Section 1: Overview Flashcards
What are the general characteristics of fungi?
Mushrooms, yeasts, molds, rusts, and smuts
Footnote
Fungi are essential decomposers in ecosystems and have various applications in medicine and food production.
What are the characteristics of molds?
Dry, fluffy, cottony, filamentous, or woolly colonies
* Reproduce through asexual spores (conidia) or sexual spores
* Examples: Aspergillus, Penicillium, Rhizopus
Molds play a significant role in food spoilage and can produce mycotoxins.
What are the characteristics of yeasts?
Single-celled organisms
* Smooth, creamy colonies
* Reproduce through budding or asexual spores (blastoconidia)
* Examples: Candida albicans, Saccharomyces cerevisiae
Yeasts are widely used in baking and brewing.
Who are the populations most susceptible to fungal infections?
Immunocompromised individuals
* People with underlying medical conditions
* Individuals taking immunosuppressive medications
These populations are at higher risk due to weakened immune systems.
What challenges are associated with treating fungal infections?
Difficult to treat due to similarities between fungal and human cells
* Antifungal medications can have side effects
* Fungal infections can be resistant to treatment
This resistance complicates treatment options and necessitates ongoing research.
What specimens are collected for fungal infections?
Skin scrapings
* Hair, nails
* Biopsy
* Sputum, bronchial washings
Specimen type depends on the suspected site and type of infection.
What are laboratory precautions for fungal infections?
Inhalation of fungal spores can cause respiratory infections
* Direct contact with fungal cultures can lead to skin infections
Proper lab safety protocols are essential to prevent exposure.
What is the purpose of potassium hydroxide (KOH) preparation in fungal diagnosis?
Dissolves keratin, making fungal elements visible
KOH preparation is a common method for examining skin and nail samples.
What is the incubation time for fungal cultures on Sabouraud dextrose agar (SDA)?
Typically takes 4-6 weeks
Incubation times can vary depending on the specific fungus.
What are the ways parasites enter the body?
Fecal-oral route
* Skin penetration
* Vector-borne transmission
* Sexual transmission
* Ingestion of undercooked meat
Understanding these transmission routes is crucial for prevention.
What is organotrophism in parasitology?
The tendency of parasites to have specific tissue tropisms
This affinity for certain tissues can influence the symptoms and treatment of parasitic infections.
What are the general characteristics of parasitic infections?
Varying degrees of severity
* Can cause a wide range of symptoms
* Diagnosis often involves microscopic examination
Symptoms can include fever, diarrhea, and organ damage.
What specimens are collected for parasitology?
Stool specimens
* Blood smears
* Tissue biopsies
These specimens are necessary for identifying different types of parasites.
What is the troph form of a parasite?
Active, feeding stage of the parasite
The troph form is responsible for the symptoms associated with parasitic infections.
What is the cyst form of a parasite?
Dormant, resistant stage of the parasite
Cysts are often used for transmission and can survive harsh conditions.
What are the main components of a virus structure?
Nucleic acid core (DNA or RNA)
* Protein capsid
* Some viruses have an envelope
The structure is critical for the virus’s ability to infect host cells.
How are viruses classified?
Based on nucleic acid type, structure, and replication strategy
Classification aids in understanding the behavior and treatment of viral infections.
What are the methods for diagnosing viral infections?
Direct detection of the virus
* Detection of viral antigens
* Detection of viral nucleic acid
* Serological tests
Each method has its advantages and is chosen based on the clinical context.
What is antigenic drift?
Gradual changes in viral antigens due to mutations
This process can affect vaccine effectiveness and the virus’s ability to evade the immune response.
What is antigenic shift?
Sudden, major changes in viral antigens due to reassortment of viral genes
Antigenic shift can lead to pandemics when a new virus emerges.
What causes influenza pandemics?
A new influenza virus emerges with novel antigens that humans have no immunity against
Typically originates in birds or pigs, highlighting the importance of surveillance in these animal populations.
What are the characteristics of the Herpesviridae family?
Herpes simplex virus 1 (HSV-1)
* Herpes simplex virus 2 (HSV-2)
* Varicella-zoster virus (VZV)
* Cytomegalovirus (CMV)
* Epstein-Barr virus (EBV)
Each virus has distinct clinical manifestations and risks.
What are prions?
Infectious proteins that cause neurodegenerative diseases
* Lack nucleic acid
* Misfolded proteins that induce other proteins to misfold
Examples include Creutzfeldt-Jakob disease and mad cow disease.
True or False: Prions are more complex than viruses.
False
Prions are simpler than viruses and lack nucleic acid.
How do prions differ from viruses?
Prions lack nucleic acid
* Prions are more resistant to inactivation
* Prions cause neurodegenerative diseases
Understanding these differences is critical for disease management and prevention.
