poopy parasites Flashcards
what is the name of the active replicating form of a protozoa?
trophozoite
what is the name of the inactive form of a protozoa?
a cyst
which 4 groups can protozoa be divided into? what is this classification based upon?
classification based upon their ogans of locomotion
- amoebas
- flagellates
- ciliates
- sporozoans
what type of locomotion do amoeba do?
pseudopod locomotion
what type of protozoa is entamoeba histolytica?
an amoeba
list the 5 important flagellate protozoa
- giardia lambia
- trichomonas vaginalis
- trypanosoma cruzi (american trypanosomiasis)
- brucei (african tryp.)
- leishmania species
what group is balantidium coli part of?
ciliate protozoa
what type of locomotion do sporozoans do?
NO locomotion (maybe slight amoeboid movement)
what group is the plasmodium species part of?
sporozoan protozoa
what 4 parasites are in the plasmodium species?
P. virax- malaria
P. flciparum
P. ovale
P. malariae
what two groupings can be helminthes be classified into?
cestodes and nemotodes
what is the classification for flat worms/tape worms?
cestodes
how are cestodes acquired?
eating underprepared meat
what are the 3 major members of the cestode group?
taenia solium-pork tapeworm
taenia saginata- beef tapeworm
diphyllobothrium latum-fish tapeworm
what is the grouping with round worms called?
nematodes
what are the 5 common members of nematodes?
- ascaris lumbricoides
- anclostoma duodenale
- necator americanus (hookworms)
- trichuria trichirua (whip worm)
- enterobius vermicularis (pin worm)
what species are the malaria parasites?
plasmodium
what are the 4 parasites in the plasmodium species?
p. falciparum
p. vivax
p. ovale
p. malariae
what parasite does HbS and HbC protect against?
P. falciparum malaria
people who lack duffy red blood cell antigen are resistant to which parasite?
P. vivax
what parasite is the predominant form of malaria in africa?
P. falciparum
what are the stages in a classical malaria attack and how long does it last?
last 6-10 hours
- cold stage
- hot stage
- sweating stage
- fatigue
what is protein-1 (PfEMP-1)
the P. falciparum erythrocyte membrane protein that is central to malaria pathogenesis.
this protein is expressed on infected red blood cells
what two host molecules does PfEMP-1 proteins adhere to?
CD36 and ICAM-1
on what cells is CD36 expressed?
microvascular endothelium
monocytes
platelets
what role is CD36 thought to play in malaria infection?
it is a cytoadherence receptor thought to mediate the sequestration of parasites
what is the role of ICAM-1
it is the principal cytoadherence receptor for sequestration of infected red blood cells in the cerebral microvasculature (cerebral malaria)
what is the involvement of chondroitin sulfate A (CSA)?
parasitized erythrocytes may bind to it which is on the placenta- this can account for malaria’s role in pregnancy
what are the 3 types of leishmania forms in people?
- cutaneous-skin sores
- visceral-can be life threatening attacking organs
- mucosal-less common and can be a consequence of a cutaneous infection
how do leishmania parasites spread?
sand flies
what is the causative agent in american trypanosomiasis?
T. cruzi
what causes american trypanosomiasis?
kissing bugs, insects
occurs when contaminated bug feces get into human skin
what is Romana’s sign?
swelling around the eye
it is where the parasite entered the skin and caused local infection
what is human babesiosis?
it is a zoonotic disease transmitted during the blood meal of an infected hard bodied tick
that tick that transmits baesia can also transmit what bacteria?
borrelia burgdoferi (lyme disease)
in the US and canada, what is the most commonly diagnosed enteric parasite?
giardia lamblia
how is giardia acquired?
through oral ingestion of giardia cysts through contaminated water or through person to person or foodborne transmission
what is the diagnosis of giardia made?
demonstrating cysts in teh stool or detection of giardia antigen in the stool
how does transmission of crytosporidiosis occur?
ingestion of oocytes
where and why is one of the places that is a high risk factor for crytosporidiosis?
recreational pools
because it is highly resistant to chlorination and can be tied to fecal-oral contamination at these pools
When do symptoms begin for an infection with crypto? and what is the most common symptom? How long do the symptoms last?
2 to 10 days
watery diarrhea
Last 1- 2 weeks
What is the most common host defesense defect associated with crypto?
HIV. Immuno compromised people recover without treatment
Where in the body do entamoeba histolytica usually infect?
Intestinal and extraintestinal infections
How does one get infected with entamoeba histolytica?
Ingestion of cysts in contaminated water with fecal matter
What is the most common disease manifestation in a E. Histolytica infection?
Diarrhea without dysentry
What is a more severe form of an E. Histolytica infection?
Liver abscess - RIGHT lobe (80%)
- RUQ pain and fever or
- Weight loss, fever, abdominal pain
What are the hosts of T. Vaginalis
ONLYYY humans
Is infection with Trichomonas vaginalis common?
Yes very - in US and worldwide
If you have a woman with T. Vaginalis infection what can you suspect?
She is a RATCHET, dirty sexual hoe with a smelly vaggg
- High risk sexual behavior
What are symptoms of an infection with T. Vaginalis?
-Vaginal discharge - 42% - FROTHY
-Odor 50%
edema 22-37%
I’m going to throw up…
What can an infection wtih T. Vaginalis be mistaken with?
Cnadidiasis and bacterial vaginosis
Do people always have a nasty frothy discharge with T. Vaginalis?
No –50% of women are asymptomatic
Most men are asymptomatic
What type of worm is ascariasis?
An intestinal nematode - round worm
What is the most common helminth infection?
Ascaris Lumbricoides - more than 1/4 of world’s population!! wo0owza
What is the appearance and location of ascaris lumbricoides?
White and pinkish 15-35 cm
Live and mate in the lumen of jejunum
How many ova do ascaris lumbricoides female worms secrete?
200,000 each day
When is ascariasis lumbricoides infectious?
When eggs in the single cell stage are passed in the feces and reach a favorable environment
What is the life cycle of ascariasis?
- eggs are ingested - hatch in small intestine
- larvae penetrate intestinal wall –> venous blood through liver –> heart (4 days later)
- 6-10 days - break into alveoli and ascend tracheobronchial tree
- Swallowed - return to small intestines and develop into mature worms
-Adult worms Live 10-24 months
What are the symtpoms of an ascariasis infection?
Most people are asymptomatic
-some - pulm symptoms after 2nd week of ingestion - hypersensitivity response
-kids - plug up ileocecal valve
Perforation, intususception, volvulus, death
How is whipworm transmitted?
Through the soil
Is an infection with whipworm common?
Yes - 3rd most common round worm
Poor rural communities with poor sanitary conditions
What type of worm is whipworm?
Intestinal Nematode
What is the lifecycle of the whipworm?
- eggs shed in stool - undergo maturation
- Ingested - hatches in GI tract and matures to adult worm
- adult worm lives for 1-3 years
What is a severe infection of whipworm?
It can occur in the distal part of colon
May lead to rectal relapse - recurring
What kind of worm is a hookworm
Soil transmitted helminth (nematode)
Where are helminth infections common?
Where feces are used as fertilizer
What is the lifecycle of the helminth?
- eggs passed into stool
- hatch - warmth, moisture, shade
- released rhabditiform larvae grow in feces or soil
- penetrate human skin (foot)
- carried thru blood to heart and lungs
- penetrate alveoli, go to pharynx
- swallowed
- reach small intestine - reside and mature
What is the infectious stage of the hook worm?
Rhabditiform
What is the most common worm infection in the US?
Human pinworm - enterobius vernicularis
Where is a place susceptible for pinworm infections?
schools, daycares
How is a person infected with pinworms?
Ingesting their eggs (directly or indirectly)
Where are the eggs of a pinworm deposited?
Around the anus at night
What is the most common clinical presentation of infection with pinworm?
Itchy anal region
What is a tapeworm?
An intestinal cestode - flat and segmented
What is the main cause of tapeworm infections?
Eating undercooked meat from infected animals
What are the three most common tapeworms?
- Taenia saginata - beef (also black bears)
- Taenia solium - pork (also boar)
- Diphyllobothrium latum - fish
How do the animals get infected with tapeworm?
After eating human feces with Taenia eggs
Where do the taeinia eggs hatch and do they stay there?
They hatch in the animals small intestine, migrate to striated muscle
What is the name of the infectious tapeworm?
cysticerci
What do cysticerci do once a human ingests them?
They migrate to the small intestine and mature to adults - produce segments and eggs passed in feces
What is a condition in which a person infects themselves with T. Solium?
They will develop cysticercosis
- eggs hatch in intestine
- invade intestinal wall and migrate to striated muscles, brain, liver —> neurocystericosis
What are the largest worms that can infect people?
Diphyllobothrium latum - fish or broad tapeworm
- can grow up to 30 feet
What should you avoid if you don’t want a nasty diphyllobothrium latum infection?
- raw food
- sushi, sashimi, carpaccio di persico, tartare, ceviche, marinated herring
What stage is the cyst?
The resistant stage of the parasite. It is also infective to the human host
What are flat worms ?
Cestodes
What is an important feature of P. falciparum’s pathogenesis ?
Ability of its mature trophozoites and schizont forms to sequester in deep venous microvasculature
