Dreadful viral disease which is completely eradicated is :-

Answer

**Step-by-Step Text Solution:**

1. **Identify the Question**: The question asks for a dreadful viral disease that has been completely eradicated.

2. **Recall Information about Viral Diseases**: Consider various viral diseases and their status in terms of eradication.

3. **Focus on Eradicated Diseases**: Among the viral diseases, smallpox is known for being completely eradicated.

4. **Understand the Characteristics of Smallpox**: Smallpox is a highly contagious infectious disease characterized by symptoms such as fever, vomiting, skin rash, and mouth ulcers.

5. **Identify the Causative Agent**: The causative agent of smallpox is the variola virus.

6. **Historical Context**: The last natural case of smallpox was reported in 1977, and the World Health Organization (WHO) declared smallpox eradicated in 1980.

7. **Conclude the Answer**: Therefore, the dreadful viral disease that is completely eradicated is smallpox.

**Final Answer**: Smallpox

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