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Re-infection of the mosquito: Difference between revisions

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'''Navigation'''</br>
'''Navigation'''</br>
<span style="font-size:80%">(click blue highlighted text to return to page)</span></br></br>
<span style="font-size:90%">>[[Malaria_Index|Main Malaria Index]]''</span></br>
<span style="font-size:90%">[[Malaria Index|Malaria main index]]</span></br>
<span style="font-size:90%">>>[[Malaria_Biology|Malaria Biology Index]]''</span></br>
<span style="font-size:90%">>[[Malaria Biology|Basic malaria biology]]</span></br>
<span style="font-size:90%">>>>Current page: '''Sexual replication'''</span>
<span style="font-size:90%">>>This page: <u>''Re-infection of the mosquito</u></span>
 
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<span style="font-size:160%; color:navy">The initial infection of the host</br></span>
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<gallery mode="nolines" widths=300px heights=300px>
File:Mosquito uptake.jpg|<span style="font-size:90%">''Development within the the mosquito''</span>|link={{filepath:Mosquito uptake.jpg}}
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When a mosquito feeds from a malaria infected host, the blood meal will contain parasites of all forms. Importantly these forms include male and female gametocytes. The pH and temperature changes with the mosquito midgut cause the gametocytes to gain full sexual maturity (gametogenesis). The male gametocyte then undergoes 3 cycles of division to generate 8 male sexual forms (gametes). These then 8 gametes then "break out" of the male microgametocytes in a process known as exflagellation, and fuse with the female oocyte (derived from the macrogametocyte). Then following successful fusion move to the next stage of development with the mosquito gut wall. Finally the parasite enter the salivary glands of the mosquito as sporozoites where a new infection can be initiated. 
 
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|colspan="1" style = "font-size:100%; color:black; background: #afbddb |'''Re-infection'''
|colspan="1" style = "font-size:100%; color:black; background: gainsboro |'''Relevance to blood'''
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File:Liver 0.jpg|<span style="font-size:90%">''Infection of the mosquito''</span>|link={{filepath:Liver 0.jpg}}
If samples of blood undergo delayed spreading then the changes to pH and temperature caused by storage may partly mimic the conditions within the mosquito midgut leading to changes that would only normally be seen in the mosquito. Some may be difficult to recognise but are clearly atypical in appearance, others such as "exflagellation" have very clear appearances. It is important to be able to recognise these forms as they can cause confusion and mis-diagnosis.
 
 
 
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<span style="font-size:90%">''The gametes of ''P.falciparum'' are seen in the process of exflagellation from  the male gametocyte in a sample that has undergone delayed processing''</span>
<span style="font-size:200%">&#x2192;</span>[[Images of gametocyte development in stored blood|Click for additional clinical images]]


The initial mosquito bite (Image A): blood from the host is taken through as mosquito mouthparts (m) from small vessels (v). At the same time fluid from mosquito salivary glands passes into the vessel. If a mosquitos is host to the malaria organism then parasites enter the blood with this saliva (in the form of '''"sporozoites"''' (sp)). 


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[[Storage changes in malaria]]

Latest revision as of 18:36, 2 November 2024


Navigation
>Main Malaria Index
>>Malaria Biology Index
>>>Current page: Sexual replication


The initial infection of the host


When a mosquito feeds from a malaria infected host, the blood meal will contain parasites of all forms. Importantly these forms include male and female gametocytes. The pH and temperature changes with the mosquito midgut cause the gametocytes to gain full sexual maturity (gametogenesis). The male gametocyte then undergoes 3 cycles of division to generate 8 male sexual forms (gametes). These then 8 gametes then "break out" of the male microgametocytes in a process known as exflagellation, and fuse with the female oocyte (derived from the macrogametocyte). Then following successful fusion move to the next stage of development with the mosquito gut wall. Finally the parasite enter the salivary glands of the mosquito as sporozoites where a new infection can be initiated.



Relevance to blood

If samples of blood undergo delayed spreading then the changes to pH and temperature caused by storage may partly mimic the conditions within the mosquito midgut leading to changes that would only normally be seen in the mosquito. Some may be difficult to recognise but are clearly atypical in appearance, others such as "exflagellation" have very clear appearances. It is important to be able to recognise these forms as they can cause confusion and mis-diagnosis.


The gametes of P.falciparum are seen in the process of exflagellation from the male gametocyte in a sample that has undergone delayed processing


Click for additional clinical images