The presence of which disease is confirmed by Widal Test?

The correct answer is Option (3) → Typhoid

Option (1) Malaria — Incorrect. Malaria is caused by Plasmodium; it is found by seeing the parasite in a blood smear, not by the Widal test.

Option (2) Pneumonia — Incorrect. Pneumonia is an infection of the alveoli of the lungs by bacteria such as Streptococcus pneumoniae; the Widal test does not detect it.

Option (3) Typhoid — Correct. Typhoid fever is caused by Salmonella typhi. The Widal test confirms it.

Option (4) AIDS — Incorrect. AIDS is caused by HIV and is diagnosed by the ELISA test.

NCERT Extract:
Common Diseases in Humans – “… Salmonella typhi is a pathogenic bacterium which causes typhoid fever in human beings. These pathogens generally enter the small intestine through food and water contaminated with them and migrate to other organs through blood. Sustained high fever (39° to 40°C), weakness, stomach pain, constipation, headache and loss of appetite are some of the common symptoms of this disease. Intestinal perforation and death may occur in severe cases. Typhoid fever could be confirmed by Widal test : A classic case in medicine, that of Mary Mallon nicknamed Typhoid Mary, is worth mentioning here.”