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.
An infectious disease is a disease that is caused by the invasion of a host by agents whose activities harm the host's tissues (that is, they cause disease) and can be transmitted to other individuals (that is, they are infectious).ature of Infectious Diseases. Microorganisms that are capable of causing disease are called pathogens. Although microorganisms that cause disease often receive the most attention, it is important to note that most microorganisms do not cause disease.