Tetanus in the context of "Bacterium"

Bacteria are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit the air, soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in mutualistic, commensal and parasitic relationships with plants and animals. Most bacteria have not been characterised and there are many species that cannot be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology.

Like all animals, humans carry vast numbers (approximately 10 to 10) of bacteria. Most are in the gut, though there are many on the skin. Most of the bacteria in and on the body are harmless or rendered so by the protective effects of the immune system, and many are beneficial, particularly the ones in the gut. However, several species of bacteria are pathogenic and cause infectious diseases, including cholera, syphilis, anthrax, leprosy, tuberculosis, tetanus and bubonic plague. The most common fatal bacterial diseases are respiratory infections. Antibiotics are used to treat bacterial infections and are also used in farming, making antibiotic resistance a growing problem. Bacteria are important in sewage treatment and the breakdown of oil spills, the production of cheese and yogurt through fermentation, the recovery of gold, palladium, copper and other metals in the mining sector (biomining, bioleaching), as well as in biotechnology, and the manufacture of antibiotics and other chemicals.

Vaccination is the administration of a vaccine to help the immune system develop immunity from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism. In stimulating the body's adaptive immunity, they help prevent sickness from an infectious disease. When a sufficiently large percentage of a population has been vaccinated, herd immunity results. Herd immunity protects those who may be immunocompromised and cannot get a vaccine because even a weakened version would harm them.

The effectiveness of vaccination has been widely studied and verified. Vaccination is the most effective method of preventing infectious diseases; widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the elimination of diseases such as polio and tetanus from much of the world. According to the World Health Organization (WHO), vaccination prevents 3.5–5 million deaths per year. A WHO-funded study by The Lancet estimates that, during the 50-year period starting in 1974, vaccination prevented 154 million deaths, including 146 million among children under age 5. However, some diseases have seen rising cases due to relatively low vaccination rates attributable partly to vaccine hesitancy.

Vaccine equity means ensuring that everyone in the world has equal access to vaccines. The importance of vaccine equity has been emphasized by researchers and public health experts during the COVID-19 pandemic but is relevant to other illnesses and vaccines as well. Historically, world-wide immunization campaigns have led to the eradication of smallpox and significantly reduced polio, measles, tuberculosis, diphtheria, whooping cough, and tetanus.

There are important reasons to establish mechanisms for global vaccine equity. Multiple factors support the emergence and spread of pandemics, not least the ability of people to travel long distances and widely transmit viruses. A virus that remains in circulation somewhere in the world is likely to spread and recur in other areas. The more widespread a virus is, and the larger and more varied the population it affects, the more likely it is to evolve more transmissible, more virulent, and more vaccine resistant variants. Vaccine equity can be essential to stop both the spread and the evolution of a disease. Ensuring that all populations receive access to vaccines is a pragmatic means towards achieving global public health. Failing to do so increases the likelihood of further waves of a disease.

Alexandre Émile John Yersin (22 September 1863 – 1 March 1943) was a Swiss-French physician and bacteriologist. He is remembered for his work as a pioneer in microbiology and immunology. Yersin is the co-discoverer of both the Diphtheria and Tetanus toxins (1890 with Émile Roux) and of the bacillus responsible for the bubonic plague or pest (1894, with Kitasato Shibasaburō). The bacteria was later named in his honour: Yersinia pestis. Yersin also demonstrated for the first time that the same bacillus was present in the rodent as well as in the human disease, thus underlining the possible means of transmission.

The Pasteur Institute (French: Institut Pasteur, pronounced [ɛ̃stity pastœʁ]) is a French non-profit private foundation dedicated to the study of biology, micro-organisms, diseases, and vaccines. It is named after Louis Pasteur, who invented pasteurization and vaccines for anthrax and rabies. The institute was founded on 4 June 1887 and inaugurated on 14 November 1888.

For over a century, the Institut Pasteur has researched infectious diseases. This worldwide biomedical research organization based in Paris was the first to isolate HIV, the virus that causes AIDS, in 1983. It has also been responsible for discoveries that have enabled medical science to control diseases such as diphtheria, tetanus, tuberculosis, poliomyelitis, influenza, yellow fever, and plague.

Tetanus toxin (TeNT) is an extremely potent neurotoxin produced by the vegetative cell of Clostridium tetani in anaerobic conditions, causing tetanus. It has no known function for clostridia in the soil environment where they are normally encountered. It is also called spasmogenic toxin, tentoxilysin, tetanospasmin, or tetanus neurotoxin. The LD₅₀ of this toxin has been measured to be approximately 2.5–3 ng/kg, making it second only to the related botulinum toxin (LD₅₀ 2 ng/kg) as the deadliest toxin in the world. However, these tests are conducted solely on mice, which may react to the toxin differently from humans and other animals.

C. tetani also produces the exotoxin tetanolysin, a hemolysin, that causes destruction of tissues.

Clostridium tetani is a common soil bacterium and the causative agent of tetanus. Vegetative cells of Clostridium tetani are usually rod-shaped and up to 2.5 μm long, but they become enlarged and tennis racket- or drumstick-shaped when forming spores. C. tetani spores are extremely hardy and can be found globally in soil or in the gastrointestinal tract of animals. If inoculated into a wound, C. tetani can grow and produce a potent toxin, tetanospasmin, which interferes with motor neurons, causing tetanus. The toxin's action can be prevented with tetanus toxoid vaccines, which are often administered to children worldwide.