Lec47 Kinetoplasts and Toxoplasma

Question 1

What is the vector of leishmania species?

Answer 1

• sandlfy [luczomya, phelbotomine species]

Question 2

What is the parasite and vector of chagas disease?

Answer 2

• parasite: trypanosoma cruzi

- vector: kissing or riduviid bug [triatoma species]

Question 3

What is the parasite and vector of sleeping sickness?

Answer 3

parasite: trypanosoma brucei Gambiense or Trypanosoma brucie Gambiense
vector: tsetse fly

Question 4

What is life cycle of leishmania?

Answer 4

• sandfly takes blood, injected promastigote stage into skin
• promastigotes phagocyttized by macrophages
• matures inside macrophages
• multiplies in cells of various tissues
• sandfly takes blood meal and ingests infected macrophages
• ingestion of parasitized cell
• parasite matures in sandfly

Question 5

What clinical signs of leishmania?

Answer 5

• spectrum of presentations –> can be cutaneous, mucocutaneous, visceral
• painless ulcers with surrounding erythema

Question 6

Where does leishmania occur?

Answer 6

• Africa, central and south america, europe, asia, middle east
• 15 million infected

Question 7

What cells does leishmania infect?

Answer 7

its in intracellular parasite –> infects mononuclear phagocytes and leukocytes

Question 8

What is reservoir host for leishmania?

Answer 8

rats/rodents, dogs

Question 9

Where do you get cutaneous leishmaniasis? What two species?

Answer 9

south and central america, mexico, a few bands in africa/middle east
Leishmania mexicana
leishmania tropica

Question 10

Where do you get mucocutaneous leishmaniasis? What species?

Answer 10

leishmania braziliensis
south america and india, parts of southern europe
can start as cutaneous then get involvement of mucous membranes

Question 11

Where do you get visceral leishmaniasis? what species? signs?

Answer 11

leishmania donovani
south america, peru, brazil
spreads to liver and spleen

Question 12

What are signs of cutaneous leishmaniasis?

Answer 12

• ulcer at site of sandfly bite
• ulcer can heal within a month
• painless ulcers with surrounding erythema
• at border of ulcer can find intracellular amastigotes

Question 13

What are signs of mucocutaneous leishmaniasis [espundia]?

Answer 13

• species spreads from cutaneous to mucous membranes in nose, oropharynx, larynx
• slow erosive destruction of tisses

Question 14

How do you treat leishmania?

Answer 14

• pentavalent antimonals [sodium stibogluconate or meglumine antimonate]
• 2nd choice: amphotericin B
• miltefosine

Question 15

What are side effects of pentavalent antimonals?

Answer 15

• cardio toxicity
• nephrotoxicity
• pancreatitis
• sterile abscess at injection site

Question 16

What are signs of visceral leishmaniasis [/dum dum fever/kala azar]?

Answer 16

• incubation period 3-8 mos after cutaneous ulcer
• massive heptosplenomegaly
• fever
• skin grayish and dark
  hypergammaglobuliemia, anemia, weight loss

Question 17

How do you diagnose visceral leishmaniasis?

Answer 17

• bone marrow biopsy or splenic aspirate

Question 18

How do you distinguish leishmania amastigotes and histoplasma capsulatum under microscope?

Answer 18

leishmania has kinetoplast = bar-like structure next to nucleus of leishmania protozoa

Question 19

What is geo distribution of T. cruzi?

Answer 19

south america, central america

Question 20

What is life cycle of T. cruzi?

Answer 20

• triatomine bug takes blood meal, passes metacyclic trypomastigotes in feces that enter bite wound or mucoous membrae
• parasite penetrates cells at bite wound site
• parasite matures within cells by binary fission to amastigotes
• trypomastigotes ingested by triatomine bug taking blood meal –> multiply and mature and gut

Question 21

What is sign of acute phase of chagas disease?

Answer 21

romana’s sign [chagoma] = unilateral edema of eye where paraistes have been innoculated

Question 22

What are clinical signs of chronic phase of chagas disease?

Answer 22

= megasyndrome

• cardiomegaly
• paucity of parasitemia, cardiac muscle cells heavily parasitized
• megaesophagus
• megacolon

Question 23

Where do trypomastigotes of chagas disease replicate? is there antigenic variation?

Answer 23

• south american trypanosomiasis ones do not replicate in blood
• do not undergo surface antigenic variation even though elicit intense immune response

Question 24

How do you diagnose south america trypanosomiais?

Answer 24

• peripheral blood smear

- recover by xenodiagnosis [let insect you bread fead on pt and then check insect] and grow in culture

Question 25

How do you treat acute phase of trypanosomiasis cruzi?

Answer 25

- benzinadole or nifurtimox

Question 26

What is mech of action nifurtimox?

Answer 26

- forms oxygen radicals in parasites [south american trypanosomiasis]

Question 27

How is south american trypanosomiasis transmitted?

Answer 27

- feces of riduvid/triatomine bug

Question 28

Where is trypanosoma brucei gambiense found? what kind of sleeping sickness does it cause?

Answer 28

- in central and west africa | - causes chronic diseease

Question 29

Where is trypanosoma brucei rhodesiense found? What kind of sleeping sickness does it cause?

Answer 29

- in east africa | - acute form

Question 30

How is sleeping sickness [african trypanosomiasis] transmitted?

Answer 30

- by tsetse fly in rural endemic foci | - often disease of livestock

Question 31

What is result of sleeping sickness if untreated?

Answer 31

fatal

Question 32

Where do trypomastigotes of sleeping sickness replicate? is there antigenic variation?

Answer 32

- replicate in blood | - undergoes antigenic variation by VSPs [variable surface proteins]

Question 33

What is life cycle of trypanosomiasis?

Answer 33

- tsetse fly takes blood meal and injects trypomastigotes - parasite transforms/multiple in bloodstream/lymph/spinal fluid and travel to different sites then return to blood - tsetse fly takes blood meal and ingests trypmastigotes - in tsetse fly midgut mature

Question 34

What happens in stage 1 of african trypanosomiasis?

Answer 34

- winterbottoms sign: parasites proliferate extracellular at site of inoculation --> have inflammatory nodule - spread to lymphatics/blood stream, have months of waves of parasitemia - mos to yrs later --> penetrate CNS --> fever, nausea, lethargy, headache, facial edema

Question 35

What is unique about pathogenesis of stage 1 sleeping sickness for T. b. rhodesiense?

Answer 35

- more acute course --> myocarditis, CHF, pericardial effusion, pulm edema - may have death in wks to mos often before CNS invation

Question 36

What happens in stage 2 of african trypanosomiasis?

Answer 36

- CNS --> headache, inability to concentrate, personality change, seizure, coma, death - daytime somnolence = disruption of normal circadian rhythm

Question 37

How do you treat east african sleeping sickness [T. b. rhodesiense]? Early? Late?

Answer 37

early: suramin late: melarsoprol

Question 38

How do you treat west african sleeping sickness [T. b. gambiense]? Early? Late?

Answer 38

early: pentamidine late: melarsoprol

Question 39

How do you diagnose african trypanosomiasis?

Answer 39

- peripheral blood smear | - visualization CSF

Question 40

What is definitive host of toxoplasmosis?

Answer 40

- cat --> kitty litter

Question 41

How is toxoplasma transmitted?

Answer 41

- consumption undercooked meats - from cats [kitty litter] - in utero

Question 42

What are clinical signs of toxoplasmosis?

Answer 42

- most common = asymptomatic - acute infection in normal host: mono-type illness, lymphadenopathy - can have progressive infection/reactivation with cellular immune deficiency --> encephalitits, pneumonia, retinal disease

Question 43

How do you get congenital toxoplasmosis?

Answer 43

- new infection occurs in woman during pregnancy - usually neonatal infection = subclinical - may progress to cause mental retardation, hydrocephalus, blindness

Question 44

What is toxoplasmosis chorioretinits?

Answer 44

- can occur in congenital infection or in acquired infection in normal or compromised host

Question 45

How do you diagnose toxoplasmosis?

Answer 45

- ring enhancing lesions in brain

Question 46

What are two things that show ring enhancing lesions in brain on CT?

Answer 46

- toxoplasmosis | - CNS lymphoma

Question 47

What does toxocara canis normally infect?

Answer 47

a nematode that normally infects dogs | kids who play in sandbox can get it

Question 48

What is clinical effect of toxocara canis?

Answer 48

- in humans can disseminate and cause visceral larva migrans [VLM]

Question 49

Difference toxocara and toxoplasma?

Answer 49

toxoplasma: protozan parasite toxocara: dog worm

Question 50

What is botfly?

Answer 50

- botfly = dermatobium hominus - captures a mosquito and glues her eggs to the abdomen, when mosquito feeds --> eggs drop, hatch, burrow in skin - causes tender erythematous expanding lesion with breathing hole