Parasitology and Parasitic Disease Transmission

Vocabulary flashcards covering core terms, concepts, modes of transmission, parasitic entities, and diagnostic techniques from the parasitology lecture transcript.

Life cycle

The whole process of a parasite's growth, development, and reproduction, which proceeds in one or more different hosts depending on the species.

Infective Stage

A stage of a parasite that can invade the human body and live in it.

Route of infection

The specific entrance through which the parasite invades the host human body.

Mode of Infection

The method by which the parasite moves from the source to the susceptible host.

Direct life-cycle (monoxenous)

A life cycle involving only one host and no intermediate host.

Indirect life-cycle (heteroxenous)

A life cycle involving more than one host, including an intermediate host and a final host.

Alternation of Generation (heterogenetic)

A parasite life cycle phenomenon characterized by regular alternations of sexual and asexual reproductions.

Carrier

A person with an asymptomatic infection that can be transmitted to another susceptible person.

Zoonoses

Diseases that are transmitted from infected animals to humans.

Vertical Direct Mode of Transmission

Transmission of a parasite from mother to child through congenital/transplacental or transmammary (breast milk) routes.

Horizontal Direct Mode of Transmission

Parasite transmission effected through respiratory droplet spread, sexual intercourse, blood transfusion, or direct skin penetration.

Fomites

Inanimate objects such as clothing, bedding, books, money, eating and drinking utensils, feed sacks, or hair combs that carry and transmit pathogens.

Inoculation (Parenteral)

Transmission wherein pathogens are introduced directly into the bloodstream or tissues via breaks in the skin, such as insect bites, animal bites, or contaminated medical needles.

Mechanical disease transmission

Transportation of pathogens on vector body parts (e.g., wings, hairs) without any change in the number, form, or developmental stage of the pathogen.

Biological disease transmission

Transmission in which a parasite must spend a part of its life cycle inside an arthropod vector to multiply or develop into the infective stage.

Hereditary (transovarian) transmission

Biological transmission in which the causative agent is transmitted to the immature stage (usually the egg) from the parent organism.

Propagative transmission

Biological transmission where only the number of pathogens increases while the developmental stage remains constant.

Cyclodevelopmental transmission

Biological transmission where only the developmental stage (form) of the disease pathogen changes while the number remains constant.

Cyclopropagative transmission

Biological transmission where the disease pathogen undertakes a change in both number and developmental form.

Tolerance

A form of host resistance in which symptoms are suppressed or unusually large doses of a drug, toxin, or protein are able to be endured.

Hypersensitivity

A state of host resistance where only a few cells surrounding infected cells are affected or where there is an increased susceptibility to an antigen.

Immunity

The biological condition by which a host body is capable of resisting or overcoming an infection or disease through immune factors.

Phagocytosis Inhibitors

Microorganism components, such as polysaccharide or polypeptide capsules, that enable an invading pathogen to resist being engulfed, ingested, or lysed by phagocytes.

Giardia lamblia

An intestinal protozoan flagellate with worldwide distribution that lives in the small intestine and results in malabsorption.

Entamoeba histolytica

An intestinal protozoan that can invade the colon to cause bloody diarrhoea (amoebic dysentery) and amoebic liver abscess.

Cryptosporidium parvum

An intestinal protozoan parasite that causes diarrhoea and is more prevalent in immunocompromised patients.

Balantidium coli

A large motile ciliated parasite living in the colon of pigs, humans, and rodents that can lead to colonic ulceration.

Plasmodium spp.

Blood-borne systemic protozoa (P. falciparum, P. vivax, P. ovale, P. malariae) that cause malaria.

Toxoplasma gondii

A protozoan parasite transmitted by ingesting oocysts from cat feces, causing ocular problems and neonatal toxoplasmosis.

Trypanosoma

Haemoflagellates causing sleeping sickness in Africa (transmitted by Tsetse fly) and Chagas disease in South America (transmitted by Reduviid bug).

Trichuris

A soil-transmitted whipworm prevalent in warm, humid conditions that can cause diarrhoea, rectal prolapse, and anaemia.

Enterobius

An intestinal pinworm prevalent in cold and temperate climates, primarily affecting children.

Ascaris

A worldwide intestinal roundworm transmitted via the faecal-oral route that lives in the small intestine and causes eosinophilia.

Onchocerca volvulus

A tissue microfilarial parasite transmitted by black flies that can cause visual impairment, blindness, and severe skin itching.

Taenia saginata

The beef tapeworm acquired by ingesting contaminated, uncooked beef, typically causing minimal symptoms.

Taenia solium

The pork tapeworm acquired by ingesting uncooked pork containing cysticerci, which can cause cysticercosis in muscles and the brain.

Clonorchis sinensis

A liver fluke widespread in China, Japan, Korea, and Taiwan acquired by ingesting infective metacercariae in raw or pickled fish.

Floatation Method

A microscopic concentration technique using zinc sulfate or saturated salt solution to detect protozoan cysts and helminth eggs.

Sedimentation Method

A microscopic concentration technique using formalin-ether concentration that is effective for heavy eggs and larvae.

Coproculture

A stool/faecal culture technique where eggs hatch and develop to the L3 larval stage to distinguish nematode species.

Harada-Mori filter paper technique

A culture technique used for the recovery and diagnosis of Strongyloides and hookworm larvae.

Baermann technique

A specific culture/diagnostic technique utilized for larvae recovery.