Unit 2: Eukaryotic Microorganisms and Parasites

Question 1

What is the relationship between a parasite and its host?

Answer 1

Parasites derive nutrients from a living host.

One organism, the parasite, lives off of another organism, the host, harming it and possibly causing death.
The parasite lives on or in the body of the host.

Question 2

Examples of Parasites:

Answer 2

tapeworms, fleas, barnacles

Question 3

• fungi that exist either in yeast or mold form

- depends on environmental conditions

Answer 3

dimorphic fungi

Question 4

term used to describe any fungal infection:

Answer 4

mycosis

Question 5

• type of fungi
• unicellular
• reproduce by budding

Answer 5

yeast

@ 37 degrees celsius

Question 6

• type of fungi
• multicellular
• reproduce by spore formation; produce vegetative and aerial hyphae

Answer 6

mold

@ 25 degrees celsius

Question 7

the appearance of the dimorphic fungus changes with:

Answer 7

CO2 concentration

Question 8

Fungi tend to be very weak pathogens / opportunistic.

True or False?

Answer 8

True

Question 9

Mycoses are classified into five groups:

Answer 9

• Systemic
• Subcutaneous
• Cutaneous
• Superficial
• Opportunistic

Question 10

• fungal infections deep within the body
• not restricted to any particular region of the body, but can affect a number of tissues and organs
• usually created by fungi that live in the soil
• spores are transported by inhalation; these infections typically begin in the lungs and spread to other body tissues
• not contagious from animal to human or from human to human
  (Type of Mycoses)

Answer 10

Systemic mycoses

Question 11

• fungal infections beneath the skin caused by saprophytic fungi that live in soil and on vegetation
• ex. sporotrichosis - acquired by gardeners and / or farmers
• infection occurs by direct implantation of spores or myclelial fragments into a puncture wound in the skin
  (Type of Mycoses)

Answer 11

Subcutaneous mycoses

Question 12

• dermatophytes secrete keratinase, an enzyme that degrades keratin, a protein found in hair, skin, and nails
• infection is transmitted from human to human or from animal to human by direct contact or by contact with infected hairs and epidermal cells (as from barber shop clippers or shower room floors)
  (Type of Mycoses)

Answer 12

Cutaneous mycoses

Question 13

• fungi that are localized along hair shafts and in superficial (surface) epidermal cells
• these infections are prevalent in tropical climates
  (Type of Mycoses)

Answer 13

Superficial mycoses

Question 14

• generally harmless in its normal habitat but can become pathogenic in a host who is seriously debilitated or traumatized
• who is under treatment with broad spectrum antibiotics, whose immune system is suppressed by drugs or by an immune disorder, or who has a lung disease
  (Type of Mycoses)

Answer 14

Opportunistic mycoses

Question 15

Example of an opportunistic pathogen:

Answer 15

Pneumocystis - opportunistic pathogen in individuals with compromised immune systems and is the most common life threatening infection in AIDS patients

Question 16

Amebae move by extending blunt, lobe-like projections of the cytoplasm called:

Answer 16

pseudopods

Question 17

• the transmission of a pathogen from one host to another when the pathogen reproduces in the vector
• Active process and is more complex than mechanical transmission

Answer 17

biological (vector) transmission

Question 18

• forms pseudopods
• causes keratitis: inflammation of the clear tissue on the front of the eye (cornea)
• source of infection: water

Answer 18

Ancanthamoeba species

Question 19

• forms pseudopods

- causes amoebic dysentery (aka bloody diarrhea; almost always pathogenic; fecal oral transmission)

Answer 19

Entamoeba histolytica

Question 20

• flagellated
• causes prolonged fatty (mucousy) diarrhea
• found in stream water - both humans / animals can be infected

Answer 20

Giardia lamblia / Giardia intestinalis

Question 21

• flagellated
• causes vaginal infections - vaginitis - (less often, urethral infections in males)
• sexually transmitted

Answer 21

Trichomonas vaginalis

Question 22

• causes toxoplasmosis: infection with a common parasite found in cat feces and contaminated food
• can cause serious complications for pregnant women and people with weakened immune systems
• can be spread by: unclean needles or unscreened blood; by mother to baby by pregnancy, labor, or nursing; through contaminated food or water

Answer 22

Toxoplasma gondii

Question 23

• nonmotile adult
• looks like dark dots, bands, or rings inside RBCs (intracellular parasite)
• causes malaria (blood to blood transmission via infector, usually a mosquito)

Answer 23

Plasmodium species

Question 24

Examples of biological vectors:

Answer 24

• mosquitoes
• ticks
• fleas

Question 25

• Platyhelminthes (flatworms) and Nematoda (roundworms)
• classified based on shape
• multicellular eukaryotic animals that generally possess digestive, circulatory, nervous, excretory, and reproductive systems

Answer 25

Helminths

Question 26

• tapeworms / flatworms

- use hooks and suction cup-like structures for attachment

Answer 26

Taenia species

Question 27

• most common global human worm infection
• diagnosed by finding worm eggs in feces passed in stool
• worms may also be coughed up (roundworm)
• causes ascariasis: larvae and adult worms live in the small intestine and can cause intestinal disease

Answer 27

Ascaris lumbricoides