Parasitology I

Front 1

These are normally and consistently found in or on the body in the absence of disease

Back 1

Normal Flora

Front 2

This describes the close association or living together of organisms of different species

Back 2

Symbiosis

Front 3

A type of symbiosis where the parasite benefits and host neither benefits or is harmed

Back 3

Commensalism

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Type of symbiosis in which both the host and parasite benefit

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Mutualism

Front 5

An obligatory relationship in which one organism, the parasite is metabolically dependent on another oragnism, the host. The host is usually harmed.

Back 5

Parasitism

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Parasites that cannot survive in a free-living state

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Obligate parasites

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Parasites that normally have a free-living existence and establish a parasitic relationship with a host if the opportunity presents itself

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Facultative parasite

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Parasites that live inside their host

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Endoparasites

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Parasites that live outside their host

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Ectoparasites

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Hosts in which a parasite reaches sexual maturity and reproduces

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Definitive hosts

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Hosts in which some development of the parasite occurs but does not mature

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Intermediate hosts

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ANIMALS that harbor a species of parasite that is also parasitic for humans and from which a human may become infected.

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Reservoir hosts

Front 13

ARTHROPODS or other living carriers that transport a pathogenic parasite from an infected to non-infected host.

Back 13

Vector hosts

Front 14

Animals that ingest infected intermediate hosts and becomes intermediate host themselves.

Back 14

Paratenic hosts

Front 15

Oragnisms that harbor a life stage of a parasite but do not transmit the parasite to another host thus not allowing it to continue its life cycle.

Back 15

Dead-end hosts

Front 16

Secretion of acids, bile salts, and lysozymes are what type of defense mechanism?

Back 16

Chemical barrier

Front 17

Intact skin, mucus on the lining of the membranes, nasal hairs, cilia, peristaltic movement and normal microbial flora are examples of what type of defense mechanism?

Back 17

Physical barrier

Front 18

Antiparasitic factors in the serum (i.e. antibodies) and the competition for nutrients by normals flora prevent parasite invasion. What is this called?

Back 18

Microbial antagonism

Front 19

Damage to infected liver, cardiac muscle, and kidney cells is characterized by swollen cells packed with aluminous or fatty granules, indistinct nuclei and pale cytoplasm.

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Parenchymatous degeneration

Front 20

Damage to infected liver cells results in deposition of large amounts of fat in cells imparting a yellowish color to the cells.

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Fatty degeneration

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Death of cells or tissues resulting from persistent cell degeneration gives the tissues an opaque appearance

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Necrosis

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An increase in cell number results from accelerated cell division produces an elevated cell metabolic rate due to an increase in host body repair activity that follows inflammation.

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Hyperplasia

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An increase in cell or organ size due to the presence of intracellular parasites.

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Hypertrophy

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Conversion of one type of tissue into another without the intervention of embryonic tissue

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Metaplasia

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May be benign (localized with no invasion of adjacent tissues) or malignant (invading adjacent tissues)

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Neoplasms

Front 26

1. To concentrate parasitic forms in fecal samples, they are placed in what type of solution?
2. Once placed in this solution, what happens to the parasite?
3. Then where are they observed?

Back 26

1. Zinc sulfate solutions of high osmolarity.
2. They float
3. Collect it on a glass slide and observe it with a light microscope.

Front 27

1. What test is used to view microscopic arthropods?
2. How does it work?

Back 27

1. KOH preparations
2. It causes most tissue elements to become dissolved leaving parasitic forms that retain their shape and color and are observed with light microscopy.

Front 28

1. This is used when intracellular structures are to be examined.
2. How does it work?

Back 28

1. Giemsa stain
2. It stains tissue and blood cells showing blue-colored intracellular parasites, sometimes with a halo around them

Front 29

1. What is a standard procedure for staining parasites in fecal material?
2. How does it work?

Back 29

1. Trichome stain
2. It stains protozoan cells pink with blue-green organelles.

Front 30

1. What is used to ID cell types in blood smears?
2. How does it work?

Back 30

1. Wright's stains
2. It stains leukocytes and erythrocytes as well as protozoans or microfilariae in blood smears.

Front 31

1. What is used to ID small protozoans in fecal smears?
2. How does it work?

Back 31

1. Acid-fast stain
2. It stains cells pink with blue background marking them easy to find.

Front 32

Name the substances that block energy production in protozoan cells

Back 32

Antimony sodium gluconate

Front 33

Name the substances that inhibit protein synthesis

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Azithromycin
Oxytetracycline

Front 34

Name the substances that inhibit hemoglobin breakdown of erythrocytes

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Chloroquine and diloxanide furoate

Front 35

This inhibits enzyme activity in protozoan cells

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Metronidazole

Front 36

This inhibits DNA synthesis and damages protozoan cell membranes

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Nifurtimox

Front 37

These inhibit DNA synthesis and disrupt mitochondria

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Pyrimethamine, sulfadiazine, and trimethroprim sulfamethoxazole

Front 38

This inhibits enzyme activity and damages intracellular organelles

Back 38

suramin

Front 39

This increases Ca2+ permeability producing a muscle paralysis and vacuolization and vesiculation of the worm's tegument

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Praziquantel

Front 40

This inhibits phosphorylation in the tapeworm mitochondria

Back 40

Niclosamine

Front 41

This damages microfilarial membranes and immobilizes larvae

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Diethylcarbamazine

Front 42

These inhibit cytoplasmic microtubule formation

Back 42

Albendazole
Mebendazole
Thiabenazole
Triclabendazole

Front 43

This increases chloride permeability producing a paralysis of nematode muscles

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Ivermectin

Front 44

This is a neurological poison

Back 44

Malathion

Front 45

Define protozoans

Back 45

Microscopic, parasitic, unicellular organisms, ranges in size fro one um to 100 um that occur singly or in colony formations

Front 46

Entamoeba histolytica
1. Epidemiology
2. Transmission

Back 46

1. Wordwide - human and nonhuman mammals: reservoirs and definitive hosts.
2. During period of cysts passing and can continue for years after symptoms subside

Front 47

Entamoeba histolytica
1. What is their life cycle?
2. Describe the pathogenesis.
3. Does it provide partial/protective immunity?

Back 47

1. Cysts are excreted in feces, ingested by humans and they cysts develop in the large intestine. Then cysts are excreted in the feces.
2. The incubation period is 2-4 weeks. The Amoebas secrete cytolytic and histotoxic toxins. They create flask shaped lesions in the large intestines (and granulomas in the brain, spleen, liver, lungs, and skin)
3. No

Front 48

Entamoeba histolytica
What are the symptoms of amoebiasis?

Back 48

GI/RT/Liver/Eyes/Brain/Skin
GI: Fever, bloody diarrhea, leukocytosis, anemia, nausea, vomiting, abd. pain.
RT: Chest pain and cough
Hepatitis: + chills, fever, and elarged liver
Brain abscess: Can be fatal
Conjunctivitis: from untreated water during shower
Skin sores: Mainly in immunosuppressed individuals

Front 49

Entamoeba histolytica
List some diagnostic tests and describe positive findings

Back 49

Iodine stained preparation
Trichrome stained smears
See central karyosome or cysts with 1-4 nuclei

Front 50

How would you differentiate between Entamoeba histolytica and Entamoeba dispar?

Back 50

First do a trichrome stain and then differentiate by immunoassay or indirect hemagglutination assay (ELISA)

Front 51

How would you treat amoebiasis? And how do these drugs work?

Back 51

Metronidazole inhibits the amoebic stages.
Diloxanide treats the cyst stages.
Make sure that you treat asymptomatic individuals too!

Front 52

1. What causes dientamoeba diarrhea?
2. Describe the epidemiology
3. Transmission?

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1. Dientamoeba fragilis
2. Worldwide, human and non-human mammals
3. Unknown, but might be fecal-oral

Front 53

1. Describe the life cycle of dientamoeba fragilis.
2. Does it have cysts?
3. What is another source of infection?

Back 53

1. Amoebas are ingested and they colonize in the cecum, colon, and appendix. Then they are passed in the feces.
2. No
3. Nematode (Enertobius vermicularis) can carry it in its eggs

Front 54

1. What is the incubation period of dientamoeba fragilis?
2. Describe the pathogenesis.
3. What organ can they infect?
4. What type of cell do they have a preference for?
5. Partial/protective immunity?

Back 54

1. Days to weeks
2. They move by pseudopodia and irritate the mucosa ofhte large intestine resulting in secretion of excess mucous and hypermobility of the lower bowel.
3. The appendix and it will fibrose
4. They LOVE erythrocytes
5. No

Front 55

Describe the symptoms of an infection with dientamoeba fragilis.

Back 55

GI: Diarrhea, nausea, vomiting, abd pain, or fibrosis of the appendix

Front 56

What are some diagnostic tests used to ID dientamoeba fragilis? Describe the positive findings

Back 56

Tricrome stain of fecal smears. See two nuclei.
If placed in water, cell will swell and cytoplasmic granules will exhibit Brownian movement.

Front 57

What would you use to treat person infected with dientamoeba fragilis?

Back 57

Metronidazole

Front 58

What is the infectious agent of blastocystosis? Epidemiology?

Back 58

Caused by blastocystis hominis. Worldwide in humans as reservoirs and definitve hosts.

Front 59

Describe the life cycle of blastocystis hominis

Back 59

People are infected by ingestion of contaminated food or water with cysts. Anaerobic amoeba forms develop in the large intestine reproduce by binary fission and produce cysts that pass out with feces.

Front 60

1. What is the incubation period of blastocystis hominis?
2. Describe the pathogenesis
3. Partial or protective immunity?

Back 60

1. Unknown
2. Generally doesn't cause clinical disease unless it invades the large intestine. Virulence is very low.
3. No

Front 61

Describe the symptoms of persons infected with blastocystis hominis

Back 61

Fever, chills, abdominal pain, diarrhea, nausea, and vomiting

Front 62

Describe the diagnostic test used to ID blastocystis hominis. Describe positive findings.

Back 62

Trichrome stain of fecal smears. Findings: round cysts with a large vacoule surrounded by several small dark-staining nuclei with a cytoplasmic rim and thick slime capsule.

Front 63

What would you use to treat a person infected with blastocystis hominis?

Back 63

Metronidazole