What does it mean to have an infectious disease?

Asymptomatic carrier

Someone who carries a pathogen and shows no signs of a disease but can spread it to other people who can become sick.

Causation

When a change in one factor results in a change in another.

Cholera

Intestinal infection by the bacterium Vibrio cholerae characterized by watery diarrhea.

Correlation

A connection between two factors.

Gastroenteritis

Inflammation of the stomach and intestines is usually caused by numerous viruses and bacteria.

Syphilis

A sexually transmitted disease caused by a bacterium, Treponema pallidium.

Tuberculosis (TB)

A disease caused by the bacterium Mycobacterium tuberculosis, that affects mostly the lungs, and can be deadly, if left untreated.

Agar

Complex carbohydrate isolated from algae that is used to solidify liquid broths (media) for growing microbes.

Electron microscope (EM)

A microscope that uses electrons instead of light to visualize an object. It is the primary tool to study cell structures and small microbes such as viruses.

Maggot

The larva of a fly.

Media

Mixtures of nutrients that are used for artificial growth of microbes under laboratory conditions.

Miasma

The Greek word for "pollution" or "bad air".

Sap

Solution used to transport important nutrients, minerals, and hormones inside a plant.

Athlete's foot

Fungal infection of the skin that affects mostly the webs of the toes and the soles of the feet.

Autism

A neurological disorder; people who have it experience challenges in communication, social interactions, and behavior.

Leprosy

Chronic infectious disease caused by Mycobacterium sp. It affects the skin, eyes, respiratory tract, and nerves.

Lyme disease

An infectious disease caused by Borrelia species and transmitted by ticks.

Measles

A highly infectious (easily spread) disease caused by the measles virus.

Mumps

An infection caused by the mumps virus, characterized by painful swelling of the salivary glands on both sides of the face.

Pure culture

Bacterial culture composed of only one type, species, of bacteria that usually originates from a single cell.

Rubella

An infection caused by the rubella virus, highly dangerous for a fetus if contracted by the mother in the first 20 weeks of a pregnancy.

Bacterial colony

A cluster of billions of bacterial cells that originated from one single cell and are visible with a naked eye on the agar surface.

Germinate

Used to describe the beginning of growth of dormant life forms such as seeds and spores.

Latent TB

Dormant or inactive form of the disease when infected people have TB bacteria in their lungs but they do not grow and divide, hence don't cause symptoms, and can't infect other people.

Phytoplankton

Microscopic organisms in water environments that photosynthesize and fix carbon from the atmosphere.

Vector

An organism that transmits a pathogen from a reservoir to a host.

Acid reflux

Mucosal damage of the esophagus caused by stomach acid flowing into the esophagus from the stomach.

Control group

During an experiment, the subjects in a control group are treated identically to the experimental group with the exception of the tested factor, e.g., a drug, a procedure or another factor.

Duodenum

The first section of the small intestine located below the stomach.

Endoscopy

A procedure used to examine a patient's digestive tract. It is performed with an endoscope, a flexible tube equipped with a camera and light to provide pictures of the digestive tract.

Esophagus

The tube that connects the mouth with the stomach.

Hypothesis

A testable explanation of a phenomenon.

Peritonitis

Inflammation of the peritoneum, the thin tissue that lines the inner wall of the abdomen and covers most of the abdominal organs.

Placebo

Medically ineffective treatment such as a sugar pill.