In medicine, the blood can be divided into groups depending on its content of specific proteins. 4 is isolated biological fluid type, each may be different on one more feature - Rh-factor, which is determined by the presence or absence of antigen D.
Take into account the type of blood transfusion is vital, as it is necessary to maintain pregnancy. The frequency of blood spread with different antigens is not the same: the first positive can be found in 40% of the inhabitants of the planet, and the most rare blood group - the fourth negative.
What are the most rare and why
The unequal distribution of the number of people in the world with different types of blood due to the fact that they are evolutionarily formed under the influence of external factors. Among the different blood groups is the rarest - is the one that is considered by the scientific community, appeared later.
According to the study, the researchers, initially all people existed on Earth, had the first blood type. This was at a time when the main occupation was hunting mankind. Later, 15 000 - 20 000 years ago, people began to engage in agriculture. This led to a change in diet. According to the scientific hypothesis, the prevalence in the diet of plant foods has affected the emergence of the second group.
Later, about the historical period when people began to breed livestock, there was a third type of biological fluid. Fourth - the most rare blood group in humans, emerged as a result of the offspring of people with different blood types - the second and third.
On the definition of what is the world's rare blood type, it is also affected by Rh factor. Statistical data show that a positive indication on the ground about 85%, and the negative - 15%. These differences are important in carrying out blood transfusions, because you can not pour the material, which does not coincide Rh - it can lead to complications and even be fatal.
Thus, among all the blood types of Representatives with a negative Rh factor less.
Statistics on the international distribution
World statistics rarity of blood groups is represented in the table:
| Blood type | rh + | Rh- |
|---|---|---|
| I (0) | 36,44% | 4,33% |
| II (A) | 28,27% | 3,52% |
| III (B) | 20,59% | 1,39% |
| IV (AB) | 5,06% | 0,40% |
Statistical data are heterogeneous, depending on the region of residence. For example, the first type is common in Africa and South America, and the second - in Eastern Europe.
Thus, the rarest blood type in the world - this is the fourth negative. A distinctive feature of the fourth group of people is that they are universal recipients. This means that it is possible to pour in the biological fluid of any type, paying attention only to the Rh factor. They begin to produce antibodies to the donor material falls, so do not have a problem with the transfusion.
But the fourth group can not be used in transfusion recipients from the first, second and third - allowed donors to act only for members of the same type.
In modern medicine, transfusion try to use material that matches the majority of symptoms, and the presence of antibodies in the first place. The use of non-matching of the biological fluid with the recipient is practiced only in exceptional cases, when there is a suitable donor and the procedure to be performed urgently.
Bombay phenomenon
In 1952 in the city of Mumbai, which is located in India, in the study, doctors found several people mass outbreak of malaria antigens A and B were not present in the blood whose material However, on this basis, and they can not be attributed to the first type, ie. K. Absent antigen H, which is characteristic for the zero group and is needed for building the antigens A and B.
This discovery has been called "Bombay phenomenon" in the place of the first detection feature. The biological fluid with the absence of antigens A, B and H is the most rare in the world. Number of people with such characteristics about 0.0001%. In India, they occur more frequently - about 0.01% of the local population. This is due to a resolution on the conclusion of marriages between close relatives.
Because patients with clinical indications Bombay phenomenon is often confused with the carriers of the first type or zero. Such an error can become dangerous when the need for blood transfusion.
Biological material can be used Representatives Bombay phenomenon for transfusion to all people - this is possible due to the absence of antigens to which the recipient organism may secrete antibodies begin, leading to unwanted consequences. Like humans with the first group, people with Bombay phenomenon may make universal donor, pay attention to when the procedure is necessary only on a coincidence of the Rh factor.
Transfuse these people can only be a blood material, t. To. On any fall antigens, they begin to produce antibodies. This becomes a problem, that is, to a biological fluid that does not contain antigens A, B and H, -.. The most rare blood type in the world. If necessary, it becomes extremely difficult to find a donor.
People with Bombay phenomenon may have difficulty in determining paternity. Conducting a special test will not be able to confirm the family relationship, because people with Bombay phenomenon does not inherit from their parents antigens contained in the biological fluid.
