Viral Rash: Types, Symptoms, and Treatment in Adults and Babies
Ebola: How A Vaccine Turned A Terrifying Virus Into A Preventable Disease
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The Ebola virus devastated west Africa in 2014, claiming over 11,000 lives in Sierra Leone, Liberia and Guinea.
It was the largest Ebola outbreak since the virus had first been discovered in the Democratic Republic of Congo in 1976.
Ebola is a terrifying virus which, if left untreated, causes bleeding inside the body and through the eyes, nose, mouth and rectum.
Case fatality rates have varied from 25% to 90% in past outbreaks, depending on circumstances and the response.
The 2014 outbreak in west Africa exposed a critical gap in global preparedness for infectious diseases: the absence of effective vaccines.
There were no drugs or vaccines approved to treat or prevent Ebola or ready to enter into clinical trials at the outset of the epidemic. Therefore, many felt it was ethically necessary to conduct such research as quickly and safely as possible.
As a biologist and epidemiologist, I travelled to Guinea amid the chaos to coordinate the laboratory activities of the rVSV-ZEBOV Ebola vaccine trials.
Almost 10,000 participants were enrolled in trials to make sure the drug was safe and effective to use. The trials would last two years and involved more than 500 scientists and healthcare workers.
My five-year-old daughter, Ashanti, spoke words that strengthened my resolve: "People need you to support them. If you don't go, who will?"
READ MORE: Mpox vaccines: where they come from and what stands in the way of distributing them in Africa
Her encouragement fuelled me as I led the trial's laboratory operations, navigating immense logistical and emotional challenges.
We had to set up a full laboratory in a week, to process thousands of samples. Delivering the vaccine required ultra cold freezers (minus 80°C); none were available in the country.
We had to address vaccine hesitancy among the population of Guinea, including the medical and academic community.
Of course there was also fear of getting infected by a disease that was a virtual death sentence.
First line workers and individuals in close contact with confirmed Ebola cases were vaccinated with rVSV-ZEBOV. This created a protective "ring" around the infected.
As a field coordinator, I witnessed firsthand the challenges of conducting research into the safety of the vaccine in the middle of an outbreak.
Collaboration between the World Health Organization, Médecins Sans Frontières, the medical research centre Epicentre and local health authorities proved pivotal.
These efforts also underscored the importance of adaptable, rapid-response research during health crises.
READ MORE: 154 million lives saved in 50 years: 5 charts on the global success of vaccines
On 18 August 2015 the preliminary results of the trial were announced. They marked a turning point in the fight against Ebola. The vaccine's near-perfect efficacy offered a rare moment of hope.
Today Sierra Leone is embarking on a nationwide campaign with the rVSV-ZEBOV vaccine, trademarked as Ervebo.
The campaign will target 20,000 frontline workers in 16 districts. These include healthcare workers, traditional healers, community health and social workers, laboratory personnel, motorcycle taxi drivers and security forces. Anybody who will be involved in any response to future outbreaks.
The Ervebo vaccine, developed by Merck, is a single-dose vaccine. It works by using a modified virus to produce antibodies against Ebola, equipping the immune system to recognise and neutralise the virus upon exposure.
Clinical trials have shown its efficacy exceeds 95% in preventing infection from the Zaire Ebola virus strain, the deadliest variant.
Get CNN Health's weekly newsletterThe vaccine was deployed during the 2018-2020 Ebola epidemic in the Democratic Republic of Congo under emergency use authorisation.
This allows a medical product to be used without being authorised by the relevant drug agencies, such the Food and Drug Administration in the United States, the European Medicines Agency and the African Medicines Agency.
It was also used in Burundi, Uganda, South Sudan and Rwanda in preventive vaccination campaigns to protect healthcare and frontline workers.
Ervebo is now a cornerstone in the fight against Ebola, particularly in controlling outbreaks caused by the Zaire strain.
However, its success depends on ensuring equitable access and strengthening healthcare systems.
Challenges do persist, including limited vaccine supply, logistical hurdles in remote regions, and vaccine hesitancy fuelled by misinformation.
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Addressing these obstacles requires coordinated efforts between governments, health organisations and communities.
Additionally, establishing local vaccine manufacturing in Africa should be a long-term goal, giving affected countries greater control over supply and distribution.
While Ervebo is a monumental achievement, it cannot end Ebola on its own.
The virus's ability to persist in animal reservoirs such as bats and to then be transmitted to humans means that vaccination must be part of a broader strategy.
Integrating vaccination, surveillance, outbreak response and community engagement is essential for achieving long-term control.
Ervebo's success provides a model for addressing other infectious disease outbreaks, like mpox. Clinical trials during the mpox outbreak could potentially lead to new and effective vaccines.
Skin May Play A Hidden Role In Ebola Infection
Ebola, a severe hemorrhagic disease caused by a virus endemic in parts of East-Central and West Africa, is generally known to spread through contact with bodily fluids from individuals who have the infection.
Ebola virus on the skin surfaceMore recent outbreaks, such as the 2013-2016 Ebola epidemic in West Africa, have shown that infectious Ebola virus (EBOV) is also found on the surface of the skin of those who have succumbed to infection or at late times during infection.
Although this suggests that the virus can be transmitted from skin contact with someone in the later stages of the disease, researchers have not yet fully understood how the virus exits the body and appears on the skin's surface.
In a recent study, scientists at University of Iowa Health Care, working with colleagues at Texas Biomedical Research Institute and Boston University, have uncovered a cellular route that EBOV uses to traverse the inner and outer layers of skin and emerge onto the surface.
The researchers identified new cell types within the skin that are targeted by EBOV during infection and confirms that human skin tissues actively sustain EBOV infection.
Possible route of Ebola infectionThe results, published in the journal Science Advances, suggest that the skin's surface may be one possible route of person-to-person transmission.
"The skin is the largest organ in the human body yet is woefully understudied compared to most other organs. Interactions of EBOV with skin cells have not previously been extensively examined," said study senior author Wendy Maury, a professor of microbiology and immunology at the University of Iowa.
"Our work provides evidence for one mechanistic avenue that EBOV uses to exit from the human body. A comprehensive understanding of which cells are targeted during virus infection is critical for rational development of antiviral approaches."
Human skin model for tracking EbolaThe research team, guided by Maury and Kelly Messingham, a research professor of dermatology at the University of Iowa, designed a new method for discovering which skin cells are infected by Ebola virus.
They constructed a human skin explant system using full-thickness biopsies from healthy individuals, preserving both the deeper (dermal) and surface (epidermal) layers of skin.
Next, the team placed these explants dermal side down in culture media, adding virus particles to simulate how EBOV would move from the bloodstream outward toward the skin's exterior.
This setup let the researchers use specialized tracing and labeling techniques to observe how the virus progressed from one layer of skin to the next, tracking which cells became infected as time passed.
Skin cells prone to Ebola infectionPrior clinical and animal studies indicated that skin cells could become infected with EBOV, yet they did not identify the particular cells involved.
In this work, the authors showed that EBOV infects several cell types in the skin explant, including macrophages, endothelial cells, fibroblasts, and keratinocytes.
Some of these cells are also infected by EBOV in other tissues, but keratinocytes – particular to skin – had not been previously recognized as an EBOV replication site.
Notably, the virus appeared to replicate more actively in the epidermal layer than in the dermal layer when compared on a per-gram basis. Within three days, infectious virus was detected at the epidermal surface, underscoring the virus's ability to rapidly move through skin to the surface.
In addition to mapping how the virus travels through the skin, the scientists demonstrated that human skin explants offer a realistic, three-dimensional model for examining potential antiviral treatments against EBOV. This model could be an economical and valuable tool for exploring new therapies.
"This study explores the role of the skin as a potential route of Ebola virus infection and identifies, for the first time, several cell types in the skin that are permissive to infection," Messingham said.
"In total, these findings elucidate a mechanism by which EBOV traffics to the skin's surface and may explain person-to-person transmission via skin contact."
New insights into Ebola infectionBeyond its discoveries about the skin, the research also zoomed in on interactions between the Ebola virus and two particular skin cell types, fibroblasts and keratinocytes.
The team found specific receptors on these cells that facilitate the virus's entry, adding further clarity on how EBOV infects skin on a molecular level.
By clarifying one route the virus may take to exit the body, these findings expand our knowledge of Ebola's spread and highlight why skin-to-skin contact in advanced cases of infection can pose such a risk.
Ongoing public health concernUnderstanding these pathways, and identifying the cell types that the virus relies on, can influence future efforts to develop effective treatments and prevention measures.
This work also sets the stage for further investigations into how EBOV might exploit other organs or tissues and suggests potential ways to block the virus's path at the skin level.
With Ebola remaining an ongoing global health concern, insights like these can help scientists target the virus more effectively and better protect those at risk of infection.
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Study Traces Ebola's Route To The Skin Surface
Ebola is a deadly hemorrhagic disease caused by a virus that is endemic in parts of East-Central and West Africa. Most people are aware that a primary route for person-to-person transmission is through contact with bodily fluids from an infected person. But more recent outbreaks, including the 2013-2016 Ebola epidemic in West Africa, demonstrated that infectious Ebola virus (EBOV) is also found on the skin's surface of those who have succumbed to infection or at late times during infection. Although evidence suggests that EBOV can be passed on from skin contact with a person in the later stages of the disease, very little is known about how the virus makes its way out of the body and onto the skin's surface.
In a new study, researchers at University of Iowa Health Care and colleagues at Texas Biomedical Research Institute and Boston University, have traced a cellular route the virus uses to traverse the inner and outer layers of skin and emerge onto the skin's surface. The study identifies new cell types within the skin that are targeted by EBOV during infection and shows that human skin specimens actively support EBOV infection. Overall, the findings, which were published Jan. 1 in Science Advances, suggest that the skin's surface may be one route of person-to-person transmission.
"The skin is the largest organ in the human body yet is woefully understudied compared to most other organs. Interactions of EBOV with skin cells have not previously been extensively examined," says Wendy Maury, PhD, UI professor of microbiology and immunology, and senior author of the study. "Our work provides evidence for one mechanistic avenue that EBOV uses to exit from the human body. A comprehensive understanding of which cells are targeted during virus infection is critical for rational development of antiviral approaches."
Human skin model helps trace EBOV escape
The research team, led by Maury and Kelly Messingham, PhD, UI research professor of dermatology, developed a new approach to examine which cells within the skin are infected by Ebola virus.They created a human skin explant system using full-thickness skin biopsies from healthy individuals, which contained both deeper (dermal), and surface (epidermal) layers of skin.
To study how Ebola virus moves through skin, the explants were placed dermal side down in culture media and virus particles were added to the media so that they entered the skin from the underside, modeling virus egress from the blood to the surface of the skin. The researchers used virus-tracing and cell-tagging techniques to follow the journey of the virus through the skin layers to the upper surface of the skin, identifying which cells were infected over time.
Previous clinical and animal studies had reported that cells within the skin become infected with EBOV, but the specific cells targeted by the virus had not been identified.
In the new study, the team showed that EBOV infected several different cell types in the skin explant, including macrophages, endothelial cells, fibroblasts, and keratinocytes. While some of these cell types are also found to be infected by EBOV in other organs, keratinocytes, that are unique to the skin, had not been previously appreciated to support EBOV infection.
Interestingly, virus replication was more robust in the epidermal layer than the dermal layers on a per gram basis. Additionally, the infectious virus was detected on the epidermal surface within three days, indicating that the virus rapidly spreads and moves through the explants to the skin's surface.
The researchers also showed that human skin explants can serve as complex, three- dimensional organ models for studying the efficacy of antivirals against EBOV, providing a new, highly useful, and inexpensive model system for therapeutic testing.
Finally, the team also focused on the interactions of EBOV with two specific skin cell types, fibroblasts and keratinocytes, and identified specific receptors on these cells that allow uptake of Ebola virus.
"This study explores the role of the skin as a potential route of Ebola virus infection and identifies, for the first time, several cell types in the skin that are permissive to infection," says Messingham. "In total, these findings elucidate a mechanism by which EBOV traffics to the skin's surface and may explain person-to-person transmission via skin contact."
In addition to Messingham and Maury, the study team included UI researcher Paige Richards, Anthony Fleck, Radhika Patel, Jonah Elliff, Samuel Connell, Tyler Crowe, Juan Munoz Gonzalez, Francoise Gourronc, Jacob Dillard, and Aloysius Klingelhutz. MarijaDjurkovic and Olena Shtanko at Texas Biomedical Research Institute, and Robert Davey at Boston University were also part of the team.
The research was funded in part by grants from the National Institute of Allergy and Infectious Diseases.
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