prefi L5

Protozoa

Single-celled parasites that can live and multiply inside a human host

Helminths

Multicellular parasitic worms that live in or on humans

Ectoparasites

Multicellular parasites that live on the skin, such as head lice, pubic lice, and scabies mites

Natural resistance

No invasion of the host by the parasite

Symbiosis

Colonization of the host by a parasite or organism with benefits to both

Commensalism

Colonization in which one organism benefits without benefiting or harming the host

Sterilizing immunity

The host develops immunity, eliminates the parasite, and is cured

Concomitant immunity

The host develops resistance but is not cured, allowing the parasite to remain

Ineffective immunity

The host fails to develop resistance and is not cured

Antigenic concealment

Parasites hide their antigens from the host's immune system

Antigenic variation

Parasites change their antigens through random mutation, genetic recombination, or gene switching

Random mutation

A mechanism of antigenic variation that generates new antigens through genetic changes

Genetic recombination

Rearrangement of genes that rapidly changes parasite surface molecules

Gene switching

A mechanism in which a parasite switches expression from one gene to another

Antigenic shedding

Parasites release antigens that bind antibodies instead of allowing antibodies to attack the parasite itself

Antigenic mimicry

Parasites express antigens similar or identical to host molecules

Immunologic diversion

A parasite causes the immune system to produce proteins that divert its attention

Immunologic subversion

Parasites avoid immune effector mechanisms involving complement, cytokines, and immune cells

Humoral immunity

An adaptive immune response involving antibodies that neutralize parasites, promote complement lysis, enhance phagocytosis, and support antibody-dependent cellular cytotoxicity

Cell-mediated immunity

An adaptive immune response involving immune cells that help control and eliminate infections

Antibody-dependent cellular cytotoxicity

An immune mechanism in which antibodies help immune cells destroy parasites

Eosinophils

White blood cells attracted to parasitic infection sites through chemotactic factors released during immune responses

Serodiagnosis

Diagnosis of parasitic diseases through detection of parasite antigens or antibodies in specimens

Antigen detection

A diagnostic approach that identifies parasite antigens in a specimen

Antibody detection

A diagnostic approach that identifies antibodies produced against a parasite

Rapid antigen detection test

An immunochromatographic test that detects soluble parasite proteins using capture antibodies on a strip

Real-time polymerase chain reaction

A molecular method used for rapid detection of babesiosis and malaria

Nested multiplex polymerase chain reaction

A molecular diagnostic method used for bloodborne and gastrointestinal parasites

Loop-mediated isothermal amplification

A molecular method used to detect bloodborne and gastrointestinal parasites

Toxoplasma gondii

A parasite whose definitive host is the cat and which causes toxoplasmosis

Tachyzoite

The rapidly multiplying stage of Toxoplasma gondii in the intermediate host

Bradyzoite

The stage of Toxoplasma gondii that forms tissue cysts

Sporozoite

The stage of Toxoplasma gondii found within the oocyst

Definitive host

The host in which a parasite undergoes sexual reproduction; for Toxoplasma gondii, this is the cat

Transplacental transmission

Transmission of tachyzoites from an infected mother to the fetus

Immunoglobulin M

An antibody used to help identify recent toxoplasmosis infection, although it lacks specificity

Immunoglobulin G

An antibody used to help assess previous toxoplasmosis infection

Immunoglobulin G avidity test

A test that helps distinguish recent from previous toxoplasmosis infection; high avidity suggests older infection, while low avidity suggests more recent infection

Congenital toxoplasmosis

Toxoplasmosis transmitted from an infected mother to her fetus

Fungi

Eukaryotic organisms with nuclei and rigid cell walls that are widely distributed in the environment

Saprophytes

Organisms that obtain nutrients from dead and decaying matter

Mycosis

An infection or disease caused by fungi in humans or animals

Yeast

A unicellular fungal form that reproduces by budding

Mycelial form

A multicellular fungal form that reproduces by spores or conidia

Dimorphic fungi

Fungi that exist in either yeast or mycelial form

Hypersensitivity

An allergic reaction to fungal spores that may occur upon contact or as a chronic condition

Mycotoxicosis

Poisoning caused by consuming food contaminated with fungal toxins

Mycetismus

Mushroom poisoning caused by ingesting toxin-producing mushrooms

Superficial mycosis

A fungal infection affecting the outer layers of the skin

Cutaneous mycosis

A fungal infection involving keratinized tissues such as skin, hair, and nails

Subcutaneous mycosis

A fungal infection causing deeper skin lesions after traumatic implantation of fungi

Systemic mycosis

A fungal infection involving deep organs and potentially spreading throughout the body

Opportunistic fungal infection

An infection caused by fungi that take advantage of weakened host defenses

Dermatophytes

Fungi that infect skin, hair, and nails and require dead keratin for growth

Dermatomycosis

A fungal disease affecting the skin, hair, or nails

Toll-like receptors

Receptors that stimulate inflammatory cytokines and type one interferons and help shape adaptive immunity

C-type lectin receptors

Receptors involved in fungal recognition and the induction of innate and adaptive immune responses

Dectin-1

A fungal recognition receptor that recognizes beta-glucans

Dectin-2

A fungal recognition receptor that recognizes high-mannose structures

Th1 response

A cell-mediated immune response important for clearance of cryptococcosis and histoplasmosis in the cited experimental context

Pneumocystis jirovecii

An opportunistic fungus that causes pneumonia and is common in patients with acquired immunodeficiency syndrome

Aspergillus fumigatus

The most commonly isolated Aspergillus species and a common cause of allergic bronchopulmonary aspergillosis

Otomycosis

A superficial fungal infection of the external auditory canal or auricle, commonly associated with Aspergillus niger

Pulmonary aspergilloma

A solid mass of fungal hyphae that forms a fungus ball in a lung cavity

Invasive pulmonary aspergillosis

An invasive Aspergillus infection commonly occurring in neutropenic patients

Disseminated aspergillosis

Aspergillus infection that spreads through the bloodstream or extends from the lungs into surrounding tissues

Candida albicans

A yeast that commonly lives as a commensal on the skin, gastrointestinal tract, and female genital tract and is a leading cause of human fungal infections

Candidiasis

A fungal infection caused by Candida species

Thrush

Oral candidiasis that may occur following broad-spectrum antibiotic use

Mannan and anti-mannan detection

A combined serologic approach recommended in the reviewer for diagnosing Candida infection

Cryptococcus neoformans

An encapsulated opportunistic fungus that can enter through the lungs and cause life-threatening central nervous system infection

Cryptococcal capsule

The major virulence factor of Cryptococcus neoformans that interferes with phagocytosis and other immune functions

Cryptococcal meningitis

A life-threatening infection of the meninges caused by Cryptococcus species, particularly in immunosuppressed patients

India ink examination

A test for Cryptococcus neoformans with high specificity but low sensitivity

Cryptococcal capsular polysaccharide antigen

An antigen detected in cerebrospinal fluid through latex agglutination, enzyme immunoassay, or lateral flow assay

Histoplasma capsulatum

A dimorphic fungus associated with soil contaminated by bird and bat guano that causes histoplasmosis

Histoplasmosis

A fungal infection acquired by inhaling mycelial fragments and microconidia, commonly affecting the lungs

Histoplasma H band

A precipitating antibody band that is found in fewer than ten percent of cases and signifies active infection

Histoplasma M band

A precipitating antibody band found in up to eighty percent of exposed individuals that may indicate previous exposure or active disease

Complement fixation test for histoplasmosis

A serologic test in which a titer of one is to eight is positive and a titer of one is to thirty-two is associated with histoplasmosis in the reviewer

Coccidioides immitis

A dimorphic fungus that causes coccidioidomycosis and is associated with the southwestern United States

Coccidioidomycosis

A fungal infection also known as Valley fever, acquired by inhaling arthroconidia

Tube precipitin test

A serologic test for coccidioidomycosis associated with immunoglobulin M detection

Complement fixation test for coccidioidomycosis

A serologic test associated with immunoglobulin G detection

Immunodiffusion test

A serologic test for coccidioidomycosis that detects immunoglobulin G and immunoglobulin M

Enzyme immunoassay for coccidioidomycosis

A sensitive test that detects specific immunoglobulin G and immunoglobulin M antibodies

Malassezia furfur

A fungus associated with tinea versicolor, dandruff, and seborrheic dermatitis

Piedraia hortae

A fungus that causes black piedra of the hair

Trichosporon species

Fungi that cause white piedra of the hair

Sporothrix schenckii

A fungus that causes sporotrichosis

Fonsecaea pedrosoi

A fungus that causes chromoblastomycosis

Pseudallescheria boydii

A fungus that causes eumycotic mycetoma

Trichophyton species

Dermatophytes that cause tinea infections involving keratinized tissues

Rhizopus species

Opportunistic fungi associated with zygomycosis

Beta-D-glucan

A fungal cell wall component detected in serum as a marker of many fungal infections

Peptide nucleic acid fluorescence in situ hybridization

A molecular method used to identify Candida species in blood cultures

Platelia Aspergillus enzyme immunoassay

A serologic method used in larger or reference laboratories to support the diagnosis of aspergillosis