Typhoid is an infectious bacterial disease caused by Salmonella typhi that mainly spreads through contaminated food or water (faecal-oral route). The major symptoms include high fever, loss of appetite and diarrhoea. The bacteria enters the human body through the contaminated water and food, and invades the intestinal cells of the human body.
Bacteria creates perforations in the small intestines, kill the host cells and enter into the abdominal cavity. A person can be tested for typhoid by analyzing blood and stool samples. Typhoid fever can be confirmed by a Widal test.
Plague is a life-threatening and infectious disease caused by the bacterium Yersinia pestis and it is not a viral disease. The bacterium is mainly found in rodents (rats) that feed on the blood of these animals to transmit the disease. This disease is also known by the name of black Plague as the black rats act as carriers of this dangerous disease. It can also spread from person to person through the air or by any other means of contact.
Cholera disease is caused by the bacterium Vibrio cholerae. Cholera appears with symptoms like severe diarrhea and vomiting, usually resulting in a painless, watery diarrhea in humans. In severe cases affected individuals lose water and develop dehydration, it could lead to death, if the body is not hydrated. It is diagnosed by the physician based on signs and symptoms the patient is showing and headache is not a primary symptom used for diagnosing cholera. Headache can be due to several reasons and it need not be a symptom of an underlying disease.