With every breath you take, there is always the risk of disease-causing agents entering your body. While the human body has its own mechanism of dealing with such situations, there are times, when our body is not able to fight these disease-causing bacteria, viruses, or other such pathogens. A lung infection occurs when the pathogens enter the lungs and start multiplying. As a result, the body's immune system gets activated, thereby sending white blood cells to the site of infection (air sacs present in the lungs). Normally, lungs are filled with air, but this infection causes a buildup of fluid and pus, which in turn gives rise to breathing problems and various distressing symptoms. Contributing Factors Exposure to pathogens is the main contributing factor for this lung infection. Though several disease-causing bacteria are present in our surroundings, some bacteria even live on the surface of the human body. For instance, Streptococcus pneumoniae bacterium lives in the upper respiratory tract in some individuals. Problems arise when it enters the lungs. Influenza A and B, respiratory syncytial virus (RSV), herpes simplex, varicella zoster virus, adenoviruses, or parainfluenza viruses are some of the viruses that could cause this lung infection. Many a time, cold or flu might also develop into pneumonia. This lung infection is referred to as community-acquired, when it occurs outside the hospital settings or a health-care environment. The term 'hospital-acquired' is used, when the infection develops in a person who is already hospitalized for the treatment of an illness. Some people are at a greater risk of developing this infection. The risk increases in case of:

• People with a weakened immune system due to a chronic illness or malnutrition
• People who are taking immunosuppressants
• Infants and children aged 2 years or younger
• People aged 65 years or above
• Smokers
• People in health-care settings, especially those recovering from a surgery

People affected by chronic lung conditions (COPD, bronchiectasis, cystic fibrosis), recent viral respiratory infection (cold, flu, laryngitis), or other serious medical conditions such as diabetes, heart disease, and cirrhosis of the liver are at a greater risk. Symptoms and Treatment The symptoms that might be experienced by the affected individual include:

• Shallow breathing
• Chills
• Coughing up phlegm
• Pain while breathing or coughing
• Sweating
• Headache
• Muscle pain
• Nausea
• Vomiting
• Fever
• Fatigue
• Malaise

Generally, an X-ray examination of the chest, sputum analysis, and blood tests are conducted to identify the causal organism and examine the condition of the lungs. If the causal organism is a bacterium, the treatment involves the use of antibiotics. While antibiotic therapy can help destroy or arrest the growth of bacteria, it is extremely essential to take ample rest and stay hydrated at all times. In severe cases, where the affected individual is experiencing breathing difficulty due to accumulation of fluid in the lungs, oxygen therapy might be required. Since various strains of bacteria have become immune to antibiotics, taking preventive measures such as immunization with pneumonia vaccine will provide protection against this respiratory disease. If the causal organism is a virus, the treatment would involve the use of anti-viral drugs. Many a time, cold or flu can progress into this lung infection, which is why the administration of flu shots, especially during the flu season, will also prove beneficial. Certain anti-flu drugs such as amantadine, oseltamivir, rimantadine, or zanamivir might be prescribed. The causal organism can spread to others through person-to-person contact, or inhaling the respiratory secretions of the affected person when he coughs or sneezes. Therefore, one must take all possible steps to avoid contact with an infected person. Don't use the personal belonging of the infected person. The administration of the vaccine is a precautionary measure that will prove beneficial. Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.