Term
| How do parasites try to avoid a vigorous immune response against them? |
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Definition
| They use molecular mimicry. They try to make their antigens close to self antigens of the host. 10-1 |
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Term
| Name the 3 types of parasites. |
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Definition
| Protozoa, helminths, and ectoparasites. 10-2 |
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Term
| Define definitive and intermediate host. |
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Definition
Many parasites required 2 or more host species to complete their life cycle:
Definitive: where the parasite reproduces sexually. Intermediate: where it reproduces asexually. 10-2 |
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Term
| What is the host for schistomiasis before humans? |
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Definition
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Term
| Where does a human get schistomiasis from? |
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Definition
| Infested slow moving water with infected snails. 10-6 |
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Term
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Definition
| acute schistomiasis. 10-7 |
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Term
| Which drug is used to treat schistomiasis? |
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Definition
| Praziquantel. Affects membrane permeability of the worm. 10-7 |
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Term
| The pork tapeworm's name is... |
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Definition
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Term
Cysticercosis is caused by...
What is cystcercosis? |
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Definition
Tanenia solium. (pork tapeworm) 10-7
It's infection with larval cysts (most critical location is in the brain, called neurocysticercosis, causes siezures) |
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Term
| Hydatid disease is caused by which organism? Describe hydatid disease (briefly) |
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Definition
Echinococcus granulosus (a Cestode (tapeworm)). 10-7
encysted oncospheres in human organs, esp. liver |
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Term
| Which tapeworm is carried by dogs? |
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Definition
| Echinococcus granulosus. 10-7 |
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Term
| What ectoparasite causes scabies? |
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Definition
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Term
| This is an infestation of the skin by larvae of flies (maggots). An ectoparasitic infestation. |
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Definition
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Term
| Name the six anti-malarial drugs and briefly describe how each works. |
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Definition
Quinine, Chloroquine: erythrocytic stage of Plasmodium spp.
Primaquine: only drug available w/ activity against exoerythrocytic form of P. vivax and P. ovale that live in the liver.
Artemisinin derivatives: Use for chloroquine and uinine resistant strains.
Mefloquine, Atovaquone/Proguanil: prophylaxis
10-8
Quality Control Pays After Malaria Attacks |
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Term
| This drug is active against the erythrocytic stages of Plasmodium spp. |
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Definition
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Term
| This drug is active against the asexual erythrocytic stages of Plasmodium. |
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Definition
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Term
| This drug is the only effective anti-malarial that is active against exo-erythrocytic forms of P vivax and P ovale that reside in the liver. |
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Definition
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Term
| Anti-malarial that is active against chloroquine resistant forms, but should only be used in combination therapy to prevent emergence of resistance. |
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Definition
Artemisinin derivatives.
10-8 |
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Term
| How can parasites be distinguished from bacteria? |
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Definition
Parasites are eukaryotes (nucleus, 80S ribosomes, mitochondria) while bacteria are prokaryotes.
Parasites do not possess a cell wall
Parasites reproduce sexually |
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Term
| Describe the general characteristics of protozoa. |
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Definition
unicellular, free living
many have specific geographic distributions
divided into 4 distinct groups on the basis of method of locomotion:
1. flagella (e.g. Giardia lamblia)
2. cilia (e.g. Balantidium coli)
3.Pseudopods (Entamoeba histolytica)
4. apical microtubule complex (e.g. Plasmodium falciparum)
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Term
| Describe the general characterisitics of helminths |
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Definition
one of 3 types of parasites
Helminths are worms
Many have specific geographic distributions |
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Term
| Describe the general characteristics of ectoparasites. |
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Definition
One of three types of parasites.
Usually arthropods or arachnids
Fulfill a life cycle requirement via interaction w/ skin or hair of host.
E.g. lice, scabies, ticks
Sometimes disease is caused directly by ectoparasite, sometimes ectoparasite is vector for viral, bacterial, or protozoal infection. |
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Term
| Name the medically important protozoa. |
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Definition
Entamoeba histolytica, Giardia lamblia, Trichomonas vaginalis, Babesia, Trypanosoma spp., Microsporidia, Leishmania spp., Toxoplasma gondii, Cryptosporidium spp., Plasmodium spp., Acanthamoeba,
(Emily Goes To Beths to Meet Long Time Certified Public Accountant) |
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Term
| How might you get an Acanthamoeba infection? What part of body is infected? |
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Definition
If you wear contact lenses and you go swimming or you use "homeade saline"
Cornea is infected |
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Term
| What's the infection to worry about with contact lense wearers who go swimming? |
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Definition
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Term
| Describe the lifecycle of Entamoeba hisolytica. |
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Definition
This is a protozoa. Most important amoeba to infect humans.
1. cyst is excreted into environment and ingested via fecally contaminated food or water.
2. Cyst undergoes excystation in gut, becoming a trophozoite.
3. Trophozoite attaches to colonic mucosa, goes to portal circulation.
4. Various triggers initiate formation of new cysts in gut, which can then be shed into environment. |
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Term
| What are the clinical manifestations of entamoeba histolytica? What is the most common treatment? |
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Definition
This is a protozoa.
Diarrhea, liver abscess. Many cases arise in MEXICO.
Most common treatment: Metranidazole |
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Term
| Main clinical manifestation of Microsporidia? |
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Definition
| Diarrhea. Mostly a problem in immunosuppressed people (HIV) |
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Term
| Clinical manifestations of Trichomonas vaginalis? How is it diagnosed in the lab? |
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Definition
T. vaginalis is a protozoa
Men: most are asymptomatic
Women: vaginal discharge and vulvovaginal soreness/irriation
physical exam: copious discharge, often w/ bubbles, giving it a frothy appearance. Characteristic fish-like odor.
Lab: pear shaped organisms with a characteristic twitching motility. |
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Term
| Describe the life cycle of Trichomonas vaginalis. What kind of disease is it? |
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Definition
STD
Infected vaginal discharge contains the organism. It is mechanically passed from female to male and then to another female. |
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Term
| Most common treatment for Trichomonas vaginalis? |
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Definition
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Term
| What is the infectious target of Babesia? |
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Definition
Babesia is a protozoa, causes Babesiosis.
Target erythrocytes |
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Term
| Where might you more frequently find a Babesia infection? |
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Definition
| What infection is associated with the United States, especially Nantucket Island, Martha's Vineyard, Cape Cod, and sometimes Pennsylvania? |
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Term
| How is Babesia transmitted and describe its lifecycle. |
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Definition
Ticks (NOT mosquitos) are the vectors for infection. Infects erythrocytes
Part of lifecycle occurs in non-human vertebrates (deer and white-footed mice) |
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Term
| What is the treatment for Babesia infection? |
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Definition
Clindamycin and quinine
or
atovaquone and azithromycin |
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Term
| What type of organism is Leishmania spp.? Where is it found (geographically and in the body)? |
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Definition
Protozoa
No species are endemic to U.S. Common in central and S. America, Middle East and Africa (commonly seen in U.S. troops who've been in Iraq and Afghanistan).
Found in humans inside macrophages. Extracellular in gut of sandflies.
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Term
| Clinical manifestations of Leishmania spp.? |
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Definition
What organism causes these clinical manifestations:
very depended on host's cell-mediated immune response. Cutaneous version often seen in U.S. troops in Iraq/Afghanistan
Visceral version manifests as fevers and hepatosplenomegaly (enlarged liver and spleen). |
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Term
| What disease does Trypanosome spp. cause? What type of organism is it? |
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Definition
Protozoa
What bug manifests clinically in the following way?:
Two forms: American and African.
American found throughout Cental and S. America (not US) transmitted by kissing bugs and causes Chagas' disease.
African: transmitted by tsetse fly and causes sleeping sickness (an often fatal meningo-encephalitis). |
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Term
| What causes Chagas' disease? |
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Definition
| American form of Trypanosoma spp. (causes what disease?) |
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Term
| Name the medically important helminths. |
|
Definition
Cestodes (tapeworms)
Roundworms
Nematodes
Trematodes (Flukes)
CRNT (like BRNT, got a worm, but even worse) |
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Term
| Where will you most frequently find intestinal roundworm infections? |
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Definition
What organism is described here?
Most prevalent in impoverished rural areas where kids play on contaminated soil around homes or where farmers use human poop to fertilizing crops.
Exception: Pinworm occurs commonly in U.S. and is not associated with any SES. Common in siblings w/in the same family. |
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Term
| What kind of clinical manifestation does pinworm have? What type of organism is it? |
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Definition
Helminth-intestinal roundworm.
Manifestation: perianal itch. |
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Term
| How do you treat intestinal roundworms? What about pinworm specifically? |
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Definition
Albendazole or ivermectin
praziquantel for pinworm (a.k.a. Enterobius vermicularis) |
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Term
| Enterobius vermicularis aka? |
|
Definition
|
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Term
| How do tissue nematodes cause disease? |
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Definition
larvae of roundworms are transmitted by mosquitoes etc (filariasis)
After bite the larvae go to lymphatics and mature.
Females get fertilized and then discharge microfilariae (new larvae) into blood.
Lymphatics become blocked, causing elephantiasis. |
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Term
| What is the final destination point for schistosomes? Describe clinical manifestations of chronic schistosomiasis. |
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Definition
Final destination: veins of GI tract or veins of bladder.
Clinical manifestions: Liver disease, bladder cancer, neurologic disease. |
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