结核杆菌 z-bo 2020-08-18 613

　　Scientists studying tuberculosis are discussing its origin, and recent studies have shown that tuberculosis is likely to spread from Africans to seals and sea lions. These animals brought bacteria to South America and infected the indigenous people there. After that, Europe landed on the continent and became infected. Anne Stone, professor of human evolution and social evolution at Arizona State University, said: "We found that the Mycobacterium tuberculosis strain is most similar to the scorpion seal and sea lion strain." Stone said: "This discovery surprised us. There are differences between ancient human strains and modern tuberculosis strains." The latest "close relatives" of the circulating Mycobacterium tuberculosis strains are some strains found in Europe. The researchers clearly showed that about 1,000 years ago, the Peruvian genome had caused some Mycobacterium tuberculosis before Europeans arrived in South America, causing the survival of local residents. For scientists with tuberculosis, the question is "what kind of bacteria existed before exposure to tuberculosis?"

　　In this study, researchers have collected five years of genetic samples from all over the world, and advanced genome sequencing technology has completed the detection of Mycobacterium tuberculosis DNA and more accurate genome sequencing of ancient samples. Among the 76 samples before and after the formation of the New World, 3 samples from Peru (750-1350 AD) contained Mycobacterium tuberculosis DNA. Then, the researchers focused on these three samples and captured them using chip technology that maps the complete genome. By comparing modern genomes and animal microbiota databases, the researchers discovered unique strains related to animals, among which seals and sea lions are closely related. "Our research shows that before the Columbia era, human tuberculosis was transmitted by clams (sea lions and seals). You may have been infected with host bacteria and have transported these bacteria across the sea to South America." Stone explained . Early research suggests that other animals, such as cats, may also be infected with tuberculosis. The Southern United Kingdom Public Health Service and the Institute of Animal Health and Veterinary Medicine contracted tuberculosis in nine cats in Berkshire and Hampshire in southern England. , Screened 24 people who had been exposed to tuberculosis in these cats. As a result, 2 people were diagnosed with "active tuberculosis" with active disease and started treatment. The other two have "recessive tuberculosis". That is, they have been infected but not yet sick. The type of bacteria isolated from the confirmed person is highly consistent with the type of tuberculosis pathogen in the infected domestic cat, and it can be inferred that the patient is infected with the domestic cat. according to

　　Experts from the Ministry of Health and Public Health say that domestic cats are rarely infected by this bacteria. Although the aforementioned cases of cats infecting humans have been detected for the first time, the public health risk is still "very low". However, experts also suggest that if a domestic cat is diagnosed with Mycobacterium tuberculosis, those in close contact with the cat should undergo a physical examination and seek medical advice.