CDC's adapted Ebola virus works in trials, as pressure for funds grows

Ebola Makona virus
Ebola Makona virus


Yesterday researchers from the Centers for Disease Control and Prevention (CDC) published encouraging findings that showed the antiviral remdesivir and antibodies in the ZMapp treatment regimen were effective in fighting the current strain of Ebola. The findings were published in The Lancet Infectious Diseases.

The study also demonstrated that a reverse-engineered virus that CDC scientists developed served as an admirable substitute for virus circulating in the Democratic Republic of the Congo (DRC), given that they did not have access to the real thing.

Test of 2 field treatments

The two experimental treatments have been in use in the DRC since last November. Though clinical data showed their efficacy, the drugs had been developed during the 2014-2016 West Africa outbreak for use against a different strain of Ebola virus. And because Ebola is an RNA virus, it can mutate, leaving some to wonder if the treatments would be as effective against the current strain seen in the DRC.

The CDC researchers reverse-engineered a sample of the current outbreak strain—the Ituri strain—in a CDC biosafety level 4 laboratory (the highest-security type) to test the treatments. They created the synthetic virus because no samples or isolates of the current strain have been made available by the DRC.

"As technology progresses and rapid sequencing of virus strains in low-resource settings in the field becomes more and more feasible, if isolates are unavailable, we recommend a policy whereby reverse genetics is used to generate outbreak strains as a standard practice," the authors of the study concluded.

This is the first time reverse genetics technology has been used to generate an Ebola virus isolate. In addition to showing ZMapp and remdesivir's efficacy, the synthetic strain also validated two diagnostic tests being used currently in the DRC.

"Having access to this virus will allow us to explore whether other compounds or potential therapies affect the virus in the lab,” said Inger Damon, MD, PhD, chief strategy officer for the CDC’s 2018 Ebola response and director of CDC’s Division of High-Consequence Pathogens and Pathology in a press release.

In a Statstory, several Ebola researchers reacted to the work. Though they called the effort impressive, they said obtaining virus isolates from the current outbreak would have been useful.

"I don't know anyone who has isolates from this outbreak," said Tom Geisbert, PhD, of the University of Texas Medical Branch in Galveston.

"They did a great job here in a short period of time, but man, that takes a lot of resources and a lot of money and a lot of energy to make a cloned virus by reverse genetics. And it would be so much easier if somebody had just sent the isolate."

Need for funding grows

In order to contain and ultimately end the current Ebola outbreak in the DRC's North Kivu and Ituri provinces, the United States must fulfill its funding promise to the World Health Organization (WHO), and other nations must also take on the challenge of beating this disease.

That's the message of an editorial yesterday in Nature, which says that. of the G7 countries, only Germany and the United Kingdom are on track to meet their pledges to the WHO.

"The United States, Canada, France, Italy and Japan have not contributed their share. And because the United States is relied upon as the world's biggest health-emergency funder, its shortfall is disconcerting," the authors write.

According to Nature, the WHO has requested $98 million for the Ebola response but has only received half of it. Meanwhile, the WHO's African office warned in its latest situation report that suboptimal funds could lead to further transmission in the region.

"Without adequate funding to fill the current gap, response activities will be compromised, negatively impacting  the  entire response, resulting in a drastic reduction in vital health services available and a cessation of operations during this critical time of the outbreak," the WHO said.

Steady transmission in Beni and Mabalako

In the past 3 weeks, DRC has recorded 250 cases of the virus, with 36% from Beni and 22% from Mabalako, the WHO update said. Response workers receive an average of 1,775 alerts each day, of which 1,645 (93%) were investigated within 24 hours of reporting.

"Case incidence rates remained largely unchanged in the past week," the WHO said. "While the number of new cases continues to ease in former hotspots, such as Butembo, Katwa  and Manama health zones, there has been an increase in cases in Beni and a high incidence continues in parts of Mabalako Health Zone."

The DRC ministry of health will likely confirm 9 new Ebola cases today, raising outbreak totals to 2,437 according to the WHO's online Ebola dashboard.

Yesterday the DRC confirmed 10 new cases, including 8 in Beni. Officials also confirmed 11 new deaths, raising the fatality total in this outbreak to 1,641 deaths. A total of 322 suspected cases are also still under investigation.

Vaccination continues with Merck's rVSV-ZEBOV; 155,800 people have been vaccinated with the vaccine since August of 2018.

See also:

Jul 9 Lancet Infect Dis study

Jul 9 CDC press release

Jul 9 Stat article

Jul 9 Nature editorial

Jul 10 WHO situational report

WHO Ebola dashboard

Jul 9 DRC report

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