What is Black malarial pigment is seen in: September 2009 and explain in detail?
Ans. B: P.falciparum In well-stained preparations the nuclei of the parasites are always stained red and the cytoplasm blue. The presence of malaria pigment is very characteristic of the older stages of Plasmodium sp. P. falciparum often contains a single black dot. P. vivax often contains countless fine golden yellow/brown specks of malaria pigment. In P. ovale and P. malariae the pigment inclusions are many and brownish black. Countless fine red spots in the red blood cell (Schiiffner's dots) can be seen in P. vivax and P. ovale (the more mature the parasite, the more dots). In P. ovale the dots are sometimes called James's dots. Sometimes a few flecks can be observed in P. falciparum (Maurer's dots or clefts). P. malariae almost never exhibits dots (Ziemann's dots). The visibility of these dots depends to a great extent on the acidity (pH) with which the thin slide preparation is stained (slightly alkaline: pH = 8 is best). The acidity is impoant because blood smears are usually stained for haematological tests with a slightly acid pH.