Trachoma has been popular for at least three or four thousand years and has been paid attention to since microbiology. 1887, Koch, one of the founders of microbiology, isolated a kind of bacteria, Kirks Willebrand, from trachoma lesions, which was considered as the pathogen of trachoma. He first put forward the "bacterial pathogen theory" of trachoma, but it was quickly denied. In 1907, Haberstedt and Prova Zeke found inclusion bodies in trachoma lesions, which were thought to be viruses, but there was no conclusion. In the mid-1920s, Nicholas proved that trachoma materials were still infected by bacteria filtered by sand sticks. He first put forward trachoma's "viral pathogen theory", but failed to prove it. 1928, Hideki Noguchi isolated a bacterium from trachoma and used it as a pathogen, and once again put forward the theory of bacterial pathogen, which attracted wide attention. At 1930, Tanghe repeated Noguchi's experiment, but they got a negative result. 1933, Tang implanted "Bacillus granulosus" preserved in the United States into the eyes of 12 volunteers including himself, which proved that it was not pathogenic, overthrew the "bacterial pathogen theory" and regained the upper hand. Until 1954, despite the efforts of many laboratories, it was still inconclusive because the virus was not isolated. As early as 1930s, when Tang studied the nature of viruses and inclusion bodies, he gradually formed a view that microorganisms are a long series from small to large in nature, and there are "transitional microorganisms" between known viruses and bacteria, such as Rickettsia and Mycoplasma bovis. He believes that trachoma pathogen is a kind of "big virus" which is bigger than vaccinia virus and close to rickettsia, and its many characteristics are close to parrot fever and mouse lymphogranuloma virus. Following this idea, he made a research plan, and simultaneously carried out trachoma inclusion body research, monkey infection test and virus isolation test. In order to ensure the reliability of pathological materials, he specially invited Zhang, an ophthalmologist from Beijing Tongren Hospital, to identify the selected typical cases, and started work from June 1954.
During this year, Tang personally took his assistant to search 20 1 materials of trachoma clinic in Tongren Hospital, and found 48 cases of inclusion bodies. It was found that there were four forms of inclusion bodies: scattered type, hat type, mulberry type and stuffing type, and the formation and evolution process were expounded, which clarified the confused understanding since 1907 discovered trachoma inclusion bodies. He wrote in his paper: "Protozoa and protozoa are both evolutionary forms of trachoma virus. Protoplast stands for static, and protoplast stands for active reproduction. The protoplasm becomes the protoplasm, and the protoplasm produces the protoplasm. ..... We can infer that the precursor of trachoma virus invades or is swallowed into epithelial cells, that is, it becomes a precursor by increasing its volume, propagates and develops into scattered inclusion bodies, then continues to develop into hat-shaped or mulberry-shaped inclusion bodies, and finally becomes a stuffed inclusion body. At this time or before, the protozoa returned to the protozoa, and finally the cells were filled with the protozoa and ruptured, and the protozoa spewed out, and then invaded other healthy cells and repeatedly infected. " He actually described the development cycle of trachoma pathogen invading host cells. After successfully isolating Chlamydia trachomatis, it was completely confirmed in artificial infection and animal models. It is known that the development cycle of Chlamydia trachomatis is about 48 hours.
This year, the monkey infection experiment in Tang was also successful. He and his assistant caused trachoma in monkeys, and found that the anatomical structure of conjunctiva was different between monkeys and people, and the symptoms after trachoma were different: there were no scars and pannus. They also found trachoma inclusions in monkeys that had never been found before.
However, their efforts to isolate the virus failed this year. In 195 1 and 1953, Japanese scholars Arakawa and Kitamura reported that the virus was successfully isolated by inoculation in the brain of young rats or chorioallantoic membrane of chicken embryos, but it was not recognized because the virus could not be obtained. Tang thinks it is possible to isolate trachoma virus by their method. Because he thinks trachoma is similar to psittacosis and mouse lymphogranuloma virus, the latter two can grow in the brain of mice. So he decided to start the experiment of virus isolation by repeating the experiments of Arakawa and Kitamura. However, in a year, he and his assistant collected samples from 20 1 typical stage II trachoma patients and inoculated more than 2,500 young rats. None of them showed symptoms similar to those described by Arakawa and Kitamura, and no virus was isolated. The experiment failed. Although Tang did not completely deny the possibility of isolating trachoma virus with young mice, he decided to shelve it and isolate it with chicken embryos.
From June 65438 to July 0955, the virus isolation experiment was resumed. This time, he did not use Arakawa's chorioallantoic membrane inoculation, but used the yolk sac inoculation commonly used in Rickettsia research. He analyzed the factors affecting virus isolation, and thought that in addition to selecting sensitive animals and appropriate infection routes, it was necessary to inhibit the growth of miscellaneous bacteria, and decided to add antibiotics as inhibitors to the samples. At that time, it was known that streptomycin was ineffective in the treatment of trachoma, and whether penicillin had a curative effect was unknown, so these two antibiotics were chosen, but it was not so smooth that a virus was isolated after only eight tests.
The first trachoma virus in the world was named TE8 by Tang, T stands for trachoma, E stands for eggs, and 8 is the eighth experiment. Later, laboratories in many countries called it "Down virus". Although the virus was isolated, the success rate was too low, and it was later learned that penicillin could kill the virus. They improved the method: the penicillin was cancelled, the dosage of streptomycin was increased, the action time of streptomycin in the sample was prolonged, and the success rate was greatly improved. Using the improved method, the virus isolation rate reached 50%, and eight viruses were isolated continuously in less than two and a half months. The experiment was successful, and it was suggested that Tang publish the results as soon as possible, because many laboratories in the world are scrambling to isolate trachoma virus, and if they don't publish it as soon as possible, they are afraid of being preempted. However, Tang, who is rigorous in style, disagrees. He believes that the requirements of Koch's law have not been met. Koch's law requires that microorganisms are the pathogens of infectious diseases. First, it must be able to isolate microorganisms from the corresponding cases. Secondly, a pure culture capable of culturing this microorganism in vitro is needed; Third, isolated microorganisms should be able to cause typical injuries and symptoms in another healthy host; Fourthly, we should be able to isolate this microorganism from this host again. Tang has done a lot of work, which proves that TE8 can be propagated in chicken embryos, and infected monkeys with it can cause typical trachoma and find inclusion bodies, and can be separated from monkey eyes again to obtain "pure culture". He also used a graded filter membrane to prove that TE8 is filterable, and measured its size between 120-200 nm. Then, he published a paper in June 1956+00. Finally, he implanted TE8 into one of his eyes on New Year's Eve of 1957, which caused a typical trachoma. In order to observe the whole course of disease, he insisted on receiving treatment for more than 40 days, which undoubtedly proved the pathogenicity of TE8 to human beings.
The successful isolation of trachoma virus caused great repercussions in the international scientific community, because it was a key breakthrough and pushed trachoma research, which had been at a low tide for a long time, to a climax. Collier 1957 of the Liszt Institute in the United Kingdom obtained TE8 and TE5, which quickly confirmed the work of Tang et al. 1958, he isolated trachoma virus in Gambia, West Africa by Tang's method. Soon, doctors in the United States, Saudi Arabia, Israel and other countries and regions also isolated trachoma virus. 1958, Jones isolated trachoma virus from the cervix of a woman with sexually transmitted diseases in the United States, which solved the problem of sexually transmitted diseases affecting tens of thousands of people every year in the United States alone. With pathogens, we can carry out systematic and in-depth research, thus confirming that the pathogens of trachoma, psittacosis and mouse lymphogranuloma belong to a group of microorganisms between bacteria and viruses. This led to a major change in the classification of microorganisms, adding a chlamydia order, and trachoma virus was officially renamed Chlamydia trachomatis. Using pathogens to test, it is proved that many simple methods, such as drying, insolation and hot water scalding, can effectively disinfect many commonly used disinfectants, and many specific drugs have been screened out. The treatment and prevention of trachoma have made unprecedented progress in just a few years.