In a setting I am working on there is a civilization based in a tropical floodplain that’s dependent on paddy field agriculture to maintain its population. Problem is that all the standing water and moist soil creates the perfect conditions for mosquitoes, and those buggers spread absolutely awful diseases that kill millions of people every year. The people in my setting do not have access to modern pesticide, vaccinations, spraying and cannot simply drain the water away due to their agrarian economy. The few things in their favor are a very high degree of social cohesion and a centralized state that’s obsessed with maintaining cleanliness as a religious mandate.

How can a pre modern society significantly reduce the effects of mosquito borne diseases when removing the water supply and pesticide sprays are not an option?

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    $\begingroup$ Remember that people did live in areas infested with mosquitoes in premodern times. Perhaps look at those? ...I also seem to recall a Nobel prize being given out a few years back for someone realizing that a specific malaria remedy in ancient chinese folk medicine actually works really well (at least as long as you prepare it according to the ancient recipe and not more recent ones) and isolating the compound responsible. It's very possible that premodern medicine can have treatments for things like this. $\endgroup$
    – Hearth
    Commented Sep 9, 2022 at 17:21
  • $\begingroup$ @Hearth Do you have a link for that recipe? It sounds fascinating. $\endgroup$
    – user71781
    Commented Sep 9, 2022 at 22:51
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    $\begingroup$ I'm afraid I don't, but you can look up the name of the scientist who won the prize, Youyou Tu, and perhaps find more information about her research. My understanding is that the more modern way it's used in chinese traditional medicine is to make a tea, but it turns out that heating destroys the compound responsible for the antimalarial effect. The older formula I think just involved chewing on a paste made from the leaves, or something along those lines. Probably didn't taste anywhere near as good as the tea. $\endgroup$
    – Hearth
    Commented Sep 9, 2022 at 22:55
  • $\begingroup$ You're the creator. Just don't have mosquitoes. Or don't talk about them. $\endgroup$
    – NomadMaker
    Commented Sep 9, 2022 at 22:57
  • $\begingroup$ @Hearth Thank you for the name and additional info $\endgroup$
    – user71781
    Commented Sep 9, 2022 at 23:30

3 Answers 3


They can favor the presence of animals feeding on those mosquitoes at any stage of their development:

  • fishes can feed on the larvae while they are in the water
  • insects and spiders can pray on larvae and adults
  • birds and mammals can feed on the adults

It very known the consequence of Mao's order to exterminate the sparrows:

Sparrows were suspected of consuming approximately four kilogrammes of grain per sparrow per year. Sparrow nests were destroyed, eggs were broken, and chicks were killed. Millions of people organized into groups, and hit noisy pots and pans to prevent sparrows from resting in their nests, with the goal of causing them to drop dead from exhaustion. In addition to these tactics, citizens also simply shot the birds down from the sky. The campaign depleted the sparrow population, pushing it to near extinction.

While the campaign was meant to increase yields, concurrent droughts and floods as well as the lacking sparrow population decreased rice yields. In the same month, Mao Zedong ordered the campaign against sparrows to end. Sparrows were replaced with bed bugs, as the extermination of sparrows had upset the ecological balance, which subsequently resulted in surging locust and insect populations that destroyed crops due to a lack of a natural predator.

Here it is about turning the knob the other way around: increase the natural enemies of the mosquito, so that by reducing the mosquito population also the chances of contracting the mosquito-born diseases get lower.

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    $\begingroup$ +1, since I put fishes in the pond, the mosquito population dropped quite a lot $\endgroup$
    – bobflux
    Commented Sep 9, 2022 at 10:12

Echoing the advocation for natural control methods, but could also:

  1. Use mosquito netting in dwellings - surprisingly effective.
  2. Disrupting the larva with small film of natural oil in standing water outside the rice paddies.
  3. As mentioned fish in the rice paddies, -also as an extra form of protein, This would require some type of management but this wikipedia article briefly talks about mosquito control and the advantages of poly culture.
  4. Bat houses, Bats eat lots of mosquitos - maybe Bats are well thought of becasue of that.
  5. Natural insect repellents from plants -efficacy may be suspect but may have a place.
  6. Thin light clothing that covers the person reducing the number of bites.
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    $\begingroup$ Quinine for malaria could possibly be discovered, maybe said civilisation is into making teas or cordials from tree bark extracts, and finds some Cinchona trees. After a while they'll possibly notice those who drink the tea or cordial regularly don't get sick as much. $\endgroup$ Commented Sep 9, 2022 at 16:59

Frame Challenge, your civilization doesn't need do anything special

Sickle Cell disease (or some other recessive gene that grants resistance to a blood borne pathogen at the cost of death if you have 2 copies of it), natural acquired immunity (AKA, what vaccines replicate) and lots of children

  1. Sickle cell disease:

If you have the sickle cell disease mutation from one of your parents makes you resistant to malaria. Having it from both parents generally leads to death(without industrial medicine) Having it from neither parent means you will probably die when the yearly plague hits the village.

Therefore the average adult in your country will be recessive for sickle cell disease, with a small percentage of the population not having it.

  1. Malaria (and other mosquito born pathogens) grant immunity/or resistance to themselves after exposure.

Vaccines are a modern day method to recreate this naturally occurring immunity with a significantly lower risk of death/long term health consequences.

  1. Lots of children

Pre-modern societies have lots of children with a high mortality rate (for the children not strong enough to survive disease). A lot of cultures adapted to high child mortality by not naming children until they reach a certain age. I believe this was a way to emotionally distance themselves from the baby that is probably going to die. Not sure how well it worked... But its was very common so it must have worked a little.

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    $\begingroup$ We are here, so at least it worked in species survival! $\endgroup$ Commented Sep 9, 2022 at 22:08
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    $\begingroup$ This is a great challenge, but I am aware of sickle cell and the behavioral adaptation to have more children when infant mortality is high. I am just asking for a way to counteract the deaths in a way that’s not pure evolution $\endgroup$
    – user71781
    Commented Sep 9, 2022 at 22:53

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