Infectious medicine

Infectious disease (infectiology)

Gram stain of bacteria: a test frequently performed in infectiology
Significant diseases	Infections, e.g. osteomyelitis, pneumonia, tuberculosis, HIV/AIDS, influenza, also public health issues e.g. epidemics, antimicrobial resistance, bioterrorism
Significant tests	Gram staining, microbiological cultures (including blood cultures), serological tests, genotyping, polymerase chain reaction (PCR), medical imaging
Specialist	Infectious disease specialist, Infectiologist

Infectious disease, also known as infectious diseases, infectious medicine, infectious disease medicine or infectiology, is a medical specialty dealing with the diagnosis, control and treatment of infections. An infectious disease (ID) specialist's practice may consist largely of managing nosocomial (hospital-acquired) infections, or it may be out-patient based.

ID specialists typically serve as consultants to other physicians in cases of complex infections , and often manage patients with HIV/AIDS and other forms of immunodeficiency. Although many common infections are treated by physicians without formal expertise in ID, the ID specialist may be consulted for cases where an infection is difficult to diagnose. They may also be asked to help determine the cause of a fever of unknown origin.

ID specialists can practice both in hospitals (inpatient) and clinics (outpatient). In hospitals, ID specialists help ensure the timely diagnosis and treatment of acute infections by recommending the appropriate diagnostic tests to identify the source of the infection and by recommending the appropriate antibiotic to treat the infection. For certain types of infections, involvement of an ID specialists may improve patient outcomes. In clinic, ID specialists can provide long-term care to patients with chronic infections such as HIV.

ID is historically associated with travel medicine and tropical medicine, as many diseases acquired in tropical and subtropical areas are infectious in nature.

ID specialists employ a variety of diagnostic tests to help identify the pathogen that is causing an infection. Common tests include Gram staining, blood cultures, serological tests, genotyping, and polymerase chain reaction (PCR).

ID specialists employ a variety of antimicrobial agents to help treat infections. The type of agent used depends on the organism that is causing the infection. Antibiotics are used to treat bacterial infections; antiviral agents treat viral infections ; and antifungal agents treat fungal infections.

In the United States, ID is a subspecialty of internal medicine or pediatrics (i.e., an internist or pediatrician trains for an additional 2 years as a medical fellow to qualify as an ID specialist and sit for the ID boards).