Week 3: Extraintestinal Protozoa Flashcards
What is the malaria vector (give organism and genus)? What is the post-bite incubation time?
Anopheles mosquito
Incubation time post-bite: 8-24 days
What are the 4 main Plasmodium species for malaria?
- P. vivax
- P. falciparum
- P. malariae
- P. Ovale
List the Plasmodium species in order from the one that contributes the most to malarial infections to the one that contributes the least
- P. vivax (80%)
- P. falciparum (15%)
- P. malariae (4%)
- P. Ovale (1%)
Describe the malarial life cycle. Include infective and diagnostic stages
- Mosquito injects sporozoites into human bloodstream (infective)
- Liver gets infected and houses schizonts
- Schizonts rupture and release merozoites
- Merozoites infect RBCs
- Ring stage forms (trophozoite )in RBC (diagnostic)
- Trophs asexually multiply and multiply as merozoites (schizont stage) (also diagnostic)
- Schizonts rupture and release merozoites, thus rupturing RBCs (also diagnostic)
- Merozoites infect other RBCs as trophozoites. Cycle continues
- Some merozoites become gametocytes instead of trophozoites
Define the following:
Schizont
Schuffner’s dots
Merozoites
Gametocyte
Trophozoite
Schizont = multi-nucleated cell that contains merozoites. Rupture releases these daughter merozoites
Schuffner’s dots = Stippling in RBCs
Merozoites = free Plasmodium parasite that infects RBCs. Mature in to trophs or gametocytes
Gametocyte = Sexual precursor cell that mates and undergoes meiosis
Trophozoite = motile, reproductive, feeding stage of parasite. Ring-form for malaria
What are some natural mechanisms of malarial resistance? Does complete immunity exist?
Duffy Ag negative individuals resistant to P. vivax due to change in RBC surface antigens
Sickle cell anemia trait
Complete immunity does not exist
List some malaria symptoms
-Splenomegaly
-dry cough
-vomiting/nausea
-muscle/joint pain
-jaundice
-fever
-shivering
-fatigue
-convulsions
What are the stages of paroxysm?
- Cold (shivering)
- Hot (dry burning sensation of skin + headache)
- Sweating (declining temp, fatigue, weak)
How do you detect and identify malaria?
Thick smear = detection
Thin smear = identification (examine at least 300 fields at 100x)
Identify the following traits of this malarial parasite. Which Plasmodium species is this?
Plasmodium falciparum
*Note that acolé means edge ring
The following is the gametocyte for which malarial species?
Plasmodium falciparum
Identify this malarial parasite and stage (ring, schizont, gametocyte)
P. falciparum ring form
Identify this malarial parasite and stage (ring, schizont, gametocyte)
P. malariae ring form
Identify this malarial parasite and stage (ring, schizont, gametocyte)
P. malariae ring form
Identify this malarial parasite and stage (ring, schizont, gametocyte)
P. malariae schizont
Identify this malarial parasite and stage (ring, schizont, gametocyte)
P. malariae gametocyte
Identify the components in the image. Which ring-form malarial parasite is this?
P. vivax
Identify this malarial parasite and stage (ring, schizont, gametocyte)
P. vivax amoeboid troph
Identify this malarial parasite and stage (ring, schizont, gametocyte)
P. vivax ring-form
Identify this malarial parasite and stage (ring, schizont, gametocyte)
P. vivax schizont
Identify this malarial parasite and stage (ring, schizont, gametocyte)
P. vivax gametocyte
Describe the life cycle of Babesia. Include infective and diagnostic stages
- Mouse tick introduces sporozoites into host bloodstream (infective)
- If asexual, mature in to trophs and produce merozoites in cycle (diagnostic). Transmit via blood-transfusion
- If sexual, mature into trophs, then merozoites, then gametes that fertilize in the tick gut to form sporozoites that ticks can pass on to humans
Which malarial parasite does Babesia resemble?
P. falciparum
Identify the parasite
Babesia
Identify the parasite
Babesia
Identify the parasite
Babesia
Describe the life cycle of Trichomonas vaginalis. Include infective and diagnostic stages
- Trophozoites in vaginal or prostatic secretions and urine (diagnostic)
- Multiplies by longitudinal binary fission
- Trophs in vagina or orifice of urethra (infective stage)
The following is the troph for which parasite?
Trichomonas vaginalis
It has no cyst stage by the way
Identify the parasite
Trichomonas vaginalis
What disease conditions does Trypanosoma cause?
Sleeping sickness (brucei) and Chagas’ disease (cruzi)
Describe the Leishmaniasis life cycle (include vector of transmission). Include infective and diagnostic stages
- Sandfly injects promastigote into skin and introduces parasite (infective stage)
- Mononuclear cells (such as macrophages) phagocytose promastigotes
- Promastigotes survive to transform into amastigotes, meaning macrophages are now infected (diagnostic stage)
- Amastigotes multiply in cells of various tissues and infect other cells (also diagnostic)
- Sandfly takes blood meal, thus ingests infected macrophages
- Amastigotes transform into promastigote stage in sandfly gut
- Promastigotes divide and migrate to proboscis
- Repeat cycle
Identify the parasite and stage of life cycle
Leishmania spp. amastigote
Identify the parasite and stage of life cycle
Leishmania spp. promastigote (not found in humans. This stage happens in sandfly gut)
Describe the Trypanosoma brucei life cycle (include vector of transmission). Include infective and diagnostic stages
- Infective stage: Tsetse fly takes blood meal and introduces metacyclic trypomastigotes
- Metacyclic trypomastigotes transform into bloodstream trypomastigotes and travel to various sites
- Trypomastigotes multiply by binary fission in various bodily fluids (e.g., blood, lymph, and spinal fluid)
- Diagnostic stage: Circulating trypomastigotes in blood during acute phase - usually undetectable in latent phase
- Tsetse fly takes blood meal (bloodstream trypomastigotes ingested)
- In the tsetse gut, trypomastigotes transform into procyclic trypomastigotes
- Procyclic trypomastigotes leave the midgut and transform into epimastigotes
- Epimastigotes multiply in fly salivary gland, where they transform into metacyclic trypomastigotes
- Repeat cycle
Identify the parasite and life cycle stage
Trypanosoma brucei bloodstream trypomastigote
Describe the Trypanosoma cruzi life cycle (include vector of transmission). Include infective and diagnostic stages
- Infective stage: Triatomine “kissing” bug takes blood meal BUT introduces metacyclic trypomastigotes through its feces, which enter the bite wound
- Metacyclic trypomastigotes get into various cell types at bite site
- Amastigotes multiply by binary fission inside infected cells
- Diagnostic stage: Intracellular amastigotes transform into trypomastigotes, then rupture cell to exit into bloodstream
- Triatomine bug takes blood meal and ingests trypomastigotes
- Trypomastigotes transform in to epimastigotes in bug gut
- Epimastigotes multiply in midgut
- Metacyclic promastigotes in hindgut
- Repeat cycle
ID the following parasite in the image
Trypanosoma cruzi
What’s the name of the bug vector for Trypanosoma cruzi that the CDC calls triatomine but Darrell calls ______ in his Ppoint?
Reduviid bug
What’s an amastigote?
Small, ovoid, non-flagellated form
What’s an epimastigote?
Flattened, spindle shaped, flagellated form seen in gut, or saliva of vector
What’s a trypomastigote?
Flagellate form w/ kinetoplast at posterior end and undulating membrane
extending along entire body
Describe the Naegleria fowleri life cycle. Include diagnostic and infective stages
- Cyst
- Infective stage: Becomes trophozoite
- Transform into flagellated form
- Promitosis
- Amoebae penetrate nasal mucosa (typical in water sports)
- Diagnostic stage: Trophs in CSF and brain tissue
Identify the parasite in the image. Indicate stage
Naegleria fowleri trophozoite
Describe the Acanthamoeba lifecycle. Include infective and diagnostic stages
- Cysts
- Infective stage: Transform into trophozoites
- Mitosis
- Amoeba trophs enter human body through
-eye
-nasal passages to lower respiratory tract
-ulcerated or broken skin - Can result in
-eye keratosis
-granulomatous amoebic encephalitis
ID the following parasite
Acanthamoeba
