Allergies Don’t Cause a Fever — At Least, Not Directly
Ebola's Exponential Growth
Monday, October 13th 2014 - 00:26 UTC
The U.S. Government's Centers for Disease Control warned recently that we could have 1.4 million cases of Ebola by January. By Gwynne Dyer - Here are two good things about the Ebola virus. It is unlikely to mutate into a version that can spread through the air, as some other viruses have done. And people who have been infected by Ebola cannot pass it on to others during the incubation period (between two and 21 days). Only when they develop detectable symptoms, notably fever, do they become infectious to others, and only by the transfer of bodily fluids.
Here are three bad things about Ebola.
The "bodily fluids" that can transmit it include even the tiniest droplet of sweat: just the slightest touch can pass the virus on. The death rate for those who become infected is 70%. And the U.S. Government's Centers for Disease Control warned recently that we could have 1.4 million cases of Ebola by January.
Since the number of known cases so far is only around 7,500, that suggests that the number of new cases is doubling approximately every two weeks. This is called exponential growth: not 1, 2, 3, 4, 5, 6... But 1, 2, 4, 8, 16, 32.... If you put one grain of wheat on the first square of a chess-board, two on the second, and keep doubling the grains every square, there are not enough grains of wheat in the world to get you to the 64th square.
Exponential growth always slows down eventually, but the question is when? A vaccine would slow it down, and the British pharmaceutical giant GlaxoSmithKline already has one under development, but it is still in an early stage of testing. Human volunteers are now being given the vaccine to check for unforeseen side effects.
If no serious side-effects are found, the vaccine will then be given to health workers in West Africa. A process that normally takes years is being compressed into mere months, and 10,000 doses of the vaccine are already being produced (for the health workers).
But it will be the end of the year before we know if it actually gives a useful degree of protection from the virus.
If it does, then millions of doses would have to be produced and injected into the people of Liberia, Sierra Leone, and Guinea, where Ebola is already an epidemic— or tens of millions of doses if the disease has spread by then to more populous countries like Ivory Coast, Ghana or, worst of all, Nigeria, which has 175 million people.
Until and unless a vaccine becomes available in very large quantities, the only way to stop the exponential spread of Ebola in the affected countries is to isolate the victims, a task that is very difficult in mostly rural countries with minimal medical facilities. Liberia with 4.2 million people, had only 51 doctors and 978 nurses and midwives at the start of the crisis, and some of those have already died or fled.
You don't need to find and isolate everybody who gets the disease to break the exponential pattern. Just isolating 75% of them as soon as they become infectious would drastically slow the spread. But at the moment, in the three most affected countries, only an estimated 18% of the victims are being taken to treatment centers (where, of course, most of them will die).
This is why the most important intervention so far has been the dispatch of 3,000 U.S. Troops to Liberia, with the primary job of creating 17 large tent hospitals and training 500 nurses to work in them. Britain is providing 200 new hospital beds in its former colony of Sierra Leone, with 500 more in the next few months. Cuba has sent 165 health workers, China has sent 60, and France has sent various teams to help its former colony, Guinea.
But with the exception of the American aid to Liberia, it is all woefully inadequate. Nine months after the first case of Ebola was confirmed in Guinea, we are still playing catch-up, and playing it badly. Why is that? Aren't the developed countries also at risk if the virus continues to spread?
Well, no, or at least their governments don't think so. Even without a vaccine, they are confident that their health services can find and isolate any infected people quickly and prevent Ebola from becoming an epidemic in their countries. They are probably right, and so they see the limited help they are sending to West Africa as charity rather than a vital self-interest. But they may be wrong.
As Professor Peter Piot, who first identified the Ebola virus in 1976, said in a recent interview with Der Spiegel, "I am more worried about the many people from India who work in trade or industry in West Africa. It would only take one of them to become infected, travel to India during the virus's incubation period to visit relatives, and then, once he becomes sick, go to a public hospital.
"Doctors and nurses in India often don't wear protective gloves. They would immediately become infected and spread the virus." Then you would have Ebola on the loose in a country of more than a billion people, millions of whom travel abroad each year. All hope of confining the disease to Africa and driving it back down to almost nothing, as was done in previous outbreaks, would be gone.
Fresh Hope Of Abolishing 'eye-bleeding' Ebola Which Kills Up To 90% Of Victims, As Pill Shows '100% Protection'
SCIENTISTS have found a pill that offers '100 per cent protection' against Ebola - sparking hopes of eradicating the deadly eye-bleeding disease.
Ebola is a rare but severe illness that can kill up to 90 per cent of its victims.
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The antiviral pill Obeldesivir offered up to 100 per cent protection to macaques exposed to EbolaCredit: GettyFirst identified in 1979, outbreaks of the disease have been reported with increasing frequency since 1994.
The most recent Ebola outbreak has been declared in Uganda.
The disease previously resulted in 2,299 deaths when it tore through Uganda and the Democratic Republic of Congo (DRC) between 2018 and 2020.
Meanwhile, the 2013–2016 West African Ebola epidemic infected 28,600 people and caused 11,325 deaths.
Scientists have raced to create vaccines and treatments that mimic natural antibodies - called monoclonal antibodies (mAb) - to eradicate the deadly disease since its discovery.
A vaccine was only widely approved in 2019, and while two mAb-based treatments have shown success in human clinical trials, they need need to be at cold temperatures so they remain effective.
This is costly and can make the treatments difficult to administer in the world's poorest regions.
Researchers from The University of Texas Medical Branch at Galveston said: "There from the here remains a need for Ebola virus disease countermeasures that can be more rapidly and widely deployed in resource-limited regions."
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The 9 symptoms of pneumonia as Newcastle boss Eddie Howe misses more gamesTreatments given orally in pill form would be much easier to dish out during outbreaks, they noted.
Thomas Geisbert, a virologist who lead the new study published in Science Advances, told AFP: "We're really trying to come up with something that was more practical, easier to use, that could be used to help prevent, control, and contain outbreaks."
First case of deadly Ebola-like Marburg virus with a fatality rate as high as 88pc detected in Guinea, West AfricaFor their study, researchers tested the antiviral Obeldesivir, a "polymerase inhibitor" that blocks an enzyme responsible for the virus replicating.
The team infected rhesus and cynomolgus macaques (monkeys) with a high dose of the Makona variant of the Ebola virus through their noses and mouths.
A day after exposure, ten monkeys then received an Obeldesivir pill daily for ten days, while three control monkeys received no treatment at all and died.
Obeldesivir protected 80 per cent of the cynomolgus macaques and 100 per cent of the rhesus macaques, which are biologically closer to humans.
The disease onset was slower, so researchers were able to explore how the drug worked in real time.
The drug not only cleared the virus from the treated monkeys' blood but also triggered an immune response, helping them develop antibodies while avoiding organ damage from the immune reaction.
Though the number of monkeys the Obeldesivir pill was tested on was relatively small, Dr Geisbert told AFP the results were significant because the macaques were exposed to an extraordinarily high dose of the virus -- roughly 30,000 times the lethal dose for humans.
Symptoms of Ebola
Ebola first manifests as a high fever, intense muscle and joint pain, headaches and a sore throat.
Initial symptoms are often followed by:
After recovering from Ebola, some people may have symptoms for two years or longer.
These symptoms can include:
People can get infected with Ebola by touching:
Ebola enters the body through cuts in the skin or when touching one's eyes, nose or mouth.
Source: WHO
The drug was previously found to be able to combat several RNA viruses – including the filovirus family to which Ebola belongs – when macaques were given it 24 hours after exposure, infected via their muscles.
This causes the disease to strike much faster and makes it harder to track the drug's effect.
Dr Geisbert said one of the most exciting aspects of Obeldesivir is its "broad-spectrum" protection, compared to the approved antibody treatments that only work against the Zaire species of Ebola (there are four species of Ebola).
"That's a huge advantage," Dr Geisbert said.
Researchers said their results indicate that Obeldesivir could be given to people after being exposed to Ebola.
"These findings suggest that Obeldesivir treatment affords the opportunity for the development of adaptive immunity while mitigating excessive inflammation, potentially preventing fatal outcomes," they wrote.
But they said the drug needs to be tested further.
"Results from these preclinical studies support further advancing Obeldesivir as a post exposure prophylaxis for filovirus infections.
"Future testing of Obeldesivir treatment in nonhuman primates beyond the early filovirus post exposure prophylaxis should focus on evaluating the dose, the duration of treatment and delaying treatment until the onset of detectable clinical signs of illness.
"The benefits of oral interventions promote the rapid and wide deployment as post exposure prophylaxis particularly in a resource limited outbreak setting."
Pharmaceutical maker Gilead is currently studying Obeldesivir in Phase 2 clinical trials for Marburg virus, a close relative of Ebola.
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