Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microimm 2500 > (O) 30: Parasitology II > Flashcards

(O) 30: Parasitology II Flashcards

1
Q

Flagellates

A

have one or more whiplike flagella
- sometimes has an undulating membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Amebae

A

use pseudopodia or protoplasmic flow to move

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Sporozoa

A

undergo a complex life cycle w/ alternating sexual + asexual reproduction

move by GLIDING

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Ciliates

A

have cilia distributed in rows or patches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Trypanosoma

A

Flagellate w/ intermediate + definitive host

  • unicellular parasitic flagellate protozoa
  • most are HETEOXENOUS and transmitted via a VECTOR

Some diseases they cause are:
- African trypanosomiasis (aka African Sleeping Sickness) caused by Trypanosoma brucei - vector is Tsetse fly
- American trypanosomiasis (aka Chagas disease) caused by Trypanosoma cruzi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

African Trypanosomiasis

A

there are two types - East and West African
- BOTH are transmitted by the tsetse fly
- both are eventually fatal if not treated

East African trypanosomiasis is caused by Trypanosoma brucei RHODESIENE

West African trypanosomiasis is caused by Trypanosoma brucei GAMBIENSE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Tsetse fly and disease burden

A

Tsetse flies get nutrition from bloodmeal - reproductive cycles in their own body + eggs are laid in soil

Animals can host the human pathogen of Trypanosoma genus

T brucei brucei infects CATTLE in both West and East Africa - disease is Nagana

Trypanosomiasis in animals, especially cattle, is a major obstacle for economic devlopment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Trypanosoma life cycle

A
  1. infected tsetse fly ingests blood and injects parasites
  2. primary chancre develops at bite wound, in lymph
  3. trypomastigotes invade bloodstream (use our glucose + spreads asexually)
  4. humans are INTERMEDIATE hosts. tsetse fly bites + acquires infection
  5. undergoes sexual reproduction IN fly - tsetse fly is DEFINITIVE host
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Signs and Symptoms of Trypanosoma infection

A
  • Winterbottom’s sign (early onset): swollen lymph nodes at back
  • perivascular cuffing in brain (late onset)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Antigenic Switching

A

T. brucei cell surface is covered by a variant surface glycoprotein (VSG)

if they switch, immune system can’t identify it fast enough to eradicate it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

West vs East African Sleeping Sickness Symptoms

A

Both infections occur in 2 stages (initial hemolymphatic stage then CNS involvement)
- second stage symptoms: reversal of sleep-wake cycle, motor, sensory, mental + neurological disturbances

Main difference is time of symptom appearance + progression

West (T. brucei GAMBIENSE)
- symptoms develop over MONTHS post bite (headache, weakness, fevers)
- progress to 2nd stage in 300-500 days

East (T. brucei RHODESIENE)
- symptoms develop 1-3 WEEKS post bite
- progress to 2nd stage in 30-60 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Diagnosis and Treatment of Sleeping Sickness

A
  • no vaccine or drug for prophylaxis (can’t prevent)
  • treatment depends on type of infection and stage

Staging is done by microscopic exam of CSF
- parasite in CSF = progressed to 2nd stage (if not, parasite in blood)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Giardia Lamblia

A

Flagellate, strict anaerobe = thrives in GI TRACT of humans

  • infections by FECAL-ORAL route thru contaminated water
  • giardiasis is frequent in travellers and immunocompromised ppl

G. lamblia is common in domestic animals - many infected ppl remain undiagnosed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Giardiasis Symptoms

A

Some ppl have no symptoms at all

Usually develop 1-2 weeks after infection: (all GI related)
- diarrhea
- gas
- foul-smelling, greasy stools
- stomach cramps or pain
- upset stomach or nausea
- vomiting
- dehydration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Treatment of Giardiasis

A

If you have diarrhea, drink lots of fluid to avoid dehydration

Effective pharmaceutical treatments exist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Entamoeba Histolytica

A

Amoeba, anaerobic

Causes AMOEBIC DYSENTRY (bloody diarrhea) in humans

  • many members of this genus live in human large intestine but ONLY E. histolytica is clearly pathogenic

Transmitted via FECAL-ORAL route

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Amoebiasis

A

Most exposed ppl are ASYMPTOMATIC but some may be chronic carriers
- most common symptom is DIARRHEA

Symptomatic amoebiasis is considered invasive so treatment agent is active achainst tissue invasive forms = METRONIDAZOLE is drug of choice for intestinal and extra-intestinal infection

18
Q

Treatment of Amoebiasis

A

METRONIDAZOLE

Symptomatic amoebiasis is considered invasive so treatment agent is active against tissue invasive forms

19
Q

Balantidium coli

A

Ciliate protozoan
- ONLY known PARASITIC ciliate

  • infects GI tract/large intestine where it causes DYSENTRY
  • transmitted via FECAL-ORAL route by contaminated food/water
  • Balantidiasis is mostly ASYMPTOMATIC but ppl w/ other sicknesses can have persistent diarrhea, abdominal pain + sometimes a perforated colon
20
Q

Parasitic metazoa

A

Metazoan parasites are MULTICELLULAR organisms w/ BOTH ecto- (insects) and endoparasitic (worms, helminths) lifestyles

  • macroscopic, multi-cellular organisms
  • includes helminths and arthropods
21
Q

Classification of helminths

A
  • nematodes
  • cestodes
  • trematodes
22
Q

Nematodes

A

aka ROUNDWORMS

non-segmented roundworms
- fluid-filled body cavity

23
Q

Cestodes

A

aka TAPEWORMS

segmented flat worms
- rings around body
- very long

24
Q

Trematodes

A

aka FLUKES

non-segmented flatworms
- leaf-like shape

25
Q

Mechanisms of entry and niche selection w/ helminths

A

Transmission
- fecal-oral (cyst - larva - adult worm)
- transdermal (cyst - larva - adult worm)
- verctor-borne (larva - adult worm)
- predator-prey (egg - larva - adult worm)

26
Q

Helminth reproduction

A
  • male and female reproduce by mating followed by egg production
  • most trematode and cestode parasites contain male AND female sex organs but often need another worm to exchange sperm w/ before egg production
  • some species produce both sperm and eggs and self-fertilizing (are HEMAPHRODITIC)
27
Q

Mechanisms of helminth survival

A

Immune evasion strategies
- incorporation of host serum proteins on surface - hide from immune response
- inhibition of complement system
- secretion of anti-inflammatory molecules

Non-immune evasion strategies
- avoiding direct contact w/ host tissue (ex. living in lumen of small intestine)
- PAUSING LIFE CYCLE when host develops resistance

28
Q

Ascariasis

A

Nematode/roundworm

Main specie that infects humans is A. lumbricoides

  • a soil-transmitted helminth (geohelminth)
  • very large nematodes that parasitize the human intestine

Ascariasis is the most COMMON helminth infection in the world and HUMANS are the DEFINITIVE host

29
Q

Ascariasis life cycle

A
  1. Eggs are ingested - go into stomach
  2. Larvae hatch in small intestine, enter bloodstream + go to liver
  3. Larvae migrate to heart - start to mature in tissues
  4. Larvae reach lung capillaries
  5. Larvae enter alveolar spaces
  6. Larvae migrate up trachea + are swallowed down into esophagus then back into stomach and small intestine
  7. Adults mature in small intestine
  8. Eggs pass out in feces + embryonate in soil
30
Q

Symptoms of Ascariasis

A
  • parasitic infection occurs thru ingestion of eggs via fecal contamination of soil, food or water
  • mostly ASYMPTOMATIC (could have mild abdominal discomfort)
  • problems when it is untreated or other factors = high worm burden
31
Q

Treatment of Ascariasis

A

ANTHELMINTIC medications (drugs that remove parasitic worms from the body) like
- albendazole
- mebendazole

32
Q

Taenias

A

Cestodes/tapeworms

  • humans are DEFINITIVE hosts for different types of Taenia
  • humans pass the tapeworm segments/eggs in feces and contaminate soil
  • Taenia eggs can survive in MOIST environment and remain infective for days to months
  • can form cysts in muscle tissue
  • humans can be infected w/ tapeworms when they eat raw or undercooked beef or pork
33
Q

Types of Taenias

A

Taenia saginata (beef tapeworm)
Taenia solium (pork tapeworm)
Taenia asiatica (Asian tapeworm)

34
Q

Taenias Life Cycle

A
  1. Cysticerci are ingested w/ raw or undercooked beef/pork
  2. Cysticerci are released from muscle in stomach
  3. Worms mature + live in SMALL INTESTINE
  4. Scolex contains four suckers
  5. Proglottids (male + female characteristics needed to produce) pass in feces
  6. Cow ingests embryonated eggs, then oncospheres migrate to tissues and develop to cysticerci

back to #1

35
Q

Symptoms + Treatment of Taenias

A
  • most ppl w/ tapeworms have NO or mild symptoms
  • most common treatment are ORAL medications that are toxic to the adult tapeworm
36
Q

Schistosomiasis

A

Trematode parasite

  • infection occurs transcutaneously when skin comes in contact w/ contaminated freshwater in which certain types of snails (INTERMEDIATE host) that carry the parasite are living
  • freshwater becomes contaminated by schistosome eggs when infected ppl URINATE or DEFECATE in the water

humans are DEFINITIVE host
- snails are intermediate host in water to keep larva

37
Q

Symptoms + Treatment of Schistosomiasis

A

Most ppl have no symptoms when first infected
- within days after, they may get a RASH or ITCHY SKIN
- within 1-2 months of infection, they might get fever, chills, cough and muscle aches

Can develop into chronic schistosomiasis

Treated w/ PRAZIQUANTEL for 1-2 days to treat infection

38
Q

oChronic Schistosomiasis

A

repeated infection or not being treated

Symptoms include
- abdominal pain
- enlarged liver
- blood in stool or urine
- problems passing urine

can also lead to increased risk of LIVER FIBROSIS or BLADDER CANCER

39
Q

Anti-parasitic measures

A
  • clean water
  • better sanitation
  • better hygiene
  • vector control
40
Q

Vector control

A
  • reduction of areas where vectors breed (especially mosquitoes)
  • access to bed nets
  • treatment of areas w/ pesticide
  • introduction of genetically modified mosquitoes (offspring w/ natural mosquitoes are STERILE)

Microimm 2500 (29 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions