Question

Assertion: Typhoid is an acute infectious disease caused by Salmonella typhi which is found in the human intestine.
Reason: Typhoid is diagnosed by a widal test.
A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false

Answer 1

Typhoid fever is a life- threatening bacterial infection. It usually spreads through contaminated food and water. The infected bacteria grow and multiply within the human host. Typhoid fever is very common in areas having water pollution. The symptoms of typhoid include prolonged fever, headache, nausea, fatigue, abdominal pain, constipation or diarrhoea. Typhoid is generally treated with antibiotics.

Complete explanation:
Typhoid is caused by the bacteria Salmonella typhi. When infected, the salmonella bacteria replicates and grows in the intestines, spleen, liver, gallbladder and blood of humans. The excess bacterial load in the body will then cause typhoid fever. Some people may carry the bacteria without being affected but can spread the disease to others. Hence the assertion is correct.
Widal test is usually done to detect typhoid fever. It is based on the principle that patients infected with Salmonella typhi would produce antibodies against it. When the serum containing antibodies is taken from the patients and exposed to Salmonella organisms, it will agglutinate the bacterial suspension which carries homologous antigens. Reason is correct.
Option A: Both assertion and reason are correct but Widal test does not have any linkage to Salmonella that is found in the human intestine. So, this option is incorrect.
Option A is incorrect.
Option B: Since the assertion and reason are true and reason is not the correct explanation for assertion, this option is correct.
Option B is correct.
Option C: It is known that both assertion and reason are true. So, this option is incorrect.
Option C is incorrect.
Option D: It is known that both assertion and reason are true. So, this option is also incorrect.
Option D is incorrect.

Therefore, option B. If both assertion and reason are true but reason is not the correct explanation of assertion is the correct answer.

Note:
Treatment for typhoid is usually given with antibiotics such as ceftriaxone, azithromycin and fluoroquinolones. To prevent getting typhoid, one should practice good hygiene, avoid eating raw meats and produce, drinking clean water and avoid close contact with typhoid carriers. There are also two vaccines available for typhoid- Inactivated typhoid vaccine and Live typhoid vaccine. These are active vaccines usually administered in booster doses.