Lec47 Kinetoplasts and Toxoplasma Flashcards
What is the vector of leishmania species?
- sandlfy [luczomya, phelbotomine species]
What is the parasite and vector of chagas disease?
- parasite: trypanosoma cruzi
- vector: kissing or riduviid bug [triatoma species]
What is the parasite and vector of sleeping sickness?
parasite: trypanosoma brucei Gambiense or Trypanosoma brucie Gambiense
vector: tsetse fly
What is life cycle of leishmania?
- 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
What clinical signs of leishmania?
- spectrum of presentations –> can be cutaneous, mucocutaneous, visceral
- painless ulcers with surrounding erythema
Where does leishmania occur?
- Africa, central and south america, europe, asia, middle east
- 15 million infected
What cells does leishmania infect?
its in intracellular parasite –> infects mononuclear phagocytes and leukocytes
What is reservoir host for leishmania?
rats/rodents, dogs
Where do you get cutaneous leishmaniasis? What two species?
south and central america, mexico, a few bands in africa/middle east
Leishmania mexicana
leishmania tropica
Where do you get mucocutaneous leishmaniasis? What species?
leishmania braziliensis
south america and india, parts of southern europe
can start as cutaneous then get involvement of mucous membranes
Where do you get visceral leishmaniasis? what species? signs?
leishmania donovani
south america, peru, brazil
spreads to liver and spleen
What are signs of cutaneous leishmaniasis?
- 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
What are signs of mucocutaneous leishmaniasis [espundia]?
- species spreads from cutaneous to mucous membranes in nose, oropharynx, larynx
- slow erosive destruction of tisses
How do you treat leishmania?
- pentavalent antimonals [sodium stibogluconate or meglumine antimonate]
- 2nd choice: amphotericin B
- miltefosine
What are side effects of pentavalent antimonals?
- cardio toxicity
- nephrotoxicity
- pancreatitis
- sterile abscess at injection site
What are signs of visceral leishmaniasis [/dum dum fever/kala azar]?
- incubation period 3-8 mos after cutaneous ulcer
- massive heptosplenomegaly
- fever
- skin grayish and dark
hypergammaglobuliemia, anemia, weight loss
How do you diagnose visceral leishmaniasis?
- bone marrow biopsy or splenic aspirate
How do you distinguish leishmania amastigotes and histoplasma capsulatum under microscope?
leishmania has kinetoplast = bar-like structure next to nucleus of leishmania protozoa
What is geo distribution of T. cruzi?
south america, central america
What is life cycle of T. cruzi?
- 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
What is sign of acute phase of chagas disease?
romana’s sign [chagoma] = unilateral edema of eye where paraistes have been innoculated
What are clinical signs of chronic phase of chagas disease?
= megasyndrome
- cardiomegaly
- paucity of parasitemia, cardiac muscle cells heavily parasitized
- megaesophagus
- megacolon
Where do trypomastigotes of chagas disease replicate? is there antigenic variation?
- south american trypanosomiasis ones do not replicate in blood
- do not undergo surface antigenic variation even though elicit intense immune response
How do you diagnose south america trypanosomiais?
- peripheral blood smear
- recover by xenodiagnosis [let insect you bread fead on pt and then check insect] and grow in culture
How do you treat acute phase of trypanosomiasis cruzi?
- benzinadole or nifurtimox
What is mech of action nifurtimox?
- forms oxygen radicals in parasites [south american trypanosomiasis]
How is south american trypanosomiasis transmitted?
- feces of riduvid/triatomine bug
Where is trypanosoma brucei gambiense found? what kind of sleeping sickness does it cause?
- in central and west africa
- causes chronic diseease
Where is trypanosoma brucei rhodesiense found? What kind of sleeping sickness does it cause?
- in east africa
- acute form
How is sleeping sickness [african trypanosomiasis] transmitted?
- by tsetse fly in rural endemic foci
- often disease of livestock
What is result of sleeping sickness if untreated?
fatal
Where do trypomastigotes of sleeping sickness replicate? is there antigenic variation?
- replicate in blood
- undergoes antigenic variation by VSPs [variable surface proteins]
What is life cycle of trypanosomiasis?
- 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
What happens in stage 1 of african trypanosomiasis?
- 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
What is unique about pathogenesis of stage 1 sleeping sickness for T. b. rhodesiense?
- more acute course –> myocarditis, CHF, pericardial effusion, pulm edema
- may have death in wks to mos often before CNS invation
What happens in stage 2 of african trypanosomiasis?
- CNS –> headache, inability to concentrate, personality change, seizure, coma, death
- daytime somnolence = disruption of normal circadian rhythm
How do you treat east african sleeping sickness [T. b. rhodesiense]? Early? Late?
early: suramin
late: melarsoprol
How do you treat west african sleeping sickness [T. b. gambiense]? Early? Late?
early: pentamidine
late: melarsoprol
How do you diagnose african trypanosomiasis?
- peripheral blood smear
- visualization CSF
What is definitive host of toxoplasmosis?
- cat –> kitty litter
How is toxoplasma transmitted?
- consumption undercooked meats
- from cats [kitty litter]
- in utero
What are clinical signs of toxoplasmosis?
- 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
How do you get congenital toxoplasmosis?
- new infection occurs in woman during pregnancy
- usually neonatal infection = subclinical
- may progress to cause mental retardation, hydrocephalus, blindness
What is toxoplasmosis chorioretinits?
- can occur in congenital infection or in acquired infection in normal or compromised host
How do you diagnose toxoplasmosis?
- ring enhancing lesions in brain
What are two things that show ring enhancing lesions in brain on CT?
- toxoplasmosis
- CNS lymphoma
What does toxocara canis normally infect?
a nematode that normally infects dogs
kids who play in sandbox can get it
What is clinical effect of toxocara canis?
- in humans can disseminate and cause visceral larva migrans [VLM]
Difference toxocara and toxoplasma?
toxoplasma: protozan parasite
toxocara: dog worm
What is botfly?
- 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
