Initially, human immunodeficiency virus (HIV) may exhibit few symptoms other than a brief illness that resembles the flu. This usually occurs two to six weeks after becoming infected, and includes:

• Fever
• Headache
• Sore throat
• Swollen lymph nodes
• Rash

Because its symptoms are similar to the flu, many people do not realize they have been infected with HIV. Nonetheless, people who are infected are able to transmit the virus to others, even when symptoms are not apparent.

Once the virus enters a person’s body, it begins to multiply and destroy immune cells. In some cases, a person may remain symptom-free for nearly a decade while this damage occurs. Eventually, symptoms will begin to appear, such as:

• Mild infections
• Swollen lymph nodes
• Diarrhea
• Weight loss
• Fever
• Cough and shortness of breath

Ten years or more after the initial infection, the last phase of HIV begins, and more serious symptoms start to appear. These are the result of severe damage to the immune system and may include:

• Soaking night sweats
  
  
• Shaking chills or fever higher than 100 Fahrenheit (38 Celsius) for several weeks
  
  
• Dry cough and shortness of breath
  
  
• Chronic diarrhea
  
  
• Persistent white spots or unusual lesions on the tongue or in the mouth
  
  
• Blurred and distorted vision
  
  
• Weight loss
  
  
• Persistent, unexplained fatigue
  
  
• Muscle and joint pain
  
  
• Swelling of lymph nodes for more than three months
  
  
• Persistent headaches

HIV infection can be passed from a mother to her child in pregnancy, delivery or through breastfeeding. Children with HIV may have difficulty gaining weight and may not grow normally. As the infection damages the immune system, these children may experience delays in mental and physical development. Children may also have severe forms of common childhood illnesses, such as:

• Ear infections (otitis media)
• Pneumonia (inflammatory infection of the lungs)