Giemsa stain is a test done on the blood cells to show the difference between human and bacterial cells, also helps to determine the different bacteria present.
Extracellular parasite what was noted in the stain; extracelluar parasites enter the body but not the individual cells, they take nutrients from the cells and release substances into the body, most live in the gut, blood and lymphatic system. Extracelluar parasites include malaria, roundworm, whipworm
Similar to platelet thrombocytes I'm guessing this is supposed to be the description of what was seen when tested with the Giemsa stain.
Here's a microscope view of thrombocytes
Hepatomegaly is basically enlarged liver, more info found
here bilirubin is a product of the liver often used to monitor the function of the liver and gallbladder.
Have they mentioned Malaria? Given your location that is my first guess
for your pup