BSE pathogens can be transmitted by air

(15.01.2011) Airborne prions are also infectious and can induce mad cow disease or Creutzfeldt-Jakob disorder. This is the surprising conclusion of researchers at the University of Zurich, the University Hospital Zurich and the University of Tübingen

They recommend precautionary measures for scientific labs, slaughterhouses and animal feed plants.

The prion is the infectious agent that caused the epidemic of mad cow disease, also termed bovine spongiform encephalopathy (BSE), and claimed the life of over 280,000 cows in the past decades. Transmission of BSE to humans, e.g. by ingesting food derived from BSE-infected cows, causes variant Creutzfeldt-Jakob disease which is characterized by a progressive and invariably lethal breakdown of brain cells.

It is known that prions can be transmitted through contaminated surgical instruments and, more rarely, through blood transfusions. The consumption of food products made from BSE-infected cows can also induce the disease that is responsible for the death of almost 300 people. However, prions are not generally considered to be airborne – in contrast to many viruses including influenza and chicken pox.

A high rate of infection

Prof. Adriano Aguzzi's team of scientists at the universities of Zurich and Tübingen and the University Hospital Zurich have now challenged the notion that airborne prions are innocuous. In a study, mice were housed in special inhalation chambers and exposed to aerosols containing prions. Unexpectedly, it was found that inhalation of prion-tainted aerosols induced disease with frightening efficiency.

Just a single minute of exposure to the aerosols was sufficient to infect 100% of the mice, according to Prof. Aguzzi who published the findings in the Open-Access-Journal "PLoS Pathogens." The longer exposure lasted, the shorter the time of incubation in the recipient mice and the sooner clinical signs of a prion disease occurred. Prof. Aguzzi says the findings are entirely unexpected and appear to contradict the widely held view that prions are not airborne.

The prions appear to transfer from the airways and colonize the brain directly because immune system defects – known to prevent the passage of prions from the digestive tract to the brain – did not prevent infection.

Protecting humans and animals

Precautionary measures against prion infections in scientific laboratories, slaughterhouses and animal feed plants do not typically include stringent protection against aerosols. The new findings suggest that it may be advisable to reconsider regulations in light of a possible airborne transmission of prions. Prof. Aguzzi recommends precautionary measures to minimize the risk of a prion infection in humans and animals. He does, however, emphasize that the findings stem from the production of aerosols in laboratory conditions and that Creutzfeldt-Jakob patients do not exhale prions.

Literature:

Haybaeck Johannes, Heikenwalder Mathias, Klevenz Britta, Schwarz Petra, Margalith Ilan, Bridel Claire, Mertz Kirsten, Zirdum Elizabeta, Petsch Benjamin, Fuchs Thomas J., Stitz Lothar and Aguzzi Adriano. (2011): Aerosols Transmit Prions to Immunocompetent and Immunodeficient Mice. PLoS Pathog 7(1): e1001257. doi:10.1371/journal.ppat.1001257

Weitere Meldungen

Schweiz

Atypische BSE bei einer Kuh im Kanton St. Gallen nachgewiesen

Die Veterinärbehörden im Kanton St. Gallen haben bei einer Kuh die atypische Form von Boviner Spongiformer Enzephalopathie (BSE) – auch Rinderwahnsinn genannt – entdeckt
Weiterlesen

Schweiz

Atypische BSE bei einer Kuh in der Schweiz nachgewiesen

Die Veterinärbehörden haben im Kanton Graubünden bei einer Kuh die atypische Form von Boviner Spongiformer Enzephalopathie (BSE) entdeckt
Weiterlesen

Bundesamt für Lebensmittelsicherheit und Veterinärwesen

Fall von atypischer BSE in der Schweiz

In der Schweiz ist ein Fall von atypischer Boviner Spongiformer Enzephalopathie (BSE) – auch Rinderwahnsinn genannt – aufgetreten
Weiterlesen

NMI Naturwissenschaftliches und Medizinisches Institut an der Universität Tübingen

Wie der Schutz vor BSE in Europa künftig gewährleistet werden kann

Taumelnde Kühe, Angst vor Ansteckung beim Konsum von Rindfleisch – die Krise um die Gehirnkrankheit BSE, den sogenannten „Rinderwahn“, hielt um die Jahreswende 2000/2001 ganz Europa in Atem
Weiterlesen

EFSA

Wissenschaftler untersuchen Ursprung vereinzelter BSE-Fälle

Die europäische Reaktion auf die Bovine Spongiforme Enzephalopathie infolge der BSE-Krise der 1980er Jahre hat zu einem deutlich verringerten Auftreten der Krankheit bei Rindern geführt
Weiterlesen

Wissenschaft

Universitäten

Neuerscheinungen