Protozoa II Flashcards
Give the Sketchy rundown on Trypanosoma cruzi.
- Transmitted by the reduviid bug, which bites people and then defecates on the wound. People then scratch the wound and rub it in.
- Causes Chagas disease (CHe’s GAS)
- Causes megacolon (large gas line with haustra), dilated cardiomyopathy (saggy heart bag on motorcycle), and achalasia (snake with large throat)
Sketchy forgot to mention that Trypanosoma cruzi is _____________.
extracellular and intracellular (recall the mole burrowing up from the ground)
Chagas’ disease is becoming more common because ________________.
the parasite that causes it has spread to dogs
What famous person died of Chagas’ disease?
Charles Darwin
There are three kinds of Leishmaniasis: _________________.
1) Cutaneous
2) Mucocutaneous
3) Visceral
Leishmania can be transmitted by _______________.
insects (sandflies) or direct contact of cutaneous lesions
Which protozoa lives inside macrophages?
Leishmania (like the goats in the desert cages)
Visceral Leishmaniasis presents with ___________________.
hepatosplenomegaly (cow with liver and spleen spots), fever (guy sweating), and pancytopenia (empty pan
Public health experts try to prevent African sleeping sickness by limiting fly bites. What time of day does the Tse tse fly bite?
Daytime
Advanced _______________ can lead to severe wasting and skin irritation from itching.
Trypanosomiasis
Because of its antigenic variation, T. brucei presents with ______________.
undulating waves of parasitemia with varying fevers
Give some numbers for the incidence of malaria per year.
- 400 million infections per year
* 0.5 million deaths
What is the incubation period of malaria?
Up to two weeks
The febrile cycle of malaria coordinates with ________________.
how long it takes for the RBCs to lyse
Mosquitoes transmit the ____________ form of malaria.
sporozoite
What three stages does malaria go through within RBCs?
Trophozoite, schizont, gametocyte
Describe the most common way by which Plasmodium falciparum causes mortality.
P. falciparum infects RBCs and makes them express a membrane protein that increases their adherence. This can lead to stroke.
How is malaria diagnosed?
- Patient symptoms: fever, chills, headache, myalgia
- Travel to endemic area
- Blood smear looking for microbes
Why is the prophylactic treatment for malaria controversial?
Resistance rapidly develops (which has already happened with chloroquine)
How do rodents and birds contract Toxoplasmosis?
From eating plant material with cysts on it.
True or false: immunocompromised people only develop symptomatic Toxoplasmosis from acute infection.
False. It can reactivate.
Toxoplasma infection during the third trimester leads to high chance of infection of the fetus, but _______________.
symptoms will be more mild
Describe the differences in where T. cruzi and T. brucei replicate.
T. cruzi replicates inside the gut. T. brucei replicates in the blood.
Describe the lifecycle of T. cruzi.
- Infection with amastigotes from Reduviid bug
- Amastigotes divide by fission
- Trypomastigotes enter blood and other tissues
- Reduviid bug ingests more from infected animal
- Trypomastigotes replicate in bug
The mortality of Chagas’ disease is _____%.
10
How is chronic Chagas detected?
Often tissue biopsies are needed because the trypomastigote form of T. cruzi will not present in many chronic Chagas cases.
The amastigotes of Leishmania transform into promastigotes in ______________.
the midgut of sandflies
Describe the life cycle of Trypanosoma brucei.
T. brucei does not form amastigote or promastigote forms, so it is always a trypomastigote. When it divides it does so by binary fission.
All forms of trypanosomiasis present with _____________ at the site of entry.
chancres
The merozoites of Plasmodium mature inside RBCs to trophozoites (which look like rings) and then ____________.
the trophozoites evolve back into merozoites to rupture the RBCs and infect more RBCs
True or false: P. falciparum and P. malariae do not infect the liver.
False. All Plasmodia infect the liver initially, but only P. vivax and P. ovale can create dormant hypnozoites in the liver.
What form of Babesia makes the Maltese cross?
Merozoite (dividing in RBCs)
The Ixodes tick introduces the ____________ form of Babesia into humans.
sporozoite
How many Toxoplasma infections occur in the U.S. each year?
- 4,000 symptomatic congenital cases
* 4,800 adults losing vision due to chorioretinitis
Those negative for the Duffy blood group cannot be infected with ___________.
P. vivax
