Lab 12 - Eukaryotic Pathogens

Question 1

what are the two types of Fungi, and what type of cells are there?

Answer 1

Yeasts - unicellular
Molds - multicellular

Question 2

What are the qualities/characteristics of yeasts?

Answer 2

1. Unicellular, non-motile, cell wall made of peptidoglycan chitin
2. Chemoorganoheterotrophs
   -(decomposition of organic matter and can cause food spoilage).
3. Facultative anaerobes (prefer o2, fermentation of bread, beer, wine)
   -Example - Saccharomyces cerevisiae.
4. Easy, cheap, and fast to grow.
   -Biotechnology - model eukaryote, production of vaccines.
5. Most are free-living, some are pathogenic.
   (example: Mycoses - superficial, local, or systemic only causing disease in immunocompromised people). Myco = fungi

Question 3

how do yeast reproduce?

Answer 3

1. Asexual: budding (cell produces a bud and divides its DNA and splits).
2. Sexual: Ascospores

Question 4

what is the example used for yeasts?

Answer 4

Candida albicans - which is a yeast that causes the disease candidiasis

Question 5

where is candida found?

Answer 5

It is part of the normal microbiota in the skin, mouth, throat, gut, vagina.

Question 6

what does candida cause?

Answer 6

causes infection in people who are immunocompromised or have had a course of antibiotics

Question 7

what is the disease that candida causes and where can it be located?

Answer 7

Causes candidiasis.
-Thrush: mouth, throat.
-Esophagus.
-Vaginal.

Question 8

is candidiasis invasive?

Answer 8

yes, it can spread to the blood, heart, brain, etc. and is a common HAI

Question 9

is candidiasis a common HAI?

Answer 9

yes

Question 10

what is the mode of transportation for candida?

Answer 10

inhaling spores or an imbalance of microbiota due to antibiotics

Question 11

what is the prevention for candida?

Answer 11

wear absorptive cotton underwear and take probiotics after antibiotics

Question 12

what is the treatment for candidiasis?

Answer 12

antifungal

Question 13

what are the characteristics of molds?

Answer 13

• Multicellular
• Non-motile
• Chitin CW
• Chemoorganohetertrophs
• Aerobic
• Most are free-living
• Some are pathogenic
• Reproduce asexually and sexually

Question 14

what does it mean when molds are chemoorganoheterotrophs?

Answer 14

-They secrete enzymes to digest food externally. (they spit out enzymes and absorb monomers/nutrients)
- Decomposition of organic molecules
- Causes food spoilage

Question 15

some molds are pathogenic, what can they cause?

Answer 15

Molds can cause mycoses that is superficial, local, or systemic (mostly in immunocompromised).

Question 16

how are molds classified?

Answer 16

Based on their reproduction. Either sexual or asexual.
Asexual:
- Fungi make spores
- The spores fly away and land on surfaces.
- The spore germinates and creates hypha.
- You get mycelium (a network of hyphae or a “fuzzy” mat).
- A spore-producing-body AKA a fruiting body is made and produces more spores.

Question 17

how is fungi grown?

Answer 17

A medium called Sabourad agar is used to grow fungi. It is selective for fungi because it is high in sugar and low in pH (which bacteria don’t like).

Question 18

Rhizopus stolonifer:
Chart

Answer 18

Causes bread mold.
Produce toxins (some): aflatoxins causing liver damage.
Mycoses:
Superficial - ringworm, nailbed funges, athlete’s food (all mostly immunocompromised).
Systemic- aspergillosis, valley fever (can go everywhere in the body)

Question 19

Aspergillus:
chart

Answer 19

Causes: aspergillosis
Pathogenesis:
- Allergic bronchopulmonary aspergillosis (ABPA): inflammation in lungs and allergy symptoms.
- Aspergilloma (fungus ball): in lungs or sinuses.
- Chronic pulmonary aspergillosis: causes cavities in the lungs.
- Invasive aspergillosis: serious lung infection, that can spread to other parts of the body.
Mode of transmission: inhaling spores.
Prevention: avoid dusty environments.
Treatment: surgical removal of aspergillomas, antifungals.

Question 20

Coccidioides:
chart

Answer 20

Causes: valley fever or coccidioidomycosis.
Pathogenesis:
-Focal: spherules in lungs
-Invasive: can cause pneumonia and spread to meninges, bones, etc.
Mode of transmission: inhaling spores.
Treatment: avoid dusty environments, especially in endemic areas.

Question 21

what are the characteristics of protozoa?

Answer 21

• Unicellular protists
• No cell wall
• Has Trophozoites: vegetative cell forms inside the host; the vegetative cell develops a protective covering called a cyst when released from the host (in stool).
• Transmission: ingestion of food/water contaminated with cysts
• Heterotrophs: get food from the host
• Reproduction: asexual or sexual

Question 22

what are protozoa subgroups based/categorized on?

Answer 22

their means of locomotion

Question 23

what are the subgroups of protozoa?

Answer 23

• Amoebas (uses pseudopodia to crawl).
• Ciliates: uses cilia
• Flagellates: uses flagella
• Sporozoans: non-motile adults

Question 24

Giardia duodenalis:
Chart

Answer 24

(Type of protozoa)
Causes: Giardiasis (GI disease).
Mode of transmission: fecal-oral route. (This happens by the feces having trophozoites and cysts, which contaminate food and water. The ingestion leads to an infection in the small intestine. Trophozoites develop cysts and are released).
Prevention: drink boiled or filtered water, sanitary food preparation, and hand hygiene.
Symptoms: cramps, diarrhea, nausea.

Question 25

what are protozoa subgroups based/categorized on?

Answer 25

their means of locomotion

Question 26

Trypanosoma brucei gambiense: Chart

Answer 26

Causes: African Sleeping Sickness. Modes of transmission: Tse Tse fly (which is the vector). Prevention: mosquito nets, repellants, avoid exposures to vectors with proper clothing, window screens, bet nets. (looks like worms but are protozoa). Life cycle: - You get bit by a Tse Tse fly, eventually gets into your bloodstream, effects and controls nervous system, could cause death.

Question 27

what are the three stages of Trypanosoma brucei gambiense infection?

Answer 27

1. Cutaneous stage: formation of papule/chancre at bite site. 2. Hemolymphatic stage: infection of blood/lymph (body pain, fever, chills, enlarged lymph nodes). 3. Nervous stage: infection of CNS (headaches, personality change, sleepiness, coma, death).

Question 28

Plasmodium: chart

Answer 28

Disease: Malaria Transmission: female (Anopheles) vector mosquito bite. Symptoms: fever, headache, chills. Prevention: - Vector control: insecticide-treated mosquito nets, indoor insecticide spraying. - Anti-malarial drugs: chemoprophylaxis, given to travelers, pregnant women, and infants. - Vaccine RTS, S/AS01: first-ever vaccine developed against a parasite

Question 29

how does malaria invade the body?

Answer 29

Invades the liver and then the blood cells, here parasites go through various life stages; they burst from red blood cells when another mosquito becomes infected during a blood meal.

Question 30

out of the 5 species, which form of plasmodium is the deadliest and most prevalent?

Answer 30

Out of 5 species, P. falciparum is the most prevalent and deadliest

Question 31

what happens to adults and children if malaria is left untreated?

Answer 31

Untreated cases can lead to severe illness Adults: multi-organ failure Children: anemia, respiratory distress, cerebral defects, and even death if untreated

Question 32

Trichomonas vaginalis: chart

Answer 32

Causes: trichomoniasis Symptoms: - 70% asymptomatic - itching, burning, soreness, and discharge from genitals. Modes of transmission: STD Prevention: abstinence, limit sexual partners, condoms

Question 33

Entamoeba histolytica: chart

Answer 33

Causes: amebiasis Symptoms: - 80% asymptomatic - Diarrhea, dysentery, cramps Mode of transmission: fecal-oral route (contaminated feces) Prevention: clean food and water consumption, personal hygiene

Question 34

Toxoplasma gondii: chart

Answer 34

Causes: toxoplasmosis Symptoms: asymptomatic, serious for pregnant, and immunocompromised. Mode of transmission: eating contaminated meat/shellfish, accidental ingestion of contaminated cat feces, congenital Prevention: cook and handle food properly; change cat litter box daily (parasites do not become infectious until 1 to 5 days after it is shed in the cat’s feces)

Question 35

What are the characteristics of helminths?

Answer 35

-Multicellular animals -Heterotrophs -Endoparasites (living inside us) -Can have multiple hosts -Reproduce sexually to lay eggs - eggs or larvae infect humans

Question 36

helminths can have multiple hosts - what does this mean?

Answer 36

They can have a: - Definitive host: supports adult form and sexual reproduction - Intermediate host: supports immature form and asexual reproduction

Question 37

what are the subgroups of helminths?

Answer 37

Nematodes (roundworms): Long worms tapered at the end Complete digestive tract with 2 openings (mouth/anus) Lots of worms don’t have 2 openings Two sexes with true reproductive organs (females are larger than males) Cestodes (tapeworms): Long segmented flatworms Scolex: the head with suckers and hooks to attach to the host’s intestinal wall Proglottids: segments with both male and female reproductive organs. Intestinal parasites No mouth or gastrovascular cavity; absorbs nutrients through the body surface Trematodes (flukes): Short, non-segmented flatworms Oral and ventral suckers for host attachment Intestinal parasites/diseases Incomplete digestive tract (one opening only)

Question 38

Ascaris Lumbricoides: chart

Answer 38

Nematode (roundworm) Causes intestinal disease ascariasis. Can be seen with naked eye. Giant human intestinal roundworm. Modes of transmission: - Fecal-oral route - Lives in intestine, reproduces to make eggs, eggs passed in feces, feces can contaminate food and water. Prevention: Prevention: sanitary disposal of human feces, don’t use human feces as fertilizer, keeping hands out of mouths, proper hand hygiene, washing/peeling/cook fruits and vegetables, and drinking clean water. Symptoms: vary None, abdominal discomfort, intestinal blockage, can spread to other parts of the body Diagnosis: microscopy of stool sample. Treatment: antihelmintics

Question 39

Taenia solium: chart

Answer 39

Pork Tapeworm (cestodes) Causes disease taeniasis Definitive host: human Intermediate host: pig Modes of transmission: eating undercooked pork containing larval cysts in muscle tissue. Prevention: don’t eat undercooked pork In the small intestine, larvae form adults; adults reproduce to make eggs; eggs are shed in feces; feces are eaten by pigs. Symptoms: None or mild Abdominal pain Loss of appetite Weight loss Upset stomach Diagnosis: microscopy of a stool sample Treatment: anthelmintics

Question 40

Schistosoma mansoni: chart

Answer 40

Trematodes; fluke Causes schistosomiasis Definitive host: human Intermediate host: snail Modes of transmission: skin penetration by larvae in snail-infested waters Prevention: avoid contaminated water, sanitary disposal of human feces, and molluscicides to kill snails An example of when this happened - was when China vs. Taiwan was in a war, and China went through the water and got this disease and lost the war Eggs in feces/urine hatch in water to form larvae that infect snail; the snail releases a different form of larvae in water, these penetrate human skin and through blood reach the liver; males and females pair up and migrate to the large intestine/bladder where they undergo sexual reproduction to form eggs.

Question 41

Clonorchis sinensis: chart

Answer 41

Trematode, fluke Causes: clonorchiasis Symptoms: none to mild to severe intestinal symptoms Definitive host: human Intermediate host: snail Mode of transmission: by eating raw/undercooked freshwater fish Prevention: avoid raw/uncooked freshwater fish Eggs are released in water; they are eaten by snails that poop larvae; these are eaten by fish; fish are eaten by humans; larvae enter bile ducts and multiply to make eggs which are passed in stools.

Question 42

Characteristics of arthropod parasites

Answer 42

- Ectoparasite: Consumes blood or tissue/tissue fluids from the host. Ex: a mosquito taking a blood meal (feeding on our blood). - Vectors: Carriers of diseases 1. Mechanical Vectors: carry pathogens externally and mechanically deposits them onto surfaces. Ex: a house fly carrying E. coli from feces. 2. Biological Vectors: carry pathogens internally and is a vital part of the pathogen’s life cycle. Ex: Mosquitos can carry malaria, Zika virus, West Nile virus, Ticks can carry Lyme disease, Rocky Mountain spotted fever

Question 43

Anopheles mosquito (insect): Chart

Answer 43

Causes disease: insect bites can vector other diseases (malaria) Modes of transmission: adult female mosquito flies from host to host Prevention: avoid exposure to vectors (similar to malaria)

Question 44

Ixodes tick (arachnid)

Answer 44

Causes disease: tick bites can vector other diseases (Lyme disease) Modes of transmission: ticks (larvae, nymphs, and adults) attach to the host from other humans or aminals Prevention: avoid exposure to vectors, via proper clothing and tick repellents, and remove ticks with forceps. Female ticks become engorged and increase in size after a blood meal.