Podcast
Questions and Answers
Which part of the respiratory tract is located above the larynx?
Which part of the respiratory tract is located above the larynx?
What is the function of cilia in the upper respiratory tract?
What is the function of cilia in the upper respiratory tract?
In which part of the respiratory system does the epithelium become shorter and lose cilia?
In which part of the respiratory system does the epithelium become shorter and lose cilia?
Which cells are the initial targets for SARS-CoV-2 viral entry?
Which cells are the initial targets for SARS-CoV-2 viral entry?
Signup and view all the answers
What receptor does the SARS-CoV-2 spike protein bind to?
What receptor does the SARS-CoV-2 spike protein bind to?
Signup and view all the answers
Which HPV type is commonly associated with plantar warts?
Which HPV type is commonly associated with plantar warts?
Signup and view all the answers
Which HPV types are most frequently found in laryngeal papillomas?
Which HPV types are most frequently found in laryngeal papillomas?
Signup and view all the answers
Which of the following is a common cause of skin warts?
Which of the following is a common cause of skin warts?
Signup and view all the answers
Condyloma acuminatum is most frequently associated with which HPV types?
Condyloma acuminatum is most frequently associated with which HPV types?
Signup and view all the answers
What is the most frequent cause of cervical cancer?
What is the most frequent cause of cervical cancer?
Signup and view all the answers
What is the hallmark feature of coronaviruses?
What is the hallmark feature of coronaviruses?
Signup and view all the answers
What is the primary mode of transmission for coronaviruses?
What is the primary mode of transmission for coronaviruses?
Signup and view all the answers
Which of the following is the viral attachment protein (VAP) for coronaviruses?
Which of the following is the viral attachment protein (VAP) for coronaviruses?
Signup and view all the answers
What is the tropism of coronaviruses?
What is the tropism of coronaviruses?
Signup and view all the answers
Common cold coronaviruses grow best at what temperature?
Common cold coronaviruses grow best at what temperature?
Signup and view all the answers
In which cells does Hepatitis A virus replicate?
In which cells does Hepatitis A virus replicate?
Signup and view all the answers
By what method does Hepatitis A virus replicate?
By what method does Hepatitis A virus replicate?
Signup and view all the answers
What is the typical duration of Hepatitis A virus shedding in stool before symptom onset?
What is the typical duration of Hepatitis A virus shedding in stool before symptom onset?
Signup and view all the answers
What is the typical disease outcome of Hepatitis A virus (HAV) infection?
What is the typical disease outcome of Hepatitis A virus (HAV) infection?
Signup and view all the answers
What is the only known reservoir for Hepatitis A virus?
What is the only known reservoir for Hepatitis A virus?
Signup and view all the answers
What is the main function of the viral capsid?
What is the main function of the viral capsid?
Signup and view all the answers
Which viral component is a lipid bilayer?
Which viral component is a lipid bilayer?
Signup and view all the answers
What type of virus is Rhinovirus?
What type of virus is Rhinovirus?
Signup and view all the answers
Which of the following is an example of a non-structural protein in viruses?
Which of the following is an example of a non-structural protein in viruses?
Signup and view all the answers
What type of virus is Hepatitis B?
What type of virus is Hepatitis B?
Signup and view all the answers
How are most viral respiratory infections typically transmitted?
How are most viral respiratory infections typically transmitted?
Signup and view all the answers
What antibody is secreted during an acute Hepatitis B infection?
What antibody is secreted during an acute Hepatitis B infection?
Signup and view all the answers
What receptor does HIV-1's VAP, gp120, bind to on host cells?
What receptor does HIV-1's VAP, gp120, bind to on host cells?
Signup and view all the answers
Which of the following is a potential outcome of chronic Hepatitis B infection?
Which of the following is a potential outcome of chronic Hepatitis B infection?
Signup and view all the answers
Which virus utilizes hemagglutinin (HA) as its VAP?
Which virus utilizes hemagglutinin (HA) as its VAP?
Signup and view all the answers
What is the name of the complete Hepatitis B virus particle?
What is the name of the complete Hepatitis B virus particle?
Signup and view all the answers
Hepatocellular necrosis in Hepatitis B is primarily caused by?
Hepatocellular necrosis in Hepatitis B is primarily caused by?
Signup and view all the answers
What is the typical incubation period for most viral respiratory infections?
What is the typical incubation period for most viral respiratory infections?
Signup and view all the answers
Which of the following viruses is a major cause of acute respiratory disease (ARD)?
Which of the following viruses is a major cause of acute respiratory disease (ARD)?
Signup and view all the answers
What is the viral receptor for SARS-CoV-1 and SARS-CoV-2?
What is the viral receptor for SARS-CoV-1 and SARS-CoV-2?
Signup and view all the answers
Flashcards
Upper Respiratory Tract
Upper Respiratory Tract
The part of the respiratory system above the larynx, including sinuses, nasal cavity, and pharynx.
Respiratory Epithelium Function
Respiratory Epithelium Function
Helps clean inhaled air by trapping debris in mucus and moving it with cilia towards the GI tract.
Lower Respiratory Tract
Lower Respiratory Tract
The part of the respiratory system below the larynx, including bronchi, bronchioles, and alveoli.
SARS-CoV-2 Entry Point
SARS-CoV-2 Entry Point
Signup and view all the flashcards
ACE2 Receptor
ACE2 Receptor
Signup and view all the flashcards
HPV Strains
HPV Strains
Signup and view all the flashcards
Skin Warts
Skin Warts
Signup and view all the flashcards
Epidermodysplasia verruciformis
Epidermodysplasia verruciformis
Signup and view all the flashcards
Condyloma acuminatum
Condyloma acuminatum
Signup and view all the flashcards
Cervical intraepithelial neoplasia
Cervical intraepithelial neoplasia
Signup and view all the flashcards
Coronaviruses
Coronaviruses
Signup and view all the flashcards
Viral Attachment Protein (VAP)
Viral Attachment Protein (VAP)
Signup and view all the flashcards
Tropism of Coronaviruses
Tropism of Coronaviruses
Signup and view all the flashcards
Transmission Routes
Transmission Routes
Signup and view all the flashcards
Production of multiple mRNAs
Production of multiple mRNAs
Signup and view all the flashcards
Nucleic acid
Nucleic acid
Signup and view all the flashcards
Capsid
Capsid
Signup and view all the flashcards
Structural proteins
Structural proteins
Signup and view all the flashcards
Non-structural proteins
Non-structural proteins
Signup and view all the flashcards
Envelope
Envelope
Signup and view all the flashcards
Acute respiratory disease (ARD)
Acute respiratory disease (ARD)
Signup and view all the flashcards
Virus Attachment Proteins (VAP)
Virus Attachment Proteins (VAP)
Signup and view all the flashcards
HIV-1 VAP
HIV-1 VAP
Signup and view all the flashcards
Influenza virus
Influenza virus
Signup and view all the flashcards
Common cold viruses
Common cold viruses
Signup and view all the flashcards
Hepatitis A Virus
Hepatitis A Virus
Signup and view all the flashcards
Replication Location of Hepatitis A
Replication Location of Hepatitis A
Signup and view all the flashcards
Hepatitis C Virus (HCV)
Hepatitis C Virus (HCV)
Signup and view all the flashcards
HCV Transmission Pathways
HCV Transmission Pathways
Signup and view all the flashcards
HCV Mutation Rate
HCV Mutation Rate
Signup and view all the flashcards
Acute HBV infection
Acute HBV infection
Signup and view all the flashcards
Chronic HBV infection
Chronic HBV infection
Signup and view all the flashcards
Transmission routes for HBV
Transmission routes for HBV
Signup and view all the flashcards
Hepatitis B surface antigen (HbsAg)
Hepatitis B surface antigen (HbsAg)
Signup and view all the flashcards
Study Notes
MABS Microbiology Overview
- The course covers virology, respiratory viruses, hepatitis viruses, papilloma and polyoma viruses, and human retroviruses.
Course Instructional Objectives
- MCRO 3.1 (Coronavirus): Students will describe the taxonomy, structure, function, transmission, pathogenesis, viral infection stages, viral gene expression, viral replication, and effects on cellular and/or human immune response of the Coronavirus family.
- MCRO 3.2 (Influenza): Students will describe the taxonomy, structure, function, transmission, pathogenesis, stages of viral infection, viral gene expression, viral replication, effects on the cellular level, human immune response, and/or treatment of the Orthomyxoviridae family (influenza).
- MCRO 3.3 (RSV): Students will describe the taxonomy, structure, function, transmission, pathogenesis, effects on the cellular level, and human immune response of the Paramyxoviridae family (RSV).
- MCRO 3.4 (Adenoviridae): Students will describe the taxonomy, structure, function, transmission, pathogenesis, viral infection stages, viral gene expression, viral replication and effects on the cellular and/or human immune response of the Adenoviridae family.
- MCRO 3.5 (Retroviruses): Students will describe the taxonomy, structure, function, transmission, pathogenesis, stages of viral infection, viral gene expression, viral replication, effects on the cellular level, human immune response, and/or treatment, especially HIV-1.
- MCRO 3.6 (Papillomaviridae): Students will describe the taxonomy, structure, function, transmission, pathogenesis, stages of viral infection, viral gene expression, viral replication, effects on the cellular level, and/or which forms of HPV are less/more likely to lead to cancer of the Papillomaviridae family.
- MCRO 3.7 (Hepatitis): Students will describe the taxonomy, structure, function, transmission, pathogenesis, stages of viral infection, effects on the cellular level, and/or human immune response of hepatitis viruses, especially HVA, HBV, and HVC.
Components of a Virus
- Viral Component: Nucleic acid, Capsid, Structural proteins, Non-structural proteins, Envelope
- Role in Viral Life Cycle: Encodes all information necessary to produce new virions, protein shell to contain/package and protect nucleic acid, proteins that form the capsid, package the genome, and/or are attachment proteins, required for replication, assembly, and disease progression, lipid bilayer anchoring for viral attachment facilitating penetration.
- Example: DNA or RNA, Icosahedral, helical, or complex, Matrix, nucleocapsid, etc.
Respiratory Viruses
- Respiratory disease accounts for 75-80% of acute morbidity in the United States.
- Most respiratory illnesses are viral (80%), transmitting via respiratory droplets or by hand transfer, with incubation periods ranging from 1-14 days.
- Common causes of acute respiratory disease include parainfluenza viruses, influenza viruses, respiratory syncytial virus (RSV), coronaviruses (including COVID-19), adenoviruses, rhinoviruses, human metapneumovirus (hMPV), and bocaviruses.
Common Respiratory Viruses
- List of common respiratory viruses
VAP and Cell Receptor Pairs
- Table relating viruses, families, structural characteristics, viral attachment proteins (VAPs), and receptors.
Summary: Coronaviruses
- Coronaviruses are large RNA viruses with a helical nucleocapsid and a lipid envelope containing Spike (S) glycoprotein, membrane glycoproteins, and envelope glycoproteins.
- Replication occurs in the cytoplasm.
- Three novel human coronaviruses cause severe acute respiratory syndrome (SARS-CoV-1, MERS-CoV, and SARS-CoV-2(COVID-19).
- COVID-19 became a pandemic, with approximately 178 million cases and 3.86 million deaths globally.
- SARS-CoV-2 is transmitted via respiratory droplets, and its Spike glycoprotein interacts with ACE2 receptors in the upper and lower respiratory tract.
- Molecular (RT-PCR) and antigen tests are available to detect SARS-CoV-2, along with antibody tests for previous exposure.
Respiratory Epithelium
- Upper respiratory tract epithelium is taller and has cilia and mucus-producing cells to clear inhaled debris.
- Lower respiratory tract epithelium is shorter, losing cilia and mucus-producing cells, facilitating oxygen and carbon dioxide diffusion.
- SARS-CoV-2 enters via the respiratory tract and nasopharyngeal/oropharyngeal cells, targeting cells in the lower respiratory tract, including airways, alveolar epithelial cells, and alveolar macrophages.
- Viral Spike glycoproteins bind to ACE2 receptors in the respiratory system, kidneys, and myocardium.
Coronavirus
- Family: Coronaviridae
- Genome: linear positive sense ssRNA
- Capsids: enveloped, helical
- Transmission: respiratory droplets, fecal-oral
- VAP: E2 or spike glycoprotein
- Tropism: respiratory tract or GI tract (epithelium)
- Production of multiple mRNAs for protein production contributing to diversity.
- Generation of many mRNAs at the same time that progeny genomes are being synthesized may promote recombination and introduce diversity into the genome.
Common Coronavirus Disease
- Infects respiratory epithelium, disrupting cilia function
- Optimal growth temperature <35°C.
- Normally causes mild upper respiratory infections.
- 10-15% of colds, predominantly in infants and children.
- Reinfection common throughout life
- Generally does not lead to severe lower respiratory tract infections.
- Makes antibodies to E2/spike glycoprotein upon infection, short-lived, no sustained protection.
Severe Acute Respiratory Syndrome (SARS)
- Caused by zoonotic coronaviruses transmitted from animals (civets, raccoon dogs, badgers) to humans.
- Spread commonly by respiratory droplets, but the virus can also be present in sweat, urine, and stool.
- Causes atypical pneumonia, with symptoms including high fever, chills, headache, dizziness, malaise, cough, difficulty breathing, and diarrhea.
- Mortality rate varies based on age and is often cytokine storm-related.
Viral Infection and the Immune System
- Overview of viral infection and immune response, including phagocytosis and activation of T-cells and cytokines
Immune System and Coronaviruses
- High recruitment of leukocytes (T cells, monocytes, neutrophils)
- Cell-mediated immunity plays a role in controlling infections, reducing severity, with some longer-term protection provided by antibodies.
- Damage caused by COVID-19 involves both viral and immune mechanisms with pro-inflammatory cytokines, lung damage, replication in alveolar airway epithelial and vascular endothelial cells.
VAP and Cell Receptor Pairs (repeated from page 6)
- Table relating various viruses to their families, structural characteristics, viral attachment proteins (VAPs), and receptors.
Summary: Influenza
- Family: Orthomyxoviridae
- Genome: single-stranded negative-sense, segmented RNA
- Structure: enveloped, pleomorphic, helical capsid
- Classification: A, B, and C; based on differences in nucleoproteins (NP) and matrix (M) proteins.
- Glycoproteins: hemagglutinin (HA) and neuraminidase (NA)
- These are important differences.
Influenza Virus
- Family: Orthomyxoviridae, linear ssRNA genome, enveloped, helical capsid
- Transmission: respiratory droplets
- Tropism: respiratory epithelium
- Major surface glycoproteins, Hemagglutinin (HA), and Neuraminidase (NA).
- HA binds to sialic acid glycoprotein receptors, and NA is required for viral release.
- Three serotypes (A, B, C).
Influenza Life Cycle
- Viral mRNA transcription and genomic RNA replication occurs in the nucleus.
- Nucleocapsids assemble in the nucleus and virus assembly occurs in the cytoplasm.
Influenza Treatment and Prevention
- Symptomatic: Acetaminophen, antihistamines
- Attachment Inhibition: HA-specific antibodies (vaccine)
- Uncoating Inhibition: Amantadine, rimantadine (blocks the M2 proton channel)
- Release Inhibition: Zanamivir, oseltamivir, peramivir (inhibit neuraminidase)
- Prevention: Vaccination
Classification of RNA Viruses
- Multiple combinations of genome and capsid structure
- RNA viruses that are single-stranded except for Reoviridae.
- Negative-sense RNA viruses are enveloped with helical capsid structure.
- All non-enveloped RNA viruses have icosahedral capsid structure.
Paramyxoviridae
- Family: Paramyxoviridae
- Virus: Respiratory syncytial virus (RSV)
- Structure: enveloped, helical capsid, negative-sense RNA
- Replication: cytoplasmic; buds from the plasma membrane
- Transmission: respiratory route
- Symptoms: illnesses such as croup, bronchitis, bronchiolitis, or pneumonia are common in infants.
Respiratory Syncytial Virus (RSV)
• Leading cause of fatal acute respiratory infections in infants and young children. • Two serotypes co-circulate during the RSV season (October–March). • Viral attachment proteins include G (glycoprotein) and F (fusion protein). • RSV primarily infects the respiratory epithelium, does not cause viremia. • Transmitted through large droplets and direct contact. • High risk populations include premature infants and elderly, and bone marrow and heart–lung transplant recipients.
Human Papillomavirus (HPV)
- More than 170 types, 40 infect the human genital tract
- Non-enveloped DNA virus with icosahedral capsid.
- Associated with: warts, benign cervical cancers, and cervical cancer.
- Several strains are low-risk, others are high-risk.
HPV Transformation
- Inactivation of p53 and Rb proteins (tumor suppression genes) by HPV proteins E6 and E7 (oncogenes), promoting cell proliferation and preventing DNA repair.
- Increases mutations and chromosomal damage, leading to transformation and/or cancer development.
HPV Diagnosis
- Microscopically, abnormal keratin production (hyperkeratosis), and large keratinocytes with clear halos around the nuclei (koilocytous).
- Pap smears/cytology to identify visible changes in cells.
- Grading systems (e.g., CIN classifications) used based on degree of dysplasia or cervical abnormality.
Hepatitis Viruses
- Diverse family of viruses primarily affecting the liver (hepatitis, inflammation).
- Most are RNA viruses except Hepatitis B, which is a DNA virus.
- Causes of hepatitis include viral infection (A, B, C, D, or E), alcohol-related damage, autoimmune disorders, or ischaemia.
Hepatitis Virus Overview
- Viral infection symptoms range from asymptomatic to chronic.
- Symptoms may result from the host immune response.
- Common features include prodrome (fever, malaise, anorexia), pre-icteric symptoms (nausea, vomiting, abdominal pain, and fever), icteric symptoms (jaundice).
- Diagnosis involves analyzing symptom progression patterns, patient history, and serology (testing for viral antigens or antibodies).
Hepatitis A Virus (HAV)
- Picornaviridae family; positive-sense ssRNA, icosahedral capsid.
- Resists inactivation by stomach acid and heat.
- Acquired by ingestion (contaminated food/shellfish or water).
- Replicates in the intestinal epithelium before spreading to the liver (particularly hepatocytes and Kupffer cells).
- Virus shedding occurs in stool for approximately 10 days before symptom onset.
- It is non-enveloped icosahedral.
- No chronic sequelae or persistent infection.
Hepatitis C Virus (HCV)
- Flaviviridae family, positive-sense ssRNA.
- Enveloped, icosahedral, non-structural proteins.
- Six genotypes, with varied geographic distributions.
- Exhibits a high mutation rate, leading to HCV quasi-species.
- Primarily affects hepatocytes, potentially B cells.
- Transmitted through blood transfusion, transplanted organs, or sexual contact.
- Chronic infection is prevalent (approx 50% of infected patients).
Hepatitis B Virus (HBV)
- DNA virus, Hepadnavirus family
- Hepatocellular necrosis is more related to the body's immune response than the virus itself.
- Acute hepatitis involves symptoms like jaundice.
- Chronic infections can lead to cirrhosis and hepatocellular carcinoma.
- Transmission: various routes including transfusion, mother-to-child, and blood exposure.
Retroviruses
- Family of RNA viruses requiring reverse transcriptase (RT) for making a complementary DNA copy of the viral RNA
- The copied DNA is integrated into the host cell's DNA
Human Immunodeficiency Virus 1 (HIV-1)
- Retroviridae family
- Positive-sense ssRNA genome
- Enveloped
- Viral attachment protein: gp160 (gp120 + gp41)
- Receptors: CD4 and coreceptors CCR5 or CXCR4
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on the human respiratory tract and viral infections in this engaging quiz. Explore how different viruses affect the respiratory system and related diseases, including HPV and coronaviruses. Delve into questions about structures, functions, and virus interactions with host cells.
