In the world we live in, micro-organisms are everywhere, and their relationships with humankind are complex. Some micro-organisms live in harmony with us and are beneficial to human health; others can cause infection under certain conditions, threatening our life and health. Research and practice in the area of anti-infection is aimed at protecting the human body from harmful micro-organisms and safeguarding the normal functioning of life.
I. Knowledge of pathogens: the “principals” of infection
Pathogens are micro-organisms or other biological factors that can cause disease, mainly bacteria, viruses, fungi and parasites.
Bacteria are a single-cell micro-organisms with different morphology and different metabolic and pathogenic mechanisms. For example, golden fungus can cause multiple diseases such as skin infections and pneumonia; cosmogenesis in the intestinal tract are usually harmless, but some strains can cause intestinal infections, urinary tract infections, etc.
Viruses are non-cellular micro-organisms that must be parasited in living cells to carry out their activities. The influenza virus triggers seasonal influenza and poses a cyclical global health threat; the HIV virus (HIV) attacks CD4+T lymphocytes in the human immune system, leading to the gradual collapse of the immune system and causing acquired immunodeficiency syndrome (AIDS).
Fungi can be divided into yeast and fungi, such as white pyrocolosis, which is a common fungus that causes oral and vaginal pyromococcal disease, and fungi, which can cause lung infections, especially in populations with low immune functions.
The parasites include insects (e.g. malaria, causing malaria), worms (e.g. aphids, vermin, etc., may be found in parts of the human intestinal tract, affecting nutritional absorption and physical health). These pathogens enter the human body by a variety of means, such as air, foam, exposure, diet, etc., in search of a suitable living environment and incubation, leading to infection symptoms.
II. Humans’ anti-infection line: Multi-defensive immunity systems
The human body has a complex and sophisticated immune system against the invasion of pathogens, including congenital and acquired immunity.
Inheritance is the natural defence of the human body, and the first line of defence consists of skin and mucous membranes. As the largest organ of the human body, the skin, like a solid wall, prevents the invasion of the vast majority of pathogens. The mucous membranes are distributed in the respiratory, digestive and urinary tracts, and the mucous and fibrosis on their surfaces capture and remove pathogens. For example, the fibrous hairs on the mucous respiratory membrane are constantly swinging and can eject inhaled aliens such as dust and bacteria. When the pathogen breaks the first line of defence, the second line of innate immunization is activated. This includes the devouring of cells (e.g., giant, neutral particles), natural lethal cells (NK cells) and a number of immune molecules (e.g., reagent systems). The oscillating cells are able to identify and swallow the pathogens and digest them; the NK cells can directly kill the cells or oncological cells infected by the virus; and the remediate system, through a series of enzyme-driven reactions, forms membranes on the surface of the pathogens, resulting in the decomposition of the pathogens to death.
Acquiring immunization is an immune defence mechanism built up by humans after birth through exposure to pathogens or vaccinations, mainly guided by T lymphocytes and B lymphocytes. When the pathogen first invades the human body, the antigen is presented to the delivery cell (e.g., a tree-thrust cell) for ingestion, processing, and handing over to T lymphocytes and B lymphocytes. T lymphocytes are divided into different subgroups, in which the auxiliary T-cells (Th-cells) are capable of excreting the cytokines, helping B lymphocytes to produce specific antibodies, while at the same time activating other immune cells; and cytotoxic T lymphocytes (CTLs) are uniquely identifiable and kill target cells infected with pathogens. B When irritated by antigens, lymphocytes are divided into plasma cells, producing a large number of specific antibodies. These antibodies can be combined with pathogens to prevent further infection of host cells and can also contribute to the osmosis of the cells to pathogens. When humans re-expose to the same pathogens, memory T lymphocytes and memory B lymphocytes can quickly identify and activate immuno-responses, quickly remove pathogens, and give humans greater immunity protection.
III. Strategies and approaches to combating infection: multi-pronged defence
In daily life, prevention of infection is essential. Maintaining good hygiene practices is the basis for preventing infection, such as hand-washing, maintaining clean ventilation in the living environment, a reasonable diet, adequate exercise, adequate sleep, etc., and helps to increase human immunity and reduce the risk of infection. For example, hand-washing can effectively remove pathogens from hands and reduce the chance of hand-borne disease transmission. During the high-prevalence influenza season, access to densely populated sites is avoided and, if necessary, the wearing of masks can reduce the inhalation of the virus. For specific pathogens, infection can also be prevented by vaccination. Vaccines are biological products that are made of antigens from pathogens or detoxified, detoxified pathogens, and after vaccination they can stimulate the human immune system to produce specific antibodies and memory cells, thus providing the human body with immunity against the corresponding pathogens. Hepatitis B vaccine, for example, can effectively prevent hepatitis B virus infection; the new corona vaccine is critical to controlling the spread of the new corona outbreak worldwide.
Timely diagnosis and treatment are critical when infection occurs. Doctors usually determine the pathogen type of infection on the basis of the patient ‘ s symptoms, signs and laboratory results, and choose the appropriate treatment. For bacterial infections, antibiotics are commonly treated. Antibiotics can kill or inhibit the growth and reproduction of bacteria by inhibiting mechanisms such as the synthesis of bacterial cell walls, the destruction of bacterial cellular membranes, the disruption of the synthesis of bacterial proteins or the metabolism of nucleic acid. However, with the widespread use of antibiotics, the problem of bacterial resistance is increasing. Therefore, the rational use of antibiotics is essential and the prescriptions of doctors should be strictly followed to avoid the abuse of antibiotics. In the case of viral infections, most of which are not currently treated with specific drugs and rely mainly on support for treatment and the human immune system. For example, in the case of common colds, patients are usually advised to rest, drink more water, and treat the symptoms (e.g., use of decals, cough pills, etc.). However, for some serious viral infections, such as AIDS, influenza and so on, there are already antiviral drugs available that can inhibit the replicability of the virus, reduce symptoms and slow the progress of the disease. In the case of fungi infections, antifibre medications are commonly used, e.g. thallium, polyolefin, etc., and their mechanisms are mainly to interfere with the synthesis or functioning of fungal cell membrane. In the case of parasitic infections, the choice of appropriate anti-parasitic drugs according to the type of parasite is required.
IV. New challenges and perspectives in the fight against infection: science and technology for the future
With the acceleration of the process of globalization, population ageing and changes in the ecological environment, new challenges are faced in the area of combating infection.
The variability and drug resistance of pathogens have become more acute. Bacteria produce resistance through mutation of genes, gene transfer, etc., rendering otherwise effective antibiotics ineffective. For example, the emergence of drug-resistant strains such as methooxin-resistant fungus (MRSA) and multi-drug-resistant nodules, has posed great difficulties for clinical treatment. Viruses can also mutate, such as influenza viruses, which require the development of a new influenza vaccine every year, and new coronary viruses are constantly changing during the global spread, adding to the complexity of disease prevention and treatment. In addition, new pathogens, such as the Ebola virus, SARS coronary virus and the new coronary virus, continue to emerge, posing unexpected threats to human health. These new pathogens are often highly pathogenic and contagious, and we have relatively little knowledge and knowledge of them and lack effective treatment and prevention.
In addressing these challenges, scientific and technological developments offer new hope in the area of combating infection. Advances in modern biotechnology have made it possible to study in greater depth the biological characteristics of pathogens, their pathogenic mechanisms and interactions with host populations, providing better target points for drug development and vaccine design. For example, genetic editing techniques (e.g. CRISP-Cas9) can be used to edit the genes of pathogens, to study the relationship between genetic function and pathogenicity, and to develop new antibacterial or antiviral drugs. High-throughput sequencing techniques allow rapid and accurate genomic sequences of pathogens, facilitate timely detection of pathogen variability and provide strong support for disease surveillance and control. In the area of vaccine development, new vaccine technologies, such as the MRNA vaccine, the recombinant protein vaccine and the virus vector vaccine, are emerging. The mRNA vaccine stimulates the human immune response by importing the mRNA coded antigens into human cells so that they can express the antigens in their cells. The vaccine has the advantage of rapid development and relatively simple production processes, which have been widely applied and have achieved significant results during the new coronary epidemic.
In the future, the area of anti-infection will continue to evolve on the basis of multidisciplinary cross-fertilization. On the one hand, we need to strengthen cooperation and communication at the global level to jointly address the transnational transmission of pathogens and drug resistance. The establishment of a global pathogen monitoring network, with real-time information sharing on pathogens, allows for the timely detection of new outbreaks and effective preventive and control measures. On the other hand, it has increased its investment in basic research, explored in depth the mystery of the immune system and developed more safe, effective and widespread anti-infection drugs and vaccines. In addition, emphasis should be placed on public education, public health awareness and hygiene, and the promotion of rational use of medicines to reduce the abuse of antibiotics and control the incidence of infection at its source.
Research and practice in the area of anti-infection concerns the life and health of every human being. We are better able to prevent and respond to infectious diseases through an in-depth understanding of the properties of pathogens, mechanisms for the defence of the human immune system and strategies and methods for combating infection. In the face of changing pathogens and new challenges, and with scientific and technological progress and global cooperation, we are confident in building stronger anti-infection lines to safeguard human health and well-being.
