Do mosquitoes have a preferred blood type?
Currently, several scientists have conducted relevant experiments, but they have not been able to directly confirm the relationship between mosquito bites and blood type. related. What can be confirmed is that mosquito bites are positively correlated with the carbon dioxide people exhale and volatiles on the body surface, so people with faster metabolism are more likely to be bitten by mosquitoes.
Related experiments
1. Wood’s experiment
Wood, an expert on malaria at the University of Oxford in London, proposed that mosquito bites and Based on the novel idea of ??blood group correlation, experiments were designed and explanation hypotheses for blood group antigens were given. Now it seems that this experiment is a bit crude, and the experimental design and statistical analysis of the data did not consider and eliminate the interference of other influencing factors.
The content of the experiment is as follows:
In 1972, Greenwood found 102 people with different blood types and asked them to put their arms into a sealed box containing 20 mosquitoes. After 10 minutes, the bite status is determined by testing the blood type of the blood in the mosquito's belly. An analysis of the results of more than 100 experiments found that people with type O blood were bitten the most, leading the authors to conclude that type O blood may be the most attractive to mosquitoes. Wood is not sure why, but he speculates that the antigens that determine blood types are also distributed on the skin surface and in sweat, causing differences in the attractiveness of blood types to mosquitoes. The results of this experiment were published in the famous scientific journal "Nature".
2. Experiments by Thornton and his team
Thornton and his team also carefully designed a series of experiments to examine the effects of blood type, sweating, skin color, and body hair on mosquito bites . The advantage of Thornton's experiment is that it eliminates the effect of carbon dioxide exhaled by the subject. The experiment concluded that there was no necessary link between mosquito bites and blood type. Skin color and body hair also had no effect, while the effect of sweating was significant.
Thornton gave his own explanation for this completely different conclusion from Wood. He believed that the results obtained by Wood were likely to be affected by the carbon dioxide exhaled by the volunteers - an important factor in attracting mosquitoes. error.
3. Shirai’s experiment
In 2004, Japanese scientist Shirai began to study this problem again. This experiment was more humane for volunteers and used mosquitoes with sawed mouths (which is less humane for mosquitoes), but this also confuses the situation of landing and blood sucking. The highlight was the experiment of smearing blood group antigens on the arm for the blood group antigen hypothesis. The results show that type O blood has a significant advantage in attracting mosquitoes compared to type A blood, but not compared to types B and AB. This is consistent with Wood's results (type O blood has a significant advantage over both types A and B). ) are not exactly the same; but there is no statistically significant difference between secretory and non-secretory types of the same blood type. Experiments on arm smearing of blood type antigens showed that the H antigen of type O blood is more attractive to mosquitoes than the A antigen of type A blood, and the A antigen is more favored by mosquitoes than the B antigen of type B blood. This is similar to Wood's conclusion.
But for such results, Shirai himself believes that even the blood group antigen experiment cannot be used as evidence that mosquitoes have a preference for blood groups, because in actual situations, the concentration of antigens distributed on the human body is low enough for mosquitoes to detect less than that. Taken together, Shirai believes that his research does not prove that blood type is related to the degree of mosquito attraction. Shirai speculated that the possible explanation for the difference between Wood's experimental results and his own experimental results was the different species of mosquitoes.
4. Experiment at the University of California, Riverside, USA
Entomologists at the University of California, Riverside, studied the female Aedes aegypti mosquito (?Aedes) that transmits yellow fever and dengue fever. aegypti?) will react to carbon dioxide gas flow and human body odor. The research report was published in the October issue of the Journal of Experimental Biology. The report pointed out that mosquitoes are first attracted by exhaled carbon dioxide, then come towards the direction of skin odor, and finally land on the human body.
In the experiment, researchers placed female mosquitoes into the wind duct and filmed their flight trajectories.
Research has found that mosquitoes will only briefly fly upwind when they find a stream of carbon dioxide, but if the concentration of carbon dioxide in the stream fluctuates like biological respiration, they will fly firmly against the wind. In addition, mosquitoes are also attracted to skin odors. Mosquitoes are most attracted when the odor range is wide and the intensity remains constant (indicating that the mosquito is close to an object that can suck blood).
Compared with odor, researchers say carbon dioxide triggers mosquitoes to fly faster and more directly against the wind. Different carbon dioxide concentrations (100% to 0.5%) trigger similar flight reaction times, movement durations and speeds.
Scientists say mosquitoes' carbon dioxide receptors allow them to respond instantly to even the smallest amount of carbon dioxide gas. Carbon dioxide alone can attract mosquitoes without the aid of other odors. Skin odor only becomes important when mosquitoes are close to a blood-sucking target. In addition, mosquitoes become more sensitive to skin odors after sensing carbon dioxide.
Experimental Conclusions
Generally speaking, these studies on blood types and mosquito bites are still relatively superficial, and there are problems such as insufficient sample size and differences in the number of people with each blood type. There are many problems such as huge (maybe volunteers are really hard to find), insufficient control and comparison of various variables, etc. Although some scientists have shown interest in this issue, there are still not many studies on blood types that attract mosquitoes, and there are many differences between these studies, making it currently impossible to draw the conclusion that people with different blood types are differently attracted to mosquitoes. .
Conclusion: Mosquito detection and target location mainly rely on carbon dioxide, heat, volatile chemicals and other factors. There is currently no reliable evidence to prove that different blood types have different attractions to mosquitoes.
Related reading:
Mosquitoes
Mosquitoes are a family under the order Diptera of the class Insecta. Commonly known as midges or midges, this family of organisms is a tiny flying insect with a piercing-sucking mouthparts. Usually females feed on blood, while males suck plant juices. Blood-feeding female mosquitoes are intermediate hosts for dengue fever, malaria, yellow fever, filariasis, Japanese encephalitis and other pathogens. Mosquitoes are found on every continent except Antarctica.
Mosquitoes are divided into male and female. Male mosquitoes have filamentous antennae, and the antennal hairs are generally thicker than those of female mosquitoes. Their food is nectar and plant juices. Female mosquitoes need to bite animals to suck blood to promote the maturation of their eggs. Mosquito saliva contains a substance that dilates blood vessels and has anticoagulant effects, making it easier for blood to flow to the bite site. Substances in mosquito saliva cause the skin of the person being bitten to itch and itch.
Habits of mosquitoes
1. Habits of breeding
Mosquitoes breed in water, and different water quality and water types breed different types of mosquitoes. Managing or transforming breeding sites is a fundamental measure to prevent mosquitoes.
Type of water body: ?Main breeding species of mosquitoes?
Severely polluted water body: such as manure pits, cesspools, etc. that harass mosquitoes?
Mildly polluted water body: Such as sewage pits (ditches), clear water cesspits, water accumulation in depressions, etc. Culex quinquefasciatus and Culex pipiens
Do they harass clean water bodies with large areas: such as rice fields, lotus ponds, swamps, irrigation ditches, etc.?
Clean and flowing water bodies: such as mountain streams Or a stream bed, etc.?
Small natural water bodies: such as tree holes, bamboo tubes, altars, jars, etc.
2. Blood-sucking habits
Mosquitoes also pass through If blood-sucking spreads diseases, understanding the blood-sucking habits of mosquitoes can reveal their relationship with diseases.
Only female mosquitoes suck blood, not males. Female mosquitoes must feed on blood in order for their ovaries to develop and reproduce. Female mosquitoes usually start sucking blood 2-3 days after emerging. Various factors such as temperature, humidity, and light can affect the blood-sucking activity of mosquitoes. They start sucking blood when the temperature is above 10°C. Generally, Aedes mosquitoes mostly suck blood during the day, while Anopheles and Culex mosquitoes mostly suck blood at night. Some prefer human blood, while others like to suck the blood of domestic animals, but there is no strict choice. Because of their nature, mosquitoes can transmit diseases to humans and animals.
3. Habitat habits
Understanding the habitat habits of mosquitoes is the basis for formulating mosquito control measures.
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Mosquitoes must find a place to live after emerging and sucking blood. Generally speaking, mosquitoes like to live in hidden, dark and poorly ventilated places, such as under beds, behind cabinets, behind doors, wall cracks and Livestock houses, basements, etc., and mostly outdoors in grass, caves, cellars, bridge holes, stone crevices, etc.
Mosquitoes are divided into the following three types according to their different habitat habits after sucking blood: Domestic type: such as Anopheles microscopicus and Anopheles anthropophila. Semi-domestic type: Some mosquitoes such as Anopheles sinensis and Anopheles Sun Moon Lake live indoors after sucking blood, while others live outdoors. Wild-dwelling mosquitoes such as Anopheles albopictus and Aedes albopictus fly outdoors to digest the blood in their stomachs after sucking blood.
Who do mosquitoes like to bite?
1. Women during ovulation
Mosquitoes rely on the identification of smells to find prey and court mates. A unique pheromone emitted by female mosquitoes can attract male mosquitoes from a kilometer away. However, few people know that ovulating women are also highly attracted to mosquitoes.
Mosquitoes are interested in ovulating women not because their blood is sweet, but because of the nearly saturated fat in their blood. In addition to being particularly fond of ovulating women, mosquitoes also show great interest in people of both genders who have high blood cholesterol levels.
Mosquitoes like to hunt in swamps at dusk, because such temperature and humidity are the most ideal conditions for their species to breed. According to research by German scientists, mosquitoes can smell the scent of prey from a kilometer away, especially women during the ovulation period who are most "cared for" by mosquitoes. This shows that what mosquitoes love most is blood full of fat, rather than the "sweet" blood (blood with high glucose content) that people have always thought. The research results of American entomologist Jerry Butler published in a German magazine also showed that people with higher blood cholesterol levels are also the most attracted to mosquitoes. Unfortunately, scientists are still unable to explain how mosquitoes sniff out cholesterol levels in the human body.
2. Sweating a lot
Sweat contains a large amount of amino acids, lactic acid and ammonia compounds, to which mosquitoes are very sensitive. Once they smell the smell of these substances, they will have an appetite. The sweat emitted by the human body evaporates in the air and can also send a "signal" to mosquitoes. Usually, people who sweat a lot and are prone to sweating have a greater chance of being attacked by mosquitoes. This is enough to explain why we often find a few big "red envelopes" on our bodies after exercising. Mosquitoes like to bite people with rough skin and enlarged pores, usually because such people tend to have developed sweat glands or produce more sweat and other secretions. Therefore, men are sometimes more attracted to mosquitoes than women, and young people are more attracted to mosquitoes than the elderly.
3. Wear black clothes
Dark clothes have no reflective effect on mosquitoes and are susceptible to mosquito bites. It turns out that mosquitoes are afraid of light but don’t like too dark light. They like to suck blood in low-light environments. During the day, when people wear dark clothes, the reflected light is darker, which is just what they want. In addition, mosquitoes like to bite people with higher body temperatures, and dark-colored clothes have a strong ability to absorb heat. The combination of several factors naturally makes the mosquito attraction index of dark clothes greatly increase. People often think that black clothes attract mosquitoes, but according to Professor Xu, wearing dark twill jeans is actually the most likely to be bitten by mosquitoes.
4. Milk smell
Babies are easy to be attacked by mosquitoes for two reasons: First, babies have no ability to block mosquitoes, so they are not very dangerous to mosquitoes. Second: The baby has a fragrant and strong milk smell, and mosquitoes come here because of the smell.
5. Breathing heavily
People with large lung capacity naturally breathe deeply and long, and exhale more carbon dioxide. Mosquitoes will swarm after smelling this. Mosquitoes have a strong sense of smell. When humans exhale carbon dioxide and other odors, these odors diffuse in the air, and these odors are like ringing bells, telling mosquitoes that a delicious meal is just around the corner. When a mosquito tracks its target, it always follows the smell of human exhalation and zigzags until it contacts the target. Then it falls on the skin and patiently searches for a "breakthrough". Finally, it inserts the "syringe" directly into the skin to suck blood for 8-10 seconds. bell.
6. Wear makeup often
American scientists have used olfactory instruments to test and analyze more than 3,900 substances. It was found that many types of hair spray, hand cream, facial cleanser and other cosmetics are unusually attractive to mosquitoes. Most cosmetics contain stearic acid (a type of fatty acid), so mosquitoes "favor" people who wear makeup more than those who don't.
?As for a person's cholesterol level, it does not affect a mosquito's judgment unless there is enough cholesterol stored close to the epidermis. Of course, there are some smells that mosquitoes hate, such as bay leaf, lemongrass oil, lemongrass, garlic and geraniol. ?Perfumes, hairsprays, and facial creams can also attract mosquitoes, and overdoing your make-up can also cause you to get bitten by mosquitoes. Using flower-scented cosmetics such as perfume, hairspray, facial cream, and fire ointment will increase the chance of being bitten by mosquitoes. Some believe that most cosmetics contain chemicals that attract mosquitoes. Therefore, women who wear makeup are more "sought after" by mosquitoes than those who wear makeup. It is also not advisable to use soaps and shower gels with strong fragrances when taking a bath in summer. ?However, not all fragrances will attract mosquitoes. For example, the smell of citronella oil and eucalyptus oil is a good mosquito repellent.
7. Foot odor
American scientists have discovered that female mosquitoes have a special olfactory receptor that can sense the odor emitted by the human body. If you have strong foot odor, you will naturally become the target of hungry female mosquitoes.
8. Pregnant women
Scientific research always makes special discoveries. An American medical study showed that pregnant women are particularly attracted to mosquitoes, and they are more likely to be bitten by mosquitoes than other women. Twice as high. ?Researchers believe that the breath exhaled by women during pregnancy contains a variety of different chemicals, making them targets for malarial mosquito bites. In addition, pregnant women have a higher body temperature and sweat more, which is a good base for the growth of skin bacteria. These two reasons make pregnant women more susceptible to mosquitoes than other women. ?People who emit a lot of carbon dioxide have a relatively high concentration of carbon dioxide around them, so the "image" presented in the mosquito's field of vision is clearer, making it easier for mosquitoes to directionally track. Therefore, in a group, people with large lung capacity, fat people, and people with heavy breathing are more likely to be bitten by mosquitoes. Pregnant women exhale higher carbon dioxide due to their active metabolism.
9. Couples
We don’t know whether people in love overflow their sweetness into the air. But European scientists locked the experimenters in a room full of mosquitoes. The experiment was conducted many times. The result was: every time, people who were in love received more bites than single people.
How to deal with mosquito bites
After being bitten by a mosquito, most people will experience symptoms such as redness, swelling, itching, and pain. At this time, alkaline substances can be used to relieve it. For example, ammonia can be used to relieve itching. , you can also dip soap in water and apply it on the red and swollen area, which can relieve the itching within a few minutes.
If the bite is itchy, you can flick it with your fingers first, and then apply toilet water, wind oil essence, etc.
Apply or soak the itchy area with salt water, which can soften the swelling and effectively relieve itching.
The juice from aloe vera leaves can be used to relieve itching. When you are bitten by a mosquito and feel red, swollen and itchy, you can cut a small piece of aloe vera leaf, wash it and break it open, and rub it on the red and swollen area a few times to reduce the swelling and relieve itching.
Light the match and blow it out, then bake the area bitten by the mosquito. You can also apply toothpaste, red lotion, and some Wuji ointment that has anti-inflammatory, anti-itching, and analgesic effects.
Break a garlic clove and apply the cut piece on the mosquito bite. It will be cured in a while and relieve itching (this method is especially suitable for pregnant women after being bitten by mosquitoes)
In short , to prevent mosquito bites: develop good habits to avoid mosquito harassment; love cleanliness and know how to enjoy the cool; prepare early and prevent early.
Relevant information and pictures are all from the Internet: search through Baidu
Relevant reference sources are as follows:
Guoke.com:
hubei .com/ctdsb/ctdsbsgk/ctdsb58/201207/t2142589.shtml
Interactive Encyclopedia:
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Baidu experience:
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