Medically Important Parasites Quiz

An organism that lives in or on another organism (host) and benefits from the relationship, while the host is harmed.

Single-celled organisms with a simple structure, often causing infections.

Multi-cellular organisms, such as worms, that are parasitic.

The host where a parasite reaches sexual maturity and reproduces.

A host in which the parasite undergoes essential development, but does not reach sexual maturity.

A host that carries a parasite but doesn't show signs of disease.

An organism that transmits a parasite from one host to another.

An amoeba that causes amoebic dysentery and liver abscess.

Roundworms with a cylindrical body and a complete digestive tract, including a mouth and an anus.

A noncellular, highly resistant coating covering the body of nematodes.

Nematodes have separate male and female individuals.

The male nematode typically has a coiled tail.

Nematodes that live primarily in the gut.

Nematodes that live in tissues outside the digestive system.

Filariasis-causing roundworms (Wuchereria, Onchocerca, Loa) that produce motile embryos called microfilariae in blood and tissue fluids.

Tiny, wriggling embryos produced by filarial worms.

Giardia lamblia is a protozoan parasite that causes giardiasis, an intestinal infection characterized by watery diarrhea, bloating, abdominal cramps, and nausea. It is spread through contaminated water and food.

The trophozoite form of Giardia lamblia is pear-shaped with two nuclei, four pairs of flagella, and a suction disk. This form adheres to the intestinal wall and causes infection.

Trichomonas vaginalis is a protozoan parasite that causes trichomoniasis, a sexually transmitted infection. It is pear-shaped with a central nucleus and four anterior flagella. This parasite exists only as a trophozoite, meaning it does not form cysts.

Infection with Trichomonas vaginalis in women manifests as a watery, foul-smelling, greenish vaginal discharge accompanied by itching and burning. In men, infection can be asymptomatic, but about 10% may experience urethritis.

Malaria is a mosquito-borne infectious disease caused by four species of Plasmodium parasites: P. vivax, P. falciparum, P. ovale, and P. malariae. P. vivax and P. falciparum are the most common causes.

The life cycle of Plasmodium involves both sexual and asexual phases. The sexual cycle occurs in mosquitoes, and the asexual cycle occurs in humans. During the sexual cycle, sporozoites are produced, and during the asexual cycle, schizonts are formed.

Malaria is a major public health concern, affecting over 200 million people worldwide, leading to over 1 million deaths annually. It is most prevalent in tropical and subtropical regions, particularly in Asia, Africa, and Central and South America.

Amebic abscesses in the liver are a serious complication of amebiasis. This complication occurs when Entamoeba histolytica, a protozoan parasite, invades the liver, forming an abscess, which can be life-threatening if untreated.

A zoonotic disease caused by the protozoan parasite Toxoplasma gondii. It infects a wide range of animals, including birds, but doesn't cause them to get sick. Humans can get infected by consuming undercooked meat or by contact with cat feces.

A parasitic disease caused by the protozoan Trypanosoma cruzi. It is transmitted by the bite of the kissing bug, which carries the parasite in its saliva.

A parasitic disease caused by Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. It is transmitted by the bite of the tsetse fly.

A group of diseases caused by parasites called Leishmania species. These parasites are transmitted by female sandflies. There are three main forms of leishmaniasis: visceral leishmaniasis (VL), cutaneous leishmaniasis (CL), and mucosal leishmaniasis (ML).

A large class of parasites within the phylum Platyhelminthes. They include parasites like Schistosoma species (blood flukes), Clonorchis sinensis (liver fluke), and Paragonimus westermani (lung fluke).

These parasites belong to the class Cestoda. They are known as tapeworms. They have a head called a scolex and a body containing multiple segments called proglottids.

The head of a tapeworm. It is typically rounded and contains hooks and suckers that allow the worm to attach to the intestinal wall.

The segmented body of a tapeworm. Each segment contains reproductive organs. They contain the eggs of the parasite.