Parasites Flashcards
List the intestinal Helminth roundworms
- human Roundworm - Ascaris lumbricoides
- Pinworm - Enterobius
- Whipworm - Trichuris trichuria
- Threadworm - Strongylides
- Hookworms - Necator and Ancyclostoma
List the intestinal helminth Tapeworms
- Taenia saginata (beef)
- Taenia solium (pork)
- Diphyllobothrium latum (fish)
List the tissue and blood Roundworm that are ingested
- Trichenella spiralis
List the tissue and blood Tapeworm that are ingested
- Echinococcosis granulomosis
List the Helminth flatworms that enter the skin
- Schistosoma mansoni, haematobium, japonicum
List the Helminth roundworms that enter the skin
- Wachereria bancrofti
- Onchocerciasis volvulus
List the protozoa associated with malaria
- Plasmodium falciparum
- Plasmodium vivax, ovale
- Plasmodium malariae
- Plasmodium knowlesi
List the protozoa associated with blood disorders
- Plasmodium
- Babesia microti
List the protozoa associated with tissue disorders
- Toxoplasma gondii
- Pneumocystis jiroveci
- Leishmania donovanii
- Trypanosoma cruzi
- Trypanosoma brucei
- Naegleria acanthamoeba
List the protozoa associated with intestinal disorders
- Entamoeba histolytica
- Giardia lamblia
- Cryptosporidium
- Cyclospora cayetanensis
List the protozoa associated with vaginal disorders
- Trichomonas vaginalis
List some viruses that are associated with zoonotic transmission.
- Yellow Fever
- Dengue Fever
- West nile
- Hantavirus
- Orf virus
Explain the relationship between the ages of RBCs attacked by the Plasmodium types.
- P. falciparum - all ages and appear with small dots in RBC
- P. vivax, ovale - produce ring forms and tetrads in young RBC
- P. malariae - produces bands in old blood cells
What malarial species is most commonly associated with heavy parasitemia?
- Plasmodium falciparium gametocyte
Describe thick smears for malaria diagnosis.
- a few drops of blood are placed on a slide for microscopy
- used to identify the presence of parasites
Describe a thin smear for malaria diagnosis.
- one drop of blood is smeared on a slide for microscopy
- used to identify the morphology of the parasite for identification
Describe the life cycle of malaria parasites.
- Anopheles mosquito (female) bites (drools into) human
- parasite moves to the liver to mature and then released as a merozoite into the RBC
- As RBC dies merozoite released and forms gametes
What is the incubation period of malaria and exceptions?
- 8-30 days after bite
- Vivax and ovale can persist as hypnozoites in liver for years
- Malariae attacks older cells = chronic infection
What are polymorphisms of RBC that can affect the severity of malaria?
- Sickle cell
- Duffy polymorphism
What is the distribution of malaria infections worldwide?
- near equator at low elevations
- tropical climates where Anopheles mosquitos live
- Vivax absent in west Africa
- Ovale in West Africa
What are four methods of malaria transmission?
- mosquitos
- transfusion
- needle sharing
- perinatal
What are the clinical presentations for malaria?
- fever recurring every 48 hours
- recent tropical travel
- malaise
What are the three categories of parasites?
- protozoan
- helminth
- ectoparasites
What are two organs that can be attacked by P. falciparum?
- brain
- kidney
What are some medications used to prevent Chloroquine resistance?
- mefloquine
- Atovaquone-proguanil
- doxycycline
What are the morphological characteristics of the malaria causing parasites?
- P. falciparum - large lateral spine
- P. vivax, ovale - terminal spine
- P. malariae - small/no spine
What is the deadliest of the malaria species?
- Plasmodium falciparum
What malaria species is associated with chloroquine resistance?
- Plasmodium falciparum
Describe the timing of malaria prophylaxis.
- doxycycline/ atovaquone-proguanil - 2 weeks prior to exposure and continued for 4 weeks after departure
What are the characteristics of Babesia microti?
- resembles malaria infection
- found in NE U.S.
- tetrad found in RBC
- clindamycin used to treat
- spread by tick bites
How is toxoplasmosis spread?
- parasite oocytes are found in cat feces
- undercooked meats
What are the characteristics of Pneumocystis jiroveci?
- AIDS opportunistic infection
- fungus
- Treat with TMX-SMX
What are the characteristics of Leishmania donovanii?
- vector - Phlebotomine sandflies
- produces a cutaneous ulcer
- intracellular protozoan
- reservoir - dogs
What are the characteristics of Trypanosoma cruzi?
- intracellular protozoan
- manifests in Chagas disease, esophageal dysmotility
- bug feces are rubbed into wounds
What are the characteristics of Trypansoma brucei?
- protazoan infecting tissue
- in Africa
- vector - Tsetse fly
- manifests in encephalitis “African sleeping sickness”
What are the characteristics of Naegleria/ameba?
- infect tissue
- swim in fresh water
- occurs in the US
- can have WBC in stools
What are the characteristics of Giardia lamblia?
- distinct structure - raised and ghost like
- spread fecal-oral
- causes chronic diarrhea
- treated with metronidazole
What are the characteristics of Cryptosporidum?
- causes chronic diarrhea
- diagnosed with an acid-fast stain of a stool sample
- treatment is Nitazoxanide
What are the characteristics of Cyclospora cayetanensis?
- resembles cryptosporidium
- transmitted in contaminated food and water
- treatment TMX-SMX
What are the characteristics of Trichomonas vaginalis?
- passed by sexual transmission
- very motile organism
- results in a frothy discharge (vaginitis)
- treatment Metronidazole
What are cutaneous larva migrans?
- protazoa that are normally in animals that infect the skin of humans
What is the common name for nematodes?
- Roundworms ( Ascaris, Enterobius, Trichuris, Hookworms, Strongyloides)
What is the common name for cestodes?
- Tapeworms (Taenia and Diphyllobothrium)
What is the treatment for nematodes?
- Abendazole
- Ivermectin (Strongyloides only)
What are the characteristics of Ascaris?
- Helminth - intestinal roundworm
- larvae move from lymph to lungs to trachea and then to intestine
- worms mature in intestines
- eggs can be seen in stools
What are the characteristics of Enterobius?
- “pinworm”
- Helminth - intestinal roundworm
- female lays eggs on rectal skin at night
- fecal-oral transmission
What are the characteristics of Trichuris trichiura?
- “Whip worm”
- Helminth - intestinal roundworm
- worm matures in colon
- causes diarrhea and rectal prolapse
- fecal-oral transmission
What are the characteristics of Necator americanus?
- Hook worm
- Helminth Intestinal roundworm
- larvae penetrate skin and travel to lymphatics then to lung and when coughed up is swallowed and then infects intestine
What are the characteristics of Strongyloides?
- Threadworm
- Helminth intestinal roundworm
- larvae penetrate skin and travel to lymphatics then to lung and when coughed up is swallowed and then infects intestine
- Elevated eosinoplia
What are the different tapeworms?
- taenia saginata (beef) - nausea
- Taenia solium (pork) - cysticercosis in brain
- Diphyllobothrium latum (fish) - competes for B12
What is the treatment for tapeworms?
- Prazequantel
- Albendazole
What are the characteristics of Trichenella spiralis?
- Helminth - tissue and blood by ingestion
- cysts will hatch in intestine and migrate to muscle
- transmitted in undercoked meats
What are the characteristics of Echinococcosis?
- Helminth - tissue and blood by ingestion
- forms hydatid cysts
- transmission - eggs in dogs feces
- concern is the dispersal during surgery
- treatment is to aspirate and remove cysts
WHat are the characteristics of schistosomiasis?
- Helminth - skin entry
- zoonitic transmission - snails and fresh water
- can cause puritic rash, serum sickness and eosinophilic granulomas
- treatment - Praziquantel and anti-inflammatories
- distribution - mainly Africa
What are the structural specifics of shistosomiasis species?
- S. mansoni - large lateral spine
- S. haematobium - large terminal spine
- S. japonicum - small spine
What is the schistosoma life cycle?
- invades snail and develops
- released into water from snail and pentrates human skin
- matures and lays eggs in skin
- human defecates into water and eggs hatch and invade snail
What are the characteristics of bird schistosoma?
- invades human skin but does not mature so it dies and causes irritation
How is elephantiasis produced?
- wachereria bancrofti parasite invades the lymphatics and clogs the flow resulting in severe edema
- spread by masquito bites
How is onchocerciasis produced?
- spread by black fly bites (onchocerca volvulus parasite)
- River blindness - effects anterior chamber
What are the five principles of zoonotic diseases?
- vector specificity
- limited distribution
- often intracellular
- cannot live out of cell
- not transmitted person-person
What are some general characteristics of ticks?
- humans are dead end hosts
- embedded part of tick causes granuloma
- removal of tick can cure some toxic effect
- are most likely biting during mid-spring to mid summer
What are the characteristics of colorado tick fever?
- most prominent in Colorado and Utah
- causes a biphasic fever, low WBC and platlets
- can cause encephalitis
What are five characteristics of rickettsial diseases?
- obligate intracellular
- penicillin resistant
- humans are dead end organism
- serologic diagnosis is limited because of specificity
- grouped into spotted fevers and typhus
Discuss Rocky Mountain Spotted Fever
- Rickettsiae rickettsii
- mostly seen in E. US and Missouri
- causes fever, headache and rash
- seen with immunofluorescent biopsy
- treated with doxycycline
What are the differences between ehrlichiosis/anaplasmosis and RMSF?
- no rash in ehrlichiosis/anaplasmosis
What are the characteristics of Lyme disease?
- Rash initially and can manifest to arthritis and neurologic/heart conditions
- found in NE US and Wisconsin/Minnesota
What are the characteristics of Yellow fever?
- transmitted by the aedes mosquito (usually bite during day)
- Flavivirus
- Distribution - central Africa and north half of S. America
- Vaccine for travelers but prevent mosquito bites
What are ways to prevent mosquito bites?
- screen beds
- long sleeved clothes
- DEET
- plan your activity time
What are the characteristics of Dengue fever?
- transmitted by aedes mosquito
- Flavivirus
- Distribution - along the equator
- usually self limited but includes musculoskeletal pain
- can lead to a hemorrhagic fever/shock
What are the characteristics of West Nile?
- small percentage of ppl infected are symptomatic
- can be a neuroinvasive disease (encephalitis)
- transmitted by the culex mosquito
- Flavivirus
What are the characteristics of Bartonellosis?
- caused by bartonellosis bacilliformis
- “cat scratch disease”
- transmitted by sandflies and kittens
- seen in the Andean valley
What are the characteristics of Yersinia pestis?
- painful lymphadenopathy
- SW US
- transmitted by fleas
- treated with doxycycline
What are the characteristics of Mycobacterium marinum?
- causes severe cellulitis
- transmitted by saltwater fish
