Microbio Week 7 - Parasitology (Mini Exam) Flashcards
When one organism lives in close association with, and at the expense of, another
Parasite
Where do parasites live?
On or in a host
Parasites that live on a host
Ecto-parasite
Parasites that live in a host
Endo-parasite
T/F: Parasites usually kill their host
FALSE; they usually do not kill their host
The complex relationships between parasites and their hosts are the result of long ______________ histories
co-evolutionary
2 types of medically important human parasites
- Protozoans
- Helminths
Single celled “animal like” eukaryotes
Protozoans
Worms and flukes
Helminths
T/F: Parasites include bacteria and viruses
True, but the science of parasitology does NOT include them for historical reasons
There are ____ or ____ fold more parasites in nature than there are ‘free-living’ organisms
3 or 4
Each living species has ____ or more parasite, and the parasites have _________
1; parasites
Where a sexually mature adult parasite lives
Definitive host
Where a developing parasite lives
Intermediate host
Where a parasite that does not replicate or transmit, but dies (potentially causing more significant disease)
Dead end host
How were protozoans originally classified?
By motility
What were the original 4 groups of protozoans, classified by motility?
- Amoebas
- Ciliates
- Flagellates
- Sporoza
How are protozoans classified now?
By cell organelles
Which of the 4 motility classifications is still a valid taxonomic class of protozoans today?
Ciliates
What are the “Big 3” soil-transmitted nematode worms?
- Giant roundworm
- Whipworm
- Hookworm
What are major human infections related to?
The “Big 3” soil-transmitted nematode worms
How many parasites can affect humans?
~100
What are the 5 parasites of high known relevance in the US?
Pinworms
Toxoplasma
Trichomonas
Giardia
Pediculus humanus capitis (lice)
___________ and level of clean water infrastructure is the major factor of parasite habitat/transmission/epidemiology
Sanitation
___________ and __________ can exert an influence of parasite survival in the environment
Temperature and humidity
4 modes of transmission for parasite infections
- Ingestion
- Direct skin penetration
- Direct person to person
- Insect bites
How do parasites contribute to/complicate other diseases?
Malnutrition
Which type of parasitic disease is often chronic, and lacks specific identifiable patient symptoms?
Endemic
Many parasitic infections are less/more acute compared to viral or bacterial diseases
Less acute
What does co-evolution of parasites tend to favor ((except where important for transmission)?
Reduced host damage
Parasites have evolved numerous and effective _______________ and ___________ strategies (ex: antigen variation, generalized AB stimulation, etc)
immune-evasion; suppression
How can host cell and tissue damage still occur from parasites?
Immune responses to parasites
What 3 examples of immune responses to parasites?
Eosinophilia
DTH
Granuloma
The transmission of parasites involves the ability of their durable __________ to survive and develop in the environment
Eggs/larvae
A few parasites survive as adults in the soil or water, and can penetrate what?
Skin
How are protozoans that only reside in hosts directly transmitted?
Sexually
Insect bites
The definitive host of a parasite is…
where the mature form of the parasite occurs.
Which of the following is a ‘dead-end’ parasite of humans?
Balantidium coli
Entamoeba histolytica
Plasmodium
Acanthamoeba
Ascaris lumbricoides
Acanthamoeba
Which of the following parasites is not generally microscopic in its mature form, even though microbiologists usually study them?
cyclosporas
toxoplasmas
leishmanias
helminths
amoebae
helminths
Why are parasites understudied?
A. not many parasite are deadly
B. we know how to prevent and treat these infections
C. there is a only a small market for parasite treatments
D. A&B
D. A&B
Which of these are included in the field of study know as Parasitology
A. some types of worms
B. biting insects
C. infectious protozoans
D. pathogenic bacteria
E. all except D
E. all except D
Which protozoa are important in being transmitted congenitally from mother to baby?
Toxoplasma
Malaria
What is considered to be just as important as lab exam of specimens in recognizing parasitic diseases?
Geographic distribution
What are the major factors that influence parasite survival in the environment?
Sanitation
Level of clean water
Temperature
Humidity
What is the most important diagnostic tool for parasites?
Direct microscopic exam of feces
What determines the need for initial and repeated stool microscopy or serology?
Pt history, including travel
What are specialized serological (antigen or host AB) tests available for?
Protozoans
(includes many, but not all high US prevalent parasites)
How is species specific testing for the Malaria parasite, Plasmodium falciparum, done?
PCR
(it is super important to diagnose this species!!)
T/F: All these common parasitic diseases most often respond well to treatment
True
What do anti-parasite drugs target?
Eukaryotic cells
Why must dosing levels for anti-parasitic drugs be carefully applied and evaluated?
They target eukaryotic cells, making them more problematic than antibiotics
What is the most common treatment for protozoans?
Metronidizole
What is the most common treatment for worms?
Benzamidazoles
What drug is converted to an active agent only in organisms that can grow anaerobically, and then causes DNA damage?
Metronidizole
What drug interferes with nematode tubulin function, and kills worms in several days?
Benzamidazoles
Are there many parasite vaccines?
NO, but malaria and hookworm vaccines are currently being developed
What programs are valuable in preventing infection?
Mosquito and other insect vector control
What can reduce, but not likely prevent infection?
Mosquito net
Insect repellent
What should you avoid swimming and bathing in if its a high parasite prevalence region?
Fresh water
T/F: You should never drink water and stay dehydrated to avoid getting an infection in high parasite prevalence regions
FALSE; stay hydrated! Avoiding the water can have the opposite of intended effect
What foods should you avoid when visiting high parasite prevalence regions?
Avoid salad, fruit, ice, undercooked foods
