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Biology of the schizont: Difference between revisions

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'''Navigation'''</br>
'''Navigation'''</br>
<span style="font-size:90%">[[MalariaETC Index|Main malaria Index]]''</span></br>
<span style="font-size:90%">>[[Malaria_Index|Main Malaria Index]]''</span></br>
<span style="font-size:90%">>>[[Rapid diagnostic tests (RDTs)|Malaria biology main page]]''</span></br>
<span style="font-size:90%">>>[[Malaria_Biology|Malaria Biology Index]]''</span></br>
<span style="font-size:90%">This page: '''The Schizont Pathway'''</span>
<span style="font-size:90%">>>>Current page: '''Schizont Biology'''</span>


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<span style="font-size:160%; color:navy">How Malaria RDT Tests Work</br></span>
<span style="font-size:160%; color:navy">Biology of the Schizont</br></span>
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{| class="wikitable" style="border-style: solid; border-width: 5px; border-color: #023020; color:black"
|colspan="1" style = "font-size:100%; color:black; background: #afbddb |'''The schizont pathway'''
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The stage begins with the first cycle of '''asexual replication''' forming a recognisable “schizont” then concludes when the individual “merozoites” are released to infect new erythrocytes.
The stage begins with the first cycle of '''asexual replication''' forming a recognisable “schizont” then concludes when the individual “merozoites” are released to infect new erythrocytes.
<gallery mode="nolines" widths=300px heights=600px>
File:Blood_stages_schizonts_only.jpg|<span style="font-size:80%">''Basic schizont development (coloured images)''</span>|link={{filepath:Blood_stages_schizonts_only.jpg}}
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|colspan="1" style = "font-size:100%; color:black; background: #afbddb |'''Merozoite release'''
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|colspan="1" style = "font-size:100%; color:black; background: #afbddb |'''Morphological features and relevance'''
|colspan="1" style = "font-size:100%; color:black; background: gainsboro|'''Morphological features and relevance'''
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<span style="font-size:200%">&#x2192;</span> [[Click for images of schizont morphology|Click for clinical images illustrating schizont development]]
<span style="font-size:10%"></span> The progressive maturation of this parasite stage means that they have a wide range of morphological forms. However, these can be readily recognised on blood films by reference to their biology
 
[ [[Images of schizont morphology|See clinical images illustrating schizont development]] ]


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|colspan="1" style = "font-size:100%; color:black; background: #afbddb |'''Relevance of schizonts to clinical biology'''
|colspan="1" style = "font-size:100%; color:black; background: gainsboro |'''Relevance of schizonts to clinical biology'''
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Latest revision as of 18:02, 6 November 2024

Navigation
>Main Malaria Index
 >>Malaria Biology Index
 >>>Current page: Schizont Biology

Biology of the Schizont


The stage begins with the first cycle of asexual replication forming a recognisable “schizont” then concludes when the individual “merozoites” are released to infect new erythrocytes.

  • Formation and release of merozoites

    Formation and release of merozoites


(1) The stage begins with the first cycle of asexual division producing two chromatin masses
(2) This is followed by further cycles of replication
(3) In this case this results in the formation of 8 daughter parasites
(4) The daughter parasites mature and the red cell ruptures to release the “merozoites”
(5) The released merozoites very rapidly infect new red cells (so rapid that free merozoites will not usually be seen in blood).

Morphological features and relevance


(1) The number of replication cycles differs between species: the typical number of merozoites formed differs between species with as few as 8 (in P.malariae) up to a possible 32 (in P.vivax)
(2) This stage may not always occur in blood: schizonts of P.falciparum adhere within the small vessels so is not seen in blood unless infection is very severe

  • Mature schizont releasing merozoites

    Mature schizont releasing merozoites

The progressive maturation of this parasite stage means that they have a wide range of morphological forms. However, these can be readily recognised on blood films by reference to their biology

[ See clinical images illustrating schizont development ]

Relevance of schizonts to clinical biology


The release of merozoites from schizonts exposes the body to large amounts of free parasite antigens no longer contained within the erythrocytes - the result is an immune response causing high fever and illness symptoms. In some cases the development of parasites is synchronous so that all schizonts mature and release their merozoites at the same time - although rarely seen now, this pattern of development may produce a pattern of remitting fever with a distinct periodicity depending on species: underlying the older descriptive terms tertian or quartan malaria.

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