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.

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.