Malaria Drug Won’t Work for Much Longer
fivethirtyeight.com
fivethirtyeight.com
Current prevalence of resistance to artemisinin is mostly due to what happened shortly after the drugs discovery. That is, wide-spread single-mode-of-action use. This was due to uncontrolled over-the-counter use in South East Asia, which in recent years has been curtailed.
While this still happens, the WHO has gotten much much better at making sure combined therapies are used, which is the essential bit to controlling resistance.
The only tool we have to combating biological resistance (in any organism) are combined therapies. Doing so hijacks the mathematics of natural selection to make it almost impossible to evolve resistance (given high enough stacks of modes-of-action and complete treatment courses).
As the graph in the article shows, artemisinin resistance is still mostly contained to where it originally evolved (cambodia). Given careful management, we can expect slow spread, if any at all.
Fighting malaria isn't a one-punch win. It is a marathon, but one that we are very slowly winning. The disease is trending downwards and we are finally making in-roads into the most endemic regions. This slow reduction in the disease burden worldwide makes resistance harder and harder for the parasite to evolve.
Drug resistance is deadly serious, but I'm not as pessimistic as this article. Given proper tracking of resistance, and management, we'll easily have several more decades of artemisinin use.
While the only reproduce asexually within the secondary host the reproduce sexually within the primary host (mosquitoes) this means that if you have parasites that individually develop a resistance to different drugs within the secondary host (humans) could result in combined resistance once they sexually mate back within the primary host.
Malaria is also one of the most polymorphic single cell organisms in existence which is one of the main reasons why vaccination attempts were pretty futile so far which might give it a much better chance to develop resistance.
I hope that you're right, because from what I have seen recently there's still a lot of prescription drugs that you can get otc
I can believe that it takes evolution longer to adapt to it.
Of course I don't even know what "combined therapies" is, so I'm probably wrong. What am I missing?
Obviously the faster an organism mutates/replicates the harder it is to slow/stop evolution. HIV for example is "worst case scenario" but with combination therapies we've managed to make HIV a treatable disease.
At the end of the day it all boils down to one hard fact. An organism can't evolve if it is extinct. Selection works by causing deaths in a population (ex selecting those which live on). If you raise the "cost of selection" so high that an organism can't pay the cost in deaths, the population goes extinct.
As a rule of thumb, to fix an adaptive change, it takes 20 times the population in deaths. So if the current population is 1000, it'll take 20,000 deaths (and by deaths I mean removing an unfit allele from the population) over many generations to fix that adaptive allele.
>Of course I don't even know what "combined therapies" is, so I'm probably wrong. What am I missing?
Therapies or methods that employ more than one independent mode-of-action. Ex: Two drugs given at the same time.
This forces the organism to adapt to two things at once, doubling the cost of selection. As you increase modes of action, the cost rises to the point that it is impossible to adapt before the population goes extinct.
The odds of evolving multiple resistance in parallel are minuscule compared to developing it in series.
http://www.gatesnotes.com/Health/Most-Lethal-Animal-Mosquito...
This could go MUCH MUCH higher.
You probably already know this, but if your daughter shows any symptoms of malaria, make sure you tell the examining physician that she's just returned from an area that is known to have malaria. It's often one of the first things doctors test for here in Zambia, but if you live in an area without endemic malaria, they might not test for it at all.
[1]: http://www.who.int/malaria/publications/country-profiles/pro...
Also, for the blood test, make sure she actually has a fever when the blood is drawn.
Malaria (in the initial stages) may have a fever that comes and goes. The test has much higher false negative rates if the blood sample is drawn when the patient does not have a fever.
Doctors in areas where malaria is endemic generally know this, but doctors elsewhere may not. If she has any signs of a fever for the next ~2 months, it's best to get a blood sample drawn right away. Malaria is much more treatable when detected early.
I remember reading a story a couple years ago of Thais crossing the border into Cambodia where artemisinin was cheap and unregulated, but I can't find it.