Infectious diseases are of many types. Microorganisms like bacteria, fungi, viruses and parasites causes infectious diseases. The infectious agent that causes the disease is called pathogen. Moreover, the organism that is invaded by an infectious agent is called the host. Agents that cause rapid and severe diseases are said to be virulent infectious diseases. They are responsible for a quarter to a third of all deaths. Most disease-causing organisms or pathogens are microscopic in size because of their small size they referred to as microbes or microorganisms. The study of these organisms is called microbiology and who study them are called microbiologist. Not all microbes cause disease. Many such as bacteria living in our digestive tracts are beneficial and even essential to us. There are different groups of microbes or infectious agents that cause diseases.

Disease causing microbes:

  • Bacteria causes diseases such as strep throat, pneumonia, tuberculosis.
  • Viruses which cause the flu, AIDS, chickenpox and other diseases.
  • Protozoa causes malaria.
  • Fungi which causes sinusitis and skin diseases.

Transmission of infectious diseases

Infectious diseases can be spread in many ways. A particular pathogen usually has a specific way in which it is transmitted. The transmission depends on the type of cell or tissue that the agent targets.

  • Through air -When infected person coughs or sneezes the virus are released into the air, by inhaling this air infection spreads from infected person to other
  • Through contaminated food or water
  • Through body fluids
  • By direct contact with contaminated objects
  • By animal vectors such as insects, birds, bats, etc.

Once a person becomes infected, there is usually a standard course or phases that the disease runs through. These phases are characterized by certain sings such as fever, coughing, vomiting, rashes that can be observed by examining a patient. The time between infection and the appearance of signs and symptoms is called incubation period. During this period of time a person will be unaware that they are infected but they may already be contagious. The next phase called the prodromal phase a patient will experience mild, nonspecific symptoms that signal onset of some diseases. Next is the clinical phase during which the person experiences the typical signs and symptoms of disease. Treatment is done in this phase, and the number of infectious agents begins to drop. The decline phase in which the body’s activities gradually return to normal. The last phase of the infectious disease is the recovery phase. At this phase, symptoms are disappeared, and the body regains strength. Dropping the spread of Infectious diseases is done through vaccines, antimicrobial drugs, good personal hygiene and sanitation, protection against mosquitoes and quarantine.

Dr.Ravi Kiran is the best infectious disease specialist in Hyderabad. He did a rotation at the University of Chicago in the infectious diseases, due to which his interest in the infectious diseases has developed more. He also did a super specialization in the infectious diseases from University of Wisconsin, USA. He has more than 15 years of experience as a infectious doctor.


Dr.Ravi Kiran

Ph No: +919581398868