Delta Pronunciation: (del-ta). Delta letter quick facts. Delta is the fourth letter (Greek letter #4) in the modern day Greek alphabet. The Delta letter appears before Greek letter Epsilon which is pronounced (ep-si-lon), and after the letter Gamma which is pronounced (gam-ah). Delta Letter Template size: 600 X 600 pixels. Greek letter set: #1 to #12 (12 color combinations).
The most common disease-causing agents are viruses, bacteria, protozoa, and parasitic worms. Viruses are not living, but do get transferred between living organisms. The West Nile Virus is transferred from mosquitoes to humans. Vaccines are a good way to prevent the spread of viruses.iruses are the disease-causing agent that most people are familiar with. They cause colds, the flu, HIV, meningitis, polio, chicken pox, rabies, West Nile, and a number of other diseases. Viruses themselves aren't living things, but they do get transmitted between living organisms.
Bacteria cause disease. Most of these bacteria, like those listed below make their presence felt immediately and may or may not result in death. Some people though, can be infected with a bacterium that normally causes a disease and not show any harmful effects at all, people like this are called carriers.n infectious agent is simply an organism that is capable of getting past your defenses and then living/growing inside or you. Bacteria rarely, if ever, cause disease merely by being present, even the virulence factors they produce to help them invade the body often do little real harm.