Saturday, April 30, 2005

Ebola vaccine?

PharmaLive: Single-shot Outbreak Vaccine Provides Full Protection Against Ebola According to Results of New Animal Studies: "Dutch biotechnology company Crucell N.V. (Euronext, Nasdaq: CRXL) today reported new results from its Ebola vaccine studies. The studies, conducted together with the Vaccine Research Center (VRC) of the US National Institutes of Health (NIH) and the US Army Research Institute of Infectious Diseases (USAMRIID), confirm previously published results showing that a single shot of the vaccine protected monkeys completely against a lethal Ebola challenge. "

This is great news - a major step down the road to developing an Ebola vaccine for people. A vaccine would be a critical tool in stopping outbreaks, particularly by vaccinating health care workers and high-risk contacts during an outbreak. The ongoing Marburg outbreak in Angola shows the risk to health care workers during an outbreak is very high. Losing health care workers during an outbreak further exacerbates transmission, and makes it more difficult to contain.

Ebola can also have devastating effects on great ape populations. Now that there is progress towards a vaccine, there will be calls, as there have in the past, to vaccinate gorillas during outbreaks. If a vaccine is developed, the trick would be to get it into a form that makes mass vaccination of gorillas feasible - they just aren't going to line up for a shot, and they are picky eaters unlikely to eat baits randomly distributed on the ground.

The issue highlights the two main hypotheses of Ebola transmission in gorillas. Are outbreaks maintained by gorilla-to-gorilla transmission, or are the outbreaks maintained by continued introduction from some other animal reservoir like bats or insects. If gorilla-gorilla transmission is the main route, then ring vaccination around affected areas might stop an outbreak. However, if transmission is mainly from some highly mobile reservoir species to gorillas, then its unlikely that enough gorillas could be vaccinated to stop an outbreak ... which ones would you vaccinate?

The great ape connection is key: recent research has shown that the recent outbreaks of Ebola can be traced to consumption of wildlife (mainly apes but other species as well: Wild Animal Mortality Monitoring and Human Ebola Outbreaks, Gabon and Republic of Congo, 2001–2003,)

Some basic questions need to be answered about the epidemiology of Ebola. What is the reservoir? What precipitates outbreaks in the reservoir, then in wild mammals like apes? Research is ongoing.

New diabetes drug derived from Gila monster venom

Although humans have used animals and plants for millenia as a source of medicine, the recent announcement of a new diabetes drug derived from the venom of a Gila monster is a reminder of the importance of biodiversity.

From the NY Times:
The New York Times > Business > Lizard-Derived Diabetes Drug Is Approved by the F.D.A.: "A diabetes drug derived from a poisonous lizard has been approved by the Food and Drug Administration, its developers, Amylin Pharmaceuticals and Eli Lilly, said yesterday.

The drug, called Byetta, will be the first in a new class of drugs to reach the market for Type 2 diabetes, the form that usually occurs in adults. Studies have shown it can help control blood sugar and also help people lose a few pounds."


and further down in the article:

"Byetta is a synthetic version of a peptide, or small protein, found in what has been variously described as the saliva or the venom of the Gila monster, a poisonous lizard that lives in the Southwest and Mexico.

The discovery was made in the early 1990's by Dr. John Eng, a researcher at the Veterans Affairs Medical Center in the Bronx, who was working on a way to discover new hormones. He realized the Gila monster hormone was similar to glucagon-like peptide 1, an incretin hormone produced in the human digestive tract. "

Friday, April 29, 2005

H5N1 in Smuggled Eagles | CDC EID

From the CDC's journal, Emerging Infectious Diseases:

H5N1 in Smuggled Eagles | CDC EID: "We report the isolation and characterization of a highly pathogenic avian influenza A/H5N1 virus from Crested Hawk-Eagles smuggled into Europe by air travel. A screening performed in human and avian contacts indicated no dissemination occurred. Illegal movements of birds are a major threat for the introduction of highly pathogenic avian influenza."

Although not a new story, it is good to see it in the scientific literature. This paper really highlights how the trade in wildlife could be a fundamental threat to human health. Think monkeypox, Ebola, SARS, HIV/AIDS ... all diseases that have entered the human population through consumption and trade of wildlife. The trade in wildlife is one of the major threats to biodiversity the world over. Perhaps with increasing recognition of the threat to human health something will be done about it.

Interesting post on ProMED from President of NA Deer Farmer's Association

There was an interesting post on ProMED today by Gary Nelson,
President of the North America Deer Farmer's Association. Apparently,
4 of the 5 CWD-positive deer on the two farms in upstate NY were
actually rehabilitated deer, brought into captivity as fawns (ProMED/AHEAD/EDR post 20050428.1187). Gary Nelson suggested that CWD was brought in from the wild, and the ProMED moderator agreed.

It seems unlikely to me that there would have been no transmission on the farm and the deer were all positive when they came in. I suspect more information is required to guess at which direction CWD moved in this case. For example, in Wisconsin there is a very low prevalence in fawns (~1 in 1000), so it is possible or even likely they came in CWD-free and became infected on the farm. We will likely never know for sure. In any case this really highlights the risks associated with wildlife rebabilitation and wildlife 'farming'.

Thursday, April 28, 2005

Chronic Wasting Disease Found in Oneida County Wild Deer

Chronic Wasting Disease Found in Oneida County Wild Deer: "The New York State Department of Environmental Conservation (DEC) today announced it has received a preliminary positive result for chronic wasting disease (CWD) in a wild deer sampled in Oneida County. If confirmed, this will be the first known occurrence of CWD in the wild in New York State."

Discovering CWD in wild deer is not unexpected, given the previous detection of positive deer in captive deer farms. One positive of the 213 deer tested, less than 1/2 a percent, is fairly low relative to the outbreak in south-central Wisconsin (2-3%). Continued surveillance around the postive farms and in the affected area will be important to provide useful information to make reasonable management decisions.

Here are some useful CWD links:

CWD in New York
CWD Alliance
NWHC CWD Site