Parasitology Lab 4: Protozoa Overview

Parasitology Lab 4

• Parasitology is the study of parasites
• Protozoa are single-celled eukaryotic organisms in the kingdom Protista
• Protozoa are classified by their motility and other characteristics
• Important protozoa groups include Alveolata, Excavata, and Sarcomastigota
• Alveolata includes Apicomplexa, the organism infecting the red blood cells
• Apicomplexa include Eimeria, Plasmodium, and Babesia
• Babesia parasites infect mammals
• Babesia are intracellular endoparasites that replicate in red blood cells (RBCs)
• Babesia life cycle involves ticks as the vector
• Humans can be infected when ticks bite them, spreading the parasite through blood transfusions
• Typical stages of the life cycle are sporozoites, trophozoites, and merozoites
• Babesia merozoites form tetrads in RBCs
• Final hosts of Babesia are ticks, which transmit the parasite to intermediate hosts (rodents)
• Babesia causes disease in livestock and humans

Sarcocystis

• Sarcocystis is an endoparasite of the intestines
• Final hosts are humans
• Intermediate hosts are sheep, cattle, and pork
• Humans acquire Sarcocystis by consuming uncooked infected beef or pork that contain sarcocysts tissue
• Sarcocysts may be found in the muscles of the final and intermediate hosts
• Sporulated oocysts are diagnostic for Sarcocystis. These can be found in both final and intermediate host faeces for diagnosis.

Classification

• Alveolata is the infrakingdom
• Apicomplexa is the phylum
• Eucoccidiorida, is the order
• Eimeriorina, one of the suborders, has Sarcocystis
• Aconoidasida is another class
• Piroplasmorida is in that class

Laboratory Techniques

• Zinc sulfate flotation is a technique to isolate protozoan cysts and eggs from fecal samples for microscopy.
• Specific protocol is used in the laboratory for this method.