Groups Ask U.S. Health and Environmental Agencies to Investigate Potential Link Between Pathogenic Fungus and Introduced Genetically Engineered Eucalyptus Trees
Neil Carman, Sierra Club
Anne Petermann, Global Justice Ecology Project
Rachel Smolker, Global Justice Ecology Project
June 14, 2007
Scientists and environmental groups sent a letter yesterday to federal agencies requesting an investigation concerning the public health and environmental risks of a pathogenic fungal organism Cryptococcus gattii. associated with certain Eucalyptus tree species. They are asking the U.S. Departments of Health & Human Services, Agriculture, Interior, and the Environmental Protection Agency to determine if the hazardous pathogen is present in genetically engineered (GE) Eucalyptus trees being grown by GE Tree company ArborGen in Alabama. Signatories of the letter included the Sierra Club, Global Justice Ecology Project, Center for Food Safety, Dogwood Alliance, and Southern Forest Network.
"We know the Cryptococcus gattii pathogen is associated with Eucalyptus trees in other countries and a federal investigation is urgently needed to fully assess ArborGen's proposed Alabama outdoor field trials of genetically engineered Eucalyptus," stated Dr. Neil Carman of the Sierra Club. "The chief concern is that the USDA in its Environmental Assessment completely failed to conduct an evaluation or consultation with other agencies regarding the potential of Cryptococcus gattii to be present in or to become established in the newly introduced Eucalyptus trees. Federal officials must conduct a thorough investigation in view of the pathogenic characteristics of Cryptococcus gattii and observed abilities for spores to be transported through the environment via multiple pathways," he continued.
Dr. Rachel Smolker, a research biologist with Global Justice Ecology Project, stated, "Cryptococcus gattii is considered by the Centers for Disease Control as an 'emerging infectious disease.' Inhalation of spores causes respiratory and central nervous system infection leading to fatal fungal meningitis. It affects other mammalian species in addition to humans." Dr. Smolker added, "Cases of C. gattii disease are increasing and spreading geographically, possibly associated with the introduction of Eucalyptus species worldwide. C. gattii has been isolated from Eucalyptus in India, Spain, Colombia, Brazil, Paraguay, Africa, Mexico, Southeast Asia and California."
Dr. Joseph Heitman, MD, PhD, Director of the Center for Microbial Pathogenesis at Duke University Medical Center, and an expert on Cryptococcus stated that, "Introducing large numbers of eucalyptus trees in the United States has the potential to provide a suitable habitat for Cryptococcus gattii."
Scientists and environmental groups are concerned because both ArborGen's permit application and the U.S. Department of Agriculture's Environmental Assessment failed to assess the potential of the Eucalyptus hybrid trees to harbor and spread the fungal pathogen C. gattii into the environment. This is made more pertinent by virtue of the fact that ArborGen's genetically engineered hybrid is a cross between E. grandis and E. urophylla, and E. grandis is one of the Eucalyptus species known to be associated with C. gattii. The USDA's Environmental Assessment contains not a single mention or citation on C. gattii. One reason for this oversight is that USDA may have been mislead by ArborGen since the permit application APHIS permit provides no information or citations on C. gattii and its association with Eucalyptus species. The letter requested that the U.S. Department of Agriculture deny ArborGen's request to grow genetically engineered Eucalyptus trees pending thorough investigation by the appropriate federal agencies of the potential human health and environmental risks of alien Eucalyptus trees with their potential to carry and transmit Cryptococcus gattii.
ArborGen permit (APHIS permit No. 06-325-111r) U.S.
Department of Agriculture's Environmental Assessment (USDA Docket No. APHIS-2007-0027)
C. gattii was first discovered in Australia, where it has been associated with various species of Eucalyptus trees, including six species E. camaldulensis, E. tereticornis, E rudis, E. gomphocephala, E. grandis and E. blakeleyi. While usually associated with Eucalyptus species, the pathogenic fungus has been found independently in some cases, and the precise nature of its' relationship to Eucalyptus species, like many other aspects of its' biology, remains poorly known.
Scientists reporting in the medical and mycology literature have on occasion noted the potential link between C. gattii infection and Eucalyptus planting. For example, the authors of a study of C. gattii in Taiwan warned that "Facing the increasing adaptive plantation of Eucalyptus in Taiwan, the importance of field study regarding the role of Eucalyptus plantations in Taiwan and occurrence of Cryptococcosis in human beings cannot be over-emphasized."
The origins of a recent outbreak of C. gattii on Vancouver Island are unknown, but it is now associated with many indigenous tree species. Normally C. gattii thrives in tropical and subtropical climates, yet the Vancouver Island outbreak reveals that the organism can survive for years and adapt to new environments in unforeseen ways. Dr. Joseph Heitman, MD, PhD, Director of the Center for Microbial Pathogenesis at Duke University Medical Center was part of the team of researchers that investigated the Vancouver outbreak. He can be reached for details on Cryptococcus at Tele: 919-684-2824, email: firstname.lastname@example.org. Dr. Heitman was not a signatory on the letter to federal agencies, but provided a quote for this release.
The state of Alabama and other southern states along the Gulf of Mexico may fit in with the ability of C. gattii to thrive in subtropical climates. Outbreak pathways of C. gattii include air and water giving it ample opportunities to spread. According to genotype testing by Fraser et al.(7) indicating 30 identical loci between the two discovered strains, the Vancouver Island strain of C. gattii is identical to one in California collected in 1992 from Eucalyptus camaldulensis trees. This is of interest given the capacity of C. gattii to survive in water for long periods, and suggests that colonization can occur via waterways over long distances and time periods.
Researchers at ArborGen, LLC used genetic engineering, classic hybridization and cloning to produce 355 Eucalyptus hybrids being grown in Alabama. Certain genetic details about the clones are Confidential Business Information. Today we understand that monocultures facilitate emergence of pathogens and that a pathogen that can affect other mammalian species as well as humans is of particular concern. Federal agencies need to fully evaluate the risks of this new fungal pathogen before allowing potentially adverse field trials to continue in Alabama and risk release of C. gattii into the environment. The risk may or may not be independent of genetic engineering, however, a precautionary approach would be advisable. Neither ArborGen nor USDA/APHIS have proposed any assessment or biological monitoring for C. gattii during or after the Alabama field trials.
Public health agencies in the U.S. need to be more concerned about the association between C. gattii and widely introduced Eucalyptus species. Species in the genus Eucalyptus are not native to the U.S. and have been introduced in California, Florida and now Alabama. Yet U.S. public health officials, environmental and government regulatory agencies have evidently failed to assess the increased public health risk associated with planting alien Eucalyptus trees. Given the advancing state of our understanding of C. gattii, any further introduction of Eucalyptus should not be permitted without a thorough assessment of the risk of also inadvertently introducing or providing widespread habitat for this dangerous pathogen. Doing so could put millions of Americans at risk of exposure.
Copies of the letter submitted to Federal agencies can be obtained from: