Parasitology Flashcards
What are the key cellular differences between parasites and bacteria/viruses?
Parasites have a nucleus and have a more complicated structure
Categories of parasites
Protozoans (Single cells)
Helminths (Multicellular)
Why are there currently no vaccines for parasitic infections?
Parasites are Eukaryotes
Parasites are more involved
Inadequate research efforts
In which type of countries are parasitic infections most prevalent?
Poor countries
Percentage of death in the Developing World attributed to Infectious Diseases?
50%
Protozoan infections transmitted by insects
Malaria
Leishmaniasis
Trypanomiasis
Helminth(s) transmissible through soil
Ascaris
Trichuris
Hookworm
Characteristics of Ascaris
Lifespan: 1 year
Eggs/day: 200,000
Length: 20 cm
characteristics of Trichuris
Lifespan: 2 years
Eggs/day: 5000
Length: 5 cm
Characteristics of Hookworm
Lifespan: 5 years
Eggs/day: 50,000
Length: 15 nm
Other name of lymphatic filariasis
Elephantiasis
Parasite transmitted by snails
Schistosomiasis
The population at risk of STHs
1/3 of worldwide population
What characterizes adult worms in the human gastrointestinal tract regarding replication and egg production?
-Survive for years
-Do not replicate in human host
-Produce eggs that are excreted with feces
How are Soil Transmitted Helminths (STH) typically diagnosed?
By examining a feces sample
How is the intensity of STH infection determined?
By the number of eggs per gram of feces
What diagnostic method is commonly used to determine STH intensity?
Microscopy
What is the main goal of treating Soil Transmitted Helminth (STH) infections?
To remove adult worms from the intestine
What are the most common drugs used to treat STH infections?
Benzimidazoles
Ivermectin
What does STH treatment NOT eliminate?
The eggs
Why is STH treatment often focused on school-age children?
To reduce worm burden and improve health and cognitive development
What causes elephantiasis?
Wucheria Bancroft
What causes Onchocerciasis and how is it transmitted?
Caused by Onchocerca Volvus
Transmitted by blackflies through larvae
In Onchocerciasis, where do microfilariae accumulate and what condition do they cause?
Accumulate in the eye, causing blindness known as River blindness
How may helminth infections affect autoimmune diseases?
Reduce overall inflammation associated with autoimmunity
Help prolong survival of helminths in intestines
May have a reverse correlation with allergies
How is helminth therapy being tested to treat autoimmune diseases?
Using male helminth eggs to treat diseases like Crohn’s disease or inflammatory bowel disease
What is a vector in parasitology?
A vector is an organism that transmits a disease from one host to another
By which two criteria can diseases be ranked?
Number of deaths caused
Impact on the health of the infected
What does DALY stand for and what does it represent?
Disability Adjusted Life Years; Healthy years lost
What are the stages of the Plasmodium life cycle?
- Infection by mosquito
- Formation of sporozoites which go to the liver within an hour
- Sporozoites develop into merozoites which infect red blood cells
- Merozoites reproduce via asexual cycle until the lysis of the red blood cell
- Merozoites develop into gametocytes which are transmitted to the mosquito
In what type of climates is Malaria mostly found?
Warm climates
What do merozoites do that causes blood flow blockage?
They are sticky and eventually block the blood flow
What do merozoites develop into within the host?
Gametocytes
What are the stages of the Trypanosoma brucei life cycle?
Tsetse fly injects T.brucei into the bloodstream
T.brucei multiplies by binary fission in blood, lymph, and spinal fluid
Tsetse fly ingests T.brucei during a blood meal
T.brucei multiplies by binary fission in the midgut of the fly
T.brucei transforms into an infectious stage
T.brucei enters the salivary gland and multiplies
What are the stages of the Trypanosoma cruzi life cycle?
Trypomastigote infects human host
Amastigote infects muscle cells until they burst
Amastigotes transform back into Trypomastigotes
Triatomine becomes infected and perpetuates the cycle
What are the stages of the Leishmania life cycle?
Promastigote is transferred through the Sandfly
Promastigote is ingested by a macrophage
Promastigote transforms into Amastigote form within the macrophage
Amastigote reproduces within the macrophage
Macrophage bursts, releasing Amastigotes to continue the cycle or be taken by a sandfly
When are gametocytes transmitted to the mosquito?
When the mosquito takes a blood meal
How is Malaria diagnosed?
Through microscopy, observing the ring stage of the merozoite in the red blood cell
What is a common treatment for Malaria?
Artemisinin
What is another name for Human African Trypanosomiasis?
Sleeping sickness
What happens to the host’s blood when Trypanosomes multiply extensively?
Blood becomes overwhelmed by the parasites
What is trypanosome cruzi and where is it primarily found?
A South American version of trypanosome brucei
Why are Chagas Disease cases exported to other countries?
Due to the long asymptomatic period
What are the major forms of Leishmaniasis and the species that cause them?
Visceral Leishmaniasis:
Leishmaniadonovani
Cutaneous Leishmaniasis:
Leishmaniamajor
How can Chagas Disease be transmitted through blood?
Through blood transfusion if the blood is not checked
Which organs does Visceral Leishmaniasis affect?
Liver, spleen, bone marrow
What medication is used to treat Visceral Leishmaniasis?
Ambisome
Why is it difficult to develop resistance to Ambisome for Visceral Leishmaniasis?
Because it acts so quickly
What is PKDL and what happens to treated patients with Visceral Leishmania?
PKDL: Post-Kalazar Dermal Leishmaniasis
Approximately 10-25% of treated patients develop rashes containing parasites that want to get out
What diagnostic method is used to check for antibiotics in blood samples for Leishmaniasis?
Using blood samples to check for antibiotics
