Tetanus (from Ancient Greek τέτανος 'tension, stretched, rigid'), also known as lockjaw, is a bacterial infection caused by Clostridium tetani and characterized by muscle spasms.

[2] Other symptoms of tetanus may include fever, sweating, headache, trouble swallowing, high blood pressure, and a fast heart rate.

The bacteria generally enter through a break in the skin, such as a cut or puncture wound caused by a contaminated object.

[4] Tetanus occurs in all parts of the world but is most frequent in hot and wet climates where the soil has a high organic content.

The cause of the disease was determined in 1884 by Antonio Carle and Giorgio Rattone at the University of Turin, and a vaccine was developed in 1924.

[10] Prolonged muscular action causes sudden, powerful, and painful contractions of muscle groups, called tetany.

Other symptoms include fever, headache, restlessness, irritability, feeding difficulties, breathing problems, burning sensation during urination, urinary retention, and loss of stool control.

The first sign is trismus or lockjaw, then facial spasms (called risus sardonicus), followed by stiffness of the neck, difficulty in swallowing, and rigidity of pectoral and calf muscles.

Spasms may occur frequently and last for several minutes, with the body shaped into a characteristic form called opisthotonos.

As the result of a public health campaign, the death toll from neonatal tetanus was reduced by 90% between 1990 and 2010, and by 2013, the disease had been largely eliminated from all but 25 countries.

Local tetanus is an uncommon form of the disease, in which people have persistent contraction of muscles in the same anatomic area as the injury.

[1] Cephalic tetanus is the rarest form of the disease (0.9–3% of cases),[18] and is limited to muscles and nerves in the head.

Due to C. tetani being an anaerobic bacterium, it and its endospores thrive in environments that lack oxygen, such as a puncture wound.

Manure-treated soils may contain spores, as they are widely distributed in the intestines and feces of many animals, such as horses, sheep, cattle, dogs, cats, rats, guinea pigs, and chickens.

[1] Rarely, tetanus can be contracted through surgical procedures, intramuscular injections, compound fractures, and dental infections.

Additionally, the rough surface of rusty metal provides crevices for dirt containing C. tetani, while a nail affords a means to puncture the skin and deliver endospores deep within the body at the site of the wound.

[30][31] Tetanus neurotoxin (TeNT) binds to the presynaptic membrane of the neuromuscular junction, is internalized, and is transported back through the axon until it reaches the central nervous system.

[35] There are four main steps in tetanus's mechanism of action: binding to the neuron, internalization of the toxin, membrane translocation, and cleavage of the target VAMP.

[36] The toxin travels from the wound site to the neuromuscular junction through the bloodstream, where it binds to the presynaptic membrane of a motor neuron.

[32] There is a consensus among experts that this new channel is involved in the translocation of the toxin's light chain from the inside of the vesicle to the neuron cytosol, but the mechanism is not well understood or agreed upon.

It has been proposed that the channel could allow the light chain (unfolded from the low pH environment) to leave through the toxin pore,[37] or that the pore could alter the electrochemical gradient enough, by letting in or out ions, to cause osmotic lysis of the vesicle, spilling the vesicle's contents.

After a major public health effort, Uganda was certified as having eliminated maternal and neonatal tetanus in 2011.

[citation needed] To survive a tetanus infection, the maintenance of an airway and proper nutrition are required.

An intake of 3,500 to 4,000 calories (15,000 to 17,000 kJ) and at least 150 g of protein per day is often given in liquid form through a tube directly into the stomach (percutaneous endoscopic gastrostomy), or through a drip into a vein (parenteral nutrition).

[50][48] Of likewise efficiency is penicillin, but some raise the concern of provoking spasms because it inhibits GABA receptor, which is already affected by tetanospasmin.

Extended head and neck, tail rigors (tail becomes rigid and straight), abnormal gait (walking becomes stiff and abnormal), arched back, stiffness of the jaw muscles, lockjaw, twitching of eyes, drooping eyelids, difficulty swallowing, difficulty or inability to eat and drink, abdominal bloat, spasms (uncontrolled muscular contractions) before death.

[56] In 1884, Arthur Nicolaier isolated the strychnine-like toxin of tetanus from free-living, anaerobic soil bacteria.

The etiology of the disease was further elucidated in 1884 by Antonio Carle and Giorgio Rattone, two pathologists of the University of Turin, who demonstrated the transmissibility of tetanus for the first time.

[1] In 1891, C. tetani was isolated from a human victim by Kitasato Shibasaburō, who later showed that the organism could produce disease when injected into animals and that the toxin could be neutralized by specific antibodies.

In 1897, Edmond Nocard showed that tetanus antitoxin induced passive immunity in humans, and could be used for prophylaxis and treatment.