Term
| How can you distinguish Parasites from bacteria? |
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Definition
Eukaryotes with
1) Nucleus
2) 80s ribosome
3) Mitochondria
4) No CELL WALL
5) Sexual reproduction. |
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Term
| What are the 2 types of Endoparasites? |
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Definition
Live inside the body of the host
1) Protozoa (protista)
2) Helminths (animalia) |
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Term
| What are the 4 groups of Protozoan Endoparasites? |
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Definition
Based on locomotion
1) Flagella (Giardia lamblia)
2) Cilia
3) Pseudopods (Entamoeba histolytica)
4) Apical microtubule complex (Plasmodium falciparum) |
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Term
| What are the different types of endoparasitic Helminths? |
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Definition
1) Roundworms (nematodes)
2) Flatworms
- tapeworms (cestodes)
-flukes (trematodes) |
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Term
| What are the medically important Ectoparasites? |
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Definition
All belong to the Phylum Arthropoda and fulfill life cycle through interaction with skin or hair of host.
1) Insecta (lice and fleas)
2) Arachnida (ticks, spiders) |
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Term
| Explain the basic lifestyle of a parasite |
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Definition
Involve "intermediate" and "definitive hosts."
Example) Flatworms such as Flukes use mollusks as first intermediate host and later infect skin of other hosts. |
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Term
| What is the life cycle of Entamoeba histolytica? |
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Definition
Remember, Entamoeba histolyitica are unicellular protozoae that use pseudopods for movement and are common in Mexico.
1) "Cyst" is excreted into environment and ingested by another person through fecally-contaminated food or water.
2) Cyst undergoes excystation in the gut and becomes of "trophozoite," which attaches to the colonic mucosa, sometimes penetrating into portal circulation (liver abscesses can follow)
3) Triggers can initiate formation of new cysts in gut, which can be shed into environment. |
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Term
| How do you treat a case of Entamoeba histolytica? |
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Definition
| Metranidazole and subsequenc diloxanide |
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Term
| What parasitic infection should contact lens wearers be concerned about? |
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Definition
Acanthamoeba (Protozoa).
Can infect cornea if lens is worn while swimming in surface water. |
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Term
| What is the "brain eating ameba" found in warm freshwater and soil? |
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Definition
Naegleria fowleri
enters nose through water and causes meningo-encephalitis |
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Term
| What clinical symptoms does Giardia lamblia cause and how can you treat? |
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Definition
Frothy Diarrhea (seen in US)
Metranidazole (potent anaerobic and parisitic coverage) |
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Term
| What is the life cycle of Trichomonas vaginalis? |
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Definition
Worldwide.
Very common in women with multiple sexual partners (50 % of incarcerated women), causing vaginal discharge (frothy/bubbly) with pain and irritation and FISHY ODOR.
Highly site-specific, and no vector is needed.
1) Infected vaginal discharge passes to male and then to another female.
Can survive outside of body but no evidence to link this to transmission. |
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Term
| How could you diagnose/treat a case of Trichomonas vaginalis? |
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Definition
1) Wet mount specimen will reveal pear-shaped flagellated organisms with twitching motility
2) Smells like fish
Treat with Metranidazole |
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Term
| What is the life cycle and treatment options of Babesia? |
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Definition
**Look for maltezic cross in RBCs!**
-Tick vector infects erythrocytes and leads to functional asplenia mostly in northeastern US.
1) Deer, white-footed mice are intermediate hosts
2) Ticks are vectors |
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Term
A patient who was recently a soldier in Iraq presents with cutaneous leishmaniasis, fevers and hepatosplenomegaly.
What parasitic infection do they have? |
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Definition
Leishmania spp. (sand fly vector!)
Intracellular amastigotes in macrophages in humans and extracellular promastigotes in gut of sandflies.
Can present with ulcers or visceral involvement |
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Term
| What parasite is transmitted by "kissing bugs" causing Chagas' disease with esophageal and colon dysmotility and cardiomyopathy? |
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Definition
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Term
| Which parasite is transmitted by the Tsetse fly causing sleeping sickness and sometimes fatal meningo-encephalitis? |
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Definition
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Term
| How does a case of Toxoplasma gondii present? |
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Definition
| A patient presents with opportunistic eye infections from perinatal transmission and reactivation encephalitis in T-cell immunocompromised patients. |
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Term
| What is the typical life-cycle of an intestinal roundworm (helminth)? |
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Definition
1) Female worms in gut of human produce eggs
2) eggs embryonate and infect humans by ingestion of infected eggs (Ascaris, Enterobius, Trichuris), or by penetration of skin by larval worms (hookworm and Strongyloides) |
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Term
| What is the typical clinical presentation/treatment for Intestinal roundworm infections? |
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Definition
1) Associated with perianal itch (pinworm) as well as disseminated infection (strongyloidiasis).
2) Treat with Albendazole/mebendazole or Ivermectin |
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Term
| What is the typical life cycle of a Tissue Nematodes (causing Filiaris) such as Onchocerca, Wuchereria or Brugia? |
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Definition
OUTSIDE US
Filiaris occurs when larvae of roundworms are transmitted by mosquitos and manifests with River blindness and Elephantiasis (from lymphatic destruction)
1) Mosquito bite causes it to enter lymphatics where they mature into adult worms.
2) Fertilized females may discharge microfilariae into blood. |
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Term
| What is the life cycle of Trematodes (flukes) such as Schistosoma hematobium, japonicum and mansoni |
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Definition
Schistosomiasis transmission requires Snail/slow water/human skin/veins
1) Snail intermediate host
2) Slow moving fresh water (where cercariae have been released from snail)
3) Human entry into snail infested water through skin, followed by migration to lungs and liver with maturation into adults.
4) Veins of bladder or GI tract are final destination |
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Term
What are the clinical manifestations of acute Schistosomiasis (Katayama fever) and chronic Schistosomiasis?
How do you diagnose/treat? |
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Definition
- Katayama- Fever
- Chronic- liver disease, bladder cancer or neurological disease |
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Term
| Why is the Cestode (tapeworm), Taenia solium, of clinical concern? |
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Definition
Pork tapeworm can acquired by ingestion of T. solium eggs or consuming raw pork containing larval cysts.
Taeniasis and Cysticerosis (larval cysts) can develop.
NEUROCYSTICERCOSIS can cause seizures (common in Latin America and Asia) |
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Term
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Definition
The Cestode (tapeworm), Echinococcus, is carried by dogs and causes Echinococcus granulosus.
1) Eggs enter and hatch in GI tract, forming oncospheres that penetrate the intestinal mucosa and enter circulation.
2) The oncospheres encyst in human organs like the liver and cause multiloculated large cysts.
2) Oncospheres cause |
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Term
| What are the most common ectoparasites infecting humans? |
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Definition
1) Lice (scalp hair, body hair, pubic hair)
2) Scabies (arachnid, Sarcoptes scabei that causes itchiness and scaley rash)
3) Myiasis (maggots) of subcutaneous tissue |
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Term
| What is the mechanism of action of the 6 different anti-malarial drugs? |
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Definition
1) Chloroquine-erythrocytic stages of Plasmodium (resistance common)
2) Quinine- erythrocytic stages/combined with doxycycline- good against Chloroquine-resistant forms
3) Primaquine- Only drug against hypnozoite forms of P. vivax and P. ovale in liver
4) Artemisinin derivatives- Act against chloroquine-resistant and quinine resistant forms.
5) Mefloquine- prophylaxis and treatment
6) Atovaquone/proguanil- prophylaxis and treatment. |
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Term
| Explain a hypothetical treatment regimen for a case of Malaria. |
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Definition
1) Treat prophylactically with Mefloquine and Atovaquone/proguanil (can continue if needed)
2) Try Chloroquine
3) If resistant, try Quinine with doxycycline
4) If resistant, try Artemisian derivatives in combination |
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Term
| What is the most common serological marker of Parisitic infection? |
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Definition
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Term
| What parasite causes liver abscesses and is treated with Metranidazole? |
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Definition
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Term
| Which Diarrhea-inducing protozoa are often found in the US? |
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Definition
1) Giardia lamblia (frothy)
2) Cryptosporidium (prolonged) |
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Term
| When might you see a microsporidia (protozoa) infection? |
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Definition
| Immunocompromised (AIDS). |
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Term
| You see RBCs with small dots on them. What protozoan infection are you concerned about? |
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Definition
| Plasmodium falciparum (Malaria) |
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Term
| How could you treat Babesia? |
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Definition
| - Treat this protozoa with Clindamycin and quinine or atovaquone and Azithromycin (macrolide). |
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Term
| A patient with HIV presents with opportunistic eye infections. What protozoa could be involved? |
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Definition
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Term
| How do the intestinal round worms, Ascaris, Enterobius (pinworm), and Trichuris (whipworm) gain access to humans? |
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Definition
1) Eggs in GI
2) Eggs in feces
3) Fecal-oral ingestion
4) Blood
5) Lungs
6) Throat
7) Swallow |
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Term
| How do the intestinal round worms, Hookworm and Strongyloides stercoralis gain access to humans? |
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Definition
| Penetration of skin by larval forms. |
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Term
| Which intestinal worm is seen pervasively in the US without socioeconomic distrubution? |
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Definition
| Pinworm presenting with perianal itch. |
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Term
| Which intestinal roundworm presents with disseminated infection (hyper-infection if combined with HIV) |
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Definition
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Term
| How does one diagnose and treat Shistomiasis? |
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Definition
1) Treated with Praziquantel which effects membrane permeability of worms
2)
- Urine= hematobium
- Feces= japonicum and mansoni |
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Term
| What are the 3 important Cestodes (tapeworms)? |
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Definition
1) Taenia solium (pork)- Seizures
2) Taenia saginata (beef)- not as bad
3) Echinococcus (dog)- Liver cysts and hydatid disease |
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Term
| Why would you avoid performing surgery to remove Myiasis ectoparasitic infections? |
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Definition
| 1) Butt "wiggles", you could cause them to spill out! |
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Term
| How do you treat lice/scabies? |
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Definition
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Term
| What are your therapeutic options for Lice? |
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Definition
| Permethrin, Ivermectin, Malothion |
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Term
| What do Chloroquine and Quinine have in common as far as Malaria treatment? |
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Definition
| They are both Erythrocytic |
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Term
| When should you treat with Artemisinin derivatives? |
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Definition
Forms resistant to other treatments.
USE IN COMBINATION because of resistance |
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Term
| How does primaquine treat malaria? |
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Definition
| Exo-erythrocytically in "liver-stage" |
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Term
| What is the problem with treating malaria with Mefloquine?, Doxycycline or Atovaquone? |
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Definition
Can use M and A prophylactically
Mefloquine- They go crazy!
Doxycycline- Photosensitivity and yeast infections
Atovaquone- $$$$ |
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Term
| Which parasites can you treat with Albendazole and mebendazole? |
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Definition
Intestinal Round worms!
Pinworm, whipworm, Ascaris, Echinococcus, Strongloids, Cysticercosis |
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Term
| What would you treat Trichomonas, Giardia and Amebiasis with? |
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Definition
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Term
| Why would you prescribe ivermectin? |
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Definition
| Strongyloides, Ascaris, Onchocerca, whipworm, lice and scabies! |
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Term
| What are the medically important Protozoa? |
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Definition
Caring about PBL Takes Time after The GAME
1) Crytposporidium- Prolonged diarrhea- common in Us
2) Plasmodium spp- intracellular/malaria
3) Babesia- Functional aspleina- Maltezec cross in RBC- common in northeastern US
4) Leishmania spp. - Ulcers and visceral symtpoms from Sandfly
5) Trichomonas vaginalis- Sexual transmission leading to Vaginal discharge with fishy odor that is treated with Metranidazole- seen worldwide
6) Trypanosoma
7) Toxoplasma gondii- Eye infection (retinitis) from perinatal transmission and reactivation
8) Giardia lamblia- Frothy diarrhea treat with Metranidazole- Common in US
9) Acanthamoeba- Corneal infections
10) Microsporidia- AIDS (actually a fungi)
11) Entamoeba histolytica- Liver abscess and bloody diarrhea treated with Metranidazole- uncommon in US |
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Term
| What drugs effectively treat tapeworms (Cestodes) and intestinal round worms ( |
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Definition
Albendazole and Mebendazole
Most intestinal round worms are also covered by Ivermectin |
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