Doctors have warned of a serious illness that does not appear to be fast, but can cause death, especially for long-distance travelers and those who spend a lot of time in airplanes. The disease is known as deep vein thrombosis, the place where the blood clot develops in the vein, which can later reach the lungs, causing death. “Sitting on a plane, train or bus for long periods increases the risk of deep vein thrombosis,” Dr Sarah Brur, medical director of HealthSpan, told The Sun. She added that vacationers also have to be in the case of the symptoms of this disease, because the incidence of deep vein thrombosis can be fatal after 8 weeks of returning home from a long trip. What are the most prominent symptoms of this disease? Redness in the affected area. Swelling of the legs accompanied by pain, especially if the affected person is more sensitive than others. Coloration of affected area due to poor blood flow and lack of access to it. High body temperature. Often, the person with the deep vein thrombosis will have no idea of the disease until the onset of symptoms, and may be at an advanced stage of the disease. At this particular stage, the clot can explode and pass through the blood stream, and can reach the lungs, leading to pulmonary embolism, with high risk of death.