Correct Answer: Diabetes

Solution : Let's check each option –
First option: Diabetes; Diabetes is a deficiency disease caused by a deficiency of insulin.
Second option: Swine flu; Swine flu is a type of influenza A virus.
Third option: Chickenpox; Chickenpox is caused by the varicella-zoster virus.
Fourth option: Malaria; Malaria is caused by the Plasmodium parasite

So, the first option is different from others as it is caused by a deficiency of insulin, not by some causative agents. Hence, the first option is correct.