Salmonella typhi typically enters the small intestine through ____A_____ and spreads to other parts of the body through ____B_____.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A–consumption of contaminated food and water; B–blood
Salmonella typhi is the bacterium that causes typhoid fever. Like many gut pathogens, it is taken in with what we eat and drink, and it must survive the acid of the stomach to reach the small intestine.
Blank A – consumption of contaminated food and water. The bacteria enter the small intestine through food and water contaminated with them. Inhaling droplets is the route of pneumonia and the common cold, which infect the respiratory tract, and skin contact is the route of fungal infections such as ringworm. Neither leads to the small intestine.
Blank B – blood. From the intestine the bacteria migrate to other organs through blood. This is why typhoid causes sustained high fever, weakness, stomach pain, headache and loss of appetite.
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.”