Parasites Flashcards
Parasitism
An association beneficial to one partner and harmful to the host
Definitive host
Harbors the adult or sexually mature stages of the parasite’s life cycle
Intermediate host
Harbors the larval or sexually immature form of the parasite (or asexual development)
Reservoir
An infected animal serving as a source from which other animals can become infected
Vector
A living carrier that transport the parasite from infected to non infected host
Trophozoite
metabolically active
Cyst
non motile, protected by a membrane. Infective, dormant.
What invasive amoeba infects 10% of the world and causes colitis and ulcer formation?
Entamoeba histolytic (protozoa is an intestinally invasive protozoa that infects 10% of the world’s population in tropical, unsansitized regions.
How is Entamoeba histolytica spread and symptoms
Spread from fecal/oral cysts that develop from trophozoites in feces found in water (cysts can survive in water). NOT caused by undercooked meat. Symptoms: abdominal pain, mucus/bloody stool, tear drop ulcers, RUQ pain, can rupture
What do you treat Entamoeba histolytica with?
metronidazole
Which protozoa is commonly found in bodies of water, prisons, daycare, and mental health institutions?
Giardia lamblia which is spread fecal/oral from cysts in feces
How do you diagnose and identify giardia lamblia?
Diagnose from cysts or trophozoites in stool, giardia antigen test, or string test. The trophozite: is pear shaped, has two nuclei that look like eyes, ventral sucking disk, and 4 pairs of flagella. Cyst looks like a potato with 4 nuclei
What are symptoms and treatment of giardia lamblia?
The trophozoites coat the distal villi causing lack of malabsorption and IgA deficiency. Also causes foul smelling diarrhea and flatulence. Treat with metronidazole
Which parasite is a gastrointestinal protozoa that has an infectious oocyst?
Cryptosporidium has oocyst which is shed in stool of infected patients with Isocyclospora and Cryptosporidium. This parasite tends to infect immunocompromised.
What are symptoms and treatment for cryptosporidium parvum?
In immunocompetent: mild self limiting enterocolitis
In immunocompromised: 50 or more stools a day, dehydration that last a long time. You diagnose by seeing acid fast oocysts in stool and try treating with nitrazoxanide/paromycin
Parasite comes from imported fruits, causes diarrhea, and has acid fast oocysts in stool?
Cyclospora cayetanesis which you can treat with TMP-SMX
This parasite is fecal/oral from contaminated water, causes diarrhea in immunocompromised, and has acid fast oocysts in stool?
Cystoisospora beli which you treat with TMP-SMX
This parasite is sexually transmitted trophozoite, causes vaginosis?
Trichomonas vaginalis which you diagnose from cervical smear or antigen test and treat with metronidazole
This parasite causes retinochoridits and neurological deficits in immunocompromised patients?
Toxoplasma gondii
What are symptoms of toxoplasma gondii?
Asymptomatic in immunocompetent , in immunocompromised causes immunodeficiency, neuro deficits, pneumonitis, and retinochorditis.
Congenitally: trans-placental, usually unaffected but some show chorioretinis, jaundice, fever, anemia, hydrocephalus.
What is life cycle of toxoplasma gondii?
Cats are definitive host and eat oocysts in rodents and birds. Cats shed the oocysts in stool, and once they sporulate they become infectious. The oocysts can become motile tachyzoites or nonmotile bradyzoites.
What do you treat toxoplasma gondii (protozoa)?
Diagnose from PCR and serology and treat with Pyramethamine and Sulfas (in AIDs patientts)
This parasite is free living and is primary cause of amebic meningitis?
Naegleria fowleri (protozoa) which we find in warm fresh water and it’s susceptible to chlorine so we can treat with Amphotericin
This parasite causes keritinitis is free living and likes to infect contact lenses?
Acanthamoeba (protozoa)can be found in tap water because it’s chlorine resistant and cause keritinitis which causes blindness.
What are symptoms of Acanthamoeba and where can it be found?
in contact wearers it causes keritinits>ulcers> blindness. In immunocompromised it causes granulomatous amoebic encephalitis. Besides being in water and soil, it can be found in air conditioning ducts and legionella
How are Leishmania spp. diagnosed?
Diagnose with giemsa biospy or scraping for cutaneous amastigotes and giemsa smear of bone marrow or spleen for visceral amastigotes. Under microscope there a rod shaped kinetoplast besides nucleus.
What are symptoms of Leishmania (protozoa) spp?
Cutaneous - most common, benign lesions
Mucocutaneous - simple lesion that mestasize to mucosae
Visceral - causes “Kalal Azar” which causes hepatosplenomegaly, high mortality, and spleen/ liver involvement.
What are characteristics of cestodes, trematodes, and nematodes (helminths)?
Cestodes - segmented, hermaphrodite, no cavity, sucker, and hook
Trematode - leaf shape, hermaphrodite except schistosoma, oral and ventral sucker
Nematodes - has a cavity like a worm, dioecious, lips and teeth
What are characteristics of cestodes?
Have scolex, segmented with sex proglottids, suckers, monecious.
What is beef tape worm and some characteristics?
Taenia saginata, it has four suckers but no hooks, usually asymptomatic in humans unless eat undercooked meat. Humans can only hold adult tapeworm (no cysticercosis)
How do you diagnose and treat taenia saginata (cestode)?
look in stool for ova and proglottids and treat with praziquantel
What is the pork tape worm and some characteristics?
Taenia solium, has 4 suckers and hooks. Can spread from larvae in food causing tapeworm, or eggs in food causing neurocycsticercosis.
How do you diagnose and treat taenia solium?
Diangose from proglottids or eggs in stool. Treat intestinal tapeworm with praziquantel and the neurocysticercosis with albendazole
What’s life cycle of taenia solium?
infected person poops out eggs and proglottids, pig eats poop, those eggs hatch enter circulation and cause cysticeri in muscles, humans eat infected meat
What are symptoms of taenia solium infection?
larvae cause most symptoms by penetrating intestine, into blood, and go to brain where they cause hydrocephalus, motor spasm, paraplegia, chronic meningitis, seizure
What is the fish tapeworm and some characteristics?
Diphyllobthrium latum, has two suckers comes from crustaceans and fish which are intermediate host and humans who are definitive host.
What’s diagnosis and treatment for fish tapeworm?
usually asymptomatic, but causes megaloblastic anemia by absorbing all of B12. Diagnose from proglottids and eggs in poop and treat with praziquantel
What is the dog tape worm and some characteristics?
Echinococcus granulosus, humans are intermediate host, spread by eating eggs. Has scolex with 3 proglottids and 2 hooks.
What are symptoms and treatment of Echinococcus granulosus?
eggs hatch in intestine and onocospheres migrate through circulatory system causing compressed vitals, eroded biliary tract. Diagnose from serology and imaging and you need surgery
What is the dwarf tapeworm and some characteristics?
most common in US, spread from eating eggs or infected arthropod. Treat with Praziquantel
Which nematodes are ingested from eggs?
Ascaris, enterobius vernicularis, trichuris, toxocara
Which nematodes penetrate through skin?
strongyloides, ancylostoma, necator
Which nematode do you need to ingest larvae?
trichinella spiralis
Which nematode do you need to ingest via arthropod?
dracunculus medinensis
Which parasite comes from soil, is common, and can be a foot long?
Ascaris lumbricoides
What’s life cycle, diagnosis and treatment of ascaris?
You eat, larva penetrate intestine where they enter circulation, end up at your lungs where they’re coughed (Loeffler’s) and swallowed. Diagnose from eggs, treat with albendazole
Which parasite only infects humans and cause pruritus ani? What is treatment?
Enterobius vermicularis which is also known as pinworms comes from females laying eggs and itching. Treat with albendazole, pyrantel pamoate, everyone in household is treated
Which parasite causes tenesmus which can lead to prolapsed rectum and how’s it treated?
Trichuris trichiura comes from poop in soil and worms in cecum cause you to feel like you need to keep going. Diagnose from eggs in stool and give albendazole
Which parasite have vertical transmission, are prone to pet shop owners, and cause hepatosplenomegaly?
Toxocara canis which cause hepatosplenomegaly, eosinophilia, myocarditits, and if in retina, blindness. Treat with albendazole
Which parasite is free-living and is an infectious filiarform worm that gets into circulation via the skin?
Strongyloides stercoralis, which is common in tropics, diagnosed from larvae in stool and treated with Ivermectin
Ancyclostroma dudenale, necator americanus, and anyclostoma braziliense are all…
Hookworms which penetrate skin and are coughed up and swallowed like ascaris
What are symptoms and treatment for hookworms?
They cause GI bleeding anfluid loss, microcytic iron deficiency, pot belly, finger clubbing, eosinophilic phenumonia. Diagnose from eggs and larva in stool. Treat with Mebendazole or Albendazole and Iron
Which parasite is in bear and pig meat? What are symptoms and treatment?
Trichinella spiralis which causes trichinosis = muscle pain, eosinophilia, diarrhea, nausea, periorbital edema. Use biopsy of muscle to diagnose and treat with mebendazole
What are characteristics of trematodes?
unsegmented leaf look, snail is ALWAYS intermediate, hermphrodites except bloodfluke, two suckers, no digestive tract
Which trematode live in the bile ducts of sheep?
Fasciola hepatica, usually found in Bolivia/Peru
What’s lifecycle and diagnosis of fasciola hepatica?
Eggs from sheep in feces hatch as miracidium in water. They become free swimming cercariae which collect on plants and people eat them the flukes penetrate duodenum and migrate to our bile ducts causing anemia, jaundice, rash, and diagnose from eggs in stool.
Which trematode is spread from undercooked fish and inhabits bile ducts? How’s it diagnosed and treated?
Clonocrchis sinensis which has snails as primary host until they hatch and become metacercarla in scales of fish. They cause jaundice, RUQ pain, hepatomegaly, adenomatous hyperplasia, cholangiocarcinoma, and diagnosed from eggs in stool. Treat with Praziquantel
Which trematode is found in Asia and ingested from aquatic plants (water chestnut)? how do you diagnose?
Fasciolopsis buski which causes abdominal pain, diarrhea, fever. Diagnose with eggs in stool and ELISA
Which trematode is transmitted from crab , and cause TB like granulomas? What are the symptoms?
Paragonimus westermani which causes cyst rupture leading to cough, chest pain, diarrhea, hemoptysis, urticaria.
What’s life cycle of Paragonimuc westermani and treatment?
Eggs hatch in snail forming miracidia, crab eats metacercariae form, and humans eat crab. It penetrates intestine and diaphragm. Diagnose with eggs in poop or sputum and treat with praziquantel.
