Test1: Intro To Parisitology Flashcards
(27 cards)
What are the five types of organisms that parasitize humans?
Viruses, bacteria, fungi, protozoa, metazoa (multicellular organisms).
Why are viruses, bacteria, and fungi studied under microbiology rather than parasitology?
Historical reasons led to their incorporation into microbiology.
What are the three main groups studied in parasitology?
Protozoa (single-celled), Helminths (worms), and Arthropods (insects & mites).
What is a micropredator?
A temporary parasite that feeds on a host but does not remain attached (e.g., mosquitoes).
Name four classes of medically important protozoa.
- Lobosea (e.g., Entamoeba histolytica)
- Zoomastigophorea (e.g., Leishmania sp., Giardia, Trichomonas vaginalis)
- Sporozoa (e.g., Plasmodium spp., Toxoplasma gondii, Cryptosporidium)
- Ciliophora (e.g., Balantidium coli).
What are the three classes of helminths?
- Nematoda (e.g., Ascaris lumbricoides, hookworms)
- Trematoda (e.g., Schistosoma japonicum, Clonorchis sinensis)
- Cestoda (e.g., Taenia solium, Echinococcus granulosus).
What arthropods are of medical importance?
• Class Insecta (e.g., lice, fleas, sandflies, mosquitoes).
• Class Arachnida (e.g., ticks, mites).
• Class Crustacea (e.g., Cambaroides, Potamon).
• Class Chilopoda (e.g., centipedes).
Define phoresis.
“To carry without dependence “
A symbiotic relationship where one organism carries another without biochemical or physiologic dependence.
Define mutualism.
Both organisms benefit and are metabolically dependent on each other.
Define commensalism.
One organism benefits, while the other is neither helped nor harmed.
Define parasitism.
One organism (parasite) benefits at the expense of the host.
What is the difference between an endoparasite and an ectoparasite?
• Endoparasite lives inside the host (e.g., Giardia lamblia).
• Ectoparasite lives outside the host (e.g., lice, fleas).
What is an obligate parasite?
Obligate parasites must live in a host to survive.
What is a facultative parasite?
Facultative parasites can survive in the environment but can infest a host under certain conditions.
Example: Naegleria fowleri.
What is a definitive host?
Definitive host is where the parasite reaches maturity.
Example: Vertebrate host for flukes.
What is an intermediate host?
Intermediate host is required for parasite development.
Example: Snails for flukes.
What is a paratenic host?
Paratenic host is where no development occurs, but the parasite remains infective.
What is a reservoir host?
Reservoir host is an organism that harbors the parasite and can transmit infection. Organism depends on host for survival
What is the difference between a mechanical vector and a biological vector?
• Mechanical vector: No development occurs; just transports the parasite (e.g, housefly carrying Entamoeba histolytica cysts).
• Biological vector: Parasite undergoes development in the vector (e.g., Plasmodium in mosquitoes).
Define zoonosis.
A disease primarily occurring in animals but can be transmitted to humans.
What are the three key links of disease transmission ?
- Source of infection (e.g., infected persons, carriers, animals).
- Route of transmission (e.g., food, water, insect bites).
- Susceptible host (e.g., immunocompromised individuals).
What is are four ways parasites harm the host?
1.Mechanical injury (e.g., tissue damage).
2.Toxic: venomous Inflammatory response
3.Immuno-pathological-lesion: (hyper sensitivity)
4.Robbing the host of nutrients
Name six WHO-priority parasitic diseases.
- Schistosomiasis
- Malaria
- Filariasis
- Trypanosomiasis
- Leishmaniasis
- Leprosy (previously included, now replaced by HIV/AIDS)
Why were these diseases selected as WHO priorities?
• High infection rates (e.g., Malaria affects 500M people yearly).
• High mortality (e.g., 2.5M deaths/year from Malaria).
• Chronic nature, lack of vaccines, and significant impact on underprivileged populations.
