Twenty years ago Ebola virus first emerged in simultaneous outbreaks in Sudan (ref 1) and Zaire.(ref 2) Two subsequent outbreaks have occurred, (ref 3,4) but transmission among human populations has not been sustained. Despite substantial progress in our understanding of Ebola we have not identified its natural reservoir or the trigger for its re-emergence in new outbreaks in humans. Despite all this, the number of cases will inevitably rise in the next three weeks among those already infected.
The viruses are classified in the family 'Filoviridae', with one genus, 'Filovirus'. There are four known viruses. We have Marburg virus and three Ebola viruses: Zaire, Sudan and Reston. Marburg and Ebola are distinguished by their length when purified. In the unpurified state you get all different lengths of these worm-like virions. When they are purified, the infectivity is associated with a particular particle length, which is slightly different between the Marburg and Ebola, but all of the Ebola viruses are the same length.
Human infection with African-derived strains has often occurred in caregivers, either family or medical, or in family members who have prepared dead relatives for burial. Late stages of Ebola are associated with the presence of large numbers of virions in body fluids, tissues, and, especially, skin. Individuals who come into contact with patients infected with Ebola without proper barrier protection are at high risk of becoming infected. A recent report from the DRC identified Ebola virus RNA in 100% of oral secretions in patients with Ebola virus RNA in their serum.
The needle used for Lokela?s quinine injection was inadequately sterilized, so Ebola had spread from patient to patient as the needles were reused. They called Dr. Ngoi Mushola, the area director, for help. He taught them how to sterilize their needles and purify water. He also told the nurses to instruct patients? families not to bury their dead inside or close to their homes as tradition dictated, since Ebola could spread from dead bodies. He also called authorities in Kinshasa, the nation?s capital, for help. Kinshasa sent a microbiologist and an epidemiologist who performed autopsies on dead patients and collected samples.
Ebola virus is transmitted by contact with blood, feces or body fluids from an infected person or by direct contact with the virus, as in a laboratory. People can be exposed to Ebola virus from direct contact with the blood or secretions of an infected person. This is why the virus has often been spread through the families and friends of infected persons: in the course of feeding, holding, or otherwise caring for them, family members and friends would come into close contact with such secretions.
The virus specifically affects liver cells and reticuloendothelial cells. Affected blood capillaries leak fluids and plasma proteins, causing intravascular coagulation and a zero clotting factor. The water volume loss in the body produces clinical shock, thereby causing the organs of the body to fail. The incubation period is typically from two to twenty-one days, and, depending on the victim, symptoms occur fairly shortly after transmission. "All forms of viral hemorrhagic fever begin with fever and muscle aches. Depending on the particular virus, disease can progress until the patient becomes very ill with respiratory problems, severe bleeding, kidney problems, and shock. With Ebola, persons develop fever, chills, headaches, muscle aches, and loss of appetite.
