Rapid interventions key to preventing Ebola outbreak

October 9, 2014

To avoid the spread of Ebola and far worse scenarios, quick and forceful implementation of control interventions are necessary, according to new research published Oct. 9 in the scientific journal Eurosurveillance.

Analyzing Ebola cases in Nigera, a country that has had success in containing the disease, researchers estimated the rate of fatality, transmission progression, proportion of health care workers infected and the impact of control interventions on the size of the epidemic. figure of transmission of the ebola virus, July-Sept. 2014 Download Full Image

The study's findings show that Ebola transmission is dramatically influenced by how rapidly control measures are put in place.

"Rapid and forceful control measures are necessary, as is demonstrated by the Nigerian success story," said Arizona State University's  Gerardo Chowell, senior author of the paper. "This is critically important for countries in the West African region that are not yet affected by the Ebola epidemic, as well as for countries in other regions of the world that risk importation of the disease."

Chowell is an associate professor in the School of Human Evolution and Social Change in the College of Liberal Arts and Sciences.

Control measures in Nigeria

The largest Ebola outbreak to date is ongoing in West Africa, with approximately 8,011 reported cases that include more than 3,857 deaths as of Oct. 5. However, just 20 Ebola cases have been reported in Nigeria, with no new cases reported since Sept.5.

All of the cases stem from a single traveler returning from Liberia in July.

The study used epidemic modeling to project the size of the outbreak in Nigeria if control interventions had been implemented during various time periods after the initial case, and estimated how many cases had thus been prevented by early initiation of interventions.

Control measures enacted in Nigeria included all people showing Ebola symptoms being held in an isolation ward if they had contact with the initial case. Once Ebola was confirmed through testing, people with Ebola were moved to a treatment center.

Asymptomatic individuals were separated from those showing symptoms, and those who tested negative without symptoms were discharged. People who tested negative, but showed symptoms – fever, vomiting, sore throat and diarrhea – were observed and discharged after 21 days if they were free of symptoms, while being kept apart from people who tested positive for the disease.

"The swift control of the outbreak in Nigeria was likely facilitated by early detection of the initial case in combination with intense tracing efforts of all subsequent contacts that the person had after developing Ebola," said Folorunso Oludayo Fasina, a senior scientist and lead author of the study at the University of Pretoria, South Africa.

"By contrast, the initial outbreak in Guinea remained undetected for several weeks, facilitating the spread of the virus to Sierra Leone and Liberia, where the inability to track and contain infectious individuals compounded the situation and resulted in an uncontrolled epidemic," said the lead author.

Brief window of opportunity

Ebola transmission is dramatically influenced by how rapidly control measures are put in place, as researchers found that the projected effect of control interventions in Nigeria ranged from 15-106 cases when interventions are put in place on day 3; 20-178 cases when implemented on day 10; 23-282 cases on day 20; 60-666 cases on day 30; 39-1599 cases on day 40; and 93-2771 on day 50.

"There is brief window of time when a rapid and forceful intervention in terms of relentless contact tracing and isolation pays off handsomely and the transmission is effectively halted and the outbreak dies out," said co-author professor Lone Simonsen, of the Milken Institute School of Public Health at the George Washington University in Washington D.C.

The person who was initially infected generated 12 secondary cases, in the first generation of the disease; five secondary cases were generated from those 12 in the second generation; and two secondary cases in the third generation, leading to a rough empirical estimate of the reproduction number according to disease generation declining from 12 during the first generation, to approximately 0.4 during the second and third disease generations. Recent estimates of the reproduction number for the ongoing Ebola epidemic in Sierra Leone and Liberia range between 1.5 and 2 (two new cases for each single case), indicating that the outbreak is yet to be brought under control.

"The effectiveness of the Nigerian response is illustrated by a dramatic decrease in the number of secondary cases over time. Overall, this is a great success story for Nigeria, which sets a hopeful example for other countries, including the U.S., which face risk of importation from high Ebola transmission areas," said Cécile Viboud, a National Institutes of Health scientist with the Fogarty International Center.

Authors of the new research are Chowell, Arizona State University; Fasina, University of Pretoria, South Africa; Aminu Shittu, Usmanu Danfodiyo University, Sokoto, Nigeria; David Lazarus, National Veterinary Research Institute, Plateau State, Nigeria; Oyewale Tomori, Nigerian Academy of Science, University of Lagos Campus, Lagos, Nigeria; Simonsen, George Washington University, Washington, D. C.; and Viboud, National Institutes of Health, Bethesda, Maryland.

New ASU, Nature journal to highlight spaceflight research

October 10, 2014

It’s a field of scientific discovery with practical applications that could be astounding: new drugs and vaccines to halt the spread of disease and infection, improved telecommunications linking people around the world, enhanced manufacturing capabilities and the very future of interplanetary exploration.

That interdisciplinary compendium of scientific research and innovation now has a new home. The International Space Station The International Space Station will begin hosting one of Cheryl Nickerson's experiments in the coming months. Photo by: NASA Download Full Image

On Oct. 10, Nature Publishing Group and the Biodesign Institute at Arizona State University announced the launch of npj Microgravity, a new open access journal. The journal is specifically dedicated to publishing research that enables space exploration and research that is enabled by spaceflight. It will also publish research utilizing ground-based models of spaceflight.

“We are in a Renaissance period for spaceflight research that has tremendous potential for breakthrough advances in diverse scientific and technological domains to benefit life on Earth and exploration of space,” said Cheryl A. Nickerson, a professor in the Biodesign Institute, who is the editor-in-chief of the new journal.

Microgravity, which astronauts experience during spaceflight, is an extreme environment in which gravity is greatly reduced. Studying it provides a unique opportunity to not only enhance future spaceflight missions, but also provides novel insight into our understanding of biological, physical and engineering sciences on Earth.

npj Microgravity, an online-only and free to access journal, captures the discoveries from reduced gravity and other similar environments, thereby providing scientists and science enthusiasts alike a way to stay at the cutting edge with the latest research.

Nickerson, who is also a professor in ASU's School of Life Sciences, is internationally recognized for her pioneering research in utilizing the microgravity environment of spaceflight as a unique research platform to provide novel insight into infectious disease mechanisms and to understand how physical forces dictate the outcome of host-pathogen interactions that lead to disease.

“I am delighted to be a part of this new initiative, which I believe is exactly the type of platform needed to highlight and broaden microgravity and analogue research into widespread mainstream acceptance with the highest values of scientific integrity historically defined by the Nature brand,” she said.

This is the latest launch in the series of Nature Partner Journals (npjs), a new series of online, open access journals published in collaboration with world-renowned international partners. As with all titles within the series, npj Microgravity adheres to high editorial standards and will publish high-quality open research.

“For over fifty years, humanity’s imagination has been captured by what lies beyond our own small planet,” said Martin Delahunty, global head of partnership journals at Nature Publishing Group. “The research undertaken into space exploration has even led to technological advances which affect our everyday life. And for the first time, scientists looking to publish on this topic will have the option of choosing a high quality, dedicated journal which is open to all.”

npj Microgravity will publish scientific research in the life sciences, physical sciences and engineering fields, which is needed to develop advanced exploration technologies and processes, particularly those profoundly affected by operation in a space environment. It will also publish research that is enabled by spaceflight and spaceflight analogues that provide novel insight into biological, engineering and physical sciences to benefit Earth-based research and the general public.

Media contact:

Joseph Caspermeyer, joseph.caspermeyer@asu.edu
Biodesign Institute