Most bacteria are harmless, but some - such as

Bacterial and viral infections have much in common. Both types of infections caused by germs - bacteria and viruses, respectively - and cover tracks, such as:

and sneezing. Contact with contaminated people, particularly through measures such as kissing and sexual intercourse. Contact with contaminated surfaces, food and water. Contact with contaminated creatures, including pets, livestock and insects such as fleas and ticks. Acute infections are short-lived. Chronic infections that can endure for weeks, months or for life. Latent infection that can cause symptoms at first, but you can activate for months and years. Most importantly, bacterial and viral infections - defined as the invasion of microbes able to reproduce in the body - may cause mild, moderate and severe disease. Throughout history, millions of people become victims of diseases such as

or Black Death, which is related to the bacterium Yersinia

plague, and which is caused by variola virus. Recently, viral infections are responsible for two major pandemics: 1918-1919 BЂњSpanish

BЂ "epidemic that killed 20-40 million people and continues

/ AIDS, which killed about 2 million people around the world in 2008. Bacterial and viral infections can cause similar symptoms such as coughing and sneezing, inflammation,,,, and seizures - all these ways, the immune system tries to rid the body from infectious organisms. However, bacterial and viral infections dissimilar in many other important aspects, most of them due to structural differences of organisms and how they react to the moment antimicrobial. Although bacteria and viruses are very small to see without a microscope, they are structurally as different as giraffes and goldfish. The bacteria is relatively complex, single-celled creatures with hard walls and thin, elastic membrane surrounding fluid or cytoplasm within the cell. Form as balls, rods or spirals, they contain all the genetic information necessary for making copies of themselves. Fossil records show that bacteria existed for about 3. 5000000000 years and it is known that bacteria can survive in various conditions, including extreme cold and heat, radioactive waste, and the human body. Most bacteria are harmless, but some - such as >> << acidophilic lactobacilli bacteria that can live in the human intestine - actually help digest food, destroy disease-causing microbes, fight with cells

, and provide the necessary nutritional substances. Less than 1% of bacteria cause disease in humans. Unlike viruses tiny: most of them smaller than the smallest bacteria. Viruses come in many forms, and have a limited genetic background. All they have protein shell and core of genetic material, either RNA or DNA. Unlike bacteria, viruses can not exist without an owner. They can reproduce itself by attaching to cells and cellular mechanism of capture cells. In most cases, they reprogram the cell to create new viruses until the cells burst and die. In other cases, they turn normal cells into malignant or cancerous cells. In addition, unlike bacteria, most viruses do cause

disease, and they quite specific information about cells they attack. For example, some viruses are programmed to attack cells of the respiratory or. In some strattera prescription cases, viruses are called bacteriophages bacteria goals. .