02. Protozoan infection

• • are not classified under kingdom animalia but under kingdom protista
  • main feature is they are unicellular eukaryotes
  • measured in micron: 1 um = 1/1000mm
  • complex subcellular organization
  • first described some 300+ years ago by leeuwenhoek when he described giardia from his own intestines


  parasitic protozoa
• parasitic protozoa are not classified under kingdom animalia but under kingdom protista
• parasitic protozoa's main feature is they are unicellular eukaryotes
• parasitic protozoa is very small, measured in micron: 1 um = 1/1000mm
• parasitic protozoa are complex subcellular organization
• parasitic protozoa are first described some 300+ years ago by leeuwenhoek when he described giardia from his own intestine
• • 30,000 living species
  • 30% are parasitic
  • all plants and animals have at least one protozoan parasite
  • importance in agriculture/veterinary/aquaculture - loss of productivity and death


  parasitic protozoa
• what are the four types of organism?


  flagellated protozoa - mastigophora

  amoeba - sacordina

  celiated protozoa - ciliophora

  apicomplexa - sporozoans
• types of nutrition


  autotrophic - holophytic or photosynthetic

  heterotrophic
• which are found in many cnidaria and other invertebrates are the best examples of these symbiots

  zooxanthellae
• two types of heterotrophic


  holozoic nutrition

  saprozoic nutrition
• reproduction in the protozoa - asexual reproduction


  binary fission

  multiple fission, merogony or schizogony
• reproduction of the protozoa - sexual reproduction

  gametogony

  syngamy

  conjugation
• what are the two types of giardia lamblia?

  lamblia intestinalis

  giardia duodenalis
• colonizes and reproduces in the small intestine causing giardiasis

  giardiasis lamblia
• giardia lamblia is attached to the epithelium by a ventral adhesive disc and reproduces by a binary fission
• in giardia lamblia trophozoites absorb their nutrients from the lumen of small intestine
• giardia lamblia lacks of

  mitochondria
• giardia lamblia is an


  anaerobic
• how long is trophozoites?

  9-12 um long by 5-15 wide
• • 9-12 um long by 5-15 wide
  • large karyosomes
  • binucleated
  • pyriform or tear-drop shaped
  • bilaterally symmetrical, with a midline called axostyle
  • tumbling motion by 4 pairs of flagella
  • found in diarrheic stools


  trophozoites of giardia lamblia
• • retracted cytoplasm
  • tough hyaline cyst wall
  • ovoid, 8-12 long by 7-10 um wide
  • 4 nuclei
  • flagella retracted into axonemes
  • deeply stained fibrils


  cysts of giardia lamblia
• • colonization leads to reduction of gut's absorptive capabilitysymptoms: diarrhea, malaise, excessive gas, epigastric pain, bloating, nausea, lost of appetitesteatorrhea - pale, foul, smelling, greasy stoolssymptomatology giardia lamblia

  • symptoms: diarrhea, malaise, excessive gas, epigastric pain, bloating, nausea, lost of appetite
  • steatorrhea - pale, foul, smelling, greasy stools

  symptomatology and pathology of giardia lamblia
• • treatment of drinking water
  • filtration and/or chemical disinfection of available surface water, such as iodine
  • filtering (1 um) or boiling
  • accurate diagnosis - antigen test, fecalysis
  • metronidazole is the current first-line theraphy


  prevention and treatment of giardia lamblia
• how to avoid recreational water illnesses:


  please don't swim when you have diarrhea

  please don't swallow the pool water

  please take a good hygiene
• • trophozoite: morphology
  • oval
  • flagellated
  • barb-like axostyle
  • no cyst form
  • can survive 24 hours in urine, semen, or even water samples


  trichomonas vaginalis
• trichomonas vaginalis geographic distribution

  worldwide

  higher prevalence among persons with multiple sexual partners or other venereal diseases
• • a sexually transmitted disease (STD)
  • the incubation period is 5 to 28 days
  • infection in women is frequently symptomatic
  • basic (pH 5-6) vaginal condition is conducive for growth
  • vaginitis (greenish-yellow frothy vaginal secretions and itching, vulvar and cervical lesions, abdominal pain)
  • in men, the infection is asymptomatic (urethritis, epididymitis, and prostatitis)


  pathology of trichomonas vaginalis
• • wet mount: observation of ''corkscrew'' motility in vaginal discharge
  • pap smear and culturing
  • PCR

  diagnosis of trichomonas vaginalis
• • treatment should include all sexual partners of the infected persons
  • metronidazole and tinidazole


  treatment of trichomonas vaginalis
• greek mastig - meaning whip, referring to the trypanosome's whip-like flagellum


  trypanosomatid
• typical eukaryotic cell, with all major organelles present


  trypanosomatid
• single large mitochondria with a condensed mitochondrial DNA structure, associated with the basal body of the flagellum


  trypanosomatid
• the cell also features a dense coat of variable surface glycoproteins (VSGs)


  trypanosomatid
• enables an infecting t. brucei population to persistently evade the host's immune system, allowing chronic infection


  trypanosomatid
• what are the trypanosomatid cellular forms


  amastigote

  promastigote

  epimastigote

  trypomastigote
• basal body anterior of nucleus, with a short, essentially non-functional, flagellum

  amastigote
• basal body anterior of nucleus, with a long detached flagellum

  promastigote
• basal body anterior nucleus, with a long flagellum attached along the cell body

  epimastigote
• basal body posterior of nucleus, with a long flagellum attached along the cell body

  trypomastigote