Notifable infectious diseases can be caused either by viruses, parasites or bacteria. That's why when speaking about notifable infectious diseases it is essential to focus upon main data regarding these infections types.

So, viral diseases are caused by viruses - microscopic obligate intracellular parasites which are able to infect cells in living biological organisms. There are lots of different viruses which have various shapes, forms and functions. Viruses are the tiniest and simplest of microbes. They are approximately ten thousand times smaller that any bacteria. Viruses are considered to be the culprits of the majority of human diseases including ever present human cold, flu, AIDS, smallpox, definite types of cancer, etc. It's worth mentioning that viruses are able to infect virtually any types of cells: fungi, protozoa, bacteria, animals, plant and, no doubt, human.

Parasitic diseases are caused by various parasites. There are over a hundred parasites types able to live in the human body. But not all of them are harmful. There are several distinguishing symptoms experienced by individuals affected by parasites: bloating, constipation, diarrhea, irritable bowel syndrome, sleeping problems, skin conditions, allergies, joint and muscle aches, nervousness, granulomas, chronic fatigue anemia, teeth grinding and other problems with the immune system.

Speaking about notifable infectious diseases caused by bacteria it's impossible not to mention about cholera and botulism. Cholera is known as an acute intestinal infection. It is caused by bacteria called Vibrio Cholerae which live in water which has been contaminated by improper sanitation or in a meal which hasn't been properly cooked (especially fish). About a million Vibrio cholerae bacteria must be ingested to the human body to cause cholera in healthy people, although increased susceptibility is usually observed in individuals with weakened immune system, with decreased gastric acidity, or malnourished people.

The disease has rather short incubation period (from one to five days) and quickly leads to diarrhea and severe dehydration of the human body. If no proper treatment is given the illness may lead to death. This is one of the notifable infectious diseases first described by the outstanding physician Garcia de Orta of the sixteenth century and was called "bad".

Speaking about botulism, it is impossible not to mention that the disease is rather rare, but at the same time it is a one of notifable infectious diseases that can entail grave complications. This is an intoxication of the human organism caused by extremely potent toxins known to be preformed in foods. These toxins are produced by the bacterium called Clostridium botulinum.

Botulism is mainly considered to be the foodborne intoxication. However it can also be transmitted via wound infections or intestinal infection in infants. Botulism prevention is based on proper food preparation practices (particularly preservation) and hygiene. Botulism may also be prevented by inactivation of the bacterial spores in heat-sterilized products or by inhibiting the growth in all other products.

Thus, nowadays fighting notifable infectious diseases is really easier than it was in the past. With appropriate precautions and hygiene, in addition to rapidly advancing medical technology, the world population becomes better equipped than ever before to avoid possible diseases.