Virus World

In past Ebola outbreaks, fatality rates have varied from 25% to 90% - but effective treatments are now available, and patients who receive care early see their chances of survival improve significantly.  An outbreak of Ebola has been declared in the Democratic Republic of the Congo - four months after the last one ended. A case was confirmed in a 31-year-old man on 5 April. He was admitted to an Ebola treatment centre on Thursday, but died hours later. The World Health Organisation's regional director for Africa, Dr Matshidiso Moeti, said: "Time is not on our side. The disease has had a two-week head start and we are now playing catch-up." Overall, this is the 14th Ebola outbreak that the Democratic Republic of the Congo has seen since 1976, which is when the virus was first discovered.

Efforts to stem the current outbreak have already begun, with officials confirming that the patient who died has received a safe and dignified burial.  More than 70 of his contacts are also being traced - and vaccinations in the city of Mbandaka are going to be stepped up. Ebola is transmitted by coming into contact with the bodily fluids of an infected person or contaminated materials.  Early symptoms include muscle aches and a fever, which resemble those seen in other common diseases such as malaria. In past Ebola outbreaks, fatality rates have varied from 25% to 90% - but effective treatments are now available, and patients who receive care early see their chances of survival improve significantly. Dr Moeti added: "The positive news is that health authorities in the Democratic Republic of the Congo have more experience than anyone else in the world at controlling Ebola outbreaks quickly."

Ebola survivors in Guinea face a more than five times greater risk for mortality after hospital discharge than the general population, according to findings from a retrospective cohort study published in The Lancet Infectious Diseases. Most deaths among survivors were tentatively attributed to renal failure, and the risk for death was higher in survivors who had longer stays inEbola treatment units, researchers reported.

“Ebola survivors are more vulnerable than previously thought, and therefore should be offered improved care, with a focus on available resources in the first few months and ideally up to a year after recovery,” WHO epidemiologist Lorenzo Subissi, PhD, told Infectious Disease News. The 2013-2016 West African Ebola epidemic resulted in 28,646 cases and 11,323 recorded deaths, giving West Africa the largest cohort of survivors of Ebola virus disease at more than 17,000 people, Subissi and colleagues noted. However, little information is currently available about deaths that have occurred in patients discharged from Ebola treatment units.

Subissi and colleagues sought to address this gap in mortality data by developing and implementing a community monitoring program called Surveillance Active en ceinture using WHO guidelines. They attempted to contact and follow up all Ebola survivors in Guinea who were discharged from Ebola treatment units from December 2015 through September 2016, recording deaths that had occurred up until the endpoint. They conducted verbal autopsies with the closest family members of the deceased and reviewed medical records shared by those family members.

A total of 1,270 survivors of Ebola virus disease were discharged from Ebola treatment units in Guinea. Of these, the researchers collected information for 1,130 (89%). They found that survivors of the disease had a more than five times increased risk of mortality up to Dec. 31, 2015 (age-standardized mortality ratio = 5.2; 95% CI, 4-6.8), a mean of 1 year of follow-up after discharge. From Jan. 1, 2016, to Sept. 30, 2016, mortality did not differ between survivors and the general population (age-standardized mortality ratio = 0.6; 95% CI, 0.2-1.4). A total of 59 deaths were reported — 37 attributed to renal failure, mostly based on reported anuria, according to the researchers. Stays in Ebola treatment units that were equal to or longer than the median stay were associated with an increased risk for late death compared with shorter stays (adjusted HR = 2.62; 95% CI, 1.43-4.79). 

Original findings published in September 4, 2019 in the Lancet Infectious Diseases:

https://doi.org/10.1016/S1473-3099(19)30313-5

Researchers in Uganda have launched the largest-ever trial of the experimental Ebola vaccine that is expected to be deployed in neighboring Congo, where a deadly outbreak has killed over 1,800 people. The trial of the Janssen Pharmaceuticals vaccine involves up to 800 people in the western district of Mbarara and is supported by Doctors without Borders and the London School of Hygiene and Tropical Medicine.

Already more than 180,000 people in Congo’s yearlong outbreak have received an experimental but effective Merck vaccine, but health experts worry about the availability of doses as the virus now spreads in a major city, Goma, along the Rwanda border. The wife and 1-year-old daughter of the man who died this week of Ebola in Goma now have the disease. Both the wife and child were doing well in treatment, Congo’s new Ebola response coordinator, Jean-Jacques Muyembe, told reporters on Friday. But he warned that about half of the cases in this outbreak are going undetected and at that rate “this epidemic could last two or three years.” The current goal is to strengthen surveillance and bring the detection rate to 80%, he said.

But he warned that about half of the cases in this outbreak are going undetected and at that rate “this epidemic could last two or three years.” The current goal is to strengthen surveillance and bring the detection rate to 80%, he said. Uganda has had multiple Ebola outbreaks in the past. While it is currently free of the virus, three people died in June after crossing into the country’s Kasese district on an unguarded footpath. Their family members were taken back to Congo for treatment.

The next Ebola outbreak could be predicted using a new UCL-developed model that tracks how changes to ecosystems and human societies combine to affect the spread of the deadly infectious disease. The model could help policymakers to decide where to target vaccine deployment, or develop healthcare infrastructure, to reduce the risk of zoonotic disease outbreaks—illnesses that spread between animals and humans.

Analysis using a mathematical model, published today in Nature Communications, shows that several countries in Africa, including Nigeria, could be at risk of Ebola outbreaks both presently, and in the future, despite having experienced no known cases to date. First author of the study, Dr. David Redding (UCL Genetics, Evolution & Environment), said: "It is vital that we understand the complexities causing animal-borne diseases to spill-over into humans, to accurately predict outbreaks and help save lives. "In our models, we've included more information about the animals that carry Ebola and, by doing so, we can better account for how changes in climate, land-use or human societies can affect human health." Designed by a UCL-led team of researchers, the model captures the impact of climate, land use and human population factors on the risk of Ebola and predicts the known set of previous outbreaks with a high degree of accuracy, even in the absence of case data. The results show that Ebola outbreaks, resulting from spill-over events, are 1.6 times more likely in scenarios with increased warming and slower socioeconomic development.

More than two thirds of all infectious diseases originate in animals, including Ebola, Lassa fever and West Nile virus. These diseases contribute to the global health and economic burden that disproportionately affects poor communities. The latest Ebola epidemic has claimed more than 2,100 lives since August 2018 and while there are signs it is in retreat, the risk of spread is still high according to a recent report by the UN....

"Ebola risk appears to worsen in future versions of our planet that have higher climate change and worse cooperation between societies. Working together to improve healthcare resources, which can contain dangerous diseases such as Ebola, appears to strongly reduce future risk, and this offers an important option for preventing future disease cases. We hope our model will help policy makers address this challenge."

Published in Nat. Communications on October 15, 2019:

https://doi.org/10.1038/s41467-019-12499-6

Amid the worsening Ebola outbreak in the Congo, now threatening to spill into Rwanda, a new study suggests that an existing, FDA-approved drug called nitazoxanide could potentially help contain this deadly, highly contagious infection. The study, published in the Cell Press journal iScience, also showed how the drug works: It enhances the immune system's ability to detect Ebola, normally impeded by the virus.

Nitazoxanide, or NTZ, is currently used to treat gastrointestinal infections caused by parasites such as Giardia and Cryptosporidium. It has been shown to be safe and even comes in a formulation for children. Study leader Anne Goldfeld, MD, of the Program in Cellular and Molecular Medicine at Boston Children's, hopes that, with further testing and validation, it could be part of the solution for Ebola. "Currently, there is no easily deployable therapy for Ebola virus," she says. "There are some very promising vaccines, but there is no oral, inexpensive medication available."

The Ebola virus caused more than 10,000 deaths in the 2014-2016 West African epidemic and more than 1,800 lives (as of August 6th) in the current outbreak in the Democratic Republic of the Congo. The virus is very good at evading human immune defenses. Though very small, it has two genes devoted to blocking immune responses. Goldfeld and collaborators Chad Mire, PhD and Thomas Geisbert, PhD at the University of Texas Medical Branch, Galveston, showed in Biosafety Level 4 laboratory experiments that NTZ inhibits the Ebola virus (isolated from an earlier outbreak). Additional experiments performed in collaboration with Sun Hur, PhD of Boston Children's showed that NTZ works by broadly amplifying the interferon pathway and cellular viral sensors, including two known as RIG-I and PKR. By deleting RIG-I and PKR in human cells through CRISPR editing, Goldfeld and University of Texas colleagues showed that NTZ works through these molecules to inhibit Ebola virus.

Goldfeld hopes to move into animal studies soon, especially given that NTZ has already been used in millions of people with minimal side effects. If effective, it could thus be easily repurposed for Ebola treatment or prevention.

The study was published on August 8, 2019 in iScience (Open Access:

https://doi.org/10.1016/j.isci.2019.07.003

Filoviruses such as Ebola virus (EBOV) cause outbreaks of viral hemorrhagic fevers for which no FDA-approved vaccines or drugs are available. The 2014–2016 EBOV outbreak in West Africa infected approximately 30,000 people, killing more than 11,000 and affecting thousands more in areas still suffering from the effects of civil wars. Sierra Leone and Liberia reported EBOV cases in every county demonstrating the efficient spread of this highly contagious virus in the well-connected societies of West Africa.

In communities, canines are often in contact with people while scavenging for food, which may include sickly bush animals or, as reported from the outbreak, EBOV infected human bodies and excrement. Therefore, dogs may serve as sentinel animals for seroprevalence studies of emerging infectious viruses. 

The authors  used a multiplex Luminex-based microsphere immunoassay (MIA) to detect dog IgG binding to recombinant filovirus antigens or LASV glycoprotein (GP) in serum from dogs that were old enough to be present during the EBOV outbreak. We identified 47 (73%) of 64 dog serum samples as potentially exposed to filoviruses and up to 100% of the dogs from some communities were found to have elevated levels of EBOV antigen-binding IgG titers.

These data support the feasibility of canines as EBOV sentinels and provides evidence that seroprevalence studies in dogs can be conducted using suitable assays even under challenging field conditions. 

Study published July 22  on PLOS Neglected Tropical Diseases:

https://doi.org/10.1371/journal.pntd.0007614