Virology is the study of viruses, about the nucleic acid and protein that are responsible for their replication in plants, animals, and humans. It reveals about the study of their distribution, biochemistry, about their histology, ecology and clinical aspects of the virus. It is the scientific discipline concerned with the viruses, physiology, molecular biology and viral diseases along with their causal agents. Cells affected by viruses and the changes in its in response to the virus lead to the manifestations of the viral disease.

The distribution of viruses and viral infections across the world is referred to as epidemiology. Most epidemiologic studies of infectious diseases have targeted the factors that influence the acquisition and spread because this knowledge is important for developing methods of prevention and control. Historically, epidemiologic studies and the application of the knowledge gained from them have been central to the control of the great epidemic diseases, like cholera, plague, smallpox, yellow fever, and typhus.

Parasitology is that the study of parasites, their hosts, and also the relationship between them. Parasitology is the science overseeing parasites that sully man, inflicting contamination and ill-being in many countries of the tropics. As a biological discipline, the scope of parasitology is not determined by the organism or setting in question, but by their approach of life. There are specific types of parasites and hosts. They torment billions of individuals, kill millions consistently, and convey devastating injuries, for example, visual disability and disfiguration on additional millions. World Health Organization surveys that one individual in every four harbors parasitic worms.

Neglected Tropical Diseases (NTDs) are a major public health problem globally. These are the Diseases that are galore in tropical Region and primarily affecting the world’s poorest population and largely within the developing countries. As they affect poor people they continue to be unnoted, therefore are referred to as “Neglected”. These diseases doesn't include the major three Infectious i.e. AIDS, tuberculosis, Malaria. Rare Diseases refer to those medical aberrations that have an effect on a very least number of the population. they're characterized by a wide diversity of disorders and symptoms that differs not only from disease to disease however conjointly from individual to an individual patient suffering from the same disease.            

Infectious diseases is a sickness caused by organism like microorganism, viruses, fungi or parasites into human beings and also plants and animals. Most of the infectious diseases are usually passed from one person to a different person, and some of the infectious diseases are transmitted by bites from insects or animals, and a few are obtained by contamination of food or by water or by being exposed to organisms that are part of nature.

Clinical immunology is a medical subspecialty largely targeted on a specific physiologic process, inflammation, that is essential to good health, notably in defense against pathogenic organisms and recovery from injury. However, inflammation, mediated by the cells and soluble products of the immune system, is also a robust contributor to the pathogenesis of diseases that affect virtually every organ system.

Vaccination may be a process of administration of an antigenic material (vaccine) into a living mechanism. The clinical effect desired is to cause stimulation of an individual's system so as to develop an adaptive immunity against the pathogen constituting the vaccine. Vaccination is the most effectual method of prevention for infectious diseases. vaccine Adjuvants are components which enhance the immune system and accelerate the immune responses to an antigen. Antimicrobial is the agent that kills or restricts the cell growth. To fight against the potential bacteria nowadays, the manufacturing firms are coming up with a lot of advanced antimicrobial liquids/soaps/sanitizers. Immunization/Vaccination is one amongst the foremost efficient public health interventions thus far, saving millions of lives and protecting countless children from health problem and disability.

A case study, explores the biology of different infectious diseases, covering a variety of topics including the virus, infection, replication, mutation, immune responses, pathology, surveillance, diagnosis, and treatment.

Advancement in genetics to sequence the whole microbe genome has been significant over the years. From the genome sequence of Haemophilus influenza in 1995, around 1554 pathogenic bacteria and 300,000 strains of human immunodeficiency virus (HIV) type 1 genome have been sequenced. The revolution in DNA sequencing technology has to a large extent matched microbial genomics and changed the way infectious diseases are studied. Though gene annotation and error correction will be a tedious process demanding more time and energy, the result will be worth it. Studying the function of gene products and the behavior of organisms and communities from their sequences and genomic data can help us develop improved tools for managing infectious diseases.

AMR-Antimicrobial Resistance has been a major concern among scientists and clinicians worldwide. It is observed that microorganisms like pathogenic viruses, bacteria, fungi, and protozoa have been developing resistance and are more difficult to treat with the existing drugs. To overcome this drawback, several natural and synthetic compounds are discovered, synthesized and tested for their antiviral, antifungal and antibacterial activity. Agents with antiviral/antibacterial/antifungal properties can have a better mode of action against pathogens serving as effective drug and can have a wider market in pharmaceutical industries to treat several infections.