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Plasmodium vivax: Morphology: Difference between revisions

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The later growth stage:
The later growth stage:
   
   
*Parasites resemble early ring forms, but are thicker and may be slightly larger
*infected erythrocytes become significantly enlarged and irregular in shape
*Additional blue/grey dots and clefts are seen in red cell cytoplasm when [[stained correctly]]
*parasites lose their ring appearnace becoming irregular and "amoeboid" in form
*These dots have low number a characteristic "dot" or "line" form [[Maurer's dots and clefts]]
*numerous red/purple Schuffners dots are predent in the cytoplasm of red cells  
*[[Red cell size and shape|Size and shape]] of infected red cells is usually unaffected, but may become crenated
*malaria pigment is often present and has an irregular distribution
*The [[Double chromatin dot forms|double dot]], [[Accolé form| accolé]], and [[multiple parasites|multiple parasite]] forms remain present




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*erythrocytes begin to increase size and shape of infected red cells enlarged and distorted during this stage *parasites have a ring form this may be quite irregular *parasites are generally large - occupying up to half of the erythrocyte *cytoplasmic schu8c3bcffneru8e28099s dots may appear at this stage but malaria pigment is not usually seen


the late trophozoite  file pvlt.jpg leftt 200px link filepath pvlt.jpg *infected erythrocytes are clearly significantly enlarged and lose their regular outline *parasites are noticeably irregular becoming amoeboid in form *numerous purple schu8c3bcffneru8e28099s dots are seen in the cytoplasm *pigment is often present with irregular distribution
 


the schizont  file pvs.jpg leftt 200px link filepath pvs.jpg *a range of maturing schizonts will generally be present within enlarged red cells *mature schizonts generally contain 16-24 separate merozoites *schu8c3bcffneru8e28099s dots can be detected in any residual cytoplasm of the erythrocyte *pigment is visible in irregularly distributed clumps over the schizont surface
the schizont  file pvs.jpg leftt 200px link filepath pvs.jpg *a range of maturing schizonts will generally be present within enlarged red cells *mature schizonts generally contain 16-24 separate merozoites *schu8c3bcffneru8e28099s dots can be detected in any residual cytoplasm of the erythrocyte *pigment is visible in irregularly distributed clumps over the schizont surface


the gametocyte  file pvg.jpg leftt 200px link filepath pvg.jpg *very large with ovoid or distorted forms *macrogametocytes female may entirely fill the erythrocyte *microgametocytes male may have a thin cytoplasmic rim with visible schu8c3bcffneru8e28099s dots *pigment is clumped over the surface of the gametocyte
the gametocyte  file pvg.jpg leftt 200px link filepath pvg.jpg *very large with ovoid or distorted forms *macrogametocytes female may entirely fill the erythrocyte *microgametocytes male may have a thin cytoplasmic rim with visible schu8c3bcffneru8e28099s dots *pigment is clumped over the surface of the gametocyte

Revision as of 23:37, 3 April 2024

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The early trophozoite


  • PVETc.jpg
  • PVET main.jpg


The earliest ring forms may be indistinguishable from other species, but during this stage the parasite tends to aquire a more irregular forms and to show signs of modification of the erythrocyte (added dots, and altered size and shape).

  • erythrocytes begin to show increased size and altered shape
  • parasites retain a ring form but may aquire a more irregular form
  • parasites are generally large - occupying up to half of the erythrocyte
  • cytoplasmic Schüffner's dots may appear at this stage, although pigment is less uncommon




The late trophozoite


  • PFLTc.jpg
  • PFLT-main image.jpg



The later growth stage:

  • infected erythrocytes become significantly enlarged and irregular in shape
  • parasites lose their ring appearnace becoming irregular and "amoeboid" in form
  • numerous red/purple Schuffners dots are predent in the cytoplasm of red cells
  • malaria pigment is often present and has an irregular distribution



The schizont


  • PFSc.jpg
  • PFS-main image 2.jpg


The asexual form:

  • Do not generally circulate in this species unless overwhelming infection
  • The asexually formed developing "merozoites" cluster untidily
  • Schizonts develop progressively to form 8-16 merozoites when mature
  • In this species the loose malaria pigment may be seen in clumps between the parasites
  • Red cell size is generally unaffected but red cells become pale as haemoglobin is metabolised by the parasites



The gametocyte

The gametocyte


  • PFGc.jpg
  • PFG-main image.jpg



The sexual replication form (very distinctive).

  • Gametocytes are elongated but are restricted into typical shape by the red cell membrane
  • They parasites are rod shaped but the membrane may cause them to curve into a “"banana" form”
  • The residual membrane (empty of haemoglobin) is often seen as a "blister" to the side of the parasite
  • The single chromatin area is in the centre of the parasite, often has pigment overlying it
  • Gametocytes may not be be seen, or may be the only form present (particularly after treatment)





the schizont file pvs.jpg leftt 200px link filepath pvs.jpg *a range of maturing schizonts will generally be present within enlarged red cells *mature schizonts generally contain 16-24 separate merozoites *schu8c3bcffneru8e28099s dots can be detected in any residual cytoplasm of the erythrocyte *pigment is visible in irregularly distributed clumps over the schizont surface

the gametocyte file pvg.jpg leftt 200px link filepath pvg.jpg *very large with ovoid or distorted forms *macrogametocytes female may entirely fill the erythrocyte *microgametocytes male may have a thin cytoplasmic rim with visible schu8c3bcffneru8e28099s dots *pigment is clumped over the surface of the gametocyte

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