Parasitic Infections Flashcards
What is an organism that lives on or in a host organism and gets its food from or at the expense of its host?
parasite
What are the different types of parasites?
- endoparasites
- ectoparasites
What are different endoparasites?
- protozoa
- helminths (worms)
What are examples of ectoparasites?
- ticks
- fleas
- lice
- mites
What is Rocky mountain Spotted Fever caused by?
either the dog tick or wood tick
Where are parasitic infections, especially those that cause diarrhea common?
low- and middle-income countries
Parasitic infections are highly associated with protozoal and helminth (1) infections worldwide
- gastrointestinal
Parasitic infections are a major cause of morbidity in many countries, primarily due to (1) and (2)
- poor water (and)
- food sanitation
Parasites have great differences in their structure, making them highly (1) and (2) often results
- antigenic
- severe diseases
What are some examples of what parasitic infections can cause?
- diarrhea
- widespread rashes
- hemorrhage
- organ failure
What are one-celled organisms that cause disease in humans?
protozoa
How do protozoa reproduce?
primarily through sexual binary fission (can be budding)
Where do protozoa flourish and multiply?
human tissues and organs
How can protozoa be transmitted?
- fecal-oral route
- vector bite (insect)
- sexual contact
Protozoa are classified by their method of transport, which includes?
- flagella or cilia may be present in some, but not all are motile
What activities occur in the trophozoite stage of protozoa?
- organism is active and feeding
- able to gather nutrients from its host
In the trophozoite stage of protozoa, they are able to gather nutrients from its host through what?
lumen of GI tract
What occurs as protozoa forms a thick wall to protect it from harsh environments as it moves through the body?
encystation
What stage becomes the “hardier” stage where protozoa can survive more easily?
cyst (formation of cyst-encystation)
When a protozoa is in the cyst stage, protozoa become what and what does that mean?
hardy - can survive extremes in temperature and severe environments
At what stage do protozoa have little need for nourishment, such as oxygen or water requirements?
the cyst stage
At what stage allows protozoa to evade our immune response and to survive longer?
the cyst stage
At what stage allows protozoa to exist outside of their dependent host?
the cyst stage
Many protozoal infections cause what?
diarrhea (fecal-oral) route
Where are you less likely to find parasitic infections?
- in the US
What are the risk factors for diarrhea related to protozoan infection? (when to test)
- travel to endemic countries
- drinking untreated water, even while hiking in the US
- swimming in poorly treated public pools where diarrhea has been present
- working with animals or on a farm
- exposure in daycare
- handling or playing
After how many days of persistent diarrhea should you test for parasites?
after 7 days
What is a flagellated protozoan that causes vaginitis and cervicitis and is acquired through sexual contact?
Trichomonas vaginalis
What is a protozoal infection that can cause fever, myalgias, and fetal consequences and is acquired through contact with cat fecal matter?
Toxoplasma gondii
What protozoal infection causes Chagas disease, is acquired through bite of a reduviid bug “kissing bug” and causes multi-organ consequences, including possible sudden cardiac death?
Trypanosoma cruzi
What does plasmodium falciparum cause?
malaria
How is plasmodium falciparum acquired and where does it live?
through mosquito bile in specific countries (lives in the saliva of a mosquito)
What causes fever, chills, headache, severe pain, other symptoms, and infection and rupture of erythrocytes in humans?
P. falciparum
What is a protozoal infection acquired through water, such as when a person has water forced into the nose (waterslides, jet skis, diving)?
Naegleria fowleri
What protozoan migrates through olfactory nerves resulting in meningoencephalitis, fever, stick neck, and mental status changes?
Naegleria fowleri
Naegleria fowleri is (1) fatal
99%
What are multicellular organisms causing disease in humans?
helminths
What are able to withstand stresses of GI tract due to structures that prevent its destruction?
helminths
Where does reproduction of helminths typically occur?
in soil, water, plant, or arthropod/animal (some are unable to reproduce in human host)
What can helminths exist as?
- eggs
- larval stage
- adult worm
How can helminths be transmitted?
- contact with soil contaminated with fecal matter
- ingestion of food or water contaminated by helminths
- via an arthropod or molluscan vector
Helminths have a preference for what climates?
warm climates
What flourishes in areas where sanitation or water is inadequately treated?
helminths
What is a major cause of morbidity and mortality in countries where sanitation or water is inadequately treated?
helminths
What can produce none, mild, or severe disease?
helminths
What population of people are at greatest risk with helminths due to them competing for nutrition and absorption of the GI tract?
pediatric patients
What worms compete for vitamin A?
roundworms
Presence of worms can cause (1)
appetite loss
What can cause reduced nutrition plus small blood loss leading to:
- mild to profound anemia
- decreased growth rate
- intellectual deficits
helminths
What is Enterobius vermicularis commonly known as?
pinworms
What is the most common helminth infection in the US?
pinworms (Enterobius vermicularis)
How are pinworms (Enterobius vermicularis) transmitted?
- fecal-oral route
- spread via contact with infected person, their clothes, bedding (fomite)
Who do pinworms (Enterobius vermicularis) typically affect?
childrent
What causes children to have anal pruritis that worsens at night due to females migrating at night to deposit thousands of eggs in the area?
pinworms (Enterobius vermicularis)
Upon bite, this type of parasite can transmit parasitic organisms during feeding to the human?
vector bites (ectoparasites)
What are some vector-related infections?
- dengue virus
- zika virus
- west nile virus
- malaria
- lyme disease
- rocky mountain spotted fever
What infection do plasmodium species cause?
malaria
What infection does Borrelia burgdorferi cause? (deer tick)
lyme disease
What infection of Rickettsia risketsii cause? (dog or wood tick)
Rocky mountain spotted fever
What condition is acquired through the bite of the Aedes aegypti mosquito and causes severe symptoms in 15% of those who develop?
yellow fever
What can cause:
- severe liver dysfunction resulting in jaundice and scleral icterus
- hemorrhage
- organ failure
yellow fever
What is the mortality rate of yellow fever in those with severe symptoms?
20-50%
What does diagnosis of parasitic infections require?
- thorough history of risk factors, such as travel and drinking untreated water
In medicine, the best way to identify parasitic infections is via (1)
microscope visualizations
What can be done in some cases, such as malaria, to visualize the organism when it is known to be present in blood?
blood smears
What may allow for identification of the specific species of malaria?
blood smears
What type of smears are done in blood smears?
thick and thin smears
What can you order when testing for parasitic infections, but it only grows out bacteria on the specialized agar plates?
stool culture
What must you order when testing for parasitic infections in cases of diarrhea where there is possible exposure to parasitic organisms?
stool for ova and parasites (stool O & P)
What are some indications for testing for parasitic infections?
- diarrhea that is prolonged or bloody
- +/- fever
What are the pros of testing for parasitic infections in stool?
- unique and specific testing that provides an accurate diagnosis
What are the cons of testing for parasitic infections in stool?
- may require several samples if the protozoal count is low or not seen on sample provided
When testing for parasitic infections, what might be elevated on a CBC if there is an infection?
eosinophil count
Typically, eosinophil count is only elevated when?
infection is severe or organ-invasive (can also depend on species of parasite involved
Some vector borne diseases require us to check (1) created against the organism?
own antibodies
Checking your own antibodies for parasitic infections is more helpful when the organism is what?
- “buried” in deep tissue
- not visualized or accessed in stool or blood
What type of test is available for testing for parasitic infections that is a specific test created that test positive through identification of an antigen is present on the parasite?
specific antigen testing
Depending on the organism suspected, antigen testing can be through (1) or (2)
- blood
- fecal matter
Specific antigen testing for Plasmodium species is through?
blood
Specific antigen testing for Giardia lamblia, Cryptosporidium sp., and Entameoba histolytica is through?
stool