated by the super-gonorrhea case, fighting pathogens has been something of an arms race: humans build better weapons, pathogens evolve counter-strategies. The present age is seeing a confluence of a number of advances that hold the promise of turning the arms race into something that might be more like a winnable war. First is progress in genetics, including techniques for inserting genes into genomes. Second is a sophisticated understanding of evolution and a fluorescence of ideas about how to harness it: in the past, evolution worked against us, as in the case of resistant strains of pathogens. We are becoming better at harnessing it. And third is a growing sophistication in thinking about systems. It is unlikely that the same sorts of mistakes will be made in the past, in which simplistic ecological interventions led to somewhat disastrous outcomes, as in the case of cane toads in Australia. Our view of ecosystems is more humble and more sophisticated than ever before.

It seems likely that pathogens, of one sort or another, are likely to be important for a substantial period of time: this is because they are moving targets with tremendous capacity for harm. On the other hand, recent advances hold the promise of taming them in a way that we have not previously seen.