- Caecum
- The large pouch forming the beginning of the large intestine.
- Calabar
- A temporary inflammatory reaction known as calabar swellings, characteristic of Loa loa infection.
- Calculus (plural calculi)
- A stone formed in tissues.
- Calorie
- A unit of heat. A nutritional calorie is the amount of heat necessary to raise 1 kg of water 1°C.
- Calvin cycle
- The biochemical route of carbon dioxide (CO2) fixation in many autotrophic organisms.
- Campylobacter
- A bacterium found in the intestines of many birds and mammals, including poultry and cattle. Although it does not commonly cause disease in these hosts, it can cause colicky abdominal pain and diarrhea in humans, with the disease being the most prevalent in June. It is mainly spread by poultry, occasionally water, and milk products not adequately pasteurized. Campylobacter pylori is now called Helicobacter pylori, the cause of peptic ulcers. The Campylobacter bacterium can produce a toxin that is genetically related to the cholera toxin.
- Candida albicans
- A yeast-like organism of the Candida genus that causes the infection Candidiasis, commonly referred to as “thrush.”
- Canker (cancrum)
- An ulceration, especially of the lip or oral mucosa.
- Capsid
- The external protein coat of a virus.
- Capsomer
- The individual protein subunit of the virus capsid and formed in repetitive sequence.
- Capsule
- A polysaccharide, or sometimes a polypeptide layer, surrounding bacterial cells peripheral to the cell wall. (See also Glycocalyx and Slime layer.)
- Carbuncle
- A massive pus-filled collection of hair follicles infected with Staphylococcus aureus, causing a crop of boils with multiple drainage channels, particularly of the neck and upper back.
- Carcinogen
- A substance that initiates tumor formation and is frequently a mutant. Carcinogenesis is the development of cancer caused by the actions of certain chemicals, viruses and unknown factors on primarily normal cells.
- Carcinoma
- A cancer of the epithelium lining skin or internal organs.
- Carrier
- A living host, animal or human, infected by an organism, but not displaying any clinical symptoms of the disease. Carriers may have asymptomatic infections or may be individuals who have recovered from the disease but continue to shed the causative agent into the environment.
- Carrier rate
- The number of individual carriers in a specific population who are infected by an organism.
- Caseous
- Describes the cheese-like consistency associated with tuberculosis lesions termed caseation necrosis.
- Cat-scratch
- A disease caused by the bacterium Bartonella henselae (formerly Rochalimaea henselae) and, as the name indicates, contracted from the bites and scratches of infected cats. Kittens account for roughly 90% of all the cases, and adult animals responsible for the other 10%. The bacteria is carried in the blood of an infected animal, with most animals usually show no signs of illness, showing up only when humans become ill. Incubation is seven to twelve days after a bite or scratch, when a small red pimple appears at the site. About two weeks later, the lymph glands will swell and become firm and painful. At the same time, a low grade fever will develop, along with tiredness, poor appetite, and headaches. In another week, the lymph glands will fill with pus before gradually returning to normal. This disease is relatively minor, but can develop into a serious illness in those with weakened immune systems and the elderly. The more serious form of the disease is called bacillary angiomatosis. This disease is not infectious and cannot be transmitted from person to person. If more than one person in the family has the disease at the same time, it will be because they have come in contact with the same infected animal. There is no antibiotic cure, despite the fact that many physicians prescribe them. Time is the only effective healer. Pasteurella multocida bacteria causes Pasteurellosis, a disease also caused by the bites or scratches of cats and dogs, accounting for about half of all cat bites. The bacteria lives in the mouths and throats of almost all cats, and about 50-60% of all dogs and wild animals can also carry the disease.
- Catabolism
- The metabolic breakdown of organic compounds.
- Catalase
- An enzyme that converts hydrogen peroxide to water and molecular oxygen.
- Catalyst
- A molecule that lowers the energy activity of a chemical reaction.
- Catarrh
- An excessive secretion of thick phlegm or mucus by mucous membranes of the nose. Catarrhal stage is the period during whooping cough characterized by fever, sneezing, vomiting, and a mild, dry persistent cough.
- CD4 cells
- T-helper cells which are targets for HIV infection.
- Cedecea (also spelled Cedecia)
- A bacterium of the family Enterobacteriaceae, mostly causing bacteraemia.
- Cell-mediated immunity
- A specific immune response involving the activity of such non-antibody producing cells as T cells (contrast humoral immunity).
- Cellulitis
- An inflammation of connective tissues occurring between muscles, characterized by erythema and edema. Cellulitis is often caused by Staphylococcus or Streptococcus strains of bacteria, usually contracted through wounds typically affecting subcutaneous tissues.
- Centers for Disease Control (CDC)
- An organization now known as the Centers for Disease Control and Prevention. It is a US federal government facility based in Atlanta, Georgia, that organizes and monitors treatment programs for preventable diseases around the world.
- Cerebrospinal fluid (CSF)
- The clear, colorless fluid that surrounds the spinal cord and brain and fills the interior cavities of these structures. This fluid undergoes characteristic pathological changes in patients suffering meningitis.
- Cestoda (Cestodes)
- A class of protozoa that includes tapeworms or specialized flatworm of the class Cestoidea, phylum Platyhelminthes, subclass Cestoda. There are five types of tapeworms that can infect humans: beef, pork, fish, dog, and dwarf tapeworms.
- Ceviche (seviche)
- Raw fish marinated in lime or lemon juice that often carry tapeworms, flukes, and the Anisakine larvae.
- Chagas’ disease
- A chronic parasitic disease that affects the heart and esophagus, caused by the protozoan parasite Trypanosoma cruzi, transmitted by biting bugs (also known as “kissing bugs”) found in South America.
- Chancre
- An ulcerated lesion associated with sexually transmissible diseases. Hard chancres are a feature of primary syphilis; and soft chancres appear in chancroid, a disease caused by Haemophilus ducreyi.
- Chemoautotroph
- An organism that obtains energy by oxidizing simple inorganic substances, as sulfides and nitrites.
- Chemolithotroph
- An organism that does not require light and oxidises inorganic compounds to gain energy, using carbon dioxide as its sole carbon source.
- Chemoorganotroph
- An organism that uses organic compounds as a source of energy and does not require light to grow.
- Chemotaxis
- The movement of cells toward or away from a chemical stimulus.
- Chemotherapeutic agent
- Any chemical substance or antibiotic used to treat disease.
- Chemotherapy
- The science of curing a disease using chemicals.
- Childbed fever
- An old term used for the infection of the reproductive organs and blood stream that commonly followed childbirth, particularly in contaminated settings. The usual cause was group A strep.
- Chlamydia
- The most sexually transmitted disease. The class Chlamydiae, is similar to the Rickettsiae, but its diseases are less severe, but far more common.
- Chloramphenicol
- An antibiotic that has been known to cause aplastic anemia, a form of anemia in which the cells of the bone marrow responsible for blood formation become suppressed and new blood cells can no longer be made.
- Chloroplasts
- Chlorophyll-containing organelles found in eucaryotic cells that carry out photosynthesis.
- Chloroquine
- An anti-malarial drug to which many strains of Plasmodium falciparum have now become resistant.
- Chlorosomes
- Cigar-shaped structures bound by a nonunit membrane containing the light harvesting bacteriochlorophyll found in green sulfur bacteria and in Chloroflexus.
- Cholera
- The disease produced by the bacterium Vibrio cholerae of the family Vibrionaceae, resulting in an intestinal infection with copious amounts of watery stools and rapid dehydration. It is transmitted via the fecal/oral route, usually as a result of contaminated water.
- Choleragen
- A cholera toxin responsible for the profuse, watery, diarrhea of the Cholera disease.
- Chorioretinitis
- An inflammation of the retina and outer membrane of the eye.
- Chromosomes
- Genetic elements carrying genes essential to cellular metabolism. Prokaryotes typically have a single chromosome, consisting of a circular DNA molecule. Eukaryote cells contain several chromosomes with each containing a linear DNA molecule complexed with specific proteins.
- Chronic
- Lasting a long time, with the tendency to progress slowly in improvement.
- Cilia (singular cilium)
- Short filamentous structures that beat rhythmically to cause movement.
- Ciliated epithelium
- Special tissues that contain numerous ciliated cells, as the tracheal surface.
- Ciliophora (ciliates)
- Protozoa that move by using fine cilia that beat in rhythmic patterns to propel the organism. Members include Balantidium and Paramecium.
- Cirrhosis
- A progressive, irreversible liver disease characterized by extensive scarring and distortion of tissue development that results in liver failure.
- Cisternal injection
- An injection made at the base of the skull into the space where the brain stem meets the spinal cord.
- Cistron
- A unit of DNA that codes for a single polypeptide.
- Citrobacter
- A bacterium of the family Enterobacteriaceae, closely related to Salmonella and one of the causitive agents for urinary tract infections.
- Class I MHC proteins
- Antigen-presenting molecules found on all nucleated vertebrate cells.
- Class II MHC proteins
- Antigen-presenting molecules, found primarily on macrophages and B lymphocytes.
- Classification
- Microorganism classification includes: Seven levels for all living things in order of generality to specifics (From there, each category can be broken down into subheadings): 1) Kingdom 2) Phylum (plural phyla) 3) Class 4) Order 5) Family 6) Genus 7) Species. Most scientists agree that all organisms can be classified within five kingdoms: Animals, Plants, Protists, Fungi, and Monerans. Disease-causing organisms usually fit into five categories from the simplest to the most complex: viruses, bacteria, protozoa, fungi, and worms.
- Clone
- 1)A population of cells derived from a single progenitor cell; 2) A number of copies of a DNA fragment obtained by allowing an inserted DNA fragment to be relicated by a phage or plasmid; 3) A bacterial colony.
- Clonal selection
- A theory that each B or T lymphocyte, when stimulated by an antigen, will divide to form a clone of itself.
- Clostridium
- A bacterium producing very serious illnesses: Clostridium botulinum (botulism), Clostridium difficile (serious diarrhea), Clostridium perfringens (gas gangrene, a common cause of food poisoning), Clostridium tetani (tetanus or lockjaw). C. pasteurianum is one Clostridium member that actually is helpful to humans. It causes plants to acquire nitrogen and, thus, is fundamental to the world’s food production.
- CNS (Central Nervous System)
- The brain and spinal cord.
- Coagulase
- An enzyme released by invading staphylococci that causes blood plasma to coagulate and form a layer around the bacteria interfering with access of white blood cells.
- Coccidioidomycosis
- The potentially fatal disease known as Valley Fever, caused by inhalation of the spores of the fungus Coccidioides immitis, and can result in pneumonia and meningitis. Progressive coccidioidomycosis is one of the definitive diseases for AIDS. Coccidioidomycosis Serology Laboratory is a facility at the University of California at Davis that performs serological tests on the blood and cerebrospinal fluids of patients with coccidioidomycosis.
- Coccoid
- Round or sphere-shaped.
- Coccus (plural cocci)
- A sphere-shaped bacterium.
- Code
- The genetic information associated with the triplet base sequence of DNA.
- Codon
- A base triplet (a sequence of three purine and/or pyrimidine bases) in messenger RNA that codes for a single amino acid.
- Coenzyme
- A molecule involved in the transfer of smaller molecules between enzymic reactions by accepting or donating electrons or functional groups, as in the cases of NAD+ and FAD.
- Coliform
- Gram-negative, non-spore-forming, aerobic or facultatively anaerobic, rod-shaped bacteria that ferment lactose and produce acid and gas within forty-eight hours at 35°C (95°F). When found in significant numbers, it could indicate water pollution of Enterobacteriaceae, often normal flora of the human intestinal tract, that can turn pathogenic and cause infections.
- Colonization
- The multiplication of a microorganism after it has attached to host tissues or other surfaces.
- Colitis
- An inflammation of the colon, also known as the large intestine.
- Colorado tick fever
- A disease transmitted by the wood tick Dermacentor andersoni.
- Cometabolism
- The metabolic transformation of a substance while a second substance serves as primary energy or carbon source.
- Commensal species
- Two species that coexist in such a way as to benefit one while the other is unaffected (contrast symbiosis).
- Communicable
- A synonymous term for a contagious disease, which can be transmitted from one person to another.
- Complement
- A system of about thirty proteins in the blood that work with antibodies to form a powerful defence system against foreign cells.
- Complement fixation
- A serological reaction which depends on the binding of complement in an antigen-antibody complex.
- Compromised host
- An individual with a decreased resistance to infection.
- Conidia (singular conidium)
- The germination of a fungal spore.
- Conjugation
- The process whereby bacterial DNA is transferred between individual cells through a pilus.
- Conjunctivitis
- An inflammation of the tissue surrounding the eyeball known as the conjunctiva.
- Contagious
- Transmissible (see also communicable).
- Cook-Chill
- A catering system whereby whole meals or their components are cooked to an initial temperature of about 70°C (158°F), then rapidly chilled to just above freezing temperatures, usually between 0° and +3°C (32° to 37.4°F). They are then stored and transported prior to reheating and being eaten.
- Coronaviruses (adenovirus)
- Another group behind the common cold. Colds can actually be caused by a variety of viruses – rhinoviruses, coronaviruses, coxsackieviruses, picornavirus family or adenoviruses.
- Cortex
- The region around the core inside the spore coat of an endospore.
- Coryza
- An acute inflammation of the nasal mucosa, accompanied by profuse nasal discharge.
- Corynebacterium diphtheriae
- The bacterium responsible for the disease diphtheria.
- Coxsackieviruses
- Viruses composed of about thirty members that infect the intestines, but can also cause meningitis, throat ulcers, myositis, an inflammation of muscle, and heart attacks (when there is an inflammation of the heart muscle). Generally, they are noted for producing diseases resembling poliomyelitis, but without paralysis; but there is a strong connection between Coxsackieviruses and insulin-dependent diabetes since the virus appears to destroy insulin-secreting cells in the pancreas.
- Coxiella burnetii
- The organism responsible for Q fever and orginally called Rickettsia burnetii.
- Creatinine
- A component of urine that can accumulate in the blood if the kidneys are not working properly.
- Croup
- A swelling of the epiglottis or pharynx that produces a hoarse cough.
- Cryptosporidium
- A protozoan parasite known to cause diarrhea infections (cryptosporidiosis) in both humans and animals. They are 1/16th the size of a dust particle that floats in the air, and have been found in over 85% of the water supplies in the US. They are passed through the feces of an infected animals (mostly cattle) and are not killed by boiling or the routine chlorination or filtration of water.
- Crytococcus
- A fungus causing cryptococcosis, a disease of the lungs and brains, particularly in patients with weakened immune systems. Disease is contracted through the inhalation of Cryptococcus neoformans spores found in soil and habitats of pigeons.
- CT (computed tomography)
- A computerized X-ray scan used to locate tissue damage.
- Cutaneous
- Related to the skin.
- Cutaneous larva migrans
- A syndrome caused by dog and cat hookworm larvae and characterized by lesions on the skin at their point of entrance.
- Cyclops
- A tiny organism that serves as the host for the larval forms of the roundworm causing gnathostomiasis.
- Cyanobacteria
- A class of bacteria which photosynthesize and produce oxygen much like plants. It was previously known as blue-green algae.
- Cyanosis
- The bluish discoloration of the skin that results when oxygen does not reach certain tissues.
- Cyst
- The resting or encapsulated dormant stage of some protozoan parasites and bacteria that is resistant to environmental changes, being passed from host to host.
- Cysticerci
- Cyst-like organisms.
- Cysticercosis
- The disease caused by infection by the larval stage of the pork tapeworm Taenia solium affecting the brain, eyes, and muscles, and characterized by seizures and brain deterioration.
- Cystitis
- An infection of the urinary bladder that differs from a fairly new perplexing disorder known as Interstitial cystitis. Cystitis often results from various strains of bacteria, usually E. coli or Proteus, that adhere to the uroepithelial cells, causing inflammation of the urinary bladder. Infection, more commonly, moves upwards from the urethra rather than downwards from the kidneys.
- Cystoscopy
- The visual examination of the urinary tract with a special device called a cystoscope.
- Cytokines
- Cells that include about twenty different hormones of the immune system, including interferons and interleukins. They act as the communication link between immune cells that comes usually in brief and local pulses. When present in excessive amounts, they can have harmful effects.
- Cytomegalovirus (CMV)
- A virus in the herpes family that mainly infects the retinas of immunocompromised patients, causing blindness.
- Cytopathic effect
- Observable changes that occur in cell cultures resulting from viral infections.
- Cytotoxins
- A type of toxin that acts by inhibiting the host cell protein synthesis and may also be involved in adherence.
