Nematollahi Lectures Flashcards by Clayton Corbridge

A close, long-term association between organisms of different species is called what?

Symbiosis

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A symbiotic relationship in which one member benefits at the other member’s expense is called what?

Parasitism

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Parasites that are unable to survive outside of its host are called?

Obligatory parasites

*Facultative can exist independent of host

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Parasites that establish themselves inside the body are called?

Endoparasites

*Outside the body are ectoparasites

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The host in which the adult or sexual phase of the parasite occurs is called what?

Definitive host

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The host in which the larval or asexual phase of a parasite occurs is called what?

Intermediate host

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When a host other than the normal host is harboring a parasite it is said to be?

Accidental/incidental host

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When the host that harbors a parasite that infects humans it is said to be?

Reservoir host

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Stage in the parasitic life cycle that is capable of invading a definitive host is called what?

Infective stage

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Stage in the parasitic life cycle that can be identified by examining the specimen from the host is called?

Diagnostic stage

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What are the 5 classes of Protozoa parasites?

1-Amoebas (Rhizopods)
2-Ciliates
3-Flagellates
4-Sporozoans
5-Apicomplexans

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Which GI parasites move by pseudopodia, multiply by binary fission, are found in nature and are transmitted in water, food, sexually and on flies/cockroaches?

Amoebas

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What are the two stages of the life cycles of most parasitic amoebas and flagellates?

1-Trophozoites (Pseudopod motility, feeding, find in diarrheal stool, non infectious)
2-Cysts (nonmotile, protected by cyst wall, infectious)

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What are the 5 parts of the life cycle of an intestinal amoeba?

1-Host ingests infective cysts
2-Cysts excyst in GI tract to form trophozoite
3-Toph multiplies (binary fission)
4-Troph encysts
5-Host excretes cysts in stool

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What are 4 things you should look at when identifying Trophozoites?

1-Size (micrometer)
2-Arrangement of chromatin
3-Clean vs dirty cytoplasm
4-Presence/absence of inclusions

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What are 4 things you should look at when identifying cysts?

1-Size (micrometer)
2-Shape
3-# of nuclei
4-Presence/absence of chromatoid bodies or other inclusions

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What two species of amoebas are the main pathogens?

1-Entamoeba histolytica (only in genus)

2-Dientamoeba fragilis

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Which amoeba is the only to have RBC inclusions, causes dysentery, is transmitted by food and water, and can be asymptomatic?

Entamoeba histolytica

*8-65 um troph, 8-22 um cyst. cysts viable for 30 days

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Which amoeba is actually a flagella but occurs as an amoeba with wide pseudopodia, doesn’t have a cyst stage and causes diarrhea, abdominal pain, etc.?

Dientamoeba fragilis

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The only known ciliate parasite of humans, which pathogen is transmitted by food and water and causes balantidiasis?

Balantidium Coli

*largest protozoa in humans

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What are the three main flagellate pathogens?

1-Dientamoeba fragilis
2-Giardia duodenalis (aka. G. lamblia, G. intestinalis)
3-Trichomonas vaginalis

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Which pathogen is in streams and ponds, has two haploid nuclei (old man with glasses) is transmitted fecal/oral route and causes Giardiasis?

Giardia Duodenalis (aka. G. Lamblia, G. intestinalis)

*very relictual flagellate (diplomonadida)

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Which pathogen is transmitted sexually, is not a pathogen per se, but indicative of pH and other vaginal imbalances, has only a trophozoite stage with no cyst stage, and causes vaginosis?

Trichomonas vaginalis

What are the two main Sporozoans?

1-Isospora
2-Sacrocystis (some encyst in tissues)

*cause diarrhea

Ctyptosporidium, cyclospora and cystisospora species are parasites related to malaria and are referred to as?

Apicomplexans

Found world-wide in mammals, reptiles and fish, which pathogen is water/food borne, causes watery diarrhea, and resists chlorine and ozone treatment?

Cryptosporidium parvum *50+ stools/day in immunocompromised. Transmits, animal-animal, animal-person, person-person. Vets, anal sex, day care all increased risk

Found on imported lettuce and raspberries, which pathogen was previously thought to be a cyanobacterium and resists chlorine?

Cyclospora cayentanesis *selt limiting diarrhea

Which pathogen is a real oddball to classify?

Blastocystis hominis *now a stramenopiles and is common organism that inhabits the intestine

A disease that is spread from animals to humans is said to be what?

Zoonotic

An increase in eosinophils in the blood such as in clonorchiasis is referred to as what?

Eosinophilia

A tapeworm infection in the muscles, brain or other tissue is called what?

Cysticercosis *most important risk of Tania solium found in pigs

Adult round worms infecting the small intestine, commonly the ascaris lumbricoides, is called what?

Ascariasis *most common roundworm infection in humans

Infestation of the scalp, typically caused by Pedicures humanus species is called what?

Pediculosis

Carried by ixodidae (hard ticks) what disease is caused by borrelia burgdorferi bacteria?

Lyme disease

A disease that is a consequence of another infection or disease is called what?

Sequelae

What organism is a pseudocoelomate, has smile nervous and excretory systems, no circulatory system, has a highly developed reproductive system and is covered with a tough protective cuticle?

Nematodes (Roundworms) *1 mm to meters long

What are some examples of nematodes (roundworms) with no intermediate host?

- Enterobius vermicularis (pinworm) - Trichus trichiura (whipworm) - Ascaris lumbricoides (large intestinal roundworm) - Necator americanus (new world hookworm) - Ancylostoma duodenale (old world hookworm) - Strongyloides stercoralis (threadworm)

Flat segmented bodies with proglottids, hermaphroditic, no alimentary tract with 1 intermediate host is characteristic of what helminth?

Tapeworms (Cestodes)

Leaf-shaped with oral and ventral suckers, hemaphrodites (except blood flukes) with a blind alimentary tract and two hosts (only one in blood flukes) is characteristic of which group of helminths?

Flukes (trematodes)

Spindle shaped, separate sexes, tubular alimentary tract with no intermediate hosts (GI spp.) or variable intermediate hosts (tissue spp.) is characteristic of what group of helminths?

Roundworms (Nematodes)

Taenia saginata is found in _________ and taenia solium is found in ______

Beef, pork

What structure of cestodes contains male and female organs for reproduction?

proglottids

Which nematode species is known as a threadworm, is found in tropical and subtropical areas and is an intestinal parasite with no intermediate host growing to be 2-3 mm long in parasitic form?

Strongyloides stercoralis *causes diarrhea and ab pain, frequently asymptomatic, has both acute and chronic stages

Highest prevalence in tropical and subtropical regions, with helminth is called the large intestinal roundworm and cause ascariasis?

Ascaris lumbricoides

When infective ascaris lumbricoides eggs are swallowed, the larvae hatch and invade intestinal mucosa, then they are carried to the lungs and mature, then ascend bronchial tree to throat to be swallowed, causing what?

Ascariasis

Know as the pinworm, what helminth is found most frequently in schools or preschool children, deposits its eggs on perianal folds and is transferred hand to mouth?

Enterobius vermicularis *most typical symptom is perianal pruritus

Known as the large intestinal fluke, what helminth has a complex lifecycle, poorly developed oral and ventral sucker, is found in asian/indian areas with pigs and freshwater plants?

Fasciolopsis buski *causes fasciolopsiasis, have a snail intermediate host that infects the pigs or freshwater plants

Which helminth passes active and passive proglottids, produces mild symptoms and occasionally, appendicitis or cholangitis resulting from migrating proglottids?

Taenia saginata *cow tapeworm

Which helminth often passes passive proglottids and has a risk for development of cysticercosis?

Taenia solium *pig tapeworm (less frequently symptomatic than taenia saginata)

Which helminth has an elongated scolex, is found in northern hemisphere and south america, is found in freshwater fish, and may cause pernicious anemia?

Diphyllobothrium latum

What are two species of head lice?

P Humanus capitis (head louse) p Humanus humanus (body louse) *eggs are called nit and hatch in about one week, dies if does not have blood meal in 2 days

What is the exoskeleton of Arthropods made of?

Chitin

The process of periodic shedding of cuticle or arthropods is called what?

Ecdysis

Arthropods show various patterns of segmented fusion called what?

Tagmosis *forms heads, abdomens etc

Which 5 organisms can cause eosinophilia?

1-Clonorchis sinensis (acute phase) 2-Fasciola hepatica (acute phase) 3-Ascaris lumbricoides (eosinophilic pneumonitis/loeffler's syndrome during lung phase) 4-when hookworm larvae migrate to bowel lumen 5-Strongyloides stercoralis (acute and chronic stages)