Medical Parasitology Review Notes

Comprehensive vocabulary review flashcards covering essential parasitology terminology, diagnostic techniques, life-cycle stages, and parasitic organisms based on the MTLE Parasitology Lecture Notes.

Symbiosis

The living together of unlike organisms.

Commensalism

A symbiotic relationship in which one species benefits without harming or benefiting the other (e.g., Entamoeba coli and humans).

Mutualism

A symbiotic relationship in which two organisms benefit from each other (e.g., termites and the flagellates in their digestive tract).

Parasitism

A relationship where one organism lives in or on another for its survival at the expense of the host (e.g., Ascaris lumbricoides and humans).

Endoparasite

A parasite that lives within the body of the host; its presence denotes an infection.

Ectoparasite

A parasite that lives outside the body of the host or on body surfaces like the skin (e.g., lice); its presence denotes an infestation.

Obligate Parasite

A parasite that requires a host to complete its development.

Facultative Parasite

An organism that may exist in a free-living state but can become parasitic when the need arises.

Erratic Parasite

A parasite found in an organ or tissue that is not its usual habitat.

Aberrant Parasite

A parasite that infects a host where it cannot develop further.

Spurious Parasite

A parasite that passes through the digestive tract without causing an infection in the host.

Parthenogenetic Parasite

A female parasite capable of producing eggs without fertilization by a male, whose eggs contain larvae that hatch immediately.

Definitive Host (Final Host)

The host in which a parasite attains sexual maturity and harbors the adult stage.

Intermediate Host

The host that harbors the asexual or larval stage of a parasite.

Paratenic Host

A transport host in which the parasite remains viable and capable of infecting another host but does not undergo any further developmental progression.

Reservoir Host

An animal host that harbors an infection and allows the parasite's life cycle to continue, serving as an additional source of infection for humans.

Biologic Vector

A vector that transmits a parasite only after the parasite has completed essential development or multiplication within its body (e.g., mosquitoes in filariasis).

Mechanical Vector (Phoretic Vector)

An organism that only passively transports a parasite without supporting its growth or multiplication (e.g., cockroaches in ascariasis).

Pre-Patent Period (Biologic Incubation)

The duration of time elapsed between the initial infection and the first laboratory evidence demonstrating the infection.

Clinical Incubation Period

The duration of time between initial infection and the appearance of clinical signs and symptoms.

Auto-reinfection

A process where an individual becomes re-infected by the progeny of parasites already residing within their own body.

Superinfection (Hyperinfection)

A condition in which an already infected individual becomes further infected with massive loads of the same parasitic species (e.g., Strongyloides).

Schaudinn's Solution

A mercuric chloride-containing stool fixative considered the historic gold standard for preserving fresh fecal smears for permanent staining of protozoan cysts and trophozoites.

Polyvinyl Alcohol (PVA)

A plastic resin incorporated into fixative solutions that serves as an adhesive to bind fecal samples to microscope slides for permanent staining.

Sodium Acetate-Acetic Acid Formalin (SAF)

A mercuric chloride-free stool preservative with a long shelf-life, producing slightly less sharp permanent staining than Schaudinn's or PVA.

Cellulose Tape Method (Scotch Tape Technique)

A diagnostic perianal swab procedure used early in the morning before bathing to recover Enterobius vermicularis, Taenia spp., or Schistosoma mansoni ova.

Thick Blood Film

A dehemoglobinized, laked blood smear approximately $30$ times more sensitive than a thin film, used for detecting low-level parasitemia ($\sim 20\,\text{parasites}/\mu\text{L}$) and microfilariae.

Thin Blood Film

A methanol-fixed blood preparation in which red blood cell morphology is intact, routinely used for species-level parasite identification.

Quantitative Buffy Coat (QBC)

A centrifugation method utilizing capillary tubes precoated with acridine orange and potassium oxalate to visualize fluorescing parasite DNA under UV microscopy.

Knott's Concentration

A concentration technique for detecting low microfilaremia by mixing $1\,\text{mL}$ of blood with $10\,\text{mL}$ of $2\%$ formalin and examining the stained sediment.

Entero-Test (Duodenal Capsule Technique)

A diagnostic procedure using an ingested weighted capsule with an attached absorbent yarn to sample duodenal contents for Giardia, Strongyloides, or Cryptosporidium.

Kato Thick Smear

A clearing technique using cellophane paper soaked in glycerin and malachite green to detect thick-shelled helminth ova (such as Ascaris and Trichuris) in mass stool surveys.

Kato-Katz Method

A standardized, cellophane-covered thick smear technique recommended by WHO that uses a template with a uniform hole to quantify eggs per gram ($\text{EPG}$) for soil-transmitted helminths.

Hakansson Phenomenon

A diagnostic phenomenon in which Dientamoeba fragilis trophozoites swell in water mounts and subsequently return to their normal size, unlike other amebic trophozoites.

Primary Amebic Meningoencephalitis (PAM)

An acute, fulminant CNS infection caused by Naegleria fowleri, contracted through nasal inhalation or aspiration of warm, fresh water containing trophozoites or cysts.

Granulomatous Amebic Encephalitis (GAE)

A chronic or subacute CNS infection found mainly in immunocompromised hosts, caused by Acanthamoeba spp. or Balamuthia mandrillaris.

Winterbottom's Sign

Posterior cervical lymph node enlargement associated with the early hemo-lymphatic stage of African sleeping sickness (Trypanosoma brucei).

Romaña's Sign

Unilateral palpebral edema and conjunctivitis occurring at the site of entry of Trypanosoma cruzi in acute Chagas' disease.

Hypnozoites

Dormant exoerythrocytic liver stages seen in Plasmodium vivax and Plasmodium ovale that cause clinical relapses of malaria.

Blackwater Fever

A severe complication of Plasmodium falciparum malaria characterized by massive intravascular hemolysis leading to hemoglobinuria and dark urine.

Maurer's Dots

Irregular, coarse dark red dots or cuneiform markings found in erythrocytes parasitized by Plasmodium falciparum.

Schüffner's Dots

Fine, reddish-pink stippling seen throughout enlarged erythrocytes infected with Plasmodium vivax or Plasmodium ovale.

Ziemann's Dots

Faint, fine pinkish cytoplasmic dots occasionally seen in erythrocytes infected with Plasmodium malariae.

Maltese Cross

A characteristic tetrad formation of four budding merozoites observed in intraerythrocytic stages of Babesia spp.

Sabin-Feldman Dye Test

A serological neutralization test in which patient antibodies prevent live Toxoplasma gondii tachyzoites from absorbing methylene blue dye.

Amphids and Phasmids

Chemosensory organs located at the anterior (cephalic) and posterior (caudal) ends of nematodes, respectively.

Larva Currens

Rapidly advancing, intensely pruritic serpiginous cutaneous tracks caused by the subcutaneous migration of Strongyloides stercoralis larvae.

Ground Itch

An intense, itchy erythematous papular dermatitis at the cutaneous penetration site of hookworm filariform larvae.

Calabar Swelling (Fugitive Swelling)

Transient, localized non-erythematous subcutaneous angioedema caused by migrating adult Loa loa filarial worms.

Circumoval Precipitin Test (COPT)

A confirmatory serodiagnostic test for schistosomiasis that detects antibody-antigen bleb precipitation around lyophilized Schistosoma japonicum eggs.

Hydatid Sand

Granular sediment suspended in the fluid of an Echinococcus granulosus hydatid cyst, consisting of free protoscolices, daughter cysts, and hooklets.

PAIR Procedure

A minimally invasive percutaneous procedure for managing hydatid cysts consisting of Puncture, Aspiration, Injection of a protoscolicidal agent, and Reaspiration.