Unit 4 - Part 9 Protozoa Flashcards
What are the two main stages in the life cycle of cysts or occyst-forming protozoa?
- Trophozoites
2. Cysts or oocysts
What is the active feeding stage of protozoa?
Trophozoites
How do trophozoites reproduce?
Asexually by binary fission
True or False:
Cysts are metabolically active
False
- cysts are metabolically inactive
True or False:
Oocysts are the products of sexual reproduction
True
What three things can cysts AND oocysts do?
- Remain infective/infectious outside the hosts
- Survive the environment for a long time
- May be involved in reproduction
Describe the stages involved where a trophozoite forms into a cyst
- Trophozoite (active, feeding)
- Drying, lack of nutrients - cell rounds up, loses motility
- Early cyst wall formation
- Mature cyst (dormant, resting stage)
- Moisture, nutrients restored
- Cyst wall breaks open
- Trophozoite is reactivated
True or False:
Both simple and complex reproductive strategies are observed among protozoa
True
True or False:
Some protozoa only asexually reproduce while others only sexually reproduce
False
- some reproduce only asexually
- others reproduce BOTH sexually and asexually!
What are the two methods that protozoa can reproduce asexually?
- Binary fission
2. Multiple fission
What happens in binary fission?
A parent cell gives rise to TWO daughter cells
What happens in multiple fission (also called schizogony)?
A parent cell gives rise to multiple daughter cells
What are the 3 names for a parent cell?
- Schizont
- Meront
- Segmenter
What are the 4 different ways that a protozoa can undergo fission (what are the 4 types of fission)?
- Spherical fission
- Longitudinal fission
- Transverse fission
- Oblique fission
What occurs in sexual reproduction of protozoa?
Fusion of gametes or gametocytes to produce zygotes
What are the 5 stages of reproduction for malaria?
- Asexual phase (human is infected)
- Exoerythrocytic phase (in liver cells)
- Erythrocytic phase (in RBC)
- Gametocyte phase (in RBC)
- Sexual phase (in mosquito)
What is an example of a protozoan disease that involves mosquitos?
Malaria
What is the mode of transmission of malaria?
Female mosquitoes (Anopheles)
What are the s/s of malaria?
Fever, chills, sweats, cough, diarrhea, respiratory distress, headache, shock, renal and liver failure, pulmonary and cerebral edema, come and death
What are the three leading causes of infection-related deaths seen worldwide?
- AIDs
- Tuberculosis
- Malaria
Approximately how many deaths are associated with malaria each year?
Half a million
What are some control strategies for preventing the spread of malaria?
- prevent mosquito bites (netting or repellents)
- prevent entry (close doors/windows, have screens)
- prevent mosquito breeding (avoid water logging; kill larvae)
What is used to kill the asexual forms of malaria? the sexual forms?
Asexual = Chloroquine
Sexual = Primaquine
- these two things are used in the treatment of malaria
What is the protozoan disease that is acquired through the ingestion of water contaminated with fecal matter containing cysts?
Giardiasis (Beaver fever)
What are the s/s of Giardiasis?
Chronic diarrhea, abdominal cramps, bloating, frequent loose and pale greasy stools, fatigue, weight loss
What is the treatment for Giardiasis?
Usually self-limited
- rehydration therapy and antibiotics (metronidazole)
What happens during the intestinal phase of Giardiasis?
Excystation occurs in the small intestine
- two trophozoites are released from each cyst
- multiply by longitudinal fission
Which protozoan disease has thick and thin walled oocysts?
Cryptosporidiosis
What is the main reservoir for Cryptosporidiosis?
- Humans
- Cattle
- Other domestic animals
How does self-infection occur with crytposporidiosis?
Commonly by thin-walled oocysts
True or False:
Thick-walled oocysts of cryptosporidiosis can survive in the environment
True
What are the s/s of Cryptosporidiosis?
Profuse and water diarrhea + abdominal cramps
- sometimes malaise, fever, anorexia, and vomiting
True or False:
10-20% of AIDs patients suffer cyrptosporidiosis at some time during their illnessq
True
What is the treatment for cryptosporidiosis?
Usually self-limited
- rehydration therapy, and antibiotics (azithromycin)
True or False:
Thick walled oocysts of cryptosporidium allow for survival in the host. Thin walled oocysts of cryptosporidium allow for survival in the environment
False
- Thick walled = environment
- Thin walled = host (auto-infection)
What protozoan disease can be caused by cats?
Toxoplasmosis
What is the mode of transmission for toxoplasmosis?
Ingestion of oocysts from the fecal droppings of cats
fecal-to-hand-to-mouth
What is another mode of transmission for toxoplasmosis?
Ingestion of contaminated water or undercooked/raw meat
What can happen if a pregnant women gets infected with toxoplasmosis?
Can cause miscarriage and/or serious physical and developmental damage to the fetus/newborn
What are the s/s of toxoplasmosis?
Fever, lymphadenopathy, cerebritis, pneumonia, myocarditis, and/or death in the immunocompromised
True or False:
The damage caused by congential toxoplasmosis is reversible
False
- causes birth defects (and death) due to irreversible damage to liver, brain, and spleen
What protozoan disease does not produce any cyst or oocyst?
Trichomoniasis
What is a protozoan disease that is a common sexually transmitted disease?
Trichomoniasis
True or False:
Trichomoniasis can coexist with gonorrhea
True
- up to 40% in some cases
What are the s/s of trichomoniasis in women?
- small, pinpoint, non-raised, round, red strawberry-like rash
- thin, foamy greenish-yellow discharge w/foul odor
- cervical inflammation
What is the treatment for trichomoniasis?
Metronidazole
