Since its discovery, only a few countries have really been affected by Ebola. The virus has surfaced multiple times in the Democractic Republic of Congo, in Sudan, in Gabon, and now in Uganda. This country was last hit (and hit hard) by Ebola in 2000, when an outbreak there caused at least 425 cases, and killed more than half of those it infected. Now it’s currently causing yet another outbreak, just weeks after the outbreak in the DRC was confirmed to have ended–and the strain that’s causing this one seems to be distinct from the four known types of virus we’ve seen to date. More after the jump…

A new strain of Ebola virus has infected 51 people and killed 16 in an area near Uganda’s border with Democratic Republic of Congo, U.S. health experts said on Thursday.

Analysis of samples taken from some of the victims show it is a previously unknown type of Ebola, a team at the U.S. Centers for Disease Control and Prevention said.

“This virus didn’t behave as would be expected of some of the known strains,” Dr. Tom Ksiazek, current chief of the CDC’s special pathogens branch, said in a telephone interview.

Word on the ground is that this strain may be milder than the usual suspects. Of the two strains that have caused repeated human outbreaks, Ebola Zaire is the nastiest, followed by Ebola Sudan. Another strain, Ebola Ivory Coast, has only caused one known human infection to date, and as far as we’ve seen so far, Ebola Reston is asymptomatic when it infects humans. A new strain would bring the family members up to 5.

While this outbreak has been newly reported, it’s not really new. Rather (via ProMed), this is the “mysterious outbreak” that started back in August, but tests only recently confirmed it was Ebola:

Dr Zaramba (the director general of health services) yesterday denied reports that the government had known about the deadly epidemic outbreak weeks earlier but concealed it in order not to scare away foreign dignitaries who were scheduled to attend the just concluded Commonwealth Heads of Government Meeting in Kampala.

“It would be unethical for me to keep quiet (about an epidemic outbreak). It is true we knew there was a strange disease in western Uganda but had not got the conclusive confirmation that it was Ebola until today (Thursday) morning,” he stressed.

A team is already in place in Uganda, and the CDC said “another team was waiting for an official invitation from Uganda’s government before heading there to help.” This should help nail down the number of cases and deaths, which seem to be a bit murky and contradictory from the various reports I’ve seen so far.

It’s certainly been a big few years as far as the science behind filoviruses has gone…identification of potential reservoirs, novel strains, better insights into the ecology of the viruses. Now we need to make further strides in understanding and continue to advance the research to the point where outbreaks (in both humans and non-human primates) can be prevented as well.

Comments

  1. #1 jj mollo
    December 1, 2007

    The New Yorker has a great story on virus vs. human evolution. It made a statement implying that strains of viruses become “weaker” because of the high rate of mutation. I guess the implication is that the lack of sexual recombination allows viruses to stray off their optimal configuation by an excess of reproductive exuberance. I am more inclined to believe that viruses track their environment pretty well and exploit every opportunity pretty efficiently. The question comes down to what represents an opportunity. Why has Ebola not expanded and wiped out humanity? The answer I see most often is that it kills too fast for its own good. Therefore the appearance of milder strains is probably bad news.

  2. #2 Tara C. Smith
    December 1, 2007

    Why has Ebola not expanded and wiped out humanity? The answer I see most often is that it kills too fast for its own good. Therefore the appearance of milder strains is probably bad news.

    I don’t know about that. We already knew about the Reston strain, and serologic studies in pygmies and other African populations have shown that a small percentage of individuals are seropositive–so they’ve been exposed to some strain of Ebola at some point, and recovered. Remember that humans are incidental hosts for Ebola, so we’re not important to their evolution as a species.

  3. #3 jj mollo
    December 1, 2007

    … their evolution as a species.

    Do viruses have breeding populations? Is there any way for genetic exchange to take place among viruses? I think it’s better to think of each virus — or at least the viruses within each individual host — as its own species . They don’t know that humans are not their preferred host; they have seized the opportunity to infect a human. If they can subsequently infect another human, the mutations will have been filtered, limiting them to a more potent, human oriented subset.

    The fact that some humans have survived Ebola by dint of their immune response is less important than the questions of how they contracted it and whether they passed it on to other humans.

  4. #4 M. L. Green
    December 3, 2007

    And greetings:
    Everytime you post on this (or any of the other nasty bugs out there), Tara, I’m put in mind of “The Stand” by Stephen King. He specifically ‘engineered’ his bug for the purposes of fiction. What, really, are the factors involved, both known and merely hypothesized, that come into play if/when a pathogen mutates to a form that can cause a pandemic.

    Bear in mind that I’m up on my science but not biology, so please present material that I can ‘get’. A suggested reading list perhaps as well??

    Thanks so much,
    M.L.

  5. #5 Ben
    December 6, 2007

    It’s been an uncertain week in Uganda. I’m based in the western town of Mbarara where rumors and newspapers and even my own blogpost at THDblog suggested that there was one or more Ebola cases in town or at the University hospital. Turns out that the Saturday death was cryptococcal meningitis in an HIV positive patient and Monday the mysterious patient with massive bleeding may have been a rumor. The more troubling insight coming out from this week’s scare is the lack of routine infection control protocols in regional hospitals. The topic has come up in conversation with doctors in Mbarara and coincidentally in a DHS press release on Tanzanian healthcare. Just mentioning Ebola can send healthcare workers running (reported this week in Uganda’s New Vision), but there’s an equally dangerous mix of indifference to poorly enforced protocols, inadequate training, and lack of resources that result in doctors and nurses who stay on the job to routinely see patients without masks, gloves or adherence to other protective protocols. All of that of course in a healthcare environment where HIV+ patients with cryptococcal meningitis are sadly far too common.

  6. #6 isles
    December 9, 2007

    Here’s a knucklehead question that I’m not too proud to ask:

    Is it ee-BOWL-ah or EE-buh-lah?

  7. #7 e-okul
    January 16, 2008

    Hi, isles :) Here’s a knucklehead question that I’m not too proud to ask: Is it ee-BOWL-ah or EE-buh-lah? yes :p you ? :p

  8. #8 Another take on it
    November 24, 2008

    Yah know, I am not so sure about this ebola and marburg stuff as being only about a virus. I’m not saying that there is not a virus called ebola or marburg, and I am not saying that such a virus cannot be a, or even “the” major contributive factor, but there are other factors involved in Uganda, Congo, Sudan, etc, that are being completely overlooked and ignored.

    For instance, the vast majority, almost all of the ebola/marburg cases turned up in Africa, were at or very near to gold mining camps, where cyanides, as well as various acids such as hydrochloric and sulfuric and acid, and aqua-regia are used, and often combined with cyanides resulting in an even more toxic brew. These well known toxic chemicals are almost always being used to get the gold from the ore. Some of the cyanide is potassium cyanide, and there are other cyanides including sodium and combined with hydrochloric acid, creating hydrogen cyanide, that are created or used as well. These are used in a process wherein the ore is crushed and soaked in cyanide. The gold dissolves into the cyanide solution and is then precipitated out. The cyanide mixture is often further treated with acids to purify it or burned.

    Over in Africa, there is no control over what is done with the cyanides and acids and fume from combined solutions, and the spent solutions are usually dumped right onto the ground or into streams, and undoubtedly seep into ground water going to wells.

    And when combined or burned, they often produce even more deadly toxic substances.

    Cyanide is a potentially deadly poison. It works by making your body unable to use oxygen, without which life cannot be sustained. Certainly exposure to cyanide can weaken an individual to the point where other viral factors can take over to finish the job. Cyanide poisoning can happen quickly from single dose, or slowly from gradual repetitive lower exposures.

    Furthermore, the majority of those affected by ebola/marburg, besides being in the toxic and polluted gold mining areas, are nearly all very poor, and the poverty stricken, and quite often even have insufficient diets, and surely also are further weakened by such contributing factors.

    As such, in lower doses, it can also slowly cause the deterioration of bodily function, thereby allowing other, normally nonharmful, viruses, etc, to finish off the individual.

    Many in Africa are unwittingly exposed to cyanides and acids used in mining, and do not know it, and are never tested for such.

    There is no known research on what the combined effects of some of these indigenous viruses are capable of when combined with factors such as cyanides, acids, fumes, and poor diets, so we really do not know what the truth of the matter is.

    Such factors probably never will be known as long as the majority of aetiologists and virologists only consider viral causes as the sole root cause of these illness. It is unfortunate that there is very little crossover between toxicologists and virologists, nutritionists, etc, to look at the combined factors that are so obviously intertwined and certainly play their roles. Seldom do these differing specialized individuals even communicate with each other, let alone collaborate.

    Specialization may be necessary in todays labor market, but it certainly is harmful in furthering science and getting to the facts of the matter of various human illness, and in discovering the intercourse of roles played by both pathogens and toxins, not to mention sufficient nutrition on any live creature including mankind.

  9. #9 bharned
    March 12, 2009

    I found what “Another take on it” just said above, on the factoring in of toxins, very interesting. Now, I’m no expert, just a high school working on a project on Filoviruses, but I’m wondering about how much influence toxins could actually have. So, the people hat contract Marburg and Ebola are often near sites of mining contamination- if so, what about the cases NOT near mining contamination. In the Reston VA incident, people developed antibodies, but no symptoms. The monkeys however, living in a monkey house far from any mining or other toxins, were highly infected, to the extent of there being air-borne infections. If someone with more experience in this could post back on this, that would be great.

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