Plasmodium vivax: Morphology

. distribution p.vivax is generally considered a parasite of central and south america india and s.e.asia. the low frequency of the duffy antigen that facilitates the entry of p.vivax into erythrocytes means that this malaria species has lower frequency in africa. aside from this however plasmodium vivax infection occurs across the widest geographic area of all the human malarias extending well into temperate climates. this behaviour is enabled by the dormant stage in the human liver where the parasite can \"rest\" allowing it to survive mosquito-free cold seasons when transmission and propagation in the mosquito-host is not possible. detailed . information may be accessed here malaria atlas project . ---- the early trophozoite file pvet.jpg leftt 200px link filepath pvet.jpg *erythrocytes begin to become 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 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 ---- gallery plasmodium vivax gallery click here to see gallery of plasmodium vivax forms ---- '),