Ebola in Uganda

Lots of bad reporting and misinformation on this latest Ebola outbreak in Africa. From CNN today:

Teams in Uganda are trying to track down anyone who came into contact with patients infected with the Ebola virus, which has killed at least 14 people there this month, authorities said Monday.

The Ebola virus is a highly infectious, often fatal agent spread through direct contact with bodily fluids. Symptoms can include fever, vomiting, diarrhea, abdominal pain, headache, a measles-like rash, red eyes and, at times, bleeding from body openings.

Highly infectious?

Or from the Ugandan President in this BBC report:

Uganda's President Yoweri Museveni has urged people to avoid physical contact, after the deadly Ebola virus claimed one life in the capital, Kampala.

People should avoid shaking hands, kissing or having sex to prevent the disease from spreading, he added.

Really? Shaking hands?

A cure for Ebola (in monkeys...)

In Science Translational Medicine this week:

Successful Treatment of Ebola Virus–Infected Cynomolgus Macaques with Monoclonal Antibodies

Ebola virus (EBOV) is considered one of the most aggressive infectious agents and is capable of causing death in humans and nonhuman primates (NHPs) within days of exposure. Recent strategies have succeeded in preventing acquisition of infection in NHPs after treatment; however, these strategies are only successful when administered before or minutes after infection. The present work shows that a combination of three neutralizing monoclonal antibodies (mAbs) directed against the Ebola envelope glycoprotein (GP) resulted in complete survival (four of four cynomolgus macaques) with no apparent side effects when three doses were administered 3 days apart beginning at 24 hours after a lethal challenge with EBOV. The same treatment initiated 48 hours after lethal challenge with EBOV resulted in two of four cynomolgus macaques fully recovering.


There's a news report on this paper here: Did Scientists Just Discover a Cure for Ebola?

Ebola in apes

Caregiver at Congo's Virunga National Park wearing a facemask to limit danger of orphan ape being exposed to human diseases.

Originally it was suspected that primates such as gorillas might be the natural reservoir of the ebola virus. It is now thought that this is unlikely and that the reservoir is probably bats. One reason we think that apes are an unlikely reservoir is that they suffer fairly severe outbreaks that can kill a high proportion of the animals, (making it difficult for the virus for persist in this population). (eg Ebola Outbreak Killed 5000 Gorillas in the journal Science in 2006). In other words the virus is spilling over into the ape populations in the same way it occasionally spills over into human populations. Over the last two decades the Zaire strain of Ebola has killed roughly one third of the world's gorilla population and only a slightly smaller proportion of the world's chimpanzees

Just last December a paper in PLoS ONE: Consequences of Non-Intervention for Infectious Disease in African Great Apes highlighted the potentially dire consequences of diseases such as Ebola and SIV's for African Great Apes.

"Ebola is Beautiful"

Scientist Hunter Cole is a member of the new bioartist movement who creates works of art using scientific imagery, such as photographs of the ebola virus, seen here in her work "Ebola is Beautiful". Her other notable works include photos of mice embryos and another work entitled "Anthrax Clock," in which a woman is shown dying from anthrax poisoning in the span of 12 hours.

Hunter Cole's website here

Behind Ebola/Marburg

Chris forwarded this interesting trailer/promo for an as yet unmade documentary about Ebola and Marburg virus.

Routes of transmission

As we have seen some diseases, like AIDS, may have several routes of transmission. Although I didn't mention it several other diseases may also have sexual transmission as a possible, although not very likely, route of transmission.

Although those suffering from Ebola and related viruses are unlikely to be having sex whilst they are contagious some people do recover from Ebola - 10%-50% depending on the strain. Even though they have recovered from the disease they can still have virus in their semen up to seven weeks after they recovered. Recovered Ebola patients are advised to 'not have sex for 3 months or until tests show that semen is free of the virus.'

A conference presentation from 2001 documents the recovery of Lyme spirochetes by PCR in semen samples of previously diagnosed Lyme disease patients. This, of course, does not necessarily mean active infection is transmitted this way. Some documents state that there are no documented cases of sexually transmitted Lyme disease (eg the CDC here and here) whilst others strike a more cautious note:

The CDC position on sexual intra-human Borrelia burgdorferi (Bb) transmission is that it does not occur. We find no study that addresses sexual transmission of Bb among humans; conversely, we find no study supporting that it does not occur. Inferential data, however, suggest the possibility of human sexual transfer. The data come from sound veterinary studies, the finding of Bb in human semen and breast milk, and by similarity to Treponema pallidum where sexual transfer is abundantly documented. Our clinical experience strongly suggests that predictable, possibly inevitable Bb transfer between sexually active couples occurs.

From: Lyme disease': ancient engine of an unrecognized borreliosis pandemic?
W. T. Harvey, P. Salvato

[This post contains 90% recycled material]

Outbreak

The 1995 movie 'Outbreak' involves a fictional ebola-like virus known as Motaba which becomes airborne.

Although criticized by some for certain scientific inaccuracies the movie does depict the work of scientists better than most and raises some very important questions about how far a government could, or should go in quarantining an infected area, and how far people might go to escape that quarantine.

Marburg In The US

While looking for my weekly dose of terror this week, I stumbled upon an article about the first confirmed case of the deadly Marburg virus in the US.
Marburg is a hemorrhagic fever that is not unlike Ebola. It is indigenous to Africa, but last I checked no one was certain of where exactly the disease came from. It had been traced back to caves in Africa, which led some to suspect that bats living in these caves are the natural carriers of Marburg.
Apparently this guy went spelunking in a cave in Uganda, looking for pythons, and instead found himself a case of Marburg. The incubation period is about 5-10 days, so he made it all the way back to Denver before he showed symptoms. Tests confirmed that he did indeed have Marburg, and luckily he managed to survive (which is quite a feat considering this disease has a mortality rate over 80%). The CDC was a bit concerned about the health of hospital workers who helped the man, but so far none of them have exhibited symptoms of Marburg. Read the article here.

On a lighter note, I wanted to recommend a few of my very favorite books on the subject or terrifying hemorrhagic fevers. Anyone interested in this macabre subject should definitely check out the author Richard Preston. He writes non-fiction science books that read like exciting action novels. It is hard to come by non-fiction science that reads this well. The Hot Zone is related to Ebola and Marburg, and is full of fascinating stories about the these diseases, and their unfriendly relationships with unlucky humans (and monekys). I love this book! Also look for The Demon in the Freezer and Panic in Level 4, both are also non-fiction books about infectious disease and science. Panic in Level 4 has a few vignettes that touch a lot on disease ecology, so look for it!

Sexually transmitted Ebola ?

Because Ebola is transmitted via infected bodily fluids someone asked whether it could be sexually transmitted. I suggested this was unlikely because individuals are not infectious until they are very sick. However I was forgetting about the 10-50% of people who do recover from Ebola. Apparently even though they have recovered from the disease they can still have virus in their semen up to seven weeks after they recovered. Recovered Ebola patients are advised to 'not have sex for 3 months or until tests show that semen is free of the virus.' Another possibility is that there may be some asymptomatic carriers of Ebola. These individuals may transmit the disease sexually. I hasten to add that transmission via this route is not thought to have contributed in a significant way to any of the known outbreaks. Interesting though.

Hot off the press is a news report that Ebola may not be so hard to work with in the future after all. By removing a single gene from the virus scientists were able to stop it replicating. That's one result they might want to double check......