HP Lecture 5

• kinetoplastid protozoa

  • NTD
  • HAT, AT, leishmaniasis
  • vector borne disease
  • tsetse fly; assassin or kissing bug: adult male, female, juvenile suck blood
  • sandly: adult female suck blood
• HAT: human african trypanosomiasis (sleeping sickness)

  AT: american trypanosomiasis (chagas)

  leishmaniasis: cutaneous, mucocutaneous, visceral (liver/spleen)
• classification of kinetoplastid protozoa (KP)

  • excavates
  • euglenozoa: euglena w/ chloroplast
  • kinetoplast: mito
  • glycosome: glycolysis (in organelle)
  • diff. forms: amastigote, promastigote, epimastigote, trypomastigote undulating mmbr)
• KP

  • hemoflagellate: require heme
  • heteroxenous: NTD infectious agents
  • monoxenous: opportunistic in aids patients
  • salivaria: anterior station (HAT)
  • stercoraria: posterior station (AT)
• unique features of protozoa

  molecule: trypanothione

  organelles: glycosome, kinetoplast

  molec. bio: nuclear gene exp.; polycistronic transcription, trans-splicing

  mito gene exp.- rna editing
• trypanothione

  • glutathione in mammals for detoxification
  • spermidine is a polyamine
  • in trypanosomatids, 2 glutathiones linked to 1 spermindine to form trypanothione
• nuclear gene exp

  • spliced leader
  • mini-exon RNA
  • trans-splicing: exons from 1+ pre-mrna
  • post-transcriptional control
  • RNA binding prtn and gene reg.
  • bacterial operon
• mito gene exp.

  • rna editing
  • kintoplast DNA stuct. (kDNA)
  • maxicircle DNA (20-50 copies, kb)
  • minicircle DNA (10,000 copies, less kb): guide RNA introduce rna editing
  • concatemers: long repetitive dna seq
  • editosome
• KP

  free-living species: bodo saltans (very sim. but no concatemers)
• trypanosoma brucei

  • sub-sahara africa
  • WHO: elimination of HAT as a public health problem by 2020 (plus interruption of transmission by 2030
  • 2 human diseases
  • tsetse fly vector (male and female adults)
• History:

  european colonization in africa; they had less immune response than locals

  nagana and fly disease: david and mary bruce

  1901- castellani

  1903- Bruce (synpatry)

  1803- winterbottom- winterbottom's sign (neck)

  1881- evans- surra in camels and horses

  1901- dutton
• lifecycle

  • extracellular
  • blood and (CSF- cerebrospinal fluid)
  • adipose tissue reservoir
  • fly procyclic form: procyclin
  • fly metacyclic form: infective
  • mammalian bloodstream form: long slender and short stumy, VSG (variant surface glycoprtn)
  • proline and glucose metabolism
• pathology and diagnosis

  • early- hemolymphatic phase
  • late- meningo-encephalitic phase
  • presence of protozoa in blood/csf/adipose tissue
• therapy:

  • suramin
  • pentamidine
  • melasoprol- PTRE
  • eflornithine- DFMO
  • DNDi
  • NECT
  • fexinidazole (1st oral treatment; late stage of gambian HAT)
• genome

  • 11 pairs mega chr.
  • thousands of genes
  • 900 pseudogenes
  • 806 VSG genes
  • paraflagellar rod and tubulin genes
  • Tbb and Tbg genes 99.2% seq. identity
• variant surface glycoprtn (VSG)

  • homodimer
  • GPI linkage
  • hundreds of AA in size
  • 10 mil VSG molec. on cell surface
  • agent for antigenic variation to evade host immune response
• antigenic variation

  • change of VSG on cell surface
  • telomere (repeats)
  • 14 ES
  • presence of 70 bp repeat at VSG exp. site
  • ESAG
  • 1 ESB
  • 1 activation per 100 cell doubling
  • epigenetic control, telomeric location, transcription by RNAP 1
• HAT human genetic

  • HDL
  • TLF
  • apoL1 and A1
  • TBR: SRA
  • Tbg: TgsGP
  • kidney diseases in african americans
• vector control

  • tsetse fly- prefer blue/black color
  • glossina
  • SIT (sterile insect technique)
  • blue-black trap
• chagas disease

  • trypanosoma cruzi
  • AT
  • globalization of CD
  • 7 million got sick
• vector

  • assassin bug; kissing bug; conenose bug
  • babiero (barber bug); vinchuca (fall to ground)
  • reduviid/triatomine bug
  • triatoma infestans, rhodnius proxilus, panstrongylus megistus
  • charles darwin: voyage of beagle
• History of chagas

  • 1909 Chagas
  • Cruz: today FIOCRUZ brazil
  • berenice 22 month old girl and her cat
  • 27 years after chagas death
  • died at 73
  • chagas didn't get everything correct
• lifecycle of Chagas

  • transmission beyond bugs: transfusion, organ transplant, foodborne (consumption sugar cane juice w/ crushed infected kissing bug), transplacental transmission
  • blood test; treat blood w/ crystal violet in endemic areas
  • humans: amastigotes, trypomastigotes
  • kissing bug: trypomastigotes, epimastigotes
• Pathology

  • auto-inoculation
  • romana's sign- 1935 romana
  • chagoma
  • acute and chronic
  • myocarditis
  • mega syndrome
  • CD causes 70% cardiac deaths of young adults in endemic areas
• diagnosis

  • presence of parasites in blood
  • xenodiagnosis
• therapy:

  nifurtimox; benznidazole; fexinidazole; benzoxaboroles; proteasome inhibitors
• genome

  • aboute 12000 genes
  • 41 chr pairs
  • gene families (w/ pseudogenes)
  • trans-sialidase: 693 pseudo
  • mucin-associated surface prtn: 433 pseudo
  • family of novel kinetoplastid myosins
  • calreticulin (TcCalr): virulence factor
• Tc Types:

  • original 2 groups: I (opossum) and II (placentals)
  • 6 groups or DTU (direct typing units)
  • TcI (from original I)
  • TcII to TcVI (all from original II)
  • CD pathogen: evolved from bat trypanosome
  • Tm closely related to TcI
  • bat seeding hypo
• vector control

  • pyrethroid: synthetic version
  • natural pyrenthrum
  • pilar mateo: parasite paint
  • bolivia
  • countries free of vectorial and transfusional
  • manipulation of kissing bugs and trypanosoma cruzi: puppets and puppeteer?