Human Rhinoviruses and the Common Cold

Human Rhinoviruses

• Definition: Human rhinoviruses (HRVs) are a type of picornavirus that causes the common cold.
• Transmission: HRVs are highly contagious and spread through:
  • Direct contact with contaminated surfaces or objects
  • Airborne transmission through coughing and sneezing
  • Close contact with an infected person
• Pathogenesis: HRVs infect the epithelial cells of the upper respiratory tract, causing inflammation and symptoms such as:
  • Runny nose
  • Sneezing
  • Coughing
  • Sore throat
  • Fatigue
• Immune Response: HRVs are highly antigenically variable, making it difficult for the immune system to mount a effective response. However, the immune system can produce neutralizing antibodies against specific HRV serotypes.

Influenza

• Definition: Influenza, commonly known as the flu, is a contagious respiratory illness caused by the influenza virus.
• Types: There are three main types of influenza viruses:
  • A: affects humans and animals, and is responsible for seasonal outbreaks and pandemics
  • B: affects humans and is responsible for seasonal outbreaks
  • C: affects humans and is responsible for mild infections
• Transmission: Influenza viruses are transmitted through:
  • Airborne transmission through coughing and sneezing
  • Close contact with an infected person
• Pathogenesis: Influenza viruses infect the epithelial cells of the respiratory tract, causing inflammation and symptoms such as:
  • Fever
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Headache
  • Fatigue
• Immune Response: The immune system produces antibodies against influenza viruses, which can provide protection against future infections. However, the immune system must constantly adapt to new strains of the virus through vaccination or natural infection.

Varicella-Zoster Virus

• Definition: Varicella-zoster virus (VZV) is a herpesvirus that causes two distinct diseases:
  • Chickenpox (varicella): a primary infection characterized by a rash and fever
  • Shingles (zoster): a reactivation of the virus in adults, characterized by a painful rash
• Transmission: VZV is transmitted through:
  • Direct contact with an infected person
  • Airborne transmission through coughing and sneezing
• Pathogenesis: VZV infects the skin and nervous system, causing symptoms such as:
  • Rash
  • Fever
  • Headache
  • Fatigue
  • Painful rash (shingles)
• Immune Response: The immune system produces antibodies against VZV, which can provide lifelong protection against future infections. However, the virus can reactivate in adults, causing shingles.

Rev

• Definition: Rev is a protein encoded by the human immunodeficiency virus (HIV) that plays a crucial role in viral replication.
• Function: Rev regulates the expression of HIV genes by:
  • Binding to RNA and promoting its export from the nucleus to the cytoplasm
  • Inhibiting the production of RNA that inhibits viral replication
• Importance: Rev is essential for HIV replication and is a key target for antiretroviral therapy.

Adenoviruses

• Definition: Adenoviruses are a type of DNA virus that causes a range of diseases, including:
  • Respiratory infections
  • Gastroenteritis
  • Conjunctivitis
• Transmission: Adenoviruses are transmitted through:
  • Direct contact with contaminated surfaces or objects
  • Airborne transmission through coughing and sneezing
  • Fecal-oral transmission
• Pathogenesis: Adenoviruses infect the epithelial cells of various tissues, causing symptoms such as:
  • Fever
  • Cough
  • Sore throat
  • Diarrhea
  • Vomiting
• Immune Response: The immune system produces antibodies against adenoviruses, which can provide protection against future infections. However, the immune system must constantly adapt to new strains of the virus through vaccination or natural infection.

Human Rhinoviruses

• HRVs cause the common cold and are highly contagious
• Transmission occurs through direct contact, airborne transmission, and close contact with an infected person
• HRVs infect epithelial cells of the upper respiratory tract, causing inflammation and symptoms like runny nose, sneezing, coughing, sore throat, and fatigue
• The immune system produces neutralizing antibodies against specific HRV serotypes, but HRVs are highly antigenically variable, making immunity difficult

Influenza

• Influenza is a contagious respiratory illness caused by the influenza virus
• There are three main types: A (affects humans and animals, responsible for seasonal outbreaks and pandemics), B (affects humans, responsible for seasonal outbreaks), and C (affects humans, responsible for mild infections)
• Transmission occurs through airborne transmission and close contact with an infected person
• Influenza viruses infect epithelial cells of the respiratory tract, causing inflammation and symptoms like fever, cough, sore throat, runny or stuffy nose, headache, and fatigue
• The immune system produces antibodies against influenza viruses, providing protection against future infections, but must constantly adapt to new strains through vaccination or natural infection

Varicella-Zoster Virus

• VZV causes two distinct diseases: chickenpox (varicella) and shingles (zoster)
• Transmission occurs through direct contact and airborne transmission
• VZV infects the skin and nervous system, causing symptoms like rash, fever, headache, and fatigue, and a painful rash in shingles
• The immune system produces antibodies against VZV, providing lifelong protection against future infections, but the virus can reactivate in adults, causing shingles

Rev

• Rev is a protein encoded by HIV that regulates the expression of HIV genes
• Rev binds to RNA, promoting its export from the nucleus to the cytoplasm and inhibiting the production of RNA that inhibits viral replication
• Rev is essential for HIV replication and is a key target for antiretroviral therapy

Adenoviruses

• Adenoviruses cause a range of diseases, including respiratory infections, gastroenteritis, and conjunctivitis
• Transmission occurs through direct contact, airborne transmission, and fecal-oral transmission
• Adenoviruses infect epithelial cells of various tissues, causing symptoms like fever, cough, sore throat, diarrhea, and vomiting
• The immune system produces antibodies against adenoviruses, providing protection against future infections, but must constantly adapt to new strains through vaccination or natural infection