By Paul Rincon
BBC News science reporter
Over 700 top US scientists have protested at the massive funds being ploughed into studying the handful of organisms considered bioterror threats.
Research into candidate bioweapons has risen sharply
A letter signed by the experts suggests current funding patterns undermine public health and national interests.
This is because research funds are being diverted away from germs that are already important causes of disease.
US government funding for research into candidate bioweapons boomed after the anthrax attacks in the Autumn of 2001.
Addressed to National Institutes of Health (NIH) director Elias Zerhouni and published in Science magazine, the letter's 750 signatories include two Nobel laureates.
The protest's organiser Richard Ebright of Rutgers University in Piscataway says that while grants for potential bioterror agents such as plague, anthrax and tularaemia have skyrocketed, grants for other disease-causing germs and so-called "model organisms" such as Escherichia coli have fallen.
Prioritising research on poorly known agents could backfire - not least because the need for containment and the requirement for new experimental tools makes studying them inefficient.
Professor Ebright argues that biodefence money would be better spent researching related, but less pathogenic organisms.
Studying agents like anthrax is not cost-effective, researchers say
He also believes that increasing the number of labs and people working on bioterror agents would raise the risk of an accidental release or deliberate attack.
The National Institute of Allergy and Infectious Disease (NIAid) - the arm of NIH that deals with pathogenic organisms - awarded 15 times more biodefence grants between 2001 and 2004 than it did during the previous four-year period, says the letter.
Meanwhile, grants for work on non-biodefence disease germs fell by 27% and grants for studying model bacteria fell by 41%. The figures come from an analysis of NIH's own data. Professor Ebright believes this policy is preventing important advances in public health.
"From a public health perspective the figures speak for themselves," he told the BBC News website.
"For the range of prioritised bioweapons agents, there is an average of 0 cases per year in the US. For the range of agents that have been de-emphasised, there are thousands of cases and deaths per year."
But NIAid officials claim the figures quoted in the letter are misleading.
"The analysis was done on four study sections, but these aren't complete in terms of the overall bacterial pathogen research that we fund," said John McGowan, director of the division of extramural activities at NIAid.
He added that although there had been fluctuations in NIAid funding for different areas of bacterial research, there was no support for the drop in non-biodefence funding described by Professor Ebright.
However, Sidney Altman, a Nobel prize-winning molecular biologist at Yale University, and one of the signatories on the letter, is unconvinced.
"My own view is that... regardless of what officials in the government say, it has taken money away from basic research in microbiology," he said.
"There are clearly a lot of people who have done extremely valuable research over the years who find this objectionable."
Professor Ebright added that the letter was not questioning the decision to fund biodefence research through NIH, only what he called the body's narrow definition of biodefence - which limits research to a few agents.
NIAid's biodefence budget has risen from $42m in 2001 to $1.5bn in 2004, with $1.6bn projected for 2005.