In recent years, respiratory illnesses have been on the rise, especially those caused by viruses. Such diseases can affect the entire respiratory system, from the sinuses to the lungs. Although some symptoms associated with these conditions tend to resolve on their own, others may require medical intervention. That is why recognizing the symptoms early on and getting timely treatment may help in managing the condition. So, here are 14 early signs of respiratory infections: 1. Fever A fever is generally one of the first signs of a respiratory infection. It is the result of the immune response to viruses, as many such pathogens are sensitive to temperature changes in the body. Upon noticing this sign, one must consistently monitor their body temperature, as a persistent fever may be an indication of a severe respiratory virus. Here, seeking medical attention is important if the body temperature crosses 100.4°F (38°C). A temperature as high as 101 to 102°F (about 38.3 to 38.9°C) is common for those infected by influenza. However, fevers over 103°F require immediate treatment. At times, this symptom may be accompanied by night or cold sweats. As the internal temperature increases, the body may induce sweating to prevent overheating and help one cool down.