hemoflagellates lab Flashcards
derived its name from a distinctive organelle known as the kinetoplast
Kinetoplastida
kinetoplast from a greek origin
- kineto: movement
- plast - formed or molded
function of kinetoplast
it contains DNA which is found in the mitochondrion
helps w energy production and movement
Two Main Genera of Hemoflagellates
Trypanosomes
1. Trypanosoma brucei gambiense
2. Trypanosoma brucei rhodesiense
3. Trypanosoma cruzi
Leishmania
1. Leishmania tropics
2. Leishmania donovani
3. Leishmania braziliensis
*These reside in the blood & tissues of the host.
the 4 stages of development of hemoflagellate
go through different forms as they move between insects (invertebrate host) and mammals (vertebrate host
- Amastigote (Leishmania Form)
- ovoidal, no flagella
- intracellular - lives inside host cells especially in macrophages
- small kinetoplast
- Example: Leishmania donovani - Promastigote (Leptomonas Form)
elongated and spindle-shaped
- hv free flagellum that grows from the kinetoplast, which is located at the front (anterior) end.
- infectious stage in insects (like sandflies). - Epimastigote (Crithidia Form)
- elongated and spindle-shaped
- hv free flagellum that extends from the anterior end.
- undulating membrane
- kinetoplast is located anteriorto the nucleus. - Trypomastigote (Trypanosoma Form)
- similar to the epimastigote but with one key difference:
The flagellum follows the undulating membrane and ends at the kinetoplast, which is located behind (posterior to) the nucleus.
- infectious stage in mammals.
Example: Trypanosoma brucei
invertebrate vs vertebrate host
Invertebrate Host (No backbone):
Usually an insect, like a tsetse fly or sandfly.
The parasite develops inside the insect but does not cause disease in it.
Vertebrate Host (Has a backbone):
Usually a human or animal (like a dog).
The parasite infects the blood and tissues, causing diseases like sleeping sickness or leishmaniasis.
How to Differentiate These Stages
Look for the flagellum (present or absent).
Check the location of the kinetoplast (in front of or behind the nucleus).
how many stages does each of these have
- Leishmania
- T. brucei
- T. cruzi
Leishmania = amastigote & promastigote
T. brucei = epimastigote & trypomastigote
T. cruzi = has ALL four stages
who can trypanosomes infect
both humans and animals
Trypanosomes and Their Hosts
Trypanosoma brucei Group (Causes Sleeping Sickness):
Invertebrate Host (Insect, e.g., Tsetse Fly)
- Epimastigote stage (develops in the fly before becoming infectious).
Mammalian Host (Humans/Animals, in the Blood)
- Trypomastigote stage (moves through the blood and causes disease).
Trypanosoma cruzi (Causes Chagas Disease):
Invertebrate Host (Insect, e.g., Kissing Bug)
- Epimastigote stage (develops in the midgut of the bug).
Mammalian Host (Humans/Animals)
- Trypomastigote stage (found in the blood and gut of the mammalian host).
- Amastigote stage (hides inside cells and multiplies).
[Key Difference:
T. brucei only has epimastigote (in insect) and trypomastigote (in blood).
T. cruzi has all three stages: epimastigote (in insect), trypomastigote (in blood), and amastigote (inside cells, specifically within macrophages).]
Morphology of Trypanosomes & Amastigotes
Trypanosomes (Motile Stage in Blood):
Size: 14-33 microns long; 1.5-3.5 microns wide.
Shape: Fusiform (spindle-shaped), flattened from side to side.
Movement: Actively motile with a wavy, spiral motion due to the contractile flagellum.
Nucleus: Large, oval, single nucleus with centrally located karyosome (dense part of the nucleus).
Flagellum & Kinetoplast:
- The contractile flagellum runs along the undulating membrane.
- It starts from the kinetoplast (located at the back) and extends forward as a free flagellum.
Amastigotes (Intracellular Stage in Host Cells):
Size: 1.5-3 microns
Shape: Round or ovoid
Location: Found inside host cells, especially reticuloendothelial cells (macrophages, liver, spleen).
Lack of Movement:
No undulating membrane.
No flagellum (lost in this stage).
Nucleus: Large with a spherical or rod-shaped kinetoplast.
LIFE CYCLE:
- T. brucei group
- T. cruzi
- T. brucei group
Vertebrate host: Man
Invertebrate hosts (Tse-tse flies):
1. T. brucei gambiense
Glossina palpais
Glossina fuscipes
Glossina tachinoides
2. T. brucei rhodesiense
Glossina morsitans
Glossina palipedes
Glossina swynnertonii
Diagnostic stage: trypomastigote
Infective stage: metacyclic trypomastigote
MOT: bite of tsetse flies
- T. cruzi
Diagnostic form: trypomastigote
Infective stage: metacyclic trypomastigote
Invertebrate hosts (Reduviid bug):
Panstrongylus
Rhodnius
Eutratoma
Triatoma
MOT
Bites of reduviid bug
Blood transfusion
Transplacental transfer
Organ transplant
PATHOLOGY
- trypanosomas
- Trypanosoma brucei gambiense
West african sleeping sickness
Gambian trypanosomiasis - Trypanosoma brucei rhodesiense
East african sleeping sickness
Rhodesian trypanosomiasis - Trypanosoma cruzi
Chagas disease
Chagoma
American trypanosomiasis
[Chagas disease = The full-body infection caused by Trypanosoma cruzi.
Chagoma = A skin lump/swelling that appears at the site of infection in the early stage of Chagas disease.]
SIGNS AND SYMPTOMS
Trypanosoma brucei group
(ACUTE) & (CHRONIC)
Trypanosoma cruzi
(ACUTE) & (CHRONIC)
ACUTE:
Irregular fever or intermittent fever
Headache
Joint & muscle pain
Muscle pain aka myalgia
Joint pain aka arthralgia
Rash
Cen develop into skin lesions at the site of the bite (chunker) - more common in T. brucei rhodesiense
Hyperactive
Winterbottom’s sign - more common in T. brucei gamebiense
Enlargement of lymph nodes at cervical region
CHRONIC:
Death result either from the disease or from intercurrent infection, such as malaria, dysentery and pneumonia
Chronic - the parasite cross the blood brain barrier and can infect the CNS - terminal sleeping stage
ACUTE:
Slightly painful nodule at the site of inoculation
Metastatic lesion throughout the body notably in the heart, esophagus and lower intestines
Metastatic lesion is called Romana’s sign: swelling in one eye
[Chagoma = A small painful lump where the parasite entered.
Romana’s sign = Swelling in one eye, a special type of chagoma.
Metastatic lesions = Damage in different organs as the disease spread]
CHRONIC:
Heart failure - cardiomegaly
Megaesophagus
Megacolon
- Chronic disease has no characteristic symptoms and may last for 20 years or more
- serious and often fatal in older children and adult
[No symptoms for years, but when they appear, they can be life-threatening.]
A specific type of chagoma, common in early Chagas disease
Romana’s Sign
using laboratory reared bugs (uninfected); bugs are allowed to feed on patients suspected of being infected
Xenodiagnosis
DIAGNOSIS FOR T. BRUCEI GROUP
- Stained blood preparation
- Lymph aspirates
- Thick blood smear with giemsa stain - trypanosomes
- Xenodiagnosis - using laboratory reared bugs (uninfected); bugs are allowed to feed on patients suspected of being infected
- Serologic test
- Immunofluorescent antibody test
- Hemagglutination assay - Presence of mott cells in the CSF (T. brucei group)
- Mott cells can also be called as rasal bodies
[Mott cells = Plasma cells that store too many antibodies.] - Novy Mac Neal Nicolle culture medium (T. cruzi)
SPECIMEN OF CHOICE FOR TRYPANOSOMAS
Blood
Lymph fluid
CSF
TREATMENT FOR
- TRYPANOSOMAS
- LEISHMANIA
TRYPANOSOMAS
- African Sleeping Sickness
Pentamidine
Suramin
*Both drugs do not enter the CSF, early stage
Melarsoprol - late stage of the disease with CNS inolvement
- Chagas disease
Nifurtimox
bezuidazole
*both are partially effective in acute disease
LEISHMANIA
- Primary drugs (Antimony compounds)
Pentavalent antimonials
Sodium stibogluconate
N-methyl-glucamine antimonate
- Secondary drugs
Amphotericin B
Pentamidine (for kala azar fever)
Metronidazole
Nifurtimox
EPIDEMIOLOGY IN
- TRYPANOSOMAS
- LEISHMANIA
- TRYPANOSOMAS
African trypanosomiasis is endemic in area known as “tsetse belt” extending over a third of africa
Chagas disease is prevalent throughout central and south america - LEISHMANIA
Southern regions of america
Mediterranean
East and north america
Arabian peninsula
Persian gulf
Indian subcontinent
China
Southern soviet union
PREVENTION AND CONTROL FOR
- TRYPANOSOMAS
- LEISHMANIA
- TRYPANOSOMAS
1. Reduction of the pool of contact with tsetse fly through control measures (traps, screen insecticides)
2. Reduction of the pool of human infection by diagnosis and treatment
3. Vector control
4. Screening and sterilization of transfusion blood and health education - LEISHMANIA
1. Vaccination
2. Control of sandfly vectors
3. Protective measures form sandflies
4. Mechanical destruction of animal reservoir habitats and poisoning of animals.
Leishmania Life Stages in Different Hosts
Vertebrate Host (Humans/Animals):
Intracellular Amastigote
No flagella, round or oval in shape.
Lives inside macrophages (immune cells).
Causes Leishmaniasis by multiplying inside the host’s cells
Invertebrate Host (Sandfly):
Flagellate Promastigote
Has a flagellum, elongated shape.
Found in the midgut of the sandfly.
Infects humans when the sandfly bites and injects promastigotes into the bloodstream.
[Inside humans/animals → Amastigote (no flagella, hides in cells).
Inside sandflies → Promastigote (with flagella, free-moving).]
MORPHOLOGY OF AMASTIGOTE & PROMASTIGOTE
Amastigote:
Small (2 microns), oval-shaped.
Lives inside immune cells (monocytes, PMNs, endothelial cells)
large nucleus.
No flagellum → Non-motile.
Promastigote:
Larger (15-20 microns).
Elongated shape.
free flagellum for movement which arises from the kinetoplast at the anterior end → Motile.
[Amastigote = Small, no flagella, lives inside cells (in humans/animals).
Promastigote = Larger, has flagella, free-living in sandflies (in insects).]
LIFE CYCLE OF LEISHMANIA
Vertebrate host: Man
Invertebrate hosts (vector): sandflies, Genus Phlebotomus or Lutzomyia
Natural reservoir hosts: domestic dog, wild animals
[carry the parasite]
Diagnostic stage: amastigote/ Leishmania form
[Found inside human immune cells (macrophages, monocytes, etc.).]
Infective stage: promastigote/ Leptomonas form
[Found in the sandfly.
Enters humans when bitten by an infected sandfly.]
Sites of inhibition:
Leishmania tropica - lymphoid tissue of the skin
MOT: bite of tsetse flies (infected fly not tsetse daw…)
[1️⃣ Sandfly bites a person → Injects promastigotes → Infection starts.
2️⃣ Promastigotes enter immune cells → Turn into amastigotes → Multiply inside cells.
3️⃣ Another sandfly bites the person → Picks up amastigotes → Cycle continues.]
PATHOLOGY FOR LEISHMANIA
- Leishmania donovani
Visceral leishmaniasis
Kala-azar fever - hyperpigmentation of the skin
Dumdum fever - place or an area near Kolkata India
Black fever - hyperpigmentation
Death fever
Tropical splenomegaly - Leishmania tropica
Cutaneous leishmaniasis
Oriental sore
Old world leishmaniasis
Aleppo button
Delhi boil
Baghdad boil
Jericho boil - Leishmania braziliensis
Mucocutaneous leishmaniasis - skin and mucous membrane
Espundia
New world leishmaniasis
Visceral Leishmaniasis
Leishmania parasites are phagocytosed (engulfed) by immune cells.
Few parasites in the blood, but large numbers inside immune cells (reticuloendothelial cells) in:
Spleen
Liver
Lymph nodes
Bone marrow
Intestinal mucosa
Symptoms (Clinical Manifestations):
Fever
Malaise
Loss of appetite
Diarrhea & Cough.
Hepatomegaly
Splenomegaly
Lymphadenopathy
Anemia
Skin darkening (gives the name “Kala-azar,” meaning “black fever”).
Ulceration in the skin leaving an ugly scar
- Cutaneous leishmaniasis
In severe cases, the skin becomes thickened, resembling lepromatous leprosy.
Lesions do not heal on their own without treatment.
Initial lesion at the bite site is papule that later develops into an ulcer.
- Mucocutaneous leishmaniasis
BEGINS
Metastatic spread may occur on the oronasal and pharyngeal mucosa (mucous membranes in the nose, mouth, and throat)
SERVERE
“Tapir Nose” → Massive tissue destruction & swelling in the nose and face, similar to leprosy.
highly disfiguring leprosy like tissue destruction and swelling on the oronasal
Tapir nose
DIAGNOSIS FOR LEISHMANIA
- Iemsa or Wright’s stained smear
- specimen : skin lesion biopsies or aspirates - Specimen can be culture
- Nicole, Novy, Mac Neal (NNN) culture medium
- Schneider;s
- Drosophila medium - Montenegro skin test
- Aka “Leishman skin test”
- Intradermal injections of a suspension or killed promastigotes.
(Wheal formation indicated an infection - Redness at the site of injection) - Formol-gel test - screening test
- Use of 0.1ml serum + 1 drop of formalin = gel formation
- Positive result is gel formation
5.Serological tests
- CFT - complement fixation test
- FAT - fluorescent antibody test
- Counter-current electrophoresis
enlargement of lymph nodes at cervical region
Winterbottom’s sign
- more common in T. brucei gamebiense
muscle pain -
joint pain -
myalgia
arthralgia
2 classic signs that you know it is chronic in T. brucei group
Sleeping sickness- the hallmark of the disease (severe disturbances in sleep patterns)
Kerandel’s sign - delayed pain
