In the late 19th century, health officials began to notice an increase in patients with acute stomach disorders, many with abnormal symptoms that are uncommon with typical digestive problems ; populous metropolitan areas, including Chicago, have seen high death rates, some as high as 174 per 100,000 people. Health officials later determined that the cause was typhoid fever, a disease that dates back to the early Victorian era. Although preventative measures can be taken, more than 21.5 million people are infected with typhoid fever every year. In particular, areas with poor water sanitation report higher rates of this disease. Typhoid fever spreads through contaminated water sources, making underdeveloped countries vulnerable to infection. The cause of typhoid fever is Salmonella Typhi, a bacterium that can be found on contaminated food. The infection begins with the consumption of contaminated food, often unknowingly. Typhoid fever is divided into 4 phases, each lasting about a week. During the first phase, Salmonella Typhi begins its journey into the digestive system, where it multiplies and reproduces, spreading into the bloodstream. Due to the body's natural response to infection, a positive feedback mechanism is activated and the body begins to react by increasing the core body temperature, causing symptoms of fever, sometimes as high as 104° F. After the first stage of typhoid fever, patients may experience severe changes in blood pressure, which affect the cardiovascular system, as adequate blood pressure is vital to support body functions. Due to the change in blood pressure, the patient may have symptoms of hypertension, which can damage the heart, and in some cases be fetal due to a heart attack. Additionally...... middle of paper...... treatment, surgery may be necessary, commonly in cases of intestinal bleeding. In very rare cases, when antibiotics do not eradicate the disease, surgical removal of the gallbladder may be necessary. Although rare, cholecystectomy may not always be effective in eradicating the disease, due to its persistent state of liver infection. Typhoid fever can be prevented through several preventive measures. Health professionals strongly advise using caution when traveling on board and drinking only bottled or purified water, as underdeveloped nations may have poorly sanitized water sources. Other preventative measures recommended by healthcare professionals include vaccination against typhoid fever, practicing proper hand washing techniques, and avoiding raw or unwashed produce, as unwashed fruits and vegetables are sources of unwanted bacteria and parasites..