Study sheds light on cross-species infection for BSE

January 26, 2005

A study published early online by THE LANCET provides an estimate of the compared efficiency of oral transmission of BSE to cattle and to man.

There has been uncertainty regarding the amount of BSE material that constitutes an oral infectious dose for humans. The study estimates that a person would have to eat at least 1.5kg of neural tissue from an infected animal that was just below the detection limit when tested negative at the slaughterhouse, to be at risk of developing variant Creutzfeldt-Jakob disease (vCJD).

Jean-Phillipe Deslys (Commissariat à l'Energie Atomique, France) and colleagues gave two adult primates a 5g oral dose of ground brain tissue from a BSE-affected cow. One primate developed a neurological disease closely resembling vCJD 5 years after exposure, whereas the other remained free of disease. On the basis of these findings and data from other studies the investigators estimated that the efficiency of infection from cow to primate could be 7 to 20 times lower than that of intraspecies infection for cattle.

The results of the present study also suggest that the incubation period for BSE transmission from cattle to human can be more than a third longer than that of human to human transmission.

Dr Deslys states: "The present data do not provide a definitive minimum infective dose for transmission of cattle BSE to primates, but they do give enough information for a preliminary assessment of the adequacy of existing measures to protect the human food chain.

"Our results provide reassurance that BSE screening procedures combined with CNS removal are effective measures to protect the human food chain."

In an accompanying commentary James Ironside and Mark Head (National Creutzfeldt-Jakob Disease Surveillance Unit, University of Edinburgh, UK) write that the precise implications of this study for vCJD are difficult to assess since the number of animals used in the study were small and the minimum infectious dose of BSE-infected neural tissue for primates remains unknown.

Professor Ironside comments: "There remain fundamental problems comparing likely human exposure to BSE with experiments of this type, even in primates that mimic vCJD pathology following oral BSE exposure. Multiple oral exposure events over a period of years seems likely in the UK, and vCJD occurs predominantly in young adults, raising the possibilities of age-related susceptibility or exposure. More data will be forthcoming on some of these points from a larger studies, but it will be several years before they are likely to emerge."
-end-
Dr Jean Philippe Deslys, Groupe d'Innovation Diagnostique et Thérapeutique sur les Infections à Prions, CEA/DSV/DRM,18 Route du Panorama, 92265 Fontenay-aux-Roses BP 6 92265 Fontenay-aux-Roses Cedex, FRANCE. T) 33-1-46-54-82-79 jpdeslys@cea.fr

(comment) Professor James W Ironside, CJD Surveillance Unit, University of Edinburgh, Western General Hospital, Grewe Road, Edinburgh, Scotland EH4 2XU, UK. T) 0131-537-1980 james.w.ironside@ed.ac.uk

Lancet

Related Infection Articles from Brightsurf:

Halving the risk of infection following surgery
New analysis by the University of Leeds and the University of Bern of more than 14,000 operations has found that using alcoholic chlorhexidine gluconate (CHG) halves the risk of infection in certain types of surgery when compared to the more commonly used povidone-iodine (PVI).

How plants shut the door on infection
A new study by an international team including University of Maryland scientists has discovered the key calcium channel responsible for closing plant pores as an immune response to pathogen exposure.

Sensing infection, suppressing regeneration
UIC researchers describe an enzyme that blocks the ability of blood vessel cells to self-heal.

Boost to lung immunity following infection
The strength of the immune system in response to respiratory infections is constantly changing, depending on the history of previous, unrelated infections, according to new research from the Crick.

Is infection after surgery associated with increased long-term risk of infection, death?
Whether experiencing an infection within the first 30 days after surgery is associated with an increased risk of another infection and death within one year was the focus of this observational study that included about 660,000 veterans who underwent major surgery.

Revealed: How E. coli knows how to cause the worst possible infection
The discovery could one day let doctors prevent the infection by allowing E. coli to pass harmlessly through the body.

UK study shows most patients with suspected urinary tract infection and treated with antibiotics actually lack evidence of this infection
New research presented at this week's European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Amsterdam, Netherlands (April 13-16, 2019) shows that only one third of patients that enter the emergency department with suspected urinary tract infection (UTI) actually have evidence of this infection, yet almost all are treated with antibiotics, unnecessarily driving the emergence of antimicrobial resistance.

Bacteria in urine doesn't always indicate infection
Doctors should think carefully before testing patients for a urinary tract infection (UTI) to avoid over-diagnosis and unnecessary antibiotic treatment, according to updated asymptomatic bacteriuria (ASB) guidelines released by the Infectious Diseases Society of America (IDSA) and published in Clinical Infectious Diseases.

Subsidies for infection control to healthcare institutions help reduce infection levels
Researchers compared three types of infection control subsidies and found that under a limited budget, a dollar-for-dollar matching subsidy, in which policymakers match hospital spending for infection control measures, was the most effective at reducing the number of hospital-acquired infections.

Dengue virus infection may cause severe outcomes following Zika virus infection during pregnancy
This study is the first to report a possible mechanism for the enhancement of Zika virus progression during pregnancy in an animal model.

Read More: Infection News and Infection Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.