Do mosquitoes have a preferred blood type?

Do mosquitoes have a preferred blood type?

At present, several scientists have done relevant experiments, but they have not directly confirmed th

Do mosquitoes have a preferred blood type?

Do mosquitoes have a preferred blood type?

At present, several scientists have done relevant experiments, but they have not directly confirmed that mosquito bites are related to blood types. It can be confirmed that mosquito bites are positively correlated with carbon dioxide exhaled by people and volatile substances on the body surface, so people with faster metabolism are more likely to be bitten by mosquitoes.

Related experiments

Wood's experiment

Wood, a malaria expert at Oxford University in London, put forward a novel view that mosquito bites are related to blood types, designed experiments, and gave an explanation hypothesis of blood group antigens. Now it seems that this experiment is a bit rough, and the interference of other influencing factors is not considered and excluded in the experimental design and data statistical analysis.

The experimental contents are as follows:

1972, Greenwood found 102 people with different blood types and asked them to put their arms in a sealed box with 20 mosquitoes in it. 10 minutes later, the biting situation is judged by detecting the blood type of the blood in the mosquito's stomach. After analyzing the results of 100 experiments, it was found that people with O blood were bitten the most, and the author concluded that O blood might be the most attractive to mosquitoes. Wood didn't know the reason, but speculated that the antigens that determine blood type were also distributed on the skin surface and sweat, which led to the different attraction of blood type to mosquitoes. The results of this experiment were published in the famous scientific magazine Nature.

2. Thornton and his team's experiment

Thornton and his team also carefully designed a series of experiments to investigate the effects of blood type, sweating, skin color and body hair on mosquito bites. The advantage of Thornton experiment is that it eliminates the influence of carbon dioxide exhaled by the subjects. The conclusion of the experiment is that mosquito bites are not necessarily related to blood type, and skin color and body hair have no effect, but sweating has a significant effect.

Thornton gave his own explanation for this conclusion, which was completely different from Wood's explanation. He believes that the results obtained by Wood are likely to be influenced by the carbon dioxide exhaled by volunteers, which is an important factor to attract mosquitoes.

3. White well experiment

In 2004, Japanese scientist Shirai began to study this problem again. This experiment is more humane to volunteers, using mosquitoes with sawed mouths (not so humane to mosquitoes), but it also confuses the situation of landing and sucking blood. The highlight is the experiment of smearing blood group antigen on the arm according to the hypothesis of blood group antigen. The results showed that blood type O was obviously more attractive to mosquitoes than blood type A, but not to blood types B and AB, which was different from Wood's results (blood type O was obviously better than blood types A and B). However, there is no statistically significant difference between secretory and non-secretory types of the same blood group. The experiment of smearing blood group antigen on the arm shows that H antigen of O blood is more attractive to mosquitoes than A antigen of A blood, and A antigen is more popular with mosquitoes than B antigen of B blood, which is similar to Wood's conclusion.

But for such a result, Shirai himself believes that even the blood group antigen experiment cannot be used as evidence that mosquitoes have a preference for blood groups, because the antigen concentration distributed on the surface of human body is very low and mosquitoes cannot detect it. On the whole, Shirai believes that his research cannot prove that blood type is related to the degree of attracting mosquitoes. 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 of University of California, Riverside, USA

Entomologists at the University of California, Riverside, studied the female Aedes aegypti (? Aedes aegypti? How will it react to carbon dioxide airflow and human body odor? Research? Report? Published in the Journal of Experimental Biology (10). According to the report, mosquitoes are first attracted by exhaled carbon dioxide, then come along the direction of skin odor and finally land on the human body.

In the experiment, the researchers put female mosquitoes in ventilation pipes and photographed their flight paths. It is found that mosquitoes will only fly against the wind for a short time when they find a carbon dioxide airflow, but if the concentration of carbon dioxide airflow fluctuates like biological respiration, they will fly firmly against the wind. In addition, mosquitoes are also attracted by skin odor, and mosquitoes are most easily attracted when the odor range is wide and the intensity is constant (indicating that mosquitoes are close to blood-sucking objects).

Researchers say that carbon dioxide causes mosquitoes to fly faster and more directly against the wind than the smell. Different carbon dioxide concentrations (100% to 0.5%) have similar reaction time, exercise duration and speed.

Scientists say that mosquitoes' carbon dioxide receptors enable them to respond immediately to even the smallest amount of carbon dioxide gas. Carbon dioxide alone can attract mosquitoes without the help of other smells. When mosquitoes approach blood-sucking objects, the smell of skin becomes more important. In addition, after feeling carbon dioxide, the sensitivity of mosquitoes to skin odor will be greatly improved.

Experimental conclusion

Generally speaking, these studies on blood types and mosquito bites are still superficial, and there are problems such as insufficient sample size, huge difference in blood types (it may be difficult to find volunteers), and insufficient control and comparison of various variables. Although some scientists have shown interest in this issue, there are still few studies on blood types attracting mosquitoes, and there are many differences between these studies, so it is impossible to draw the conclusion that people with different blood types have different attractiveness to mosquitoes.

Conclusion: Mosquitoes mainly rely on carbon dioxide, heat, volatile chemicals and other factors to detect and locate targets. At present, there is no reliable evidence that different blood types have different attraction to mosquitoes.

Related reading:

mosquito

Mosquitoes are a family of Insecta, Diptera. This family is usually called mosquitoes or mosquitoes. It is a tiny flying insect with a piercing and sucking mouthparts. Usually females suck blood, while males suck the juice of plants. Blood-sucking female mosquitoes are intermediate hosts of pathogens such as dengue fever, malaria, yellow fever, filariasis and Japanese encephalitis. Mosquitoes are distributed on all continents except Antarctica.

Mosquitoes can be divided into male mosquitoes and female mosquitoes. The antenna of male mosquitoes is filiform, and the antenna hair is generally thicker than that of female mosquitoes. Their food is nectar and plant juice. Female mosquitoes need to bite animals and suck blood to promote the maturation of inner eggs. Mosquito saliva contains a substance with vasodilating and anticoagulant effects, which makes it easier for blood to gather at the bitten place. The substance in mosquito saliva makes the bitten person's skin blister and itch.

Mosquito habits

1, bad habit

Mosquitoes breed in water, and different kinds of mosquitoes breed in different water quality and different types of stagnant water. Controlling or reforming breeding grounds is the fundamental measure to prevent mosquitoes.

Water body type:? What are the main mosquito species?

Seriously polluted water: places that disturb mosquitoes, such as cesspits and cesspools?

Slightly polluted water bodies: such as sewage pits (ditches), clean water cesspits and stagnant water in depressions. Culex pipiens quinquefasciatus and Culex pipiens pallens

Disturb large clean water bodies, such as paddy fields, lotus seeds, swamps, irrigation ditches, etc.

Clean flowing water body: such as mountain stream or river bed?

Small natural water bodies: such as tree holes, bamboo tubes, jars, tanks, etc.

2. Blood-sucking habit

Mosquitoes also transmit diseases through blood-sucking. Understanding the blood-sucking habits of mosquitoes can reveal their relationship with diseases.

Only females suck blood, and males don't. Female mosquitoes must feed on ovaries to develop and reproduce. Female mosquitoes begin to suck blood 2-3 days after emergence. Many factors, such as temperature, humidity and light, will affect the blood-sucking activity of mosquitoes. When the temperature is above 10℃, start blood supply; Generally, Aedes mosquitoes mostly suck blood during the day, while Anopheles mosquitoes and Culex pipiens mostly suck blood at night. Some prefer human blood, others like to suck the blood of domestic animals, but there is no strict selectivity, so mosquitoes can spread human and animal diseases.

3, habitat habits

Mastering the habitat habits of mosquitoes is the basis for formulating mosquito control measures. ?

Mosquitoes need to find a place to live after eclosion and blood feeding. Generally speaking, mosquitoes like to live in hidden, dark and poorly ventilated places, such as under the bed, behind cabinets, behind doors, crevices in walls, barns and basements, as well as outdoor lawns, caves, cellars, bridge opening and crevices.

Mosquitoes can be divided into the following three types according to their different habitat habits: domestic type: such as Anopheles minimus and Anopheles anthropophagus. Semi-domestic type: such as Anopheles sinensis, Anopheles sinensis in Sun Moon Lake and Anopheles sinensis, some of them live indoors and some live outdoors. Wild type: Anopheles dirus, Aedes albopictus, etc. Fly outdoors to digest the blood in the stomach after sucking blood.

Who do mosquitoes like to bite?

1, ovulating women

Mosquitoes find prey by smell and have sex. A unique pheromone emitted by female mosquitoes can attract male mosquitoes one kilometer away. But few people know that women who are ovulating are also very attractive to mosquitoes.

Mosquitoes' interest in ovulating women lies not in whether their blood is sweet or not, but in the nearly saturated fat in their blood. Mosquitoes not only have a soft spot for women who are ovulating, but also show great interest in those who have high cholesterol in their blood (regardless of gender).

Mosquitoes like to hunt in swamps at dusk, because such temperature and humidity are the ideal conditions for their reproduction. According to the research of German scientists, mosquitoes can smell their prey from a kilometer away, especially women who are ovulating are most cared for by mosquitoes. This shows that mosquitoes love blood full of fat, rather than "sweet" blood (blood with high glucose content) that people used to think. Jerry Butler, an American entomologist, published a study in a German magazine, which also showed that people with higher cholesterol in their blood are also the most attractive to mosquitoes. Unfortunately, scientists can't explain how mosquitoes smell cholesterol levels in humans.

2, sweating more

Sweat contains a lot of amino acids, lactic acid and ammonia compounds, and mosquitoes are very sensitive to it. Once they smell these substances, they will have an appetite. Sweat emitted by human body volatilizes in the air, which can also send a "signal" to mosquitoes. Usually, people who sweat a lot and sweat easily are more vulnerable to mosquito attacks, which is enough to explain why we often find several big "red envelopes" on our bodies after exercise. Mosquitoes love to bite people with rough skin and large pores, usually because such people often have developed sweat glands or secrete more secretions such as sweat. So sometimes men attract mosquitoes more than women, and young people attract mosquitoes more than old people.

Step 3 wear black clothes

Clothes are dark in color and have no reflection on mosquitoes, so they are easy to be bitten by mosquitoes. It turns out that mosquitoes are afraid of light but don't like it too dark. They like to suck blood in low light. During the day, people wear dark clothes, and the reflected light is dark, just to their liking. In addition, mosquitoes like to bite people with higher body temperature, and dark clothes have strong heat absorption ability. Several factors are superimposed together, which naturally makes the mosquito attraction index of dark clothes soar. People often think that black clothes are the most attractive to mosquitoes, but according to Professor Xu, wearing dark twill jeans is actually the most vulnerable to mosquito bites.

4. Milk smell

Babies are easily attacked by mosquitoes for two reasons: First, babies are incapable of parking and there is no danger to mosquitoes. Second: the baby has a strong smell of milk, and mosquitoes come by smelling the fragrance.

5. Breathless and rude

People with large lung capacity naturally breathe deeply and long, exhaling more carbon dioxide, and mosquitoes gather after smelling it. Mosquitoes have a strong sense of smell. When humans exhale carbon dioxide and other smells, these smells will spread in the air. These smells are like the bell for dinner, telling mosquitoes that a good meal is just around the corner. When a mosquito tracks a target, it always twists and turns with the smell of people's breath until it touches the target and then falls on the skin, patiently looking for a "breakthrough". Finally, directly insert the "needle tube" into the skin to suck blood for 8- 10 seconds.

6, often make up

American scientists have used olfactory instruments to test and analyze more than 3,900 substances. It is found that hair gel, hand cream, facial cleanser and other cosmetics are very attractive to mosquitoes. Most cosmetics contain stearic acid (a fatty acid), so people who wear makeup are more favored by mosquitoes than those who don't wear makeup. ? As for a person's cholesterol level, it will not affect the judgment of mosquitoes unless there is enough cholesterol stored near the epidermis. Of course, there are also some odors that mosquitoes hate, such as bay leaves, citronella oil, citronella, garlic and geraniol. ? Perfume hair cream can also provoke mosquitoes, and if you dress up too much, you will be bitten by mosquitoes. Using cosmetics with floral fragrance, such as perfume, hair gel, face cream and fire cream, will increase the chance of being bitten by mosquitoes. Some people think that most cosmetics contain chemicals that can attract mosquitoes. Therefore, women who wear makeup are more sought after by mosquitoes than women who face the sky. Don't use soap and shower gel with strong fragrance when bathing in summer. ? However, not all scents attract mosquitoes, such as citronella oil and eucalyptus oil, but they are all good mosquito repellent.

7. smelly feet

American scientists have found that female mosquitoes have a special olfactory receptor, which can sense the smell emitted by human body. If a person's feet smell bad, he will naturally become the target of hungry female mosquitoes.

8. Pregnant women

Scientific research always makes special discoveries. A medical study in the United States shows that pregnant women are particularly attracted to mosquitoes, and the probability of being bitten by mosquitoes is twice that of other women. ? Researchers believe that women's breath during pregnancy contains many different chemicals, which makes them the target of Anopheles mosquitoes. In addition, pregnant women have higher body temperature and sweat more, which is a good base for skin bacteria to breed. These two reasons make pregnant women more vulnerable to mosquito bites than other women. ? People who emit more carbon dioxide, because of the relatively high concentration of carbon dioxide around them, present a clearer "image" in the mosquito's field of vision, which is convenient for mosquitoes to track directionally. Therefore, in a group, people with large lung capacity, fat people and people with heavy breathing are more likely to be bitten by mosquitoes, and pregnant women exhale more carbon dioxide because of their active metabolism.

9. Husband and wife, lovers

We don't know whether people in love spill sweetness into the air. However, European scientists kept the experimenter in a room full of mosquitoes, and the experiment was carried out many times. As a result, people in love are more likely to be bitten than singles.

How to deal with mosquito bites?

After being bitten by mosquitoes, most people will have symptoms such as redness, itching and pain. At this time, you can use alkaline substances to relieve itching, such as ammonia water, or you can use soap dipped in water to apply it to the redness and swelling, and it will stop itching in a few minutes.

If the bite is itchy, you can play it with your fingers first, and then apply toilet water and wind oil.

Smearing or brewing the itchy place with salt water can soften the lump and effectively relieve itching.

The juice in aloe leaves can be used to relieve itching. When you are red, swollen and itchy after being bitten by mosquitoes, you can cut a small piece of aloe leaf, break it after washing, and rub it a few times at the red and swollen place to reduce swelling and relieve itching.

Burn the place bitten by mosquitoes after blowing out the matches. You can also apply toothpaste and mercuric chloride, and apply some infinite ointment with anti-inflammatory, antipruritic and analgesic effects.

Break a garlic clove and apply a mosquito-bitten bag on the cross section. It will heal in a short time and relieve itching (the second method is especially suitable for pregnant women bitten by mosquitoes).

In short, to prevent mosquito bites, we should: develop good living habits and avoid mosquito harassment; Love cleaning, will enjoy the cool; Early preparation, early prevention.

Relevant information and pictures are all from the Internet: through Baidu search.

Relevant reference sources are as follows:

Shell net:

Hubei net/ctdsb/ctdsbsgk/ctdsb58/201207/t 2142589.shtml.

Interactive encyclopedia:

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Baidu experience:

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