Who am I and why should you be scared of me now?

I am a very common virus that leads to mild, cold-like symptoms in adults and older healthy children. But I am bad with young babies. Most infants have been infected by me before their second birthday.
I love the season from October to Spring (my season!)

More severe  disease with me may occur in the following infants:

• Premature infants
• Infants with chronic lung disease
• Immunodeficient infants
• Infants with heart disease

The following increase the risk for being affected by me:

• Day care
• Tobacco smoke
• Having school-aged brothers or sisters
• Crowded conditions
  
  
  You get to know about me 4 - 6 days after coming in contact with me.
  Antibiotics cannot make me go away
  If am nice (mild) I go away without treatment.
  Infants and children with a severe infection with me will be in the intensive care unit. Treatment will include:
  • Oxygen ( may need a ventilator)
  • humidified air
  • IV fluids
  
  I AM Respiratory Syncytial Virus
  Belonging to the Paramyxoviridae, I am virus in an enveloped, spherical, negative-strand RNA virus measuring 120-300 nm
  
  
  Diagnosis: You can find me by a direct immunofluorescence test for RSV antigen , and is reported to be 90% sensitive as compared to culture. RSV antigen may appear in the cytoplasm of cells within 8 hours of infection. Viral culture is performed in conjunction with the antigen test. The only acceptable specimen to detect me is a nasopharyngeal aspirate collected in viral transport media.
  Tomorrow I will tell you how to avoid me!!
  Source of picture and some text: http://pathology5.pathology.jhmi.edu/micro/v20n47.htm