Having explored the virtual microscope in the previous activity and looked at a normal blood smear, you will now use it to start comparing different samples. Specifically, you will be identifying infected red cells in a blood sample.
First, open thein a new browser window or tab.
Spend a few minutes comparing the normal blood smear (Slide 1 in Week 1) with the sample marked ‘Malaria’ (Slide 2 in Week 1), in the virtual microscope. Identify similarities and differences between them.
Note down the differences you notice.
One difference that you may have noticed is that of the colours of cells in the samples. Red blood cells do not normally contain a nucleus or nucleic acids so they do not stain blue. However, infected cells containing the malaria parasite (Plasmodium) are stained blue. The appearance of an infected cell depends on how far the parasite has progressed through its developmental stages.
Now take a brief look at the slide for ‘Sample 3’ (Slide 3). How is this blood smear different from ‘Normal blood smear’ (Slide 1) and ‘Malaria’ (Slide 2) samples that you have just looked at?
Make a note of any differences that you observe.
You may have observed that there are similarities between the ‘Malaria’ slide and the slide for ‘Sample 3’
The reason for this is that ‘Sample 3’ is another example of malaria in a blood smear. However, in this case, more red cells have been infected than in the ‘Malaria’ slide, and there are numerous parasites within each cell.
From this evidence you could deduce that ‘Sample 3’ represents blood taken at a later stage of infection than that of the ‘Malaria’ slide. At this later stage the infected cells are called ‘schizonts’, and you can see an example of them at position (4718, 2868) in Slide 3.