(L3) FLAGELLATES 3 & 4 (BLOOD & TISSUE FLAGELLATES) Flashcards
BLOOD FLAGELLATES
Trypanosoma brucei complex (rhodesiense & gambiense)
Trypanosoma cruzi
TISSUE FLAGELLATES
Leishmania braziliensis
Leishmania donovani
Leishmania tropica
Blood and tissue flagellates have different stages of development:
trypomastigote, epimastigote,
promastigote, and amastigote
What stage is lacking in Trypanosoma rhodesiense and T. gambiense?
Amastigote and Promastigote
What is lacking in Leishmania braziliensis, tropica and donovani?
epimastigote and trypomastigote
Amastigote in T. cuzi?
Intracellular in macrophage in skin, liver, smooth muscle with affinity for cardiac muscle
Promastigote in T. cruzi
transitional stage only
Epimastigote of T. cruzi?
midgut of triatomid bug
Trypomastigote of T. cruzi?
in feces of triatomid bug, transfer to stages of man, present in bloodstream during acute attacks
Amastigote in L. donovani?
intracellular macrophage predominantly in liver, spleen, lymph nodes, and bone marrow
Amastigote in L. braziliensis?
Intracellular macrophage in skin can be transferred to mucocutaneous junction.
Promastigote for L. braziliensis, L. tropica & L. donovani?
In midgut, later in proboscis of sand fly, transfer stage to man
Amastigote for L. tropica?
intracellular in macrophage of skin and subcutaneous tissue
Occur in the blood of the majority of vertebrate animals
Trypanosomes
Trypanosomes:
Life cycle involves a intermediate host, which is usually ________
Insects
Pathogenisis for T. cruzi?
American trypanosomiasis / Chagas disease
Habitat for T. cruzi?
Reticuloendothelial cells
Intermidiate host for T. cruzi?
reduviid/ kissing/ triatomine
reservoir host T. cruzi?
man and other vertebrates
infective form to man T. cruzi?
Metacyclic trypomastigote
Infective form to triatomid bug?
Typical trypomastigote
Mode of infxn in T. cruzi?
skin penetration
Lab identification for T. cruzi?
Blood smears, tissue biopsy, serology, culture
specimen source for. T. cruzi?
blood and tissue
Macrophage in the liver
Kupffer cell
macrophage in brain
microglia
macrophage in lungs
alveolar
macrophage in bones
osteoclasts
T. cruzi:
Occupy/develop in a posterior position in the gut of the insect vector; the infective stages (metacyclic trypomastigotes are excreted in the feces of the insects onto the skin of humans
o Gain access through skin abrasions and mucous membranes
stercorarian trypanosome
causative agent of American Trypanosomiasis
T. cruzi
Mostly in poor, rural areas of Mexico, Central America, and South America
T. cruzi
Can also be transmitted through blood transfusions, organ transplantation, during pregnancy, transplacentally, and in laboratory accidents
T. cruzi
Diagnostic stage for T. cruzi?
Amastigote
amastigote multiply by _____.
binary fission
T. cruzi:
(unilateral palpebral and periocular
swelling) may appear as a result of conjunctival contamination with the vector’s feces
Romanas Sign
T. cruzi:
(a nodular lesion or furuncle) can appear at the site of inoculation
chagoma
the most serious manifestation in T. cruzi?
Cardiomyopathy
T. cruzi:
Pathologies of the digestive tract such as
megaesophagus & megacolon
Diagnosis of T. cruzi?
Microscopic examination
Isolation of agent
Antibody detection
T. cruzi (Microscopic examination):
Of fresh _________ blood, or its buffy coat, for motile parasites
anticoagulated
T. cruzi (Microscopic examination):
Of thin and thick blood smears stained with
____, for visualization of parasites
Giemsa
T. cruzi (Microscopic examination):
Only in the first ______ – can be seen by direct exam or thick blood smears (since they move into the tissues)
2 months
Isolation of the agent (T. cruzi):
Inoculation in culture with specialized media like
NNN: Novy–MacNeal–Nicolle medium
LIT: liver infusion tryptose
Isolation of the agent (T. cruzi):
where infected triatomine bugs are fed on the patient’s blood, and their gut contents are examined for parasites 4 weeks later
Xenodiagnosis
Antibody Detection (T. cruzi)?
Indirect fluorescent antibody (IFA) test Enzyme immunoassay (EIA)
▪ Slides are prepared from a suspension of
epimastigotes
▪ Cross-reactivity can occur with sera from
patients with leishmaniasis
Indirect Fluorescent Antibody test
Who discovered Chagas disease/ Trypanosoma cruzi?
Carlos Chagas in Brazil (1909)
Most common transmitting insects (T. cruzi):
o Panstrongylus megistus
o Triatoma infestans
o Rhodnius prolixus
In stained specimen, ________ appear C, U, or Sshaped
Trypomastigotes
T. gambiense causes
Gambian or West African sleeping sickness (West & Central)
Chronic form
T. rhodesiense causes?
East African Sleeping Sickness (East & South Africa)
Acute form
T. brucei complex geographical distribution?
Tsetse belt of Africa, 2/3 of African continent
Pathogenesis of T. brucei?
African trypanosomiasis
T. brucei
Habitat
Acute:
Chronic:
Acute: reticular tissues of lymph and spleen
Chronic: CNS
T. brucei
Intermediate host?
tse tse fly
T. brucei reservoir host?
Man and other vertebrates
Infective form T. brucei to man?
Metacyclic trypomastigote
infected form to tsetse fly T. brucei?
typical trypomastigote
mode of infxn T. brucei?
bite of tsetse fly
Lab. Identification T. brucei?
blood smears, serology, tissue biopsy, culture
specimen source of T. brucei?
blood and tissue
Both are salivarian trypanosomes
T. gambiense
Vector tsetse fly of West African Sleeping Sickness (T. gambiense)?
Glossina palpalis
Much more limited, with the species found in East and Southeast Africa
T. rhodesiense
Vector tsetse fly fo T. rhodesiense?
Glossina morsitans
darker staining area found in the
anterior portion
kinetoplast
central part of trypomastigotes
nucleus
T. brucei:
3 stages of infection
- Trypanosomal chancre
- Hemolymphatic stage
- Meningoencephalitic stage
T. brucei:
can develop on the site of inoculation
trypanosomal chancre
T. brucei:
with symptoms that include fever, lymphadenopathy, and pruritus
Hemolymphatic stage
T. brucei:
invasion of the CNS can cause headaches, somnolence, abnormal behavior, and lead to loss of consciousness and coma
Meningoencephalitic stage
The course of infection is much more acute with T.b. rhodesiense than T.b. gambiense
T or F
T
frequently in T. brucei gambiense;
the posterior cervical lymph nodes are enlarged, nontender, and have the consistency of ripe plums
Winterbottom’s sign
Evasion of immune response due to antigenic variation
T. brucei
Only the ________ forms are exhibited by T. brucei complex
epimastigote and trypomastigote
Diagnosis of T. brucei?
Microscopic examination Wet preparation Concentration techniques Isolation of agents Antibody detection Blood smears
T. brucei:
Demonstrating trypanosomes by _______ of chancre fluid, lymph node aspirates, blood, bone marrow, or, in the later stages of infection, cerebrospinal fluid
microscopic examination
T. brucei:
A _______ should be examined for the motile trypanosomes, and in addition, a smear should be fixed, stained with Giemsa (or Field), and examined
wet preparation
T. brucei:
For blood samples, these include centrifugation followed by examination of the buffy coat; mini anion-exchange/centrifugation; and the Quantitative Buffy Coat (QBC) technique
Concentration techniques
T. brucei:
_______ has sensitivity and specificity that are too variable for clinical decisions
Antibody detection
T. brucei:
Thick and thin blood films are made and stained with Fields stain and examined as for malaria parasites
Blood smears
Treatment for T. brucei:
lymphatic stage
Pentamidine & Suramin
Treatment for T. brucei:
for late stage with CNS involvement
Melarsoprol or Tryparsamide
Treatment for T. brucei:
for early and late stages of Gambian
sleeping sickness
Eflornithine
causes cutaneous leishmaniasis
L. tropica
causes mucocutaneous leishmaniasis
L. braziliensis
causes visceral leishmaniasis
L. donovani
Pathogenesis of Leishmania:
Leishmaniasis
Leishmania Habitat
L. tropica:
L. brasiliensis:
L. donovani:
Lymphoid tissue of skin
skin & mucous membrane
visceral organs
Leishmaniasis is endemic in ?
Asia, America, Africa
Leishmania spp:
trasnsmitted by ____
Phlebotomus species (sandfly)
Are all debilitating and disfiguring diseases
which occur throughout the Old and New World
Leishmaniasis
They have become perfectly adapted as the proteolytic enzymes which attack other foreign bodies in the blood stream but do not destroy them
Leishmaniasis
vertebrate host
Amastigote
invertebrate host
Promastigote
2 Stages of Development for Leishmania
o Amastigote – vertebrate host
o Promastigote – invertebrate host
Domesticated and wild animals
Natural reservoir host
Leishmania spp:
o Spherical in shape
o Elongated forms are slender and torpedo like
Amastigote
Leishmania spp:
Disease association
o Kalaazar o Visceral o Dumdum fever o Death fever o Tropical splenomegaly