Protozoan Infections and Characteristics Quiz

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Questions and Answers

What is the primary cause of Entamoeba histolytica infection?

Food poisoning

Bacterial gastroenteritis

Amoebic dysentery (correct)

Intestinal obstruction

Which of the following best describes the mode of transmission for Entamoeba histolytica?

Airborne transmission

Contaminated water (correct)

Vector-borne transmission

Direct contact with infected individuals

What is a major characteristic of Naegleria fowleri?

It is primarily found in saltwater.

It is a common human pathogen.

It enters the body orally.

It typically infects through the nose. (correct)

Which symptom is associated with Giardia lamblia infection?

Diarrhea and gas Signup and view all the answers

What is a common symptom of Trichomonas vaginalis infection in women?

Vaginal discomfort Signup and view all the answers

What distinguishes Naegleria fowleri from typical pathogens?

It is not usually a human pathogen. Signup and view all the answers

What is the most common illness caused by Giardia lamblia?

Diarrheal illness Signup and view all the answers

Which of the following is NOT a characteristic of Entamoeba histolytica?

Lives in freshwater Signup and view all the answers

What is a characteristic feature of parasitic helminths in their adult form?

They can be easily visualized. Signup and view all the answers

Which of the following statements is true about nematodes?

They have over 15,000 species. Signup and view all the answers

How does one contract trichinosis?

By eating undercooked pork. Signup and view all the answers

What health problems can severe infections of Trichinella spiralis lead to?

Lack of coordination and breathing problems. Signup and view all the answers

What is the most common intestinal worm infection in the United States?

Enterobius vermicularis Signup and view all the answers

What is a key characteristic of flukes?

They have an oral sucker to attach to hosts. Signup and view all the answers

Which part of tapeworms is primarily responsible for attachment to the host's intestine?

Scolex Signup and view all the answers

What role do fungi primarily serve in ecosystems?

Decomposers breaking down organic material. Signup and view all the answers

Which of the following is a type of tapeworm known to infect humans?

Pork tapeworm Signup and view all the answers

How do flukes generally infect their hosts?

By cross-species transmission. Signup and view all the answers

What is the main mode of transmission for Cryptosporidium parvum?

Intimate contact Signup and view all the answers

What is a major consequence of Plasmodium vivax infection?

Long-term intellectual disabilities in children Signup and view all the answers

Which statement about malaria is accurate?

Can cause severe complications if untreated Signup and view all the answers

What type of mosquito is involved in the transmission of Plasmodium vivax?

A specific Anopheles mosquito that only lives in tropical environments Signup and view all the answers

What are the primary symptoms exhibited every 2-3 days in malaria?

Chills, fever, and sweats Signup and view all the answers

What is the primary role of penicillin in medical treatments?

Inhibiting bacterial enzyme activity Signup and view all the answers

What structure found in fungal cells can be targeted by antifungal drugs?

Chitin in cell walls Signup and view all the answers

Which characteristic differentiates molds from yeasts?

Molds are multicellular and filamentous while yeasts are unicellular Signup and view all the answers

What type of organism is primarily responsible for Ringworm infections?

Fungi Signup and view all the answers

Which condition is characterized by the presence of pseudohyphae?

Candidiasis Signup and view all the answers

Histoplasmosis is primarily associated with which of the following environmental sources?

Bat guano and bird droppings Signup and view all the answers

What defines a dimorphic fungus?

Can grow in two distinct forms Signup and view all the answers

What is a common mode of transmission for dermatophyte infections?

Direct contact with infected surfaces Signup and view all the answers

Which of the following best describes the life cycle of fungi?

Asexual or sexual reproduction Signup and view all the answers

In what way does Aspergillus cause diseases?

Triggers allergic reactions and can cause infections Signup and view all the answers

Study Notes

Amoeba Pathogens

Entamoeba histolytica: Primary cause of amoebiasis
- Parasite
- Causes severe diarrhea, dysentery, and abdominal pain
- Spreads through contaminated food and water
Naegleria fowleri: "brain-eating amoeba"
- Causes primary amoebic meningoencephalitis (PAM)
- Lives in freshwater
- Enters through the nose

Flagella Pathogens

Giardia lamblia:
- Giardiasis: Diarrheal illness transmitted through contaminated water
- Diarrhea, gas, greasy stool, abdominal cramps
- The most common intestinal parasitic infection in the United States
Trichomonas vaginalis:
- Common sexually transmitted infection
- Causes trichomoniasis which is often asymptomatic in men, but can still be transmitted
- In women, causes vaginal discomfort (itching and burning) and discharge. May cause pregnancy complications
- No cyst stage -- transmitted by intimate contact

"Gliding" Protozoans

Cryptosporidiosis
- Cryptosporidium parvum: often asymptomatic, but can cause intestinal symptoms and diarrhea
- Cysts can contaminate drinking water
Plasmodium vivax
- Causative agent of malaria
- Transmitted by infected mosquitoes
  - Particular mosquito only lives in tropical environments
- Major cause of:
  - Morbidity: illness, specifically causes long term intellectual disabilities in children
  - Mortality: death, especially in children under 5
- Incubation is 7-30 days
- Chills, fever, sweats (every 2-3 days) and if left untreated can develop severe complications and die -- the parasites rupture out of the red blood cells to infect more cells
- Very treatable with antimalarial drugs -- but must recognize the symptoms
- Over 600,000 malaria related deaths occur annually

Parasitic helminths

Identified by their cylindrical or flattened body shapes
Once in adult form, can be easily visualized
2 main types:
- Roundworms (nematodes)
- Flatworms (Platyhelminthes)
About half the species in each of these groups are parasitic
These are highly specialized parasites
- Limited digestive tracts, nervous systems, and locomotor abilities as parasites
- Can have complex reproductive cycles with different life stages and more than one type of host
Roundworms (nematodes)
- More than 15,000 species
- Unsegmented
- Enterobius vermicularis: is the most common intestinal worm infection in the United States
  - Pinworm causes sleeplessness and itching around the anus -- female worms lay their eggs during the night
- Trichinella spiralis
  - Causes trichinosis
  - Contracted by consuming undercooked meat (specifically pork if not cooked to 165℉), which releases the larvae and allows them to encyst in muscles
  - Causes muscle pain, fever, and swelling
  - Severe infections can lead to lack of coordination, breathing and heart problems, and even death
Flatworms (platyhelminths)
- Includes flukes, tapeworms that are parasites
- Flukes (trematodes) are unsegmented flatworms that have an oral sucker that attach to the inner walls of intestines, lungs, large blood vessels, or the liver
- Can have complex life cycles
- Leave one to infect another -- cross species
- Tapeworms:
  - Segmented flatworms that may have suckers or hooks at the scolex (head region)
  - Proglottids: Segment of the body that can be full of eggs
  - Attach to the wall of the small intestine
  - Taenia saginata and Taenia solium
    - Include a beef and pork tapeworm
    - Enter humans through consumption of undercooked meat

Fungi

Diverse group
Heterotrophic: nonphotosynthetic
Multi- or unicellular
Saprophytic or parasitic
- Act as decomposers
Many diseases are opportunistic
Often helpful:
- Act as decomposers
- Cheese!-- blue cheese, soft cheeses
- Antibiotics -- such as penicillin
Penicillin
- Among the first antibiotics to be effective against many bacterial infections caused by Staphylococci and Streptococci
- Discovered by Alexander Fleming
- Act by inhibiting enzymes required for the cross-linking of peptidoglycans in bacterial cell walls
Medical Importance -- Penicillium
- Source of antibiotics
Fungi
- Complex life cycle:
  - Asexual/sexual reproduction
- Structure:
  - Many fungal cell contain chitin (a polysaccharide)
  - Cell membranes often contain ergosterol
    - As this is specific to fungi, can be used as a target for antifungal drugs
Molds and Yeasts Morphology
- Molds -- multicellular (filamentous)
  - Filaments called hyphae -- long, threadlike chains of cells
  - For reproduction: produce spores either asexually or sexually
- Yeasts -- unicellular (nonfilamentous)
  - Budding yeasts reproduce asexually by budding off a smaller cell and can stick together
Most fungi are saprophytic: grow in environments that are rich in nutrients, low in oxygen -- grow on dead material
- Few colonize living tissue
Some fungi are dimorphic: can grow as either yeasts or hyphae (mold)
- Important for infectivity and can help survive in diverse environments
Mycoses: fungal infections
- Location:
  - Superficial: infections on surface (hair, skin, nails) -- spread by direct contact
  - Subcutaneous: infections beneath the skin -- puncture wound
  - Systemic: in the lungs
  - Opportunistic: can be everywhere -- often start in the lungs before spreading
- Many are opportunistic
- Histoplasma capsulatum:
  - Histoplasmosis: pulmonary infection
  - Dimorphic (temperature)
  - Spores in soil, bat guano, bird droppings
  - Asymptomatic or flu-like
- Ringworm
  - Dermatophytosis
  - Can be caused by 1 of 40 different species
  - Spread by direct contact
- Candidiasis -- yeast infection
  - A common yeast -- Candida albicans, and forms pseudohyphae
  - Causes infections in humans such as oral thrush, diaper rash, vaginal yeast infections, and systemic infections
- Aspergillus
  - Diverse group -- common inside and outside
  - Causes disease in immunocompromised individuals
    - Different species can cause aspergillosis -- a group of diseases
      - Pulmonary, invasive, cutaneous, allergic reactions
  - Grow in oxygen rich environments including on food (breads and potatoes) and on many plants and trees (tomatoes)

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Description

Test your knowledge on various protozoan infections, including those caused by Entamoeba histolytica, Giardia lamblia, Naegleria fowleri, and Trichomonas vaginalis. This quiz covers transmission methods, symptoms, and distinguishing characteristics of these pathogens. Challenge yourself to see how well you understand these important infectious agents.