A disease which spreads by contract-

• A disease which spreads by contact Contagious.
• Contagious (adjective)
- English Meaning: (of a disease) spread from one person or organism to another, typically by direct contact.
- Bangla Meaning: সংক্রামক।

অন্যদিকে,
• Incurable - অচিকিৎসা; অন্যরোগ্য।
- English Meaning: (of a sick person or a disease) not able to be cured.

•Fatal - প্রাণনাশক; মারাত্মক।
- English Meaning: leading to failure or disaster.

Source:
1. merriam-webster.
2. Accessible Dictionary by Bangla Academy.