Sunday, July 29, 2012

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.


Diane said...

This is really bad news. I hope that they manage to control it very quickly. Diane

AfriBats said...

Would you add your bat photos as a citizen-science observations to the AfriBats project on iNaturalist?:

AfriBats will use your observations to better understand bat distributions and help protect bats in Africa.

Please locate your picture on the map as precisely as possible to maximise the scientific value of your records.

Many thanks!