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Synchronicity Index: Difference between revisions

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<span style="font-size:90%>In some malaria infections (particularly with Plasmodium falciparum or with Plasmodium knowlesi) there may be only a single parasite stage visible in blood – this is most often early trophozoites. This process is partly a reflection of the interesting phenomenon of “synchronicity” of parasite development.  
<span style="font-size:90%>In some malaria infections (particularly with ''P.falciparum'' or with ''P.knowlesi'') there may be only a single parasite stage visible in blood – this is most often the early trophozoite stage. This process is partly a reflection of the interesting phenomenon of “synchronicity” of parasite development.</br></br></span>
IMAGE
IMAGE
While the precise reasons and mechanisms of synchronicity are not fully clear, the biological effects can be clearly seen in some cases where the stages of invasion of erythocytes, their asexual replication, then their escape from schizonts each occur in unison. The process appears to reflect the circadian rhythms of the host both in gene expression and in behaviour and results in parasites in the blood reflecting only a single stage.  
<span style="font-size:90%>While the precise reasons and mechanisms of synchronicity are not fully clear, the biological effects can be clearly seen in some cases where the stages of invasion of erythrocytes, their asexual replication, then their escape from schizonts each occur in unison. The process appears to reflect the normal circadian rhythms of host hormones, with changes seen to affect both in gene expression and parasite behaviour. This synchronicity results in parasites in blood reflecting only a single stage. </br></br>
It is thought that fevers in malaria correspond to the sudden antigen load seen during schizont release
<span style="font-size:90%>It is thought that the fevers in malaria are caused by the sudden antigen load that occurs during schizont release</br></br>
IMAGE.
IMAGE.
When schizont release is synchronous this can lead to the recognised phenomena of periodic fevers in malaria e.g. in P. falciparum infection untreated individuals may exhibit fever cycles, with a 48-hour cycle so the periodicity of fever is tertian (“tertian malaria”), whereas in P malariae disease, fever occurs every 72 hours (“quartan malaria”). This is not absolute with some infections appearing synchronous and others
<span style="font-size:90%>Therefore, when schizont release is synchronous it can lead to the recognised phenomena of periodic fevers: e.g. in ''P.falciparum'' infection untreated individuals may exhibit fever cycles,with a 48-hour cycle so the periodicity corresponding to periods of abrupt schizont release (“tertian malaria”). This is not absolute with some infections appearing synchronous and others not.</br>

Revision as of 17:09, 5 December 2024


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Synchronour development of parasites

In some malaria infections (particularly with P.falciparum or with P.knowlesi) there may be only a single parasite stage visible in blood – this is most often the early trophozoite stage. This process is partly a reflection of the interesting phenomenon of “synchronicity” of parasite development.

IMAGE While the precise reasons and mechanisms of synchronicity are not fully clear, the biological effects can be clearly seen in some cases where the stages of invasion of erythrocytes, their asexual replication, then their escape from schizonts each occur in unison. The process appears to reflect the normal circadian rhythms of host hormones, with changes seen to affect both in gene expression and parasite behaviour. This synchronicity results in parasites in blood reflecting only a single stage.

It is thought that the fevers in malaria are caused by the sudden antigen load that occurs during schizont release

IMAGE. Therefore, when schizont release is synchronous it can lead to the recognised phenomena of periodic fevers: e.g. in P.falciparum infection untreated individuals may exhibit fever cycles,with a 48-hour cycle so the periodicity corresponding to periods of abrupt schizont release (“tertian malaria”). This is not absolute with some infections appearing synchronous and others not.