Comparative insect survey

Hello all -

In my experience in the past, no see ums/midges/sand flies/biting gnats tended to attack outdoors rather than indoors.

However, in Vietnam and Thailand the interiors of every building had more than the outside patios, street, etc.

I've read online that these gnats are prevalent in Siem Reap. Are they outside and inside pests? Are they the biting kind or just the bothersome bugs-in-eyes-and-ears kind?

Thanks for your observations.


I have been living in both Thailand and Cambodia and my experience is that the main prob;em is mosquitoes. There are the day-flying mosquitoes that can bring Dengue fever, and the night-flying  mosquitoes that can bring Malaria.

I must state that in 11 years in SE Asia I have never encountered a singe case of malaria, nor dengue fever.

In Thailand I lived in a rural area, mosquitoes at night were a pest but only outside the house. No day-flying mosquitoes have been seen. I had build a stone house that could be closed at night, not the wooden houses on stilts that are open to insects. I must give credit to the many Geckos around and in the house, if any insect appeared they immediately attacked and ate them. I had no mosquito nets to sleep under, no need.

In Cambodia I have lived in a rural village in the rain forest. There, because of high humidity in the rain season, I have noticed both day-flying and night-flying mosquitoes. Sleeping under nets was necessary.

The last two years I live in a city and although in a garden area, not many mosquitoes. Only night-flying mosquitoes that start to be annoying just after dark. It has been reported that both malaria and dengue fever are risks in rural areas but not in cities like PP, SR, SHV, Koh Kong, Battambang.

Only in the rain forest [Cardamom mountains] I noticed mosquitoes inside and outside, in both other areas only outside the house, and limited to night-flying mosquitoes in both Thailand and in the city in Cambodia.

As a naturalist I would like to mention that locals cause problems for themselves as they catch frogs, insect-eating birds like swallows and the best hunters: the bats.
Swallows can eat more than a thousand insects per day, bats can eat 600 in one hour.
So it is logical to expect more insects in areas with heavy catching of those predators.

My two cents.


Cambodia expat-advisor team

Thank you so much, Joe, for your thoughtful and well-written reply. It was a pleasure to read.

I can only say you are a very fortunate man. I see the occasional mosquito in Vietnam and Thailand. I think I was bitten once in each country. But the "invisible" no-see-ums constantly attack me and I am unfortunately very sensitive and allergic.

I had a hard time in Vietnam gathering enough information to learn what was happening to me and no one else I knew. Asians seem to have a natural immunity to these bugs and some don't even believe they exist. They have no idea that the little brown-grey sarcophagi-shaped things stuck to their walls and ceiling and door frames are nests, releasing hundreds of these bugs, so they don't bother or care enough to take them down.

In Vietnam the bugs are black, and in Thailand they are beige and a bit smaller. Maybe the electric tennis racket mosquito zappers in Thailand are less well made or the no see ums are a featherweight lighter, but in Vietnam it was easy (unfortunately) to kill hundreds in one sweep of an apartment, leaving little black carcasses littered on the floor and bed. Ugh. In Thailand that doesn't work and the main way I (unfortunately) can trap them is to cover my face, their main target, with a heavy oil or Vaseline and they stick to the surface like tiny beige winged measles.

When they bite me, it hurts. It's hard to understand how such a teeny tiny bug can wield knife-like "teeth" but that's what it feels like. They bite me 24 hours a day, and inside is usually much worse than outside because there's no wind to disperse them. Without exaggeration, it's hell.

Naturally I began to wonder if my sensitivity to their bites was "all in my head" as the old expression goes. Then I met a young Hispanic American man in the airport in Vietnam with his Vietnamese American girlfriend. She had felt nothing during their vacation; he had been bitten constantly and his body covered with large welts and blisters that took days to subside. I guess I'm the lucky one there. I only have the pain of the bites and ten minutes of itching.

Then I learned that in SE Asia a lot of people call them midges, sand flies, and gnats. I researched that and found a few lonely outlier voices crying out for information and help on message boards going back as far as 2000. The answers they received are all incorrect. None of the OPs have posted in years. I can only assume the bugs drove them out of Asia.

What's so interesting to me about Cambodia is that many tourists post about the no see ums there. No one ever posts about that in Thailand except at places like Phuket, and nowhere in Vietnam. These tourists who do mention the Cambodian ones don't mention being bitten except maybe at an island. But they do say there are many of them, even clouds of them, in Siem Reap. A eureka moment for me.

This is such a crucial difference from tourist awareness in Vietnam and Thailand that I wondered if the change in geography had produced a change in entomological behaviour and they were only outside bugs in Cambodia the way they usually are in the U.S.

I guess I won't know for sure until I go there and put boots on the ground. Because airbnb and plane bookings are done so far in advance, I was trying to glean some information that would effect my reservation planning. If I knew it was possible to have even one "safe" room, I would be so happy. As in sooooooooooooooooooo happy.

My apologies for the verbose response. Does this jog anyone's memory or trigger some awareness that could be helpful to me?

(Dear readers: I have literally tried hundreds of repellents and behavioural and environmental changes except picaridin which isn't sold in Asia. I have several brands arriving from Amazon - hopefully - this week. The tried-and-failed list includes the usual chemical and herbal suspects and also garlic, vitamins, extreme cold, bleach, fans, Dettol in various strengths, topical Listerine, lemons, etc., etc.)

Thank you!

Hi. Thank you for all info, must be a nightmare for you.

First I enclose a link about herbs and plants. Realize that local people always eat Basil and Mint during their meal. It is actually to lower the spicy effect, but it could also be a way to get kind of immune to insect bites. Most of them also grow these herbs in their garden, reducing the number of insects. … ed-insects

Is there not a way you could stay in a room that is closed? I mean really closed, leaving no possibility for the biting flies to enter? Also realize they need water and will always be found near water containers.

Also if  using repellents, did you check that there is 30% DEET in it? Any lower percentage makes it useless.
If you stay long enough you will also get some immunity. Friends visiting me get bitten, I'm not, after 11 years here.

Treat the bites with the simplest remedy: Tiger balm. Get the real one from Thailand, have it with you all the time, it also comes in tiny little metal boxes that you easily put in a pocket.
If this is not really helpful, put a Hydro-cortisone cream on the bites, it takes away the itching and no need to scratch [very bad as the damaged skin attracts more insects and gets infected, try not to scratch].

Last but not least: cover you arms and legs plus your neck, it's easily done and really protects. It's no coincidence that farmers wear long sleeves and long trousers, on top hats with a neck-covering. This is all available here and can even be quite elegant. … ZR5CM9VERR

Good luck.


Thanks again, Joe, for your thoughtful and caring response. The short answer is been there, done that.

I'm more covered up 24/7 than a woman in Saudi Arabia, with rubber bands around wrists, ankles, and socks.

I've tried DEET of every strength and every brand. Interestingly, I have seen a few posts saying that DEET actually attracts no-see-ums. But there is a general consensus online among the frequently bitten that DEET doesn't work with these bugs.

"Luckily" for me they don't itch very much and for a very short period of time. If a bite does persist in itching, I've used tiger balm and yellow oil from China and green oil from Singapore. I have cortisone in every strength from 0.025% to 1.0. I have oral steroids, 4 mg. When I get burns on my face and neck from the repellent usage, I get IV prednisone at a hospital.

I have always eaten an enormous amount of herbs, especially basil and cilantro, and continue to do that here.

I do think that remedies, treatments, and deterrents are discovered anecdotally which is why it's so important to reach out for information and to share what you know. I have no doubt that there's someone in the Amazon tribal jungle who knows an herbal paste that would help me a lot, or a Chinese acupuncturist who knows just the right spot. But I don't know those guys --- yet.

But I fold that anecdotal knowledge under the general heading of science. Allergen response is found on certain genes. For some people it's more epigenetically activated than for others with the same genes. It can be hereditary, sparked by environmental exposure, or triggered by the genetic distortions of cancer cells. It's kind of a crap shoot. I once had a dog with very bad hips who was still very active, but his hip x-rays were horrifying, The vet, a good old farm boy, said, "Dogs don't walk on their x-rays." Meaning, even with the data of someone's medical/genetic profile, ya just never know how someone will react to allergens.

The key thought here for me is that tourists are noticing and reacting to no-see-ums in Cambodia. They're not doing that at all in Thailand or Vietnam. The Thai and Vietnamese no-see-ums are a different colour and weight, so they are a different subtype. Different subtypes have both physical and behavioural differences. So I'm kind of hoping against hope that the Cambodian ones do something differently: maybe don't bite as much, maybe don't come indoors, maybe stick to shade and night time, maybe are repelled by different chemicals or herbal sprays, who knows?

Yes, one safe room would be a dream come true. To eat a meal, to read a book! I haven't had a bug-tree space or moment in eight months except completely underwater in a pool. I've tried houses and apartments and hotels, city and beach and outer areas, even the 38th floor of a high rise. They are so tiny they come in cracks that are almost immeasurable but certainly invisible to the human eye.

It's been kind of a cross between The Twilight Zone and The Nightmare on Elm Street. I do feel stalked in a sense. Logic tells me that my blood alone isn't enough to support billions upon billions of bugs all over Asia, so everyone must get bitten but just not feel it or react. If these bugs ever mutate into a disease vector, we're all toast.

I know tons more about these pests, learned the hard way and from correspondence with university entomologists. But I've blathered on way too long about them already. If anyone is unfortunate enough to also be sensitive to or the target of these bugs, feel free to contact me and I will tell you more. The most important thing is if you are their victim here, you cannot take anything, anything at all, back to your home with you because you are taking them with you and they're impossible to eradicate from your home. (Not just Asian no-see-ums; I've seen the same posts from victims who vacationed in the Caribbean or South America and brought them back.)

Thanks again, Joe. I will know whassup the second I get off the plane in Siem Reap. I really want to stay in Asia. Is there a bug god out there somewhere I can give offerings to???

Joe, a friend told me about this company tonight. Unfortunately, their product is only for outdoors and for mosquitoes only which doesn't help me much. But they are testing the product in Laos and Cambodia and will post progress reports on their Facebook site. It might completely rearrange the land usage patterns of much of the country -- if it really works as promised, the entire world.

Sugar, salt and yeast.... It might work, it might not. It's specifically against mosquitoes, don't know if it works against biting flies, gnats.

But any attempt is worth trying.

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