Dear sir/madam One of my friends (boy) had visited my room last week. He was suffered from severe fever. He had stayed with me for one night and a day. As his fever was not giving any response of limit he had given his blood for check on the account a doctor's advice. Now the report manifests positive to the dengue fever. So my request is how I can take precautions to prevent it. I do not want to take a risk. Kindly please help me. Thank-you.