What is Upper Respiratory Tract Infection (UTRI)?

An Upper Respiratory Tract Infection (URTI) is a common infection that affects the respiratory system, specifically the parts of the respiratory tract located above the lungs. This includes the nose, sinuses, throat (pharynx), and voice box (larynx). URTIs are typically caused by viruses, although bacteria can also be responsible in some cases.


Common viruses that can cause URTIs include rhinovirus (which causes the common cold), influenza virus (which causes the flu), adenovirus, coronavirus, and respiratory syncytial virus (RSV), among others. Bacterial infections may be caused by bacteria such as Streptococcus pneumoniae or Haemophilus influenzae.


URTIs are highly contagious and can spread through respiratory droplets when an infected person coughs, sneezes, or talks. They can also be transmitted by touching surfaces contaminated with the virus and then touching the nose, mouth, or eyes.


What is the relationship between UTRI and oxidative stress?

The relationship between Upper Respiratory Tract Infections (URTIs) and oxidative stress is complex and multifaceted. When the body is infected with a virus or bacteria causing a URTI, it triggers various immune responses aimed at eliminating the pathogen. However, this immune response can also lead to the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS), collectively known as oxidative stress.


Here’s how URTIs and oxidative stress are related:


  • Immune Response: When the body detects the presence of a virus or bacteria in the upper respiratory tract, immune cells such as neutrophils and macrophages are recruited to the site of infection. These cells produce ROS and RNS as part of the immune response to destroy the invading pathogens.


  • Inflammation: The immune response to URTIs also involves the release of pro-inflammatory cytokines and chemokines, which can further stimulate the production of ROS by immune cells. This inflammatory process contributes to oxidative stress in the respiratory tract.


  • Epithelial Damage: The oxidative stress generated during an URTI can damage the epithelial cells lining the respiratory tract. This damage compromises the integrity of the respiratory mucosa, making it more susceptible to further infection and inflammation.


  • Antioxidant Defense: The body has natural antioxidant defense mechanisms to neutralize ROS and RNS and protect against oxidative damage. However, during an URTI, the antioxidant defense system may become overwhelmed, leading to increased oxidative stress.


  • Complications: Prolonged or severe oxidative stress during an URTI may contribute to the development of complications such as bronchitis, sinusitis, or otitis media. Oxidative stress can exacerbate tissue damage and inflammation, prolonging the duration and severity of symptoms.


  • Recovery: As the URTI resolves and the immune response subsides, oxidative stress typically decreases. However, in some cases, residual oxidative damage may persist, contributing to ongoing respiratory symptoms or susceptibility to recurrent infections.


Overall, oxidative stress plays a significant role in the pathogenesis and progression of URTIs.