Viruses and acute respiratory infections

The most common infectious diseases in Western urban communities are acute infections of the respiratory tract, and most of these are because of viruses. The viruses enter the ciliated and other cells lining the respiratory tract, multiplying there and damaging the cells. This damage is the basic pathological change and gives rise to the symptoms and signs of the disease. Virus is found in the mucous discharges and becomes airborne in droplets when the patient coughs or sneezes. Those in the size range about 5–20 μ in diameter are inhaled and impact on the upper respiratory tract. This is the most important means of transmission of infection. Respiratory infections spread freely in urban areas, and it may be difficult to follow the trail of infection from one person to the next. The chapter presents a list of viruses and other organisms causing acute infections of the respiratory tract.