Chloroquine was once a major treatment for malaria, but, in the late ’80s, the parasite that causes it started showing resistance. By the turn of the century, chloroquine was useless in much of the world.
But, intriguingly, that may no longer be the case. Some researchers were hoping to test whether resistance is permanent or temporary.
Surprisingly, as you may have guessed from the headline, it was temporary, and this has some interesting implications for both medicine and evolution.
Researchers in Dakar and Copenhagen collected 11,500 blood samples from children in Senegal infected with malaria, and where resistance to chloroquine was first reported in 1988. Then, well, they dosed it with chloroquine to see what happened.
The parasite in question reacted to the drug 70% of the time.
This doesn’t mean that other drugs will become effective if we just stop using them for a while: Malaria has a different mechanism from most infections in that it’s a protist instead of a virus or a bacteria, which is part of what makes it so difficult to treat. What applies to protists may not apply to those creatures.
Similarly, it’s not clear why the resistance faded; it could have been bred out of the population as a temporary mutation, or it could simply be that the resistant strain died off and a non-resistant strain took over.
Nonetheless, it tells us two things. One, that resistance to drugs is possibly not bulletproof and enduring in populations. And two, that new treatment ideas in malaria are possible. Considering how dangerous this virus is… that’s good news.