study guide questions w/ answers


  • What is one way that fungi function in nature (besides being a disease-causing agent)?
       - Decomposition of organic matter.

  • Which of the following is NOT a characteristic of fungi?
       - c. They have chlorophyll, are autotrophs, and require light for growth.

  • Compare and contrast yeasts and mold in a few sentences.
       - Yeasts are unicellular fungi that reproduce asexually through budding, while molds are multicellular and form long filamentous structures called hyphae. Both can cause human infections but vary in structure and reproduction.

  • What are the types of asexual reproduction of fungi and how does this differ from sexual reproduction of fungi?
       - Asexual reproduction methods include budding and spore formation. Sexual reproduction involves the fusion of two compatible mating types resulting in spores.

  • What is a dimorphic fungi?
       - A dimorphic fungus can exist in both yeast form and filamentous mold form depending on environmental conditions.

  • True or False: There are many antifungal drugs and drug resistance is not very prevalent in fungi.
       - False.

  • What are the two sources of fungi? Provide one example for each.
       - Sources include the environment (e.g., soil fungi) and the human body (e.g., Candida species).

  • How can commensal fungi cause disease?
       - Commensal fungi can become pathogenic when the immune system is compromised, leading to infections.

  • What is the difference between superficial, subcutaneous, and systemic fungal infections?
       - Superficial infections affect the outer skin and mucous membranes, subcutaneous infections penetrate deeper into tissues, and systemic infections spread throughout the body via the bloodstream.

  • Explain one of the virulence factors for fungal infections.
       - One virulence factor is the ability to produce biofilms, which protect fungi from the immune system and antifungal therapy.

  • For Dermatophytosis, match the name of the species to the infected location:
       - a. Tinea corporis - e. Ringworm
       - b. Tinea cruris - h. Jock itch
       - c. Tinea pedis - f. Athlete’s foot
       - d. Tinea capitis - g. Scalp and hair

  • What are the risk factors for Onychomycosis?
       - Risk factors include older age, diabetes, sports activities, and nail trauma.

  • What are the two main types of Candidiasis? Explain their symptoms and overall differences.
       - Oropharyngeal candidiasis (thrush) presents as white patches in the mouth, while vulvovaginal candidiasis presents with itching and discharge.

  • Why do fungal infections become more serious with comorbidities?
       - Comorbidities can weaken the immune system, making it harder to fight off fungal infections.

  • How could climate change impact fungal infections and their spread?
       - Climate change can alter habitats, increasing the prevalence and geographic spread of certain fungi, particularly in warmer, wetter conditions.

  • List two ways that a healthcare provider can identify and diagnose a fungal infection?
       - Cultures of the infected area and microscopic examination of scraped skin or other samples.

  • How does your immune system play a role in fighting off fungal infections? (be specific!)
       - The immune system utilizes phagocytosis by macrophages, production of antibodies, and activation of T-cells to eliminate fungal pathogens.

  • What are the two mechanisms of anti-fungal drugs for treatment of fungal infections? Give an example drug for each.
       - 1) Disruption of cell membrane integrity (e.g., Amphotericin B)
       - 2) Inhibition of cell wall synthesis (e.g., Caspofungin).

  • True or False: There are currently no antifungal vaccines, but there are trials underway right now.
       - True.

  • Categorize each type of protist as plant-like, animal-like, and fungi-like:
       - a. Nonmotile heterotrophs - Animal-like
       - b. Nonmotile autotrophs - Plant-like
       - c. Motile heterotrophs - Animal-like

  • Why was there an increased incidence of Malaria about 10,000 years ago?
       - Increased human populations near water sources created suitable breeding grounds for Anopheles mosquitoes, leading to more malaria transmission.

  • True or False: Children under 5 account for more than 80% of Malarial deaths in the region.
       - True.

  • Which Plasmodium parasite causes the most morbidity and mortality?
       - Plasmodium falciparum.

  • True or False: Only the male Anopheles mosquito is a host and can transmit Plasmodium.
       - False; only the female can transmit it.

  • Explain how two of the specialized structures in Plasmodium help it to better survive and invade host cells.
       - Apical organelles allow for efficient invasion of red blood cells, and dense granules release proteins that modify the host's immune response.

  • Fill in the blanks for the Malarial life cycle in both the primary and secondary hosts:
      Malarial life cycle (step by step)

    Start: infected mosquito → human

    1. An infected Anopheles mosquito bites a human

    2. It injects sporozoites into the bloodstream

    Human host (asexual stages)

    Liver stage

    1. Sporozoites travel to the liver

    2. They infect liver cells (hepatocytes)

    3. They multiply into schizonts

    4. Schizonts rupture and release merozoites into the blood

    Red blood cell (RBC) stage

    1. Merozoites infect red blood cells

    2. Inside RBCs, they develop in this order:

      • ring stage

      • trophozoite

      • schizont

    3. RBCs rupture and release more merozoites

    4. This repeating cycle causes fever and chills

    Gametocyte formation

    1. Some merozoites develop into gametocytes (male and female forms)

    2. Gametocytes circulate in the bloodstream

    Mosquito host (sexual stages)

    Ingestion

    1. A mosquito bites the infected human

    2. It ingests gametocytes

    Sexual reproduction in mosquito gut

    1. Gametocytes develop into gametes

    2. Male and female gametes fuse → form a zygote

    Development stages

    1. Zygote becomes an ookinete

    2. Ookinete penetrates the mosquito gut wall

    3. It develops into an oocyst

    Sporozoite formation

    1. Oocyst produces many sporozoites

    2. Oocyst ruptures and releases sporozoites

    3. Sporozoites migrate to the salivary glands

    Cycle repeats

    1. Mosquito bites another human

    2. Sporozoites are injected again → cycle restarts

  • What infects the hepatocytes and when the schizont ruptures in the hepatocytes what gets released? What infects the erythrocytes and when the schizont ruptures in the erythrocytes what gets released?
       - Hepatocytes are infected by sporozoites from the mosquito. When the schizont ruptures, merozoites are released. Erythrocytes are infected by merozoites that release more merozoites upon schizont rupture.

  • What do the proteins on P. falciparum do in the blood stream? How do these help the Plasmodium? What is this symptom called?
       - They cause red blood cells to adhere to blood vessel walls, which helps avoid immune clearance; it causes symptoms like severe anemia.

  • How do Plasmodium digest hemoglobin if the heme group is toxic to them?
       - They convert heme to hemozoin, which is less toxic and accumulates in their food vacuoles.

  • When do symptoms first occur?
       - Symptoms typically occur 10-15 days after infection when parasites enter the bloodstream in substantial numbers.

  • Although symptoms of Uncomplicated Malaria vary between each individual person and infection, describe the hallmark symptom?
       - Fever, often occurring in cycles.

  • List a few complications of Severe Malaria and how each is caused.
       - Cerebral malaria (due to sequestration of infected cells in the brain), anemia (due to destruction of red blood cells), and acute respiratory distress syndrome (ARDS, from severe inflammatory response).

  • What are the three R’s for the Malaria course of disease? What is the Hypnozoite and how does this play into one of the R’s?
       - The three R’s are Recognize, Respond, and Recover. Hypnozoites are dormant forms that can reactivate and cause relapse of the disease.

  • Compare and contrast the treatments for Malaria.
       - Treatments may include artemisinin-based therapies (effective but can lead to resistance) and chloroquine (effective for sensitive strains, resistance is a major issue).

  • Provide one suggestion for prevention of Malaria.
       - Use of insecticide-treated bed nets.

  • Provide a concise definition of One Health.
       - One Health is an approach that recognizes the interconnectedness of human, animal, and environmental health.

  • How are humans affecting the environment and how are these effects in turn affecting human health?
       - Deforestation and pollution lead to habitat loss and disease spread; this increases exposure to zoonotic diseases and respiratory issues.

  • What are some benefits of human-animal interactions?
       - Improved mental health, reduced stress, and support for therapy and recovery.

  • Why are bats such good hosts for infectious diseases? Name and describe two reasons.
       - High reproductive rates allow rapid infection spread; their migration and roosting habits increase contact with humans and spreading of pathogens.

  • List two other animals that commonly cause zoonotic events.
       - Rodents and birds.

  • Describe (in detail) one way that deforestation causes an increase of incidence of infectious disease?
       - Deforestation disrupts ecosystems, leading to increased contact between wildlife and human populations, facilitating zoonotic transmission of pathogens.

  • Describe (in detail) one way that climate change causes an increase of incidence of infectious disease?
       - Climate change can alter the distribution and lifecycle of vectors like mosquitoes, expanding their range and increasing human exposure to diseases like malaria.

  • Describe (in detail) at least one way in which urbanization or other land use causes an increase of incidence in infectious disease?
       - Urbanization leads to crowded living conditions and poor sanitation, facilitating the spread of infectious diseases through increased contact and vectors like mosquitoes.

  • How does protecting animal health impact human health? Give at least one example.
       - Protecting animal health reduces zoonotic disease transmission; for example, controlling rabies in dogs prevents human infections.

  • What is a neglected tropical disease? Where do they tend to occur?
       - Neglected tropical diseases (NTDs) are infectious diseases that primarily affect impoverished populations in tropical and subtropical regions.

  • Why do these diseases receive little attention despite affecting so many people?
       - They often lack funding for research and development due to low profitability and priority compared to other diseases.

  • Why do NTD’s disproportionately affect women and children?
       - Women and children may have less access to healthcare and education, increasing vulnerability to diseases and limiting resources for prevention and treatment.

  • Describe the life cycle of dracunculiasis briefly.
       - The lifecycle includes ingestion of contaminated water, maturation in the intestines, and emergence of adult females from the skin, causing ulcers.

  • How has the Carter Center and the WHO decreased the incidence so dramatically in the last 40 years?
       - By implementing water filtration and community education initiatives to reduce guinea worm infections.

  • Why is dracunculiasis not eradicated by now?
       - Challenges include continued access to contaminated water and socio-cultural factors affecting prevention efforts.

  • What are the two stages of human African trypanosomiasis? What are symptoms of each stage?
       - Stage 1: Hemolymphatic phase includes fever and headaches. Stage 2: Neurological phase includes confusion and sleep disturbances.

  • How is trypanosomiasis prevented?
       - Prevention includes avoiding tsetse fly bites through protective clothing and insect repellent, along with habitat management.

  • What are the symptoms of lymphatic filariasis? How is it transmitted? How is it prevented?
       - Symptoms include lymphedema and hydrocele. It's transmitted by mosquito bites and prevented by using insect repellent and community-wide treatment programs.

  • What are risk factors for schistosomiasis? What is its mechanism of entry? Mechanism of exit?
       - Risk factors include poor sanitation and freshwater exposure. Entry occurs through skin contact with contaminated water, and exit is through feces or urine.

  • How does schistosomiasis cause symptoms and tissue damage?
       - The immune response to eggs trapped in tissues causes inflammation and damage to organs.

  • What part of the body do soil-transmitted helminths infect?
       - They primarily infect the intestines.

  • How do these helminths impact nutritional status? What effect do this have? Who is at greatest risk and why?
       - They can cause malnutrition and anemia by consuming nutrients and damaging gut tissue; children and pregnant women are at greatest risk due to higher nutritional needs.