Protozoa - Leishmania, Ciliates, and Drugs Flashcards
Leishmania is classified in the phylum ___ and order ___.
Phylum: Metamnoda. Order: Kinetoplastida
What is the common name of the vector for Leishmania?
sandfly
What genera of vector transmit Leishmania in the Old World & New World?
Old World: Phlebotomus
New World: Lutzomyia
What 2 parasite forms occur during the life cycle?
amastigote & promastigote
Inside what cells does the parasite live in humans?
macrophage
What is found inside a parasitophorous vacuole?
parasite that fuses with lysosome at low pH
By what process does the parasite multiply?
binary fission
Why do reservoir hosts make control of parasite difficult?
Rh are dogs and rodents. These are common part of our lives and are not as severely affected as humans to these parasites, makes it harder to spot.
What is the treatment for leishmaniasis?
pentostam
From what heavy metal is Pentostam derived?
antimony (Sb)
What is the mode of action for Pentostam?
inhibition of phosphofructokinase prevents phosphorylation of fructose-6-phosphate to fructose-1,6-diphosphate and inihbits glycosis which leads to parasite death
Describe some control strategies for Leishmaniasis.
- vector control
Sandfly has short flight range
insecticide in houses & eliminate low growing bushes - protect against bites: insect repellants, bed nets, fly screens
- control of reservoir hosts: dogs, cats, & rodents
What is another name for cutaneous leishmaniasis?
oriental sore
Do cutaneous leishmaniasis cause secondary skin lesions?
no
Why don’t cutaneous leishmaniasis amastigotes spread throughout the body?
amastigotes cannot grow at core body temp
Describe the process of a punch biopsy.
circular blade extends through to subcutaneous fat. cylindrical specimen = examination
Describe the process of needle aspiration.
~0.1mL of saline into syringe
insert needle into dermis of active border
move needle back & forth under skin & rotate syringe & apply suction
What spp causes mucocutaneous leishmaniasis?
Leishamnia braziliensis
Where does the primary skin lesion form in mucocutaneous leishmaniasis?
at site of sandfly bite
Name 2 types of secondary lesions in mucocutaneous leishmaniasis & describe the pathology they cause.
- Chiclero ulcer - lesion on ear
Mexico & Central America
Pinna - cartilage poorly vasularized
weak immune system
over years pinna erodes - Espundia - skin lesions spread & invade mucous membrane
Central & South America
nose affected
long, chronic = serious disfigurement
distruction of facial cartilage = nose and soft palate eroded
into larynx & trachea = destroy voice
What species causes visceral leishmaniasis?
Leishmania donovani
Kala azar
Who were Leishman and Donovan?
discovered agent that causes leishmaniasis. physicans in India
Why are amastigotes also called LD bodies?
after Leishman & Donovan
Why does the immune system become worn down in visceral leishmaniasi?
increases production of macrophages & other phagocytes to detriment of RBC production
macrophages released when still immature
spleen & liver enlarged = hepatoslepnmagly
How is visceral leishmaniasi infection diagnosed?
amastigotes - tissue smears, blood
What is the significance of Leishmania-HIV coinfection?
emerging disease - decreases immune resources
What is the one species in the phylum Ciliophora that infects humans?
Balantidium coli
Is Balantidium coli large or small compared to other protozoans in humans?
largest protozoan parasite of humans
What structure in B. coli is lined with coarse cilia?
peristome
What structure in B. coli ingests food?
cytostome
Why are contractile vacuole unusual in a parasitic organism?
responsible for osmoregulation
What are the function of the macronucleus & micronucleus in B. coli?
macronucleus - control trophic activities
micronucleus - reproductive functions
What stimulates encystment in B. coli?
dehydration
What is the transmission stage of B. coli?
cyst
How does hyaluronidase contribute to pathology by B. coli?
digests host intestinal epithelium
What types of ulcers can form in the intestine in B. coli infection?
flask shaped ulcers
hemorrage
secondary bacterial infections
necrosis = diarrhea & hysentry = balantidial dysentry
How can B. coli infections be treated & controlled?
treated - Metranidazole
control - sanitation
Describe various characteristics of an ideal antiparasitic drug.
- effective
- less harmful to host than to parasite - no side effects
- kills all stages w/i host
- broad spectrum drug (ex: Ivermectin)
- rapid acting
- ease of administration - tablets/liquids, few treatments
- affordable
- long shelf life - chemically stable, no refrigeration
- safe for environment
How is the use of ivermectin detrimental to the environment?
passes out of host feces = in environment = kills invertebrates in soil and water
