There are bacteria everywhere around us, and in infinite quantities. Some are good, some are neutral, but most people have in mind only the bad ones.
1. Tetanus is caused by the bacterium Clostridium tetani. It enters the body via an open wound and releases a powerful toxin, tetanospasmin. The incubation period lasts from 2 days to several weeks. This infection causes fever, pain, spasms of the neck and jaws. The treatment includes sedation, administration of muscle relaxing chemicals, antibiotics and antitoxins. The vaccine confers immunity for 5 years; in the case of profound wounds, injections with antitoxins are required.
2. Typhoid fever is caused by the bacterium Salmonella enterica. The sources of infection are represented by contaminated water and food. The incubation lasts 7 to 14 days, then fever, headaches, constipation and diarrhea install. The treatment consists in antibiotics.
To avoid this infection, food must be processed and manipulated in hygienic conditions. The vaccine confers limited immunity. This disease usually accompanies wars. A huge typhus pandemic broke out during the First World War in the Eastern Europe. Since 1914, over 20 million people died of typhus.
3. Cholera is caused by the bacterium Vibrio cholerae. Humans take the bacterium from water infested with human feces. The incubation lasts 1-7 days. This disease causes chronic diarrhea, dehydration, loss of liquids and salts. These losses must be replaced. The vaccine confers limited protection, that's why hygiene is the main method of controlling cholera.
4. Plague is caused by Yersinia pestis. The black plague broke out in Europe in 1347, when a boat coming from Crimea docked at Mesina, Sicily. Besides its load, the ship transported the pest, which soon spread throughout Italy. It was like the end of the days for Europe. In four years, this bacterium killed 20 to 30 million Europeans, about one third of the continent's population. Even the remote Iceland was struck. In the Extreme East, China dwindled from 123 million inhabitants at the beginning of the 13th century to just 65 million during the 14th century, because of the pest and hunger.
The pest bacterium is transmitted by fleas and, usually, the infection jumps from rats to humans. The incubation lasts 2 to 10 days. The disease causes fever, swelling of the lymphatic ganglions and skin. Today, antibiotics can treat plague. The vaccine confers limited immunity.
This catastrophe has no match in the human history. 25 to 50 % of the inhabitants of Europe, North Africa and certain Asian areas died back then. Knowing the cause of the pandemic helped: in 1907, an outbreak of bubonic plague in San Francisco produced just several victims, as the authorities started a massive campaign for exterminating the rats, while in 1896 an outbreak in India caused 10 million deaths in 12 years, as the cause was not known.
5. Syphilis, caused by the bacterium Treponema pallida, is the most severe sexually transmitted bacterial infection. The first stage has an incubation of 3-12 weeks and it induces ulcered lesions (syphilis chancre) at the entrance of body's aperture organ. After that, it triggers skin eruptions, fever, hair loss, less severe hepatitis and genital condilloma, but if untreated, the lesions extend in several years to the nervous system, leading to death.
The treatment consists in extremely powerful antibiotics (ceftriaxone, Cefixime, and others) which are also extremely costly. Antibiotics are most effective in the first stages. People must avoid having sex with probable carriers of the infection; it requires immediate treatment, ceasing sexual contacts until the end of the treatment and informing of the recent sexual contacts, for medical control and treatment.
6. Gonorrhea is triggered by the Neisseria bacteria and it is transmitted sexually. 62 million people, aged mainly 15 to 29, are affected worldwide, especially in urban areas and of low socioeconomic level. The incubation lasts 3 days, and in men, gonorrhea produces urinary incontinence, urethra pain, reddening, penis burning sensation and testicle inflammation. In women, it induces severe pain that reaches the trumps and uterus. The treatment uses antibiotics and prevention is similar to syphilis.
7. Tuberculosis is caused by the Koch bacterium (Mycobacterium tuberculosis). It is as old as the humankind is. TBC was found even in mummies coming from the ancient Egypt and Peru. 2 million people die annually of tuberculosis. About 150 million people are estimated to have died of TBC since 1914.
One third of the people carry the Koch bacterium, which spreads through the air and milk from infested cows and affects all the body, especially the lungs. It induces prolonged coughing, fever, shivering, bloody expectoration, weight loss, sweating, tiredness, and glossy eyes.
It infects one third of the world population and each year another new 8 million cases appear. Each second a person dies of tuberculosis. It is more aggressive in women and persons between 15 and 45 years old. Mutant strains are resistant to almost all drugs and kill about 50 % of the patients. It is spread worldwide, but its advance is rampant in Bangladesh, China, Indonesia, Philippines, India and Pakistan, with over half of the new cases.
TBC has a treatment, but it cannot be eradicated because of the emergence of multiresistant strains and the long and costly treatment, of over 6 months, is often interrupted sooner than it should. The treatment also includes resting, clean air, proper diet, besides medication. 3-5 % of the new cases are coinfected with HIV. The vaccine is effective in children, but useless in adults. Current employed drugs are isoniazid, ethambutol and Rifapentin.
The BCG decreases the risk of infection, and the pasteurization of the milk, too.
8. Legionnaire's disease is caused by Legionella bacteria. The bacteria are taken from air or wet environments. It causes symptoms similar to flue or pneumonia, accompanied by renal failure. The disease requires hospitalization and treatment with antibiotics. As a prevention measure, water and air conditioning installation must be controlled.
9. Pneumonia affects 1% of the planet's population and can be produced by bacteria (like Aeromonas hydrophila) or viruses. It produces fever, shiver, sweating, cough with expectoration, muscle, head and thoracic pain, appetite loss, weakness.
This is the main cause of mortality in the world: it kills 3.5 million people each year. It attacks especially patients with severe immunodepression, those who follow chemotherapy, people who are older than 75, asthmatics, smokers, alcoholics, those with renal insufficiency and children under 2 years of age. It affects especially the poor countries.
Antibiotics work in the case of the bacteria. Therapy includes oxygen, liquids, and physiotherapy. Patients with a simple pneumonia can cure in 2-3 weeks, but elders or those with debilitating diseases can die of respiratory or cardiorespiratory failure. The vaccine trimetropin sulfamethoxazole is effective against the most frequent complications.
10. Anthrax (Bacillus anthracis) is the most famous bacterium fluttered in the bioterrorism war.
It causes an acute disease in humans and animals, and some strains are highly lethal. Moreover, its spores are extremely long-lived, up to 70 years in the soil. Anthrax cannot spread directly from human to human; but corpses are a very dangerous source of anthrax spores. Anthrax means coal in Greek, a reference to the bacterium's ability to cause black skin lesions in its victims. Anthrax is as old as tuberculosis.
The anthrax attacks the immune system and releases toxins in the blood stream, which destroys tissues and cause massive inner bleeding, and death. If the antibiotics are administered too late, no matter if the bacteria die, the toxins may kill the person.
The bacterium can be taken from infected animals or their products (skin, wool and meat). It can enter the human body through the intestines (ingestion), lungs (inhalation), or skin (cutaneous).
The treatment for anthrax infection and other bacterial infections includes large doses of intravenous and oral antibiotics, such as fluoroquinolones, like ciprofloxacin (cipro), doxycycline, erythromycin, vancomycin or penicillin. Delays of only a few days may make the disease untreatable.