Fourth US death from mad cow disease confirmed in Texas

A man in Houston, Texas has died from variant Creutzfeldt-Jakob Disease, a fatal brain disorder believed to be caused by eating beef from cattle with mad cow disease, according to the U.S. Centers for Disease Control.

It is the fourth known death from the disease in the U.S., the CDC said. The man, who died in May, was born and raised in a Middle Eastern country. The CDC declined to say which country to ensure his and his family's privacy.

The man is believed to have acquired the disease during extensive travels in Europe and the Middle East, according to Dr. Ermias Belay, associate director for medical epidemiology at the CDC. 

"It’s very likely that the exposure may have occurred outside of the United States, but we can’t say for sure exactly when," Belay told Al Jazeera.

Among the other three patients who have died in the U.S., two are U.K. citizens who are believed to have been infected before coming to the U.S., and the third was born and raised in Saudi Arabia, Belay told Al Jazeera.

Variant Creutzfeldt-Jakob Disease in humans is thought to be caused by eating cows with bovine spongiformencephalopathy (BSE), more commonly known as mad cow disease, which was first reported in the U.K. in 1996.

The number of cows afflicted with BSE in the U.K. peaked in 1993 with nearly 1,000 new cases per week, but incidence of the disease plummeted to just 11 cases in 2010. Just four cows with BSE have been found in the U.S., according to the CDC.

In humans, more than 220 cases of variant Creutzfeldt-Jakob Disease (CJD) have been reported across the world, with 177 in the U.K. and 27 in France. A “classic” form of CJD that isn’t caused by the bovine disease also occurs at a rate of about 1 per 1 million people in the U.S.

Belay said that the disease does not easily spread across species. "Despite the fact that millions of cows were infected and consumed [in the U.K.], there were only 177 human cases," he said.

He added that the U.K. was "bracing for Armageddon, so to speak, but that didn’t materialize, fortunately, because of that species barrier.”

The CDC and the Texas Department of State Health Services are both investigating the Texas patient’s history and potential sources of infection. 

There is no cure for variant Creutzfeldt-Jakob Disease, and so far, it is always fatal. Right now the presence of the disease can only be determined with certainty after a person’s death by examining spinal fluid or brain tissue, and even making a probable diagnosis is difficult.

Symptoms vary widely and can mimic other neurological diseases like Alzheimer’s and Parkinson’s, such as unsteadiness or difficulty walking. Early on, patients sometimes have psychiatric problems like depression or anxiety, another reason why it can be difficult to diagnose. But those with variant CJD become “completely immobile and mute” by the time they die, according to the World Health Organization.

“When you’ve seen one case of CJD, you’ve seen one case of CJD,” Florence Kranitz, president of the New York-based Creutzfeldt-Jakob Disease Foundation, said a neurologist once told her about knowing anything consistent about the disease.

Kranitz just returned from a conference in Italy where she said scientists discussed the potential for using treatments for Parkinson’s, Huntington’s disease and even cancer on people with diseases like CJD that are thought to be caused by transmittable pathogens called prions.

In particular, she said, a recent paper published in the journal Science Translational Medicine detailed the use of a medicine that seemed to halt the brain degeneration caused by prions in mice.

“That is encouraging,” Kranitz said, “but we’re still a long way from human trials.”

As far as the possibility of more human deaths from variant CJD, scientists believe the risk is low. “We have physicians at the local level, in the farming communities, in big cities, big places like Stanford and UCLA and John Hopkins and physicians all over the United States watching for this disease to show up in humans, and it’s just not there,” James Cullor, a professor at the UC Davis School of Veterinary Medicine, told the magazine Modern Farmer. “I think that supports the premise that the risk is very low to the human population.”