Human-to-human transmission occurs only via direct contact with blood or body fluid from an infected person (including embalming of an infected dead body), or by contact with objects contaminated by the virus, particularly needles and syringes.[24][25] Other body fluids that may transmit ebolaviruses include saliva, mucus, vomit, feces, sweat, tears, breast milk, urine, and semen. Entry points include the nose, mouth, eyes, or open wounds, cuts and abrasions.[26] Transmission from other animals to humans occurs only via contact with, or consumption of, an infected mammal, such as a fruit bat, or ape. The potential for widespread EVD infections in countries with medical systems capable of observing the correct medical isolation procedures where needed is considered low as the disease is only spread by direct contact with the secretions from someone who is showing signs of infection.[25] A persons ability to spread the disease is often limited as the individual is often too sick to travel during the infectious stages of the disease. As transmission via air is generally ruled out, the possibility of transmission between non-seat-mate airline passengers is also generally ruled out.[27] Because dead bodies are still infectious, traditional burial rituals may spread the disease. Nearly two thirds of the cases of Ebola infections in Guinea during the 2014 outbreak are believed to have been contracted via unprotected (or unsuitably protected) contact with infected corpses during certain Guinean burial rituals.[28][29] Semen may be infectious in survivors for up to 7 weeks.[1] It is not entirely clear how an outbreak is initially started.[30] The initial infection is believed to occur after an ebolavirus is transmitted to a human by contact with an infected animals body fluids. One of the primary reasons for spread is that the health systems where the disease occurs function poorly.[31] Medical workers who do not wear appropriate protective clothing may contract the disease.[32] Hospital-acquired transmission has occurred in the United States and African countries due to the reuse of needles or lack of body substance isolation.[33][34] [35][36] Some healthcare centers caring for people with the disease do not have running water.[37] Airborne transmission has not been documented during EVD outbreaks.[3] They are, however, infectious in rhesus monkeys as breathable 0.8–1.2 μm laboratory-generated droplets.[38]
Posted on: Thu, 16 Oct 2014 02:53:03 +0000