Ebola
Ebola is both the common term used to describe a group of viruses belonging to genus Ebolavirus, family Filoviridae, and the common name for the disease which they cause, Ebola hemorrhagic fever. The viruses are characterised by a long, filamentous morphology and surrounded by a lipid viral envelope. Ebolaviruses are morphologically similar to the Marburg virus, also in the family Filoviridae, and share similar disease symptoms. It has caused a number of serious and highly publicized outbreaks since its discovery, as well as featuring as the gruesome antagonist in many forms of entertainment.
Ebola is believed to be a zoonotic virus. Despite considerable effort by the World Health Organization no animal reservoir capable of sustaining the virus between outbreaks has been identified. However, it has been hypothesized that the most likely candidate is the fruit bat. In the absence of knowing where the reservoir lies, the World Health Organization has taken serious steps to ensure that all known Biosafety Level 4 agents (including Ebola) are carefully and properly contained.
Ebola hemorrhagic fever is potentially lethal and encompasses a range of symptoms including vomiting, diarrhea, general body pain, internal and external bleeding, and fever. Mortality rates are generally high, ranging from 50% - 90%, with the cause of death usually due to hypovolemic shock or organ failure.
Because Ebola is potentially lethal and since no approved vaccine or treatment is available, Ebola is classified as a biosafety level 4 agent, as well as a Category A bioterrorism agent by the Centers for Disease Control and Prevention. It has the potential to be weaponized for use during biological warfare and was investigated for this particular use by both the Soviet Union and the United States during the Cold War.
Transmission
Among humans, the virus is transmitted by direct contact with infected body fluids, or to a lesser extent, skin or mucus membrane contact. The incubation period can be anywhere from 2 to 21 days, but is generally between 5 and 10 days.
Although airborne transmission between monkeys has been demonstrated by an accidental outbreak in a laboratory located in Virginia, U.S.A, there is very limited evidence for human-to-human airborne transmission in any reported epidemics. Nurse Mayinga might represent the only possible case. The means by which she contracted the virus remain uncertain.
So far all epidemics of Ebola have occurred in sub-optimal hospital conditions, where practices of basic hygiene and sanitation are often either luxuries or unknown to caretakers and where disposable needles and autoclaves are unavailable or too expensive. In modern hospitals with disposable needles and knowledge of basic hygiene and barrier nursing techniques, Ebola rarely spreads on such a large scale.
In the early stages, Ebola may not be highly contagious. Contact with someone in early stages may not even transmit the disease. As the illness progresses, bodily fluids from diarrhea, vomiting, and bleeding represent an extreme biohazard. Due to lack of proper equipment and hygienic practices, large scale epidemics occur mostly in poor, isolated areas without modern hospitals or well-educated medical staff. Many areas where the infectious reservoir exists have just these characteristics. In such environments, all that can be done is to immediately cease all needle-sharing or use without adequate sterilization procedures, to isolate patients, and to observe strict barrier nursing procedures with the use of a medical rated disposable face mask, gloves, goggles, and a gown at all times. This should be strictly enforced for all medical personnel and visitors.
Ebola is limited on a global scale due to its difficulty in spreading by airborne transmission and the period of time that the virus can use a living and contagious victim to spread compared to other infectious diseases. In isolated settings such as a quarantined hospital or a remote village, most victims are infected shortly after the first case of infection is present. In addition, the quick onset of symptoms from the time the disease becomes contagious in an individual makes it easy to identify sick individuals and limits an individual's ability to spread the disease by traveling. Although bodies of the deceased are still infectious, many doctors implemented measures to properly dispose of dead bodies in spite of some traditional local burial rituals.