Four ebolaviruses drive a fever first reported in 1976
Ebola virus disease is a zoonotic hemorrhagic fever of humans and other primates caused by four of six known ebolaviruses. Symptoms usually begin two to twenty-one days after exposure—often four to ten—with fever and aches before vomiting, diarrhea, and organ strain. Outbreaks have struck sub-Saharan Africa since 1976; 2013–16 was the largest.
Spread requires direct contact with infected body fluids or freshly contaminated objects; airborne spread has not been documented. Fever commonly exceeds 38.3°C, then gastrointestinal losses dehydrate patients. Bleeding may appear after five to seven days—mucosal or puncture-site bleeding in roughly forty to fifty percent of cases—yet heavy hemorrhage is uncommon. Gut bleeding rates differed between Gabon's 2001 outbreak (~58%) and improved U. S. care in 2014–15 (~18%).
Control means rapid detection, contact tracing, labs, patient care, and safe burials or cremation, plus protective gear, hand hygiene, and thoroughly cooked bushmeat. Early supportive fluids raise survival versus late care. The FDA approved an Ebola vaccine in December 2019; Inmazeb gained U. S. approval in October 2020 for Zaire ebolavirus, alongside ansuvimab.
Models suggest about five percent of cases may incubate beyond twenty-one days. Community trust matters as much as antivirals: fear and unsafe funerals have fueled chains that medicine alone cannot break.
Recovery, when it comes, tends to start between one and two weeks after symptoms appear; death usually follows six to sixteen days in, most often from shock caused by fluid loss. Survivors can be left with aching joints and muscles, liver inflammation, poorer hearing, fatigue and eyesight problems, and they carry antibodies for at least ten years, though whether that protects against reinfection is unknown. Of the four species that sicken people (Bundibugyo, Sudan, Taï Forest and Zaire), Zaire is the deadliest. Fruit bats are the prime suspect as the natural reservoir, though none has been confirmed, and outbreaks cluster near freshly deforested land where wildlife and people meet.
Source: Ebola
