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PARASITOLOGY > MIDTERM LEC: Trypanosoma > Flashcards

MIDTERM LEC: Trypanosoma Flashcards

1
Q

● Located in the BLOOD AND TISSUE of humans
and other vertebrate hosts, and in the GUT of
insect vectors
● Digenetic and involves complex, pleomorphic
life cycles
● Transmission: via bite of an arthropod vector
● Main reservoir: humans
● Intermediate host: arthropod vector

A

HEMOFLAGELLATES

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2
Q

HEMOFLAGELLATES Two genera:

A
  1. Trypanosoma
  2. Leishmania
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3
Q

Vectors of hemoflagellates found in PH
○ T. cruzi:

A

Triatoma and Rhodnius bugs

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4
Q

Vectors of hemoflagellates found in PH
Leishmania spp:

A

Phlebotomus spp

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5
Q

MORPHOLOGICAL STAGES OF HEMOFLAGELLATES:
- A specialized region of the mitochondria consisting of a network of circular DNA (kDNA) that contains
many copies of the mitochondrial genome
- Crucial for replication and segregation of kDNA circles
- Consist of a deeply staining PARABASAL BODY and adjacent dotlike BLEPHAROPLAST

A

KINETOPLAST

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6
Q

MORPHOLOGICAL STAGES OF HEMOFLAGELLATES:
- Portion that is inside the body of the parasite and extends from blepharoplast to surface of the body

A

AXONEME

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7
Q
  • FREE FLAGELLUM at the anterior end that traverses on the surface
  • A SINUS EXTENSION of the cytoplasmic membrane which helps in movement by performing a vigorous, wavelike, reversible movements
A

UNDULATING MEMBRANE

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8
Q

Thin, hairlike structure which originates from the blepharoplast

A

FLAGELLUM

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9
Q

DEVELOPMENTAL STAGES
- Roundish-oval
- Size: 5 by 3 um
- Nucleus: large single, off-center
- No external flagellum
- ROUTINELY FOUND IN HUMANS
- Found primarily in tissues, as well as CNS
within macrophages, where they multiply
- Found intracellularly in vertebrate hosts of
T. cruzi and Leishmania spp.

A

AMASTIGOTE STAGE

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10
Q
  • Long and slender
  • Size: 9-15 um
  • Nucleus: one, located in or near center
  • Kinetoplast: anterior to nucleus; at anterior
    end of cell
  • NO UNDULATING MEMBRANE
  • INFECTIVE STAGE of Leishmania in the midgut
    and proboscis of the insect vector
  • May only be seen if blood sample is collected
    immediately after transmission to individual
A

PROMASTIGOTE STAGE

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11
Q
  • Long and slightly wider than promastigote form
  • Size: 9-15 um
  • Nucleus: one, located in posterior end
  • Kinetoplast: close to the nucleus than
    promasitgote
  • Flagellum: runs alongside the body as a
    short undulating membrane
  • T. gambiense and T. rhodesiense occur:
    salivary glands of the vector tsetse fly
  • T. cruzi: midgut of the vector reduviid bug
  • NOTE: ALL SPECIES OF Trypanosoma
    that infects humans assume an epimastigote
    stage in the insect vector or in culture
A

EPIMASTIGOTE

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12
Q
  • Long, slender
  • Size: 12-35 um long by 2-4 um wide
  • Assume the shape of the letters C, S, or U in
    stained blood films
  • Nucleus: single large, anterior to kinetoplast
  • Routinely found in human specimens along
    with the amastigote stage
  • Flagellum: runs alongside the entire long of
    the cell forming a long undulating membrane
  • Infective stage of Trypanosoma found in
    the arthropod vector
  • Stage found in the blood of the infected
    invertebrate
A

TRYPOMASTIGOTE

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13
Q

From the Greek words trypano (borer) and
soma (body)
● Causes Chagas disease and Human
African Trypanosomiasis
● MOT: bites of infected Tsetse flies
● Definitive host: mammals
● Intermediate host: arthropod vector
● Known to invade the CNS, blood and tissues
causing acute and chronic protozoal diseases

A

Trypanosoma spp.

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14
Q

Chagas disease or American trypanosomiasis is cause by?

A

Trypanosoma cruzi (trypanosome group Stercoraria)

Carlos Chagas - found that the trypanosomes he dissected from the intestine of a triatomid bug were the same parasites found in the blood of a child suffering from fever and enlargement of the lymph nodes.

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15
Q

Human African Trypanosomiasis (HAT) is caused by?

A

Trypanosoma rhodisiense

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16
Q

morphological stages of Trypanosoma spp.

A

Amastigotes, promastigotes, epimastigotes, and
trypomastigotes

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17
Q

Two modes of development in the vector of Trypanosoma spp.

A

salivaria & stercoraria

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18
Q

trypanosomes migrate to the MOUTH PARTS of the vector so that the infection is transmitted via their
bite (inoculative transmission)

A

Salivaria

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19
Q

trypanosomes migrate to the HINDGUT and are passed in the feces. Acquired by rubbing the feces
of the vector into the wound caused by its bite

A

Stercoraria

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20
Q

● Etiologic agent of Chagas Disease or
American trypanosomiasis
● Only parasite that was discovered and
studied before it was known to cause a
disease
● Belongs to the trypanosome group
Stercoraria

A

Trypanosoma cruzi

21
Q

Trypanosoma cruzi become a Major Food-borne Disease in _____________ (due orally acquired
ACD (Acute Chagas Disease) in Acre
(Forest Community of Seringal
Miraflores–Affecting 13 individuals who
shared pulp of Acai Berries

A

Brazilian Amazona

22
Q

LESS COMMON ROUTES FOR THE
TRANSMISSION OF T. CRUZI:

A

● Blood Transfusion
● Organ transplantation
● Transplacental transmission
● Foodborne transmission

23
Q

● AKA Trypanosoma Herpetosoma due to its subgenus that is transferred by Reduviid Bug
● Was first found as, Trypanosoma cruzi
● Common Associated Disease and Condition:
NOT KNOWN
● Infections are generally ASYMPTOMATIC
and DOES NOT TEND TO SHOW NO
PATHOLOGIC CHANGES or SIGN OF
DISEASES

A

Trypanosoma rangeli

24
Q

T. cruzi and T. rangeli are found regions of SOUTH and CENTRAL AMERICA RARE in NORTH AMERICA) particularly:

A

● Brazil
● Venezuela
● Colombia
● Panama
● El Salvador
● Costa Rica
● Honduras
● Guatemala

25
Q

Trypanosoma cruzi
● FIRST ISOLATED in

A

Panstrongylus megistus

26
Q

Furuncle-like lesions associated with induration, central edema and regional lymphadenopathy
❖ Appears on the site of entry of parasite

A

Chagoma

27
Q

EYELID SWELLING; may form if the parasite penetrates through the conjunctiva

A

Romaña’s sign

28
Q

Specimen choice detection of Trypomastigotes

A

Giemsa-stain blood slides

29
Q

reveal amastigotes

A

Lymph Node Biopsy Giemsa-stained Slides & Blood Culture

30
Q

seen in the peripheral blood smear throughout the course of the illness.

A

Trypomastigotes

31
Q
  • Cause TRYPANOSOMIASIS (general term
    used to refer to human disease caused by
    hemoflagellates of genus trypanosoma)
A

Trypanosoma brucei COMPLEX

32
Q

Scottish pathologist; identified Trypanosoma brucei as the CA of the trypanosomal diseases known as nagana (a form of the disease often found in cattle)
and sleeping sickness

A

David Bruce (1895

33
Q

Described Trypanosoma brucei rhodesiense

A

Stephens and Fantham (1910)

34
Q

3 SUBSPECIES/ Trypanosoma brucei COMPLEX:

A

● Trypanosoma brucei gambiense
● Trypanosoma brucei rhodesiense
● Trypanosoma brucei bruceI

35
Q

● Blood, Lymph, tissue space and various
organs (brain and spinal cord) and CNS
● POLYMORPHIC
○ Short stumpy forms
○ Typical slender forms
● SHAPE: Flattened, fusiform
○ Often assumes the S shape in stained blood films
● Body tapers anteriorly, blunt posteriorly
● LENGTH: 14 to 33 µm(Belizario) OR 12-35 um (Zeibig)
● WIDTH: 1.5 to 3.5 µm / 2-4 um
● NUCLEUS: CENTRAL
● KARYOSOME: Large, Centra

A

TRYPOMASTIGOTE

36
Q

Responsible for the chronic type of sleeping
sickness in Central and WEST Africa.
○ Cause 95% of all HAT cases.
○ Sleeping sickness Manifest months or
years after initial infection.

A

Trypanosoma brucei gambiense

37
Q
  • Responsible for a more acute and rapidly
    fatal form of HAT in EAST and Southern Africa.
    ● Cause 5% of all HAT cases.
    ● Symptoms may appear just weeks after infection.
A

Trypanosoma brucei rhodesiense

38
Q

● DOES NOT INFECT HUMANS
● Causes “NAGANA” In domestic and wild
animals

A

Trypanosoma brucei brucei

39
Q

caused by Trypanosoma brucei rhodiense
- Manifest few weeks after the exposure to the vector.

A

Acute HAT

40
Q

caused by Trypanosoma brucei gambiense
- Manifest months or years after the
exposure to the vector.

A

Chronic HAT

41
Q

Local, painful, pruritic, erythematous chancre located at the bite site progressing into eschar that
spontaneously resolves within 2-3 weeks.
● First sign that can be detected.

A

Trypanosomal Chancre (Initial Lesion)

42
Q

enlarged, nontender, rubbery posterior
CERVICAL LYMPHADENOPATHY

A

WINTER BOTTOM SIGN (T. bruceigambiense

43
Q
  • may manifest as a deep, delayed HYPERESTHESIA after a slight blow on a bony projection of the body.
    ● In later stages, alterations in circadian rhythm
    leading to daytime somnolence manifests,
    followed by coma then death.
    ● Affected areas: frontal lobes, pons,
    medulla, perivascular areas.
A

Kerandel’s Sign (T. brucei rhodisiense

44
Q

The ability of the trypomastigote to CONTINUOUSLY CHANGE ITS SURFACE COAT, composed of variant surface glycoproteins, so that the host’s antibodies cannot recognize the parasite.

A

antigenic variation.

45
Q

TREATMENT FOR FIRST STAGE

A
  1. IV suramin sodium
  2. Intramuscular pentamidine
46
Q

TREATMENT FOR LATE STAGE

A
  1. IV melarsoprol
  2. Usually co-administered with corticosteroids
  3. Nitrofurazone
  4. Nitrofurazone + Eflornithine
47
Q

First documented cases of sleeping sickness

A

Africa (1734)

48
Q

● DOES NOT INFECT HUMANS
● Causes “NAGANA” In domestic and wild
animals.

A

Trypanosoma brucei brucei

49
Q

Trypanosoma brucei brucei INFECT:

A

● Deer
● Cow
● Horse

PARASITOLOGY (23 decks)

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