Eating bad beef. Infected cattle, which got the disease by eating animal by-products, produce infectious beef. The prion is not damaged even by thorough cooking. It is also possible that slaughterhouse workers exposed to aerosolized cattle parts might be infected in this way.
Variable. Conceive that ingestion or contact with the prion infection could result in the disease, so best not to eat the raw meat, or even the cooked meat, if infected, or get an organ transplant from a human who has the illness. But, do not worry, the cases occurred in england, not in the usa.
Read below. Bovine spongioform encephalopathy (mad cow disease) is a prion disease, infective agents that vary from viruses in not having dna or rna. The agent can be transferred by ingestion or surgery transplanting the infected tissue (e.g. Cornea) it is fortunately extremely rare for this to happen nowadays.
Unknown. There are no cannibals in india as far as I know and cannibalism in new guinea (causing the disease kuru) no longer occurs but mad cow disease is a prion disease (a protein with no dna or RNA that viruses have) it spreads by ingestion or surgery the incubation period is about 18 months but longer periods have occasionally been reported.
Rare. From my reading, there has been a single human case in the usa, one in ireland, a few hundred in the united kingdom because of the unsafe cattle farming practices in the past, and very few elsewhere. By contrast, maybe one person in a million each year gets a classic prion disease such as cjd.
MAD COW DISEASE. Although cjd (creutzfeld jacob disease = mad cow)is the most common human prion disease, it is still rare, occurring in about one out of every one million people every year. It usually affects people aged 45–75, most commonly appearing in people between the ages of 60–65.
Rare except for. The huge outbreak of the disease about 2 decades ago in the uk that spilled over into europe. Very few cases in the usa. In the wake of this, a human disease, called varient creutzfeldt-jakob disease, was linked to eating contaminated beef. Several hundred cases have occurred in europe but none have been acquired in the usa.
The epizooic of. Bovine spongiform encephalopathy in the uk primarily is essentially over and there have been no human equivalents (so called variant creutzfeldt-jacob syndrome).
In cows? Http://www. Medicinenet. Com/mad_cow_disease/page5.htm.
Not very common. Very rare disease. There have been a few sporadic outbreaks.
Avoid infected meat. "mad cow" disease is uncommon in the usa. About 150 worldwide cases of vcjd have occurred to date, nearly all associated with beef consumption in the uk. There have been 4 confirmed cases of infected cattle in the us since 2006. Generally any cow with neurological symptoms is removed from the herd, and there are feed bans on possibly infectious materials. Avoid beef totally, if very concerned.
Incurable. The onset of "mad cow disease" or bovine spongiform encephalopathy symptoms is sudden and the progress is rapid. Many attempts have been made to alter the fatal course of the disease, with a notable lack of success.
Currently you can't. There are currently no medications available to treat/cure (vcjd) mad cow disease. One should avoid beef from area that have been identified as having diseased livestock. There is an active surveillance program in most developed countries that export beef.
Prion disease. Mad cow disease or bse (bovine spongiform encephalopathy) is a progressive neurological disorder of cattle that results from infection by an unusual transmissible agent called a prion.
Anyone. Anyone who is exposed. How it is transmitted is a bit of a mystery, as is what exactly it is.
Occupational. Mostly occupational hazard - working in the slaughterhouse for example. Eating large quantity of raw and undercooked beef has been cited - but it needs to be from infected cows. Risks are generally low since they stopped feeding the ground up dead animals back to the herd.