Ebola: US nurse 'to take legal action' over confinement

A US nurse held in quarantine in New Jersey after treating Ebola patients in West Africa says she will challenge her confinement in a federal court. Kaci Hickox said she was made to feel like a criminal after returning from Sierra Leone last Friday. Her lawyer says the case has raised "serious constitutional and civil liberties issues". The White House and mayor of New York have expressed concerns over new strict quarantine orders in several US states. The new rules in New York, New Jersey and Illinois require a mandatory 21-day quarantine period for all health workers who have had contact with Ebola patients in West Africa and just returned to the US. On Sunday New York Governor Andrew Cuomo announced an easing of the quarantine restrictions in his state. Under the latest guidelines, returning health workers who have displayed no symptoms can return to their homes for the quarantine period, where they will be monitored twice daily. Compensation will be offered for loss of earnings. Governor Cuomo was later quoted by Reuters as saying that the state wanted to encourage health workers to go to the Ebola outbreak zone. 'Too broad' The US ambassador to the UN, Samantha Power, said that all returning US health workers should be "treated like conquering heroes and not stigmatized for the tremendous work that they have done". Read More

Reservoir

Reservoir

Bats are considered the most likely natural reservoir of the EBOV, plants, arthropods, and birds were also considered. Bats were known to reside in the cotton factory in which the first cases for the 1976 and 1979 outbreaks were employed, and they have also been implicated in Marburg virus infections in 1975 and 1980.

Of 24 plant species and 19 vertebrate species experimentally inoculated with EBOV, only bats became infected.The absence of clinical signs in these bats is characteristic of a reservoir species. In a 2002–2003 survey of 1,030 animals including 679 bats from Gabon and the Republic of the Congo, 13 fruit bats were found to contain EBOV RNA fragments. As of 2005, three types of fruit bats (Hypsignathus monstrosus, Epomops franqueti, and Myonycteris torquata) have been identified as being in contact with EBOV. They are now suspected to represent the EBOV reservoir hosts. Antibodies against Ebola Zaire and Reston viruses have been found in fruit bats in Bangladesh, thus identifying potential virus hosts and signs of the filoviruses in Asia.Between 1976 and 1998, in 30,000 mammals, birds, reptiles, amphibians and arthropods sampled from outbreak regions, no ebolavirus was detected apart from some genetic traces found in six rodents (Mus setulosus and Praomys) and one shrew (Sylvisorex ollula) collected from the Central African Republic. Traces of EBOV were detected in the carcasses of gorillas and chimpanzees during outbreaks in 2001 and 2003, which later became the source of human infections. However, the high lethality from infection in these species makes them unlikely as a natural reservoir. Transmission between natural reservoir and humans is rare, and outbreaks are usually traceable to a single case where an individual has handled the carcass of gorilla, chimpanzee or duiker. Fruit bats are also eaten by people in parts of West Africa where they are smoked, grilled or made into a spicy soup.

Genome

Like all mononegaviruses, ebolavirions contain linear nonsegmented, single-strand, non-infectious RNA genomes of negative polarity that possesses inverse-complementary 3' and 5' termini, do not possess a 5' cap, are not polyadenylated, and are not covalently linked to a protein. Ebolavirus genomes are approximately 19 kilobase pairs long and contain seven genes in the order 3'-UTR-NP-VP35-VP40-GP-VP30-VP24-L-5'-UTR. The genomes of the five different ebolaviruses (BDBV, EBOV, RESTV, SUDV, and TAFV) differ in sequence and the number and location of gene overlaps.

Structure

Like all filoviruses, ebolavirions are filamentous particles that may appear in the shape of a shepherd's crook or in the shape of a "U" or a "6", and they may be coiled, toroid, or branched. In general, ebolavirions are 80 nm in width, but vary somewhat in length. In general, the median particle length of ebolaviruses ranges from 974 to 1,086 nm (in contrast to marburgvirions, whose median particle length was measured at 795–828 nm), but particles as long as 14,000 nm have been detected in tissue culture.

Replication

The ebolavirus life cycle begins with virion attachment to specific cell-surface receptors, followed by fusion of the virion envelope with cellular membranes and the concomitant release of the virus nucleocapsid into the cytosol. The viral RNA polymerase, encoded by the L gene, partially uncoats the nucleocapsid and transcribes the genes into positive-strand mRNAs, which are then translated into structural and nonstructural proteins. Ebolavirus RNA polymerase (L) binds to a single promoter located at the 3' end of the genome. Transcription either terminates after a gene or continues to the next gene downstream. This means that genes close to the 3' end of the genome are transcribed in the greatest abundance, whereas those toward the 5' end are least likely to be transcribed. The gene order is, therefore, a simple but effective form of transcriptional regulation. The most abundant protein produced is the nucleoprotein, whose concentration in the cell determines when L switches from gene transcription to genome replication. Replication results in full-length, positive-strand antigenomes that are, in turn, transcribed into negative-strand virus progeny genome copy. Newly synthesized structural proteins and genomes self-assemble and accumulate near the inside of the cell membrane. Virions bud off from the cell, gaining their envelopes from the cellular membrane they bud from. The mature progeny particles then infect other cells to repeat the cycle. The Ebola virus genetics are difficult to study due to its virulent nature.

Causes

Causes

EVD is caused by four of five viruses classified in the genus Ebolavirus, family Filoviridae, order Mononegavirales. The four disease-causing viruses are Bundibugyo virus (BDBV), Sudan virus (SUDV), Taï Forest virus (TAFV), and one called simply, Ebola virus (EBOV, formerly Zaire Ebola virus)). Ebola virus is the sole member of the Zaire ebolavirus species, and the most dangerous of the known Ebola disease-causing viruses, as well as being responsible for the largest number of outbreaks. The fifth virus, Reston virus (RESTV), is not thought to be disease-causing in humans. The five Ebola viruses are closely related to the Marburg viruses.

Transmission

Human-to-human transmission can occur via direct contact with blood or bodily fluids from an infected person (including embalming of an infected dead person) or by contact with objects contaminated by the virus, particularly needles and syringes.
The potential for widespread EVD infections is considered low as the disease is only spread by direct contact with the secretions from someone who is showing signs of infection.The symptoms limit a person's ability to spread the disease as they are often too sick to travel.Because dead bodies are still infectious, local traditional burial rituals may spread the disease.Nearly two thirds of cases of Ebola in Guinea during the 2014 outbreak are believed to be due to burial practices.Semen may be infectious in survivors for up to 3 months. It is not entirely clear how an Ebola outbreak is initially started.The initial infection is believed to occur after ebola virus is transmitted to a human by contact with an infected animal's body fluids.
One of the primary reasons for spread is that the health systems in the part of Africa where the disease occurs function poorly.Medical workers who do not wear appropriate protective clothing may contract the disease.Hospital-acquired transmission has occurred in African countries due to the reuse of needles and lack of universal precautions.Some health care centers caring for people with the disease do not have running water.Airborne transmission has not been documented during EVD outbreaks.They are, however, infectious as breathable 0.8– to 1.2-μm laboratory-generated droplets.The virus has been shown to travel, without contact, from pigs to primates, although the same study failed to demonstrate similar transmission between non-human primates.Bats drop partially eaten fruits and pulp, then land mammals such as gorillas and duikers feed on these fallen fruits. This chain of events forms a possible indirect means of transmission from the natural host to animal populations, which has led to research towards viral shedding in the saliva of bats. Fruit production, animal behavior, and other factors vary at different times and places that may trigger outbreaks among animal populations.

Ebola Signs and symptoms

Signs and symptoms

Signs and symptoms of Ebola usually begin suddenly with an influenza-like stage characterized by fatigue, fever, headaches, joint, muscle, and abdominal pain. Vomiting, diarrhea and loss of appetite are also common. Less common symptoms include the following: sore throat, chest pain, hiccups, shortness of breath and trouble swallowing. The average time between contracting the infection and the start of symptoms (incubation period) is 8 to 10 days, but it can vary between 2 and 21 days. Skin manifestations may include a maculopapular rash (in about 50% of cases). Early symptoms of EVD may be similar to those of malaria, dengue fever or other tropical fevers, before the disease progresses to the bleeding phase.
In 40–50% of cases, bleeding from puncture sites and mucous membranes (e.g. gastrointestinal tract, nose, vagina and gums) has been reported. In the bleeding phase, which typically begins 5 to 7 days after first symptoms,]internal and subcutaneous bleeding may present itself in the form of reddened eyes and bloody vomit. Bleeding into the skin may create petechiae, purpura, ecchymoses and hematomas (especially around needle injection sites). Sufferers may cough up blood, vomit it or excrete it in their stool.
Heavy bleeding is rare and is usually confined to the gastrointestinal tract.In general, the development of bleeding symptoms often indicates a worse prognosis and this blood loss can result in death. All people infected show some signs of circulatory system involvement, including impaired blood clotting. If the infected person does not recover, death due to multiple organ dysfunction syndrome occurs within 7 to 16 days (usually between days 8 and 9) after first symptoms.

Ebola virus disease

Ebola virus disease
Ebola virus disease (EVD), Ebola hemorrhagic fever (EHF), or simply Ebola is a disease of humans and other primates caused by an ebolavirus. Symptoms start two days to three weeks after contracting the virus, with a fever, sore throat, muscle pain and headaches. Typically, vomiting, diarrhea and rash follow, along with decreased functioning of the liver and kidneys. Around this time, affected people may begin to bleed both within the body and externally. The virus may be acquired upon contact with blood or bodily fluids of an infected animal.
Spreading through the air has not been documented in the natural environment. Fruit bats are believed to be a carrier and may spread the virus without being affected. Once human infection occurs, the disease may spread between people, as well. Male survivors may be able to transmit the disease via semen for nearly two months. To make the diagnosis, typically other diseases with similar symptoms such as malaria, cholera and other viral hemorrhagic fevers are first excluded. To confirm the diagnosis, blood samples are tested for viral antibodies, viral RNA, or the virus itself.
Prevention includes decreasing the spread of disease from infected animals to humans. This may be done by checking such animals for infection and killing and properly disposing of the bodies if the disease is discovered. Properly cooking meat and wearing protective clothing when handling meat may also be helpful, as are wearing protective clothing and washing hands when around a person with the disease. Samples of bodily fluids and tissues from people with the disease should be handled with special caution.

No specific treatment for the disease is yet available.

Efforts to help those who are infected are supportive and include giving either oral rehydration therapy (slightly sweet and salty water to drink) or intravenous fluids.[1] The disease has a high risk of death, killing between 50% and 90% of those infected with the virus.
EVD was first identified in Sudan (now South Sudan), the Democratic Republic of the Congo and some other Africa countries. The disease typically occurs in outbreaks in tropical regions of sub-Saharan Africa. From 1976 (when it was first identified) through 2013, the World Health Organization reported a total of 1,716 cases. The largest outbreak to date is the ongoing 2014 West African Ebola outbreak, which is affecting Guinea, Sierra Leone, Liberia and Nigeria. As of 26 August 2014, 3,069 suspected cases resulting in the deaths of 1,552 have been reported.
Efforts are under way to develop a vaccine; however, none yet exists.