Trypanosomes (Lecture 11)

what are the two main species of Trypanosoma?

gambiense and rhodesiense

where is TBG found?

West-central Africa

what are the 2 main reservoirs for TBG?

humans and livestock pigs

where is TBR typically found?

Central-east africa

what are the 3 main reservoirs for TBR?

cattle, bushbuck, hartebeest

Trypanosoma is much LESS severe in _____ animals that are _____ to the area. Conversely, _____ animals get much sicker

wild; endemic; imported

what is that Vector for Trypanosoma?

Glossina spp. Fly (Tsetse fly)

what does Nagana mean?

animal African trypanosomiasis

what species of trypanosoma causes Nagana acute?

T. brucei brucei

what species of trypanosoma causes Nagana chronic?

T. congolense

what what trait is specific to the Tsetse fly (Glossina sp.) that is different from the sandflies we talked about?

females do NOT lay eggs → live birth

Tsetse flies are fertilized _____ in their life and then produce _____ one at a time for their entire _____

one; larvae; lifetimes

the first two _____ of the larvae are _____ the mother fly

instars; inside

what is an “instar”

fly lifecycle stage

the _____ instar maggot falls to the ground, burrows in, and immediately _____ forming a hard-cased. The fly will emerge _____ days later

3rd; pupates; 20-60

Tsetse flies look for specific _____, _____, and _____ to identify what animal and where it will bite

odor; target size; color

what is one easy way that endemic regions try to mitigate the Tsetse fly?

fabric target “decoys” soaked in insecticide

Riverine flies prefer a _____ target, while savannah flies prefer a _____ target

smaller; larger

Cattle raising areas in africa are _____ the region of Tsetse flies. Why?

outside; cattle get severe illness → avoid disease

how does Trypanosoma infection first occur in humans?

during Tsetse fly blood meal

what stage of trypanosoma infects humans during the blood meal?

metacyclic trypromastigotes

once the cyclic trypomastigote is ingested into the human blood stream they transform into _____ which are carried to other sites

bloodstream trypromastigotes

trypromastigotes multiply by _____ in various _____

binary fission; bodily fluids

what are 3 examples of body fluids that the Trypomastigotes can replicate in?

blood, lymph, CSF

how is trypanosoma transmitted back to the Tsetse fly from humans?

take up trypomastigote in blood during blood meal

once back inside the fly, the trypomastigote will transform into _____ in the Tsetse fly’s _____

pro cyclic trypomastigote; midgut

after the pro cyclic trypomastigotes leave the midgut of the Tsetse fly, they transform into _____ and multiply in the _____

epimastigotes; salivary glands

after epimastigotes multiply in the Tsetse fly salivary gland, they transform into _____ which are then transmitted to humans during the blood meal

metacyclic trypomastigotes

the flagellum of the Trypanosoma runs _____

throughout the cell

what is the kinetoplast?

organelle containing mitochondria and mitochondrial DNA

In humans, a portion of the trypomastigotes will be _____ that are _____ to the Tsetse fly

stumpy trypomastigotes; pre-adapted

how many stages of Trypanosomasis are there?

2

in the FIRST stage of trypanosomiasis, parasites are found in the _____, but have NOT yet invaded the _____. This causes pretty _____ symptoms

peripheral; CNS; non-specific (similar to malaria!)

in the SECOND stage of Trypanosomiasis, the _____ has been invaded and it can cause more serious symptoms such as _____, _____ and _____.

CNS; seizures; tremors; coma

The second stage of trypanosomiasis occurs EARLIER in _____ (species)

TBR

TBG is considered _____ African Trypanosomiasis

CHRONIC

TBR is considered _____ African trypanosomiasis

ACUTE

TBG _____, _____ disease over years and is mostly through to occur in _____

mild, chronic; humans

TBG (chronic disease) is _____ in the blood and diagnosis is done either by _____ or _____

SPARSE; thick/thin blood smears; blood Buffy coat

TBR causes an _____, _____ malignant course and Death often occurs from _____

acute; aggressive; CNS encephalitis

TBR acute _____ is very common, specifically in _____ animals

zoonosis; hoofed

TBR has an _____ amount of trypomastigotes in the blood, which makes it _____ to diagnose than TBG. However, a _____ is always required to determine the severity of disease

LARGE; easier; spinal tap

T. brusei ssp. parasites are very _____, which can cause waves of _____ and _____

antigenic; fever; parasitemia

can an immune response clear T. brucei completely?

NO! → antigenic (will change surface antigens)

T. brusei causes a massive _____ response, resulting in high _____ antibodies. However the parasite can change its _____ to avoid response

B-cell; IgM; variable surface glycoproteins (VSG)

the immune system focuses on each wave of _____, which is the only _____ recognized by the immune system. However, each VSG type is _____ expressed for one wave of infection, and once it is knocked back, the smaller population with a different VSG will being to _____ (causing another wave)

VSG; major; temporally; proliferate

because of its antigenic nature, T. brusei causes _____ disease

cyclic

The key to diagnosis of T. brusei is demonstration of _____ in the _____. This is typically done via _____

parasites; peripheral blood; thick/thin blood smears

serological screening for T. brusei is don via _____

card agglutination

_____ evaluation (especially for TR) is important for determining the prognosis

CNS

_____ are the ONLY stage of trypanosoma found in patients

trypomastigotes

where will the parasites appear on a Buffy coat examination?

just above RBCs

do you treat everyone with African trypanosomiasis?

YES!

in the first stage treatment of African trypanosomiasis can _____ infection

cure

what drug is used to treat stage 1 of TBG?

pentamidine

with drug is used to treat the stage 1 TBG?

suramin

what drug is used to treat stage 2 TBG?

eflornithinew

what drug is used to treat stage 2 TBR?

melarsoprol

what are 2 main ways to prevent trypanomiasis?

avoid bites and destroy tsetse habitat

how can you avoid Tsetse fly bites?

insect repellent, protective clothing, bed nets

how can you destroy Tsetse fly habitat?

insecticide, eliminate bush along streams

the prevention of African trypanomiasis require sustained _____

investment/funding

visitors to _____ or _____ are at highest risk of Trypanosomiasis

rural areas; game parks with thick vegetation

Tsetse flies can bite through _____ fabric and are attracted by _____ and _____ colors!

lightweight; bright; dark

why are vaccines do difficult for African Trypanomiasis?

variable antigens (there are thousands of types that they can circulate through!)

what is the causative agent of American trypanosomiasis?

T. cruzi

where is T. cruzi found?

central and south america

what is the VECTOR for T. cruzi

Reduviid/tratomine insect

the Reduviid insect is also known as the _____

kissing bug

Why is the vector for T. cruzi also known as the kissing bug?

tend to bit lips and face

American trypanosomiasis is also known as _____

chagas disease

how is T. cruzi transmitted to humans?

bood mean of revudiid/triatomine bug

what stage of T. cruzi is transmitted to humans by the kissing bug?

metacyclic trypomastigotes

True or false: the T cruzi metacyclic trypomastigoes enter the blood stream via the kissing bug probuscus?

FALSE: found in the POOP! enter through bite wound or mucosal membranes

once T. cruzi metacyclic trypomastigotes enter humans, they _____ various cells at the _____ site and transform into _____

penetrate; bite wound; amastigotes

the T. cruzi amastigotes multiply by _____ in the cells of _____

binary fission; infected tissue

intracellular amastigotes transform into _____ then _____ of the cell and enter the _____

trypomastigotes; burst out; bloodstream

what are the two possibilities for T. cruzi trypomastigotes?

re-infect new cells and form amastigotes or be taken up by kissing bug

how does T. cruzi re-enter the kissing bug cycle?

Trypomastigote ingested during blood meal

inside the Triatomine bug, the trypomastigote transforms into a _____ in the _____ of the bug

epimastigote; midgut

T. cruzi epimastigotes transform to _____ in the _____ of the triatomine bug

metacyclic trypomastigotes; hinpdgut

how do metacyclic trypomastigotes leave the the triatomine bug?

through feces

many _____ species hav been recognized as T. cruzi reservoir hosts

mammalian

Triatomine bug _____ almost immediately during the blood meal to make room for their _____, this increases the _____ of Trypanosoma

defecates; food; transmission

T. cruzi trypanosomes are found in the _____ of the Triatomine, NOT in the _____

feces; bite

Triatomine insects have been found in the _____ in addition to South and Central America

USA

why is it that both male and female triatomine insects are implicated in trypanosome transmission?

both take blood meals throughout development

where do Triatomine bugs typically live?

cracks in housing, areas around it

other than direct transmission via Reduviid bug feeding, what are 4 other ways that Trypanosoma can be transmitted?

blood transfusion, congenital, transplants, oral

how have their decreased transmission of American Trypanosoma via blood transfusion?

increased testing

what is the most commonly implicated organ in transplant transmission of American trypanosoma?

hearts

what are two common food implicated in oral transmission of American trypanosoma?

acai and sugar cane juice

T. cruzi amastigotes are _____ and have a _____ flagellum

circular; stubby

T. cruzi epimastigotes are found only in the _____

Triatomine bug (not in humans!)

T. cruzi trypomastigotes are found in the _____ of humans and have a very _____ kinetoplast

blood; LARGE

the T. cruzi trypomastigote is ingested by a _____ and starts in a _____, but then breaks free into the _____

macrophage; vacuole; free cytoplasm

true or false: T. cruzi needs a parasitaceous vacuole in order to replicate

FALSE: does not require one (starts in one but then breaks out)

while Chagas disease can sometimes be _____, common chronic symptoms associated with the disease include __(4)__

mild/asymptomatic; neurological disorders, megacolon, megaesophagus, heart damage

what are the 3 main acute symptoms associated with Chagas disease?

severe anemia, muscle pain, neurological disorders

are acute or chronic symptoms more common with Chagas disease?

acute