Below are given two sets – Disease (Set-I) and Mode of spread (Set-II). Match the two sets and indicate your answer by selecting the correct code:

Choose the correct code from the options given below.

The correct option is A - III, B - I, C - II, D - IV.

By analyzing the table provided in the image, we can match each disease from Set-I with its corresponding mode of transmission/spread from Set-II:

1. A. Cholera matched with III. Ingestion of polluted water:
Cholera is a well-known water-borne disease caused by the bacterium Vibrio cholerae. It spreads primarily through the ingestion of water or food contaminated with the feces of an infected person. Therefore, it matches with III.

2. B. Trachoma matched with I. Lack of water to maintain cleanliness:
Trachoma is an infectious eye disease caused by the bacterium Chlamydia trachomatis. It is classified as a "water-washed" disease, meaning its transmission is closely linked to poor personal hygiene and a lack of adequate clean water for washing hands, faces, and clothing. Therefore, it matches with I.

3. C. Schistosomiasis matched with II. Involves water contact but not ingestion:
Schistosomiasis (also known as bilharzia) is a water-based disease caused by parasitic flatworms. Infection occurs when people come into contact with freshwater infested with larval forms of the parasite (cercariae), which penetrate the skin directly during activities like wading, bathing, or swimming. Ingestion of the water is not necessary for infection. Therefore, it matches with II.

4. D. Dengue matched with IV. Requires host:
Dengue is a viral infection transmitted to humans through the bite of infected female vector mosquitoes, primarily Aedes aegypti. These mosquitoes breed in stagnant water, and the virus requires these vector hosts to spread from one person to another. Therefore, it matches with IV.

Combining these individual matches, we get:
A - III
B - I
C - II
D - IV