Friday, November 30, 2007

A New Strain Of Ebola Identified

 

# 1304

 

 

While Avian Flu is the primary focus of this blog, I occasionally stray over to other emerging infectious diseases in the news.  Today, we are hearing about what appears to be a newly identified strain of Ebola, now causing an outbreak in Uganda.

 

First, the report, carried by MSNBC, then some discussion.

 

 

New deadly strain of Ebola emerges

Hemorrhagic virus has infected dozens in Uganda

Nov. 29, 2007


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.

 

“That tipped us off that this is probably a novel or new strain of Ebola.”


 

Ugandan health officials have said the virus appears to be unusually mild, but Ksiazek said it is not yet clear if this is the case. He said experts need to check to see how many diagnosed patients are still alive.


 

Ebola is a hemorrhagic fever, meaning it can cause internal and external bleeding. Victims often die of shock but symptoms can be vague, including fever, muscle pain and nausea.

(cont.)

 

 

Ebola, which was first identified in 1976 after simultaneous outbreaks in Sudan and Zaire, has long been a staple of movie, TV, and novel writers due to it's high mortality rate and (at times) horrific symptomology.   Depending upon the strain, up to 80% of its victims die, and some `bleed out' as their internal organs are damaged by the virus.

 

Most victims, however, don't exhibit the extreme symptoms popularized in fiction.  

 

Transmission of the virus, among humans, appears to come from direct contact with infected body fluids, or to a lesser extent, skin or mucus membrane contact.  Most outbreaks have been self-limiting and short lived.

 

Of the four strains previously identified, three pose a health hazard to humans, while the fourth (Reston) appears to only adversely affect simians.  The Reston virus, unlike the others, has been shown to be airborne transmissible.

 

While considered a zoonotic disease (it is reportedly devastating the populations of the lowland gorillas in central Africa), the primary animal reservoir has never been identified.  The fruit bat, however, is a prime suspect.   

 

Fruit bats are also implicated in other diseases, such as the Nipah Virus in Malaysia and the Hendra virus of Australia.

 

It is likely that most human infections are derived from the hunting and consumption of `bush meat', which can easily introduce zoonotic pathogens into a human population.

 

Viruses mutate and adapt, and so the emergence of a new strain of an old disease isn't terribly surprising.   Over the past three decades we've seen more than 30 new emerging infectious diseases spring forth from zoonotic sources.

 

It may take some time before researchers can tell us how this new strain of Ebola differs from the ones we already know about, and what, if any, additional threat it poses.  

 

The battle against EID's (Emerging Infectious Diseases) is an ongoing one.  Despite our advances in medicine and technology, man continues to encroach into previously largely uninhabited areas, exposing himself to a wide variety of new pathogens. 

 

And as environmentalists love to say, `Nature always bats last'.

 

 

 

For excellent coverage of the recent Ebola outbreaks in the Republic of the Congo, I'll direct my readers to Scott McPherson's blog where he carried excerpts from the diary of Zoe Young, a healthcare worker who recently returned from that region after helping to fight an outbreak of Ebola.