Parasites Flashcards
What are the four types of protozoa and how are they classified?
They are classified by locomotion. They include: amoebas, flagellates, ciliates, and sporozoans
What is a trophozoite?
The active replicating form of a protozoa, a single-cell eukaryotic parasite
What is a cyst? Is it infective?
The inactive, non-replicating form of a protozoa. It is the resistant stage of a parasite and is infective.
What kind of motion does an amoeba have. Give an example of a pathogen?
pseudopod. entamoeba histolytica.
Name the four flagellate pathogens commonly found in man.
- Giardia lamblia
- Trichomonas vaginalis
- Trypanosoma cruzi (American trypanosomiasis-Chagas disease) and brucei (African trypansomoiasis-sleeping sickness)
- Leishmania species
What kind of protozoa is Balantidium coli?
Ciliate
What is a sporozoan? Name an important pathogen in man of this type.
A protozoa that has no means of locomotion, maybe slight amoeba like motion. In man, this is seen in the Plasmodia species: P. vivax, P.ovale, P. falciparum, P. malariae
Name the three types of Helminths
Cestodes (tapeworms), Nematodes (roundworms), Trematodes (flatworms or flukes)
Where does the asexual stage of the malarial parasite occur?
In human
Where does the sexual stage of the malarial parasite occur
In the Invertebrate Host (The Anopheles mosquito)
What do mosquitos inject into man when they bite?
sporozoites
Where do sporozoites grow and multiply?
First in the liver, then the blood where it causes malaria. Liver stage development lasts about 1-2 weeks.
What are merozoites?
Daughter parasites that invade red cells after being released from the destruction of sporozoite containing hepatocytes.
What are gametocytes?
certain stage of the parasite in the blood that is ingested by a female Anopheles mosquito during a blood meal, enabling the start of a new cell cycle. . After 10-18 days, they become sporozoites that can be found in the salivary gland of the mosquito.
Describe schizonts
They are mature merozoites that infect other red cells
What are the stages of Malaria paroxysm? How long does it last?
Cold (cold sensation, shivering), Hot (fever, headaches, vomiting in children), Sweat (return to normal T- tiredness)
What is the key feature of the Plasmodium falcipurum pathogenesis? What proteins are important in this?
The ability for the mature trophozoites and schizonts to adhere to the deep venous endothelium. Key proteins include PfEMP-1 that bind to host cytoadherence receptors such as ICAM 1 (esp. in cerebral microvasculature) and CD 36.
How do Leishmania species spread? Where are they distributed?
By the bite of Plebotomine sandflies.
In tropical, subtropical, and temperate regions
What are the main forms of Leishmania? Describe clinical manifestations
Cutaneous (skin sores), Visceral ( lethal illness in internal organs; mostly spleen, liver, bone marrow ), and Mucosal (sequela/consequence of infection of cutaneous infecting species)
What genetic dispostion reduced Vivax infection?
The Duffy antigen necessary for their survival.