Malaria causes: Difference between revisions
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==Causes== | ==Causes== | ||
'' P. vivax'' is the most common cause of infection, responsible for about 80 % of all malaria cases. However, ''P. falciparum'' is the most important cause of disease, and responsible for about 15% of infections and 90% of deaths.<ref>{{cite journal | author = Mendis K, Sina B, Marchesini P, Carter R | title = The neglected burden of Plasmodium vivax malaria. | url=http://www.ajtmh.org/cgi/reprint/64/1_suppl/97.pdf | journal = Am J Trop Med Hyg | volume = 64 | issue = 1-2 Suppl | pages = 97-106 | year = 2001 | pmid = 11425182}}</ref> | '' P. vivax'' is the most common cause of infection, responsible for about 80 % of all malaria cases. However, ''P. falciparum'' is the most important cause of disease, and responsible for about 15% of infections and 90% of deaths.<ref>{{cite journal | author = Mendis K, Sina B, Marchesini P, Carter R | title = The neglected burden of Plasmodium vivax malaria. | url=http://www.ajtmh.org/cgi/reprint/64/1_suppl/97.pdf | journal = Am J Trop Med Hyg | volume = 64 | issue = 1-2 Suppl | pages = 97-106 | year = 2001 | pmid = 11425182}}</ref> The remainder of human malaria infections are caused by ''P. ovale'', ''P. malariae'', and ''P. knowlesi.'' | ||
The following table distinguishes between the different strains of ''Plasmodium'' species, all of which are causative agents of malaria infection. | The following table distinguishes between the different strains of ''Plasmodium'' species, all of which are causative agents of malaria infection. | ||
{| style="border: 0px; font-size: 90%; margin: 3px;" align=center | |||
|+'''''Comparison of ''Plasmodium'' Species Implicated in Human Malaria''''' ({{cite web |url=http://www.cdc.gov/dpdx/malaria/dx.html |title= Malaria |date= Nov. 29 2013 |website= Center for Disease Control and Prevention|publisher= Center for Disease Control and Prevention (CDC)|accessdate=Jul 24 2014}}) | |||
! style="background: #4479BA; width: 120px;" | {{fontcolor|#FFF|Strain}} | |||
! style="background: #4479BA; width: 550px;" | {{fontcolor|#FFF|Appearance of Erythrocyte (RBC)}} | |||
! style="background: #4479BA; width: 550px;" | {{fontcolor|#FFF|Appearance of Parasite}} | |||
! style="background: #4479BA; width: 550px;" | {{fontcolor|#FFF|Clinical Significance}} | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC;" |'''''P. falciparum''''' | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
*Normal appearance with Maurer's clefts: Ring, trophozoite, and schizont forms. | |||
*Distorted appearance: Gametocyte form | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
*Chromatin dots and "appliqué" (accolé): Ring form | |||
*Clump of mass and dark pigment: Trophozoite and schizont forms | |||
*Crescent or sausage shape: Gametocyte form | |||
| style="padding: 5px 5px; background: #F5F5F5;" | Tertian/subtertian fever (every 48 hours), causes severe malaria in up to 24% of cases, and is often drug resistant. | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC;" |'''''P. vivax''''' | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
*Normal with fine Schüffner dots: Ring form | |||
*Enlarged with fine Schüffner dots: Trophozoite, schizont, and gametocyte forms | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
*Large cytoplasm with pseudopods: Ring form | |||
*Large ameboid cytoplasm with yellow-brown pigment: Trophozite form | |||
*Large mass that fills all RBC with yellow-brown coalescent pigment: Schizont form | |||
*Large mass that fills all RBC with scattered brown pigment: Gametocyte form | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
Tertian fever (every 48 hours), causes severe malaria in up to 22% of cases, and is often drug resistant. Relapse is common due to dormant liver phase. | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC;" |'''''P. ovale''''' | |||
| style="padding: 5px 5px; background: #F5F5F5;" |Normal with fine Schüffner dots | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
*Sturdy cytoplasm and large chromatin: Ring form | |||
*Compact cytoplasm with dark-brown pigment: Trophozoite form | |||
*Large nuclei clustered around mass of dark-brown pigment: Schizont form | |||
*Round to oval form that fills all RBC with scattered brown pigment: Gametocyte form | |||
| style="padding: 5px 5px; background: #F5F5F5;" |Tertian fever (every 48 hours), rarely causes severe malaria or drug resistance. Relapse is common due to dormant liver phase. | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC;" |'''''P. malariae''''' | |||
| style="padding: 5px 5px; background: #F5F5F5;" |Normal with Ziemann's stippling | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
*Sturdy cytoplasm and large chromatin: Ring form | |||
*Compact cytoplasm with occasional band forms and coarse dark-brown pigment: Trophozoite form | |||
*Large nuclei clustered around mass of coarse, dark-brown pigment and occasional rosettes: Schizont form | |||
*Round to oval form that fills all RBC with scattered brown pigment: Gametocyte form | |||
| style="padding: 5px 5px; background: #F5F5F5;" | Quartan fever (every 72 hrs), rarely causes severe malaria or drug resistance. Although dormant liver phase is uncommon, infection persistence is commonly seen. | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC;" |'''''P. knowlesi''''' | |||
| style="padding: 5px 5px; background: #F5F5F5;" | Normal with Sinton and Mulligan stippling | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
*Delicate cytoplasm with appliqué (accolé) forms: Ring form | |||
*Compact cytoplasm and large chromatin with band forms and dark-brown pigment: Trophozoite form | |||
*Segmented with large nuclei around mass of coarse brown pigment and occasional rosettes: Schizont form | |||
*Round to oval form that fills all RBC with scattered brown pigment: Gametocyte form | |||
| style="padding: 5px 5px; background: #F5F5F5;" | Daily fevers, may cause severe malaria in up to 10% of cases. Drug resistance is rare. | |||
|- | |||
|} | |||
<sup><center>Adapted from Center for Disease Control and Prevention (CDC) - Malaria </center></sup> | |||
==References== | ==References== |
Revision as of 22:40, 24 July 2014
Malaria Microchapters |
Diagnosis |
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Treatment |
Case studies |
Malaria causes On the Web |
American Roentgen Ray Society Images of Malaria causes |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Malaria is a vector-borne infectious disease caused by protozoan parasites. P. vivax is the most common cause of infection, responsible for about 80 % of all malaria cases. However, P. falciparum is the most important cause of disease, and responsible for about 15% of infections and 90% of deaths.[1]
Causes
P. vivax is the most common cause of infection, responsible for about 80 % of all malaria cases. However, P. falciparum is the most important cause of disease, and responsible for about 15% of infections and 90% of deaths.[2] The remainder of human malaria infections are caused by P. ovale, P. malariae, and P. knowlesi.
The following table distinguishes between the different strains of Plasmodium species, all of which are causative agents of malaria infection.
Strain | Appearance of Erythrocyte (RBC) | Appearance of Parasite | Clinical Significance |
---|---|---|---|
P. falciparum |
|
|
Tertian/subtertian fever (every 48 hours), causes severe malaria in up to 24% of cases, and is often drug resistant. |
P. vivax |
|
|
Tertian fever (every 48 hours), causes severe malaria in up to 22% of cases, and is often drug resistant. Relapse is common due to dormant liver phase. |
P. ovale | Normal with fine Schüffner dots |
|
Tertian fever (every 48 hours), rarely causes severe malaria or drug resistance. Relapse is common due to dormant liver phase. |
P. malariae | Normal with Ziemann's stippling |
|
Quartan fever (every 72 hrs), rarely causes severe malaria or drug resistance. Although dormant liver phase is uncommon, infection persistence is commonly seen. |
P. knowlesi | Normal with Sinton and Mulligan stippling |
|
Daily fevers, may cause severe malaria in up to 10% of cases. Drug resistance is rare. |
References
- ↑ Mendis K, Sina B, Marchesini P, Carter R (2001). "The neglected burden of Plasmodium vivax malaria" (PDF). Am J Trop Med Hyg. 64 (1-2 Suppl): 97–106. PMID 11425182.
- ↑ Mendis K, Sina B, Marchesini P, Carter R (2001). "The neglected burden of Plasmodium vivax malaria" (PDF). Am J Trop Med Hyg. 64 (1-2 Suppl): 97–106. PMID 11425182.