Signs and symptoms Manifestation of Ebola begins abruptly with a sudden onset of an influenza-like stage characterized by general malaise , fever with chills, sore throat, severe headache, weakness, joint pain, muscle pain, and chest pain.[6] Respiratory tract involvement is characterized by pharyngitis with sore throat, cough, dyspnea , and hiccups. The central nervous system is affected as judged by the development of severe headaches, agitation , confusion, fatigue , depression, seizures, and sometimes coma . Cutaneous presentation may include: maculopapular rash , petechiae , purpura , ecchymoses , and hematomas (especially around needle injection sites). In general, development of hemorrhagic symptoms is indicative of a negative prognosis. However, contrary to popular belief, hemorrhage does not lead to hypovolemia and is not the cause of death (total blood loss is low except during labor ). Instead, death occurs due to multiple organ dysfunction syndrome (MODS) due to fluid redistribution, hypotension, disseminated intravascular coagulation, and focal tissue necroses . The average time between contracting the infection and the onset of symptoms is 13 days, but can be as long as 25 days. [7] Hemorrhage All people infected show some extent of coagulopathy and impaired circulatory system symptomology. [8] Bleeding from mucous membranes and puncture sites is reported in 40–50% of cases, [9] while maculopapular rashes are evident in approximately 50% of cases. [8] Sources of bleeds include hematemesis , hemoptysis, melena, and aforementioned bleeding from mucous membranes ( gastrointestinal tract , nose , vagina and gingiva). However diffuse bleeding (i.e. heavy) is rare; occurrence is usually exclusive to the gastrointestinal tract. [8][10] Causes Main article: Ebolavirus EVD is caused by four of five viruses classified in the genus Ebolavirus, family Filoviridae , order Mononegavirales : Bundibugyo virus (BDBV), Ebola virus (EBOV), Sudan virus (SUDV), Taï Forest virus (TAFV). The fifth virus, Reston virus (RESTV), is thought to be not disease causing for humans and therefore not discussed here. Transmission EVD is believed to occur after an ebola virus is transmitted to a human index case via contact with an infected animal host .[ citation needed ] Human-to-human transmission occurs via direct contact with blood or bodily fluids from an infected person (including embalming of an infected dead person) or by contact with contaminated medical equipment such as needles. [citation needed ] In the past, explosive nosocomial transmission has occurred in under-equipped African hospitals due to the reuse of needles and lack of implementation of universal precautions.[citation needed ] Aerosol transmission has not been observed during natural EVD outbreaks.[ citation needed ] The potential for widespread EVD epidemics is considered low due to the high case-fatality rate, the rapidity of demise of patients, and the often remote areas where infections occu
Posted on: Mon, 28 Jul 2014 10:23:54 +0000