[lah-suh] 
| a highly contagious viral disease, largely confined to central West Africa, characterized by fever, difficulty in swallowing, and inflammation of the pharynx, often progressing to infect the lungs, heart, and kidneys, leading to death. |
| Las·sa fever (lä'sə, lās'ə) n. An acute, often fatal viral disease endemic to West Africa and characterized by high fever, headache, ulcers of the mucous membranes, and disturbances of the gastrointestinal tract. [After Lassa, a village of northeast Nigeria.] |
Lassa fever Las·sa fever n.
A highly fatal form of epidemic hemorrhagic fever caused by Lassa virus and characterized by high fever, sore throat, severe muscle aches, skin rash with hemorrhages, headache, abdominal pain, vomiting, and diarrhea. Also called Lassa hemorrhagic fever.