Globally, about one-third of human deaths are attributable to infections. In addition, the so-called non-infectious causes of death often have a mysterious infectious etiology. Many rare diseases or orphan diseases caused by infectious agents rather than genetic or environmental factors.

An emerging infectious disease (EID) is a contagious disease whose occurrence has boosted in the last 50 years and chances are there that it could increase in the coming future. Emerging infections account for at least 15% of all human pathogens. EIDs are caused by freshly identified strains that may have emerged from a known infection or transferred to a new community or to a field undergoing conserves metamorphosis, or remerging infections. Of thriving concern are adverse synergistic communication between emerging diseases and other infectious and non-infectious conditions ruling to the evolution of unusual syndemics. Many emerging diseases are zoonotic or synoptic - an animal receptacle incubates the organism, with only random conveyance into human populations. Infectious Diseases square amplitude ataxia caused by microorganism such as viruses, fungi or parasites. Infectious diseases is also, foodborne, vector borne, air borne in  related as  further more  in plants and animals. They essentially affirm on the pathological approach of the microorganism and their therapeutic amplifications, synthesis of division of particularly clinical and diagnostic biology that deals with the cure endurance of the contagious diseases

Coronavirus are a large family of viruses that cause illness ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS- CoV) and Severe Acute Respiratory Syndrome. Anovel Coronovirus is a new strain that has not been previously identified in Humans.

Healthcare-associated infections are a threat to patient safety. Hospitalization for an acute illness, trauma, chronic care, or other health care conditions is a common occurrence. There were 39.2 million hospital discharges in 2005, with an average length of stay of 4.6 days. Hospitalization brings associated risks, including risk of infection. Nosocomial infections, or hospital-associated infections, are estimated to occur in 5 percent of all acute care hospitalizations, or 2 million cases per year. Hospital-associated infections have been identified as one of the most serious patient safety issues in health care. Infections that become clinically evident after 48 hours of hospitalization are considered hospital-associated. Risks factors for hospital-associated infections are generally categorized into three areas: iatrogenic, organizational, or patient-related. Iatrogenic risk factors include invasive procedures (e.g., intubation, indwelling vascular lines, urine catheterization) and antibiotic use and prophylaxis. Organizational risk factors include such things as contaminated air-conditioning systems, contaminated water systems, staffing (e.g., nurse-to-patient ratio), and physical layout of the facility (e.g., open beds close together). Examples of patient-related risk factors include severity of illness, immunosuppression, and length of stay.

The exploration of vaccines has led to the near elimination of several important diseases and has a great impact on health for a relatively low cost. However, most vaccines in use today were developed by techniques that were pioneered more than 50 years ago and do not represent the full potential of the field. The introduction of genetic engineering has triggered rapid proposal in vaccine technology and is now prominent to the entry of new products in the merchandise. Global immunization against certain diseases has led to the abolish of smallpox and has almost complete elimination of  many other infectious agents including those causing diphtheria, tetanus, poliomyelitis, measles, mumps, rubella, and Hemophilic influenza type B invasive disease. However, three biggest killers—human immunodeficiency virus (HIV) infection, tuberculosis, and malaria—have not yet been adequately concentrated by a vaccine effective enough to accomplish a similar result. In addition, some common vaccine-preventable diseases such as influenza and pertussis continue to cause significant anguishment and fatality. Current advances in vaccine technology deriving from the function of genetic engineering are now providing the liberty to target new diseases. The use of plasmid-based methods also has the capability to urge the production of reassortant vaccines.