Quiz 4 Flashcards
(31 cards)
Dormant Vs Active Tuberculosis (TB)
Dormant: bacteria is present in the body but are inactive and cause no symptoms. people with latent TB are not contagious
Active: The bacteria are active and multiply, causing symptoms and can be spread to others.
Primary vs. Secondary vs. Disseminated TB
Primary: initial infection, usually occurring in the lungs. May resolve or progress to active disease
Secondary: Reactivation of dormant bacteria, often due to weakened immune system
Disseminated: infection spreads beyond the lungs to other parts of the body through bloodstream
Testing for TB presence
Tuberculin Skin Test : A small amount of tuberculin is injected under the skin
Interferon Gamma release: blood tests that measure the immune response to TB bacteria.
Sputum Test: Microscopy and culture of sputum samples to detect TB bacteria.
Vaccine for TB?
BCG vaccine: used to prevent severe forms of TB in children. Not widely used in the US but is common in countries with high TB prevalence.
Pertussis Cough?
Characterized by severe coughing fits followed by a whooping sound during inhalation
Vaccine for Pertussis?
DTaP Vaccine: For children, protecting against diphtheria, tetanus, and pertussis
Tdap Vaccine : for older children, adults, as a booster
Latent infection?
Chronic Infection?
Acute Infection?
Latent: virus remains dormant within the host cell and can reactivate later ex) Herpes
Chronic: continuous, low-level production of the virus over a long period ex) Hepatitis B (HBV)
Acute : Rapid onset of disease, short duration ex) Influenza (flu)
General Structure of SARS-CoV-2
RNA or DNA: RNA virus
Enveloped or Not: Enveloped
SARS-CoV-2 host cell receptor and Host Range
Host Cell Receptor: ACE2
Host Range: primarily humans, but also other mammals
Type of Influenza Virus That is the main human pathogen
Influenza A: the primary cause of seasonal flu epidemics and pandemics in humans.
Main Spikes for the Flu virus and their roles
Hemagglutinin (HA): helps the virus bind to and enter host cells
Neuraminidase (NA) : helps the new viral particles release from the host cell
Methods of infection and Flu viral multiplication
Method of Infection: HA binds to sialic acid receptors on the host cell, allowing entry
Viral Multiplication: Involves entry, replication, assembly, and release from the host cell.
Antigenic Drift:
Definition: small, gradual changes in the genes of influenza viruses that happen over time
Mechanism: Mutations accumulate in the virus’s RNA
Impact: causes seasonal flu variations, requiring annal vaccine updates.
HIV: CCR5 Coreceptor Function
Function: a protein on the surface of certain cells that HIV uses to enter the cells.
Antigenic Shift:
Definition: Abrupt, major changes in influenza A viruses, resulting in new hemagglutinin and or proteins
Mechanism: Reassortment of genes from different virus strains infecting the small cell
Impact: can lead to pandemics since the population has little to no pre existing immunity
Cells with HIV receptors
Types: CD4+ T cells, macrophages, dendritic cells
Receptors: CD4 and either CCR5 or CCXR4
HIV mechanism of Replication
Entry: HIV binds to CD4 and a coreceptor (CCR5/CXCR4) on the host cell.
Reverse Transcription: HIV’s RNA is reverse-transcribed into DNA by reverse transcriptase (RT).
Integration: Viral DNA integrates into the host cell genome, forming a provirus.
Transcription & Translation: Host cell machinery transcribes and translates viral genes.
Assembly & Release: New viral particles are assembled and released from the host cell.
Reverse Transcriptase?
Enzyme that converts viral RNA into DNA
Provirus definition
integrated viral DNA in the host genome, capable of producing new viruses
Difference between HIV & AIDS
HIV: virus that causes AIDS. attacks and weakens immune system
AIDS: the most advanced stage of HIV infection. diagnosed when CD4+ T cell count falls below 200 cells/mm3 or the presence of certain opportunistic infections
Steps of Replication mode of HIV
Attachment and Fusion: HIV binds to CD4 receptor and coreceptor, fuses with the host cell membrane.
Reverse Transcription: RNA genome is reverse-transcribed into DNA.
Integration: Viral DNA integrates into the host cell DNA.
Transcription: Host cell machinery transcribes viral DNA into RNA.
Translation: RNA is translated into viral proteins.
Assembly and Release: New viruses are assembled and bud off from the host cell.
Bacteriophages and Their mode of Multiplication
Phages: Definition: viruses that infect bacteria
Modes of multiplication: Lytic cycle and Lysogenic Cycle
Temperate Phages
Definition: Bacteriophages that can choose between the lytic and lysogenic pathways
Can either cause immediate lysis of the host or integrate their genome into the hosts genome as a prophage
Prophage
Definition: the phage that is integrated into the bacterial hosts genome
Remains dormant and replicates along with the hosts DNA until induced to enter the lytic cycle
