Ebola Outbreak in Uganda

There has been another outbreak of the deadly and highly infectious Ebola virus in western Uganda, in the district of Kibale. A report of July 29 about it appeared in the online Guardian newspaper

Ebola was first reported in 1976 in Congo and is named for the river where it was recognized, according to the Atlanta-based US Centers for Disease Control and Prevention 

As a CDC fact-sheet states states It “is a severe, often-fatal disease in humans and nonhuman primates (monkeys, gorillas, and chimpanzees”

It manifests itself as a haemorrhagic fever, is highly infectious and kills quickly. It is "characterized by fever, headache, joint and muscle aches, sore throat, and weakness, followed by diarrhoea, vomiting, and stomach pain. A rash, red eyes, hiccups and internal and external bleeding may be seen in some patients".

A chimp family in Kibale NP. Photo by one of 70 students, not sure who.

Those gorillas and chimpanzees, both of which have strong social groups, live closely together all year long. This undoubtedly helps the rapid dispersal of the virus, which is spread by close contact, not just with a victim, but also on communal food sources and other surfaces. So much so that Dr. Jane Goodall told me that one of her primate researching colleagues in the Congo basin had had her work utterly wiped out, not once, but twice, when entire families of habituated gorillas in her study died from the disease.

Of course grieving human family members also make close contact with their sick or deceased loved ones and hospital workers are very much at risk as there is no vaccine and no specific treatment.

Black and White Colobus monkeys

There are several things to think about, and perhaps the most important source of the outbreak has been skimmed over by either the newspaper or the investigators on site. In the July 29 report a brief mention is made of “contact” with monkeys. I’m sure there is more to it than that. About 8 years ago a case occurred in the most northwesterly part of Uganda when a man died of Ebola. He had been skinning out a black and white colobus monkey he had killed for consumption.

Red colobus in Kibale NP

However, it is by no means just great apes that can be involved.

There is a very strong and growing use of bushmeat in the area.  Traditionally Ugandans were averse to bushmeat, and in particular they did not eat primates. But over the last 15 or 20 years or so a large number of refugees have fled the events in the DRC and brought with them their hunting and bushmeat culture.  Of course relationships with locals have developed and so the consumption of bushmeat has risen steadily. 

For a really comprehensive review of the possible role of wildlife in Ebola epidemiology I would recommend an on-line article by a team from the Wildlife Conservation Society in the Emerging Health Threats Journal.

Canadian & Ugandan students on a forest trail

I made numerous trips to Kibale and other areas of Western Uganda between 2002 and 2009 when I took final year vet students there for one-month wildlife conservation externships. Our first field work took place in Kibale National Park

My students and I had what, in retrospect, were some very close calls. For one thing some of us handled monkeys. But primates may not be the only zoonotic source of the virus. 

There is a body of evidence that suggests that Egyptian fruit bats and even some other species may be carriers. They too are a major source of bushmeat and also certainly carry Marburg virus, which is very closely related to Ebola. So closely in fact that they are almost indistinguishable except by very detailed examination. The produce virtually the same symptoms and sufferers almost always die.

There is a fascinating cave in the Maramagambo forest in Queen Elizabeth NP that used to be part of the tourist circuit and we visited is several times. In this clip you can see some of us getting very close to the mouth of the cave in an attempt to see the resident python. He had surely found a perfect spot to hang out, practically a case of free lunches. The background noise is not a technical glitch. It is the sound of the chittering conversations of thousands of bats.

The cave is the roosting site for those thousand of bats.We all got quite close to them and lots of close-up photos were taken.

In the mid-2008 Dutch authorities confirmed that an unfortunate woman tourist who had had direct contact with a bat in the cave died of Marburg infection after she got back to Holland. 

In a report from the Center for Infectious Disease Research and Policy it was stated that three miners died of the same infection after bat contact in a different cave in another area of the country. 

Bats don't just roost in caves. Hundreds of them use the trees in the Makerere University grounds in Kampala and as the fast-falling dusk of the tropical evening approaches thousands of them can be seen swooping across the sky as they head out for their nightly feed.

I read about the Dutch woman through the wonderful ListServ of Promed and at once alerted my colleagues in Uganda. One of them, Dr. JB Nizeyi, was the chief in-country veterinarian for the Mountain Gorilla Veterinary Project and very much involved in our teaching. I understand that the cave in QEP has been closed to tourist ever since.

Bushmeat and the bushmeat trade is an emotional issue. I discussed it at some length in my book The Trouble With Lions. I feel that as Africa’s human population continues to increase the trade will expand. In some countries (Uganda, Kenya) the human population doubles about every 20 years. People get hungry. They kill wildlife for food and for revenge when their crops are destroyed or their cattle eaten by large predators. Of course that gets us into a whole other debate, about which I have posted before, but all of it is related.

Marburg Virus and Fruit Bats

Linkhttp://www.reuters.com/article/healthNews/idUSL1166433320080711, http://www.sciencedaily.com/releases/2009/08/090801185900.htm, http://news.bbc.co.uk/2/hi/africa/6958015.stm

Just over a year ago, on July 11th 2008, there was a report on the important ListServ Promed Ahead and some other news outlets that told the terrifying story of a Dutch tourist who had died in Holland after being in contact with fruit bats in Uganda. She had visited the Maragambo Forest in Queen Elizabeth National Park, like thousands of others before her. These thousands included me, my wife and at least fifty of my students. We had gone there because there is a cave there that is home to thousands,
if not tens of thousands of Egyptian Fruit bats (Rousettus aegyptiacus) and it is mesmerizing to watch them flit in and out of the roost, never mind to see them clinging to the rock in their serried ranks.

There was an added bonus of attraction at the cave. A pair of African Fish Eagles had taken up residence just outside the entrance – grub to go as it were. Furthermore there was a resident python. In fact the last group of students had seen two pythons. So it is probable that a little biology 101 had been taking place. No exercise need for their packed lunches!



As you can imagine, the park authorities have closed the cave to tourists. The last thing they need is another catastrophe.

The Dutch doctors who cared for the dying patient and identified the cause of her death could not be absolutely certain where the virus came from, but the evidence has now mounted and seems conclusive.

The first suggestion of the link between fruit bats and Marburg, which is closely related to the better known Ebola virus, seems to have been made in 2007, as this BBC report shows.

Then came the recent (Aug 2nd 2009) report in ScienceDaily titled
'Ebola Cousin' Marburg Virus Isolated From African Fruit Bats. To quote:- “A paper published in the open-access science journal PLoS Pathogens provides new insight into the identity of the natural host of this deadly disease.”

As the authors of the PLoS article state, this brings the identification of the natural host of Ebola one step closer, as fruit bats are also strongly suspected in this disease. The first indication of this may have been in a 2005 paper in the prestigious journal Nature that can be found here.

There is one more important part of this chain. Fruit bats are a major source of bushmeat in the forests of central Africa. They are also pretty easy to catch when they return to their roosts during the day.

How many human forest dwellers have died of one of these deadly diseases and not even been noticed?

Queen Elizabeth National Park bat caves and possible disease link

Interesting to see that a case of fatal Marburg Hemorrhagic Fever (MHF) has been linked to the Maramgambo bat cave in Queen Elizabeth National Park in Uganda. I picked this report up on the important listserv PRO/AH> ProMED-AHEAD Digest of 11th July, a service to which I have been subscribing for several years.

The report describes how one unfortunate Dutch tourist, visiting the cave that is the roosting site for thousands of Egyptian Fruit Bats went down with the disease not long after she returned home and died soon afterwards despite heroic care. Genetic analysis of samples showed that her condition was indeed caused by a previously unreported type of this virus. Marburg HF has been seen before in Uganda and the DRC. One of the list’s moderators wrote, “The involvement of cave-dwelling bats in transmission of the disease is compelling, but still circumstantial.” In the last case of Marburg disease reported in Uganda the death of one man was established as being linked to his skinning of a colobus monkey.

My interest is more than merely academic. I have been to the cave several times, each time with up to a dozen students, both Canadians and Ugandans, as we have studied the human x wildlife x livestock interface. Our students, seen here at the cave entrance, not only see a seething mass of bats, but there is at least one cave-dwelling python. Packed lunches, as it were.

An African Fish eagle seems to have taken up residence nearby, abandoning his more normal diet for a guaranteed lunch-on-the–wing . At least when I have visited one of these magnificent birds is usually hanging out with 15 metres of the cave entrance. The one shown here had just taken a fish in the Okavango swamp.

In other parts of Africa Egyptian Fruit bats are known to harbour filoviruses, the group to which MHF belongs. (Marburgvirus, fruit bats - W. Africa 23 Aug 2007: ProMED-mail.

If the Marburg and Maragambo bat link is clearly established the cave might fall off our list of places to visit.

The list reports very frequently, sometimes as much as three times a week, on infectious diseases of animals (including humans) from around the world. Avian ‘flu is a hot one right now, anthrax features with great regularity, but the moderators play no favourites, and anything is up for report, with pithy comments where needed. Subscribers are invited to add comments when they feel inclined

For another way to find out what ProMED can do, especially for those who enjoy a good read, I can recommend The Eleventh Plague by Dr. John S. Marr and John Baldwin. This novel is based on the efforts of a mass murderer to terrorize with the threat of a new plague, an eleventh, as he causes havoc by killing off people with horrifying ease in ways that mimic the Biblical plagues of Egypt. The authors show the world-wide power of ProMED and its subscribers as they race to solve the riddle before it is too late. Any more and I’ll be giving away too much of the story, but the dedication is important. It reads, in part, “This book is dedicated to (these) scientists (several groups are named) and to ProMED-mail.”

Ryan commented on this posting and I have replied in the comments box, but I think it may be worth adding here as well, in case a reader does not want to go to comments.

I should have added, in the original, that Marburg virus is in the same family as the better-known Ebola virus, and produces about the same effects. Ebola has not only been linked to many deaths in people, but has caused wide-spread epidemics in great apes. Dr. Jane Goodall told me how an acquaintance of hers who studies gorillas has lost her entire study group to this scourge, not once, not twice, but three times!