Invasion and multiplication of microorganisms in body tissues, which may be clinically inapparent or result in local cellular injury due to competitive metabolism, toxins, intracellular replication, or antigenantibody response.
Invasion and multiplication of microorganisms in body tissues, which may be clinically unapparent or result in local cellular injury due to competitive metabolism, toxins, intracellular replication, or antigen-antibody response. The infection may remain localized, subclinical, and temporary if the body’s defensive mechanisms are effective. A local infection may persist and spread by extension to become an acute, subacute, or chronic clinical infection or disease state. A local infection may also become systemic when the microorganisms gain access to the lymphatic or vascular system.
An infectious disease.
Multiplication of pathogenic (disease-producing) micro-organisms within the body.
The introduction of a foreign organism into the body that can result in damage to cells, organs, or tissues.
The entry or introduction into the body of microorganisms, which then multiply.
An illness which is caused by the entry of microbes into the body.
A condition resulting from the invasion of tissue by harmful bacteria.
Invasion of disease-producing microorganisms into a body, where they may multiply, causing a disease.
A disease that results from invasion of the body by disease-causing microorganisms that multiply and produce injurious effects.
The invasion and multiplication of infectious microorganisms in body tissues. An infection may not cause symptoms, or it may produce signs and symptoms caused by the microorganisms’ injury to the body’s cells or by the body’s response to the invasion, which is the production of antibodies and inflammatory cells that are prompted by the specific cause of the infection. A common symptom of infection is fever.
invasion of the body by harmful organisms (pathogens), such as bacteria, fungi, protozoa, rickettsiae, or viruses. The infective agent may be transmitted by a patient or carrier in airborne droplets expelled during coughing and sneezing or by direct contact, such as kissing or sexual intercourse; by animal or insect vectors; by ingestion of contaminated food or drink; or from an infected mother to the fetus during pregnancy or birth. Pathogenic organisms present in soil, organisms from animal intermediate hosts, or those living as commensals on the body can also cause infections. Organisms may invade via a wound or bite or through mucous membranes. After an incubation period symptoms appear, usually consisting of either localized inflammation and pain or more remote effects. Treatment with drugs is usually effective against all but the viral infections (there is no specific treatment for most of the common viral infections, including the common cold and influenza).
The process by which a disease is transmitted via micro-organisms from one person to another. The micro-organism may be a bacterium, rickettsia, a virus, or a protozoon (single-celled animal organism). Invasion of the body by a metazoon (multicellular animal organism), e.g. an intestinal worm, is more often called an infestation.
A disease caused by microorganisms, especially those that release toxins or invade body tissues. Worldwide, infectious diseases (e.g., malaria, tuberculosis, hepatitis viruses, diarrheal illnesses) produce more disability and death than any other cause. Infection differs from colonization of the body by microorganisms in that during colonization, microbes reside harmlessly in the body or perform useful functions for it (e.g., bacteria in the gut that produce vitamin K). By contrast, infectious illnesses typically cause harm.
The invasion of body tissues by disease-causing or pathogenic bacteria.
Invasion and multiplication of germs in the body. Infections can occur in any part of the body, and can be localized or systemic (spread throughout the body). The germs may be bacteria, viruses, yeast or fungi. They can cause a fever and other problems, depending on the site of the infection. When the body’s natural defense system is strong, it can often fight the germs and prevent infection.
An invasion of the body by a harmful microorganism.
The condition of having harmful agents in the body, such as germs or viruses.
The entry of an organism or virus into a host and the establishment of a permanent or temporary parasitic relationship.
This refers to the colonization of disease-causing microorganisms, like bacteria, viruses, or fungi, within the body. These organisms multiply and instigate disease either through direct cell damage or toxin release. Typically, this process triggers a response from the immune system, which is responsible for many common symptoms.
Infection can be confined to a specific region or tissue, as seen in conditions like a boil, or it can be systemic, spreading across the body, as observed in diseases like influenza. Localized infection can occur due to the proliferation of organisms through wounds or during surgery. This type of infection is often linked with pain, redness, swelling, the creation of a pus-filled abscess at the infection site, and a rise in temperature. Systemic infectious disease typically presents with symptoms such as weakness, joint pain, and fever.
The immune system typically handles many minor infections without the need for specific treatment. A localized infection that has resulted in pus may require surgical drainage. In the case of severe systemic infections, medication such as antibacterials or antivirals might be needed. For more details about various infectious diseases, please refer to the accompanying tables.