A Season of Hemorrhagic Fevers


Uganda and the Democratic Republic of Congo have been bedeviled by viral hemorrhagic fever outbreaks this year. Since the summer, Ebola and Marburg have appeared throughout the two verdant countries killing dozens of people.

An Ebola outbreak in western Uganda began in early July, another Ebola outbreak materialized in eastern DR Congo in August, and then Marburg made an appearance in south-western Uganda as well as in the capital Kampala in October. Last month, Uganda finally declared the country free of hemorrhagic fevers after three months of battling these seemingly omnipresent sanguinary viruses. And then Ebola appeared yet again in Luweero, a village located just 47 miles from the capital. It has been an incredibly psychologically and financially taxing period for the two countries.

(Confused on the timeline of events? I certainly was! But the WHO is here to help with a chronology of Ebola outbreaks here and Marburg outbreaks here.)

Ebola and Marburg hemorrhagic fevers outbreaks in Uganda and the Democratic Republic of Congo in 2012. Red crosses represent reported cases and the green amorphous shapes represent parks, forests and reserves as identified by Google Maps. Click to visit the map, zoom in and get additional info. © Google.

The thing to remember with viral hemorrhagic fevers is that they’re not toxic miasmas, diffusing through households and indiscriminately infecting innocents. They’re viruses. They spread through contact with infected bodily fluids, resulting in the transmission of viral particles and like any other infectious disease, there’s a method to the madness. True, they’re frightful illnesses and quite deadly, but there are clear epidemiological patterns and even cultural contexts to their arrival and spread in communities.

Take these viral hemorrhagic fever outbreaks, for example. Uganda and the DR Congo are incredibly rich and diverse in their ecology – the Congo Basin is one of the largest and densely forested regions in the world – and much of their economy depends upon safari tourism and gorilla trekking (1). The livelihood of their peoples is also greatly reliant on poaching and bushmeat; for many in the DR Congo, primates, ungulates, primates and rodents are often their only form of animal protein considering the prohibitive cost of raising or purchasing domesticated animals for food (1). It can be easier and kinder on limited finances just to go into the forests to get your dinner. Coincident with the diverse wildlife and the lush wilderness that flourishes in these countries are also viruses simmering away, undisturbed for the most part.

The recent outbreaks in Uganda and the DR Congo have some local officials pinpointing the origin of the these most recent outbreaks on infected bushmeat and contaminated fruit. The Ebola outbreak in August in the Dungu district in northern DR Congo began with a hunter who found and consumed the remains of an antelope, quickly fell ill and died (2). October’s Marburg outbreak in Kabale, Uganda is speculated to have occurred when villagers ventured into the wild to collect fruits that were contaminated by fruitbats, a known reservoir of the virus (3).

An isolation camp for infected patients and suspected cases during Uganda’s Ebola hemorrhagic fever outbreak this year. Image: The Lancet. Click for source.

There’s an unexpected upside to these grim epidemics as public fears of these deadly viral hemorrhagic fevers are keeping wildlife poachers and bushmeat hunters from venturing into the forests for profit and food. Park rangers in the DR Congo report that there has been demand for bushmeat has crashed with a concomitant rise in fear of contracting a fatal disease. Media Congo, an online newspaper covering the Congo, notes, “the fight against poaching of rare species that was once the sole preserve of NGOs and officials of the Congolese Institute for the Conservation of Nature (ICCN) has become the business of everyone” (4). Giant primates have been threatened for years by poachers and bushmeat hunters and though our closest ancestors are also at great risk of contracting and dying of Ebola and Marburg, for now they’re safe from those hunting them (5).

To figure out just where the outbreaks were occurring, I began playing around with a few maps to pinpoint the locations of reported villages in relation to nearby protected park, forests and game reserves. There’s limited information on the outbreaks – even from the WHO and Medecins Sans Frontiéres/Doctors Without Borders – on the exact origins of the many victims who have traveled to hospitals seeking care and then have died and these maps are the best I could do with the limited information available. The maps give a good idea of how geographically disparate the epidemics were, the proximity of the legion parks and reserves to reported outbreaks and how the two countries are just entirely covered in lush, green forest.


Ebola may be transmitted by respiratory means; the possibility of airborne transmission of this virus would go far in explaining how transmissible the virus is within households and hospitals.

“Protein from forest wildlife is crucial to rural food security and livelihoods across the tropics.” A great read on bushmeat in the two most densely forested and least populated places in the world.

The WHO’s Global Alert & Response monitors all global epidemics and public health emergencies. This is the current list of 2012 epidemics.

The gorilla population was devastated in 2002 and 2003 as outbreaks of the Zaire strain of Ebola killed nearly 5000 gorillas in northwestern DR Congo.


(1) R Nasi et al. (2011) Empty forests, empty stomachs? Bushmeat and livelihoods in the Congo and Amazon Basins. International Forestry Review 13(3):355-368

(2) Irin News Africa (August 23, 2012) DRC: Bushmeat blamed for Ebola outbreak. Irin News. Accessed here on November 20, 2012.

(3) E Biryabarema (October 23, 2012) Killer disease reaches Uganda capital, five dead. Reuters. Accessed here on November 20, 2012.

(4) J. Kikumi (October 26, 2012) Le virus d’Ebola chasse les braconniers. Media Congo [mediacongo.net]. Accessed here on November 20, 2012.

(5) M Bermejo et al. (2006) Ebola outbreak killed 5000 gorillas. Science. 314(5805):1564

ResearchBlogging.orgNasi, R., Taber, A., & Van Vliet, N. (2011). Empty forests, empty stomachs? Bushmeat and livelihoods in the Congo and Amazon Basins International Forestry Review, 13 (3), 355-368 DOI: 10.1505/146554811798293872

Body Horrors Published in Digital & Analog!

My name, Rebecca Kreston, in yellow on the lovely cover of Scientific American’s “The Best Science Writing Online 2012” edited by Bora Zivkovic and Jennifer Ouellette.

At this very moment, I’m holding a copy of the “The Best American Science Writing Online 2012” that includes my article on Alaskan Natives, botulism and fermenting practices on page 173! The article “This Ain’t Yo Momma’s Muktuk: Fermented Seal Flipper, Botulism, Being Cold & Other Joys of Arctic Living” was selected among 721 other submissions and is published alongside 51 other knock-out articles in the sixth annual anthology of the best science writing online. Not bad odds, eh? I’ve been writing this blog for just over a year and a half now and I consider it be a privilege to be included in the ranks of some truly accomplished science journalists and bloggers. A big thank you is owed to the editors of the anthology, Bora Zivkovic and Jennifer Ouellette, for selecting me.

I’ve been very lucky to have had the article shaped by the deft hands of the very helpful and kind editors at the publishing company Farrar, Strauss & Giroux and, thanks to their efforts, the article in the book is much trimmer and slimmer than you would find on the site. The book is officially out tomorrow and available for purchase in the bibliophilic drug of your fancy, ebook or paperbook (so what’s it gonna be, partner?).

The entire list of published articles is accessible online here but you can, and should!, buy the book here! Besides the fact that my gross little article is in it, it’s a fantastic opportunity that allows you to discover and support the other amazing blogs that cover the oh-so-important sciences out in these vast interwebs. This book has got everything that you’ve ever briefly wondered about in those rare moments that you’ve daydreamed during staff meetings, classes and family dinners: the microbiology of beards, how to stop hurricanes, the dodo’s demise and so, so, so much more.

Submissions are rolling in again for this past year’s of the best online science writing and you can submit your own personal favorites by clicking on the image below. Go on, make a science blogger happy!

The Grass Isn’t Always Greener: A Marijuana-Borne Salmonella Outbreak


At the very beginning of the year 1981, the United States saw an unusually large boost in Salmonella infections across the country. Incidences of the food-borne illness had risen by nearly 20% from the previous year, surprising health officials not only with the unexpectedly high number of cases but its odd timing during the winter season.

Ohio, Michigan, Georgia, and Alabama saw most of the action from the Salmonella outbreak but from an unusual serotype of the microbe, Salmonella muenchen, and CDC investigators were unable to pinpoint its edible source. Michiganders, however, provided local investigators with an interesting lead in the case – 76% of those infected reported personal usage of or “household exposure” to marijuana (1).

Isolates of Salmonella muenchen from cases of infection in the United States, from January 1978 through August 1981. Note the massive spike in infections in January and February of 1981; not only were these cases above the expected baseline number of infected but they also occurred at an unusual date.
Image: Taylor DN et al. (1982) Salmonellosis Associated with Marijuana — A Multistate Outbreak Traced by Plasmid Fingerprinting. N Engl J Med. 306: 1249-53

This wasn’t a food-borne but a marijuana-borne outbreak.

Laboratory tests of the marijuana in question found staggering quantities of the bacteria on the drug, in some instances as high as 107 or ten million bacteria per gram of bud. Investigators found that the green stuff had reached its way across the country from California to Massachusetts, concomitantly spreading the S. muenchen outbreak.

How did the Salmonella end up in the skunk? Investigators determined that the marijuana was imported from either Jamaica or Colombia and distributors there seem to have deliberately adulterated the product with manure prior to shipment so as to increase its weight and, in turn, raise its consumer costs (2). Not only were people falling ill from their illicit drug, but they were also paying more for less!

A CDC physician, Dr. David Taylor, described the method of transmission thusly,
“The salmonella was in the marijuana. When a marijuana smoker rolled a cigarette, his hands became contaminated, and when he put the cigarette in his mouth his lips became contaminated. Then a touch or a kiss or any sort of contact could spread the infection … And not only that. Pot decreases the gastric acid, and gastric acid is an important defense against infections of all kinds” (3).

Potheads weren’t the only ones susceptible to this salmonella smoke up. Family members, including children, and roommates also became infected indirectly through person-to-person contact with those toking up or from touching contaminated household surfaces. (Infected people spreading diseases from their hands and contaminating stuff, you ask? See here.)

There’s an aphorism, “when you hear hoofbeats, think horses not zebras”. In public health and medical school, students are taught to think of the most likely scenario, the most common culprit behind a disease or outbreak. An organism commonly associated with food outbreaks? Show me your spinach! Show me your cantaloupe! Show me your ground beef! And, indeed, this often holds true with many of the microbes we humans encounter regularly – the E. coli nestled in our bagged salad greens and the TB bacterium sprayed from a cough are two good examples. But this marijuana outbreak is a lovely exception, an interesting case that I like to think shows the unpredictably and caprice of microbes. Every now and then we do need to think of horses, zebras and even giraffes.


Some background history on the “medical zebra” aphorism. I also quite like the “KISS principle”: Keep It Simple, Stupid.

Wanna look at past foodborne outbreaks in the US? Of course you do! The CDC’s Foodborne Outbreak Online Database (FOOD) can be accessed here but sadly has only data up to the year 2010.

(1) Taylor DN et al. (1982) Salmonellosis Associated with Marijuana — A Multistate Outbreak Traced by Plasmid Fingerprinting. N Engl J Med. 306: 1249-53
(2) Associated Press. (1982, May 27) Marijuana Linked to Salmonellosis. The New York Times [Online]. Accessed on September 13, 2012 here.
(3) Thompson A. (2008, June 13) Smoking Salmonella. The New Yorker [Online]. Accessed on September 13, 2012 here.

ResearchBlogging.orgTaylor DN, Wachsmuth IK, Shangkuan YH, Schmidt EV, Barrett TJ, Schrader JS, Scherach CS, McGee HB, Feldman RA, & Brenner DJ (1982). Salmonellosis associated with marijuana: a multistate outbreak traced by plasmid fingerprinting. The New England journal of medicine, 306 (21), 1249-53 PMID: 7070444