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Trypanosomiasis, Flashcards

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Biology 101 flashcards
1
Q

Trypanosomes

They are _______________

pass through different morphologic stages ( ————,————, and ________)

A

haemoflagellates

epimastigote,amastigote, and trypomastigote

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2
Q

There are two distinct types of human trypanosomes:

(1) African, which causes ______ and is transmitted by _________ (eg, _______)

(2) American, which causes _________ and is transmitted by ______ (eg, _______)

A

sleeping sickness

tsetseflies; Glossina

Chagas’ disease; kissing bugs; Triatoma

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3
Q

Types
There are two distinct types of human trypanosomes:
(1) _______, which causes sleeping sickness

– (2)_______, which causes Chagas disease

A

African

American

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4
Q

Types
There are two distinct types of human trypanosomes:
(1) African: Trypanosoma __________ and Trypanosoma _____________;
– (2) American, Trypanosoma _________

A

brucei rhodiense

brucei gambiense

cruzi

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5
Q

African Trypanosomiasis

______________(HAT), also known as ________

A

Human African trypanosomiasis

sleeping sickness,

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6
Q

African Trypanosomiasis (Sleeping Sickness)

is caused by two protozoan parasite subspecies:

-Trypanosoma ___________

– Trypanosoma __________

A

brucei gambiense

Brucei rhodesiense

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7
Q

African Trypanosomiasis is caused by two protozoan parasite subspecies:

Trypanosoma brucei gambiense (______ African trypanosomiasis) and
– Trypanosoma brucei rhodesiense (_______ African trypanosomiasis).

A

West

East

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8
Q

Epidemiology

HAT occurs only in _______, where endemic foci are found in about ____ countries – recognized tsetse fly belts

About _______ new cases are reported annually to the World Health Organization

A

sub-Saharan Africa

20

10,000

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9
Q

T b gambiense

transmitted by the _______ tsetse _________ and several other humid forest tsetse vectors, extends from ____ to Central Africa and produces a relatively (Acute or chronic?) infection with progressive ______ involvement.

A

Streamside; Glossina palpalis

West

Chronic

CNS

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10
Q

Trypanosoma brueci rhodesiense, transmitted by the _______ Glossina _______, Glossina ______, and Glossina _______, occurs in the _______ and _________ savannas of Africa, with foci west of Lake Victoria.

A

woodland-savanna

morsitans; pallidipes; fuscipes

eastern and southeastern

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11
Q

Vector: tsetse flies that belong to the genus ________

A

Glossina

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12
Q

Trypanosoma brueci rhodesiense

It causes a (smaller or larger?) number of cases but is (more or less?) virulent.

A

Smaller; more

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13
Q

________ and _________ may serve as reservoirs of T b rhodesiense, whereas _______ are the principal reservoir of T b gambiense.

A

Bushbuck and other antelopes

humans

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14
Q

Aetiological agents
Three trypanosome subspecies,

Trypanosoma brucei _____

T. brucei ————

T. brucei ______

as a group they are often referred to as the ___________

A

brucei

rhodesiense

gambiense

T. brucei complex.

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15
Q

Aetiological agents
Three trypanosome subspecies, Trypanosoma brucei brucei, T. brucei rhodesiense, and T. brucei gambiense are distinguishable morphologically

T/F

A

F

Indistinguishable

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16
Q

Aetiological agents

T. b. gambiense primarily infects _______, and may also infect __________

T. b. rhodesiense, which is primarily a parasite of ______, can infect _____,

A

humans

wild and domestic animals

wild game

humans

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17
Q

Aetiological agents of Trypanosomiasis

this __________ forms the primary basis of the distinction between the two subspecies (gambiense and rhodiense)

A

difference in host specificity

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18
Q

Aetiological agents

T. b. brucei is a parasite of ___________

A

wild and domestic animals

19
Q

Aetiological agents

T. b. brucei is infectious to humans.

T/F

A

F

T. b. brucei is not infectious to humans

20
Q

Trypanosoma appears in the blood as ______mastigotes with _____ bodies supporting a (longitudinal or transverse?) (medial or lateral?) undulating membrane and a flagellum that borders the free edge of the membrane and emerges at the (anterior or posterior ?) end as a whiplike extension

A

trypo; elongated

longitudinal; lateral

Anterior

21
Q

Trypanosoma

The kinetoplast is a ______ staining body lying immediately adjacent to the ______ from which the _______ arises
•

A

darkly

basal body

flagellum

22
Q

The kinetoplast is a ____________________________

A

circular DNA inside the single mitochondrion

23
Q

Life cycle of trypanosomes bbn

Trypanosomes are parasites with a 2-host life cycle:

_________ and ________.

The life cycle starts when the trypanosomes are ingested during a
______ by the tsetse fly from a __________ in West African trypanosomiasis or _______ in the East African form.

The trypanosomes multiply over a period of _______ in the fly’s ________ ; then, the trypanosomes migrate to the _________, where they develop into _________.

The ———————- infect humans.

A

mammalian and arthropod

blood meal; human reservoir ; an animal reservoir

2-3 weeks; midgut; salivary gland; epimastigotes

metacyclic trypomastigotes

24
Q

Pathophysiology of Trypanosomiasis

The parasites escape the initial host defense mechanisms by extensive __________________ known as major ________________________.

During the parasitemia, most pathologic changes occur in the ______,_________,________, and ________ systems.

This may be the result of immune- mediated reactions against antigens on red blood cells, cardiac tissue, and brain tissue, resulting in hemolysis, anemia, pancarditis, and meningoencephalitis

A

antigenic variation of parasite surface glycoproteins

variant surface glycoprotein (VSG)

hematologic, lymphatic, cardiac, and central nervous

25
Q

Pathogenesis of Trypanosomiasis

Infective trypanosomes of T b gambiense and T b rhodesiense are introduced through the bite of the tsetse fly and ____________ to cause variable _____ and_________ (the primary lesion), which may progress to form a ________.

A

multiply at the site of inoculation

induration and swelling

trypanosomal chancre

26
Q

Pathogenesis of Trypanosomiasis

They multiply extracellularly as ________ in the blood as well as in lymphoid tissues. They spread to lymph nodes, to the bloodstream, and, in terminal stages, to the _________, where they produce the typical _________ syndrome

A

trypomastigotes

central nervous system (CNS)

sleeping sickness

27
Q

typical sleeping sickness syndrome

________ , inability to _____, tissue _______, unconsciousness, and death.

_______ involvement is most characteristic of African trypanosomiasis.

A

lassitude; eat; wasting

CNS

28
Q

Diagnosis

A definitive diagnosis of African
trypanosomiasis requires ____________

A

demonstration of the parasite.

29
Q

Diagnosis of African trypanosomiasis

Examination of ________ and ____________ for parasites is the cornerstone of HAT diagnosis.

molecular methods like PCR are also being used.

A

blood smears and cerebrospinal fluid

30
Q

Treatment of African Trypanosomiasis

complicated because it varies according to the ________ of the disease and the ___________ causing the infection.

A

clinical stage; trypanosome subspecies

31
Q

Treatment of African Trypanosomiasis

Toxicity of the drugs used to treat HAT is a (minor or major?) problem.
Suramin, pentamidine, and organic arsenicals have been used for more than 50yrs
Eflornithine was introduced in 1990

A

Major

32
Q

Prevention of HAT

By avoiding ______ known to harbor infected insect

wearing clothing that reduces the biting of the flies, and using insect repellent.

instituting fly control principally with aerial insecticides and by altering habitats

searching for and then isolating and treating patients with the disease

____________ is not recommended m

A

areas

Chemoprophylaxis

33
Q

Chemoprophylaxis is not recommended for HAT because of the _____________

A

high toxicity of the drugs that are active against African trypanosomes

34
Q

no vaccine is available for HAT

T/F

A

T

35
Q

AmericanTrypanosomiasis (Chagas’ Disease)

vector;:——————, or “________”

A

Triatominae

kissing bug

36
Q

Epidemiology of Chagas’ disease

Chagas’ disease is endemic in all ________ and _____ countries and also in _________.

The infection is not endemic in any of the Caribbean islands.
About 8 million persons are chronically infected with T. cruzi, roughly 56,000 new infections occur each year, and about 12,000 persons die of the illness annually.

A

South and Central American ; Mexico

37
Q

Life cycle of cruzi

The T cruzi life cycle consists of 3 main developmental forms.

Epimastigotes are (intra or extra?) cellular and (infective or noninfective?) form of the parasite found in the ____ of insect vectors, where they multiply by _________

As epimastigotes move to the ______, they differentiate into ____________ which are (dividing or non dividing?) forms resistant to _________ that have the capacity to __________

They enter local cells through breaks in the skin, mucous membranes, or the conjunctivas and transform into the third morphologic form, __________.

This final form multiply (intra or extra?) cellularly until the host cell is overwhelmed, at which point they transform into _____________

A

an extra; noninfective; midgut

binary fission.; hindgut; metacyclic trypomastigotes

non dividing; mammalian complement ; infect mammalian cells.

amastigotes; intra; bloodstream trypomastigotes

38
Q

Pathogenesis of Cruzi

Infective forms of T cruzi pass to humans by triatomine bug bites

T/F

A

F

do not

39
Q

Pathogenesis of Cruzi

Infective forms of T cruzi do not pass to humans by triatomine bug bites ; rather, they are introduced when ___________________________.

At the site of T cruzi entry, there may be a ________________ or _____________

Unilateral swellingof the _____ (______ sign) is characteristic at onset, especially in children.

The primary lesion is accompanied by fever, acute regional lymphadenitis, and dissemination to blood and tissues.
• • •

A

infected bug feces are rubbed into the conjunctiva, the bite site, or a break in the skin

subcutaneous inflammatory nodule or chagoma.

eyelids; Romaña’s

40
Q

Interstitial _______ is the most common serious condition in Chagas disease.

A

myocarditis

41
Q

Other organs affected are the _______,_____, and _________ , especially with chronic T cruzi infection.

A

liver, spleen, and bone marrow

42
Q

Pathogenesis of T cruzi

Invasion or toxic destruction of nerve plexuses in the alimentary tract walls leads to _______ and _____, especially in _______ Chagas disease and megacolon are absent in ___________.

A

megaesophagus and megacolon

Brazilian

Colombian

43
Q

Treatment of chagas

________ and _______

A

Nifurtimox and benznidazole

House Microbiology (93 decks)

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