Most of the known viruses are those that cause disease in humans, domestic
animals, or cultivated plants. These hosts represent a very small fraction
of the biosphere that is available for virus infection. In addition, viruses
can persist and replicate in their hosts without causing any detectable
signs of disease. Thus, it is likely that the great majority of viruses
that exist may be completely unknown to us. Studies of viruses in wild hosts
have been of relatively small scale and narrow focus. We propose that there
would be great value to the field of virology, both intellectual and practical,
in a large scale inventory of the viruses that exist in wild host ecosystems.
Specifically, we propose an inventory of the viruses within all major host taxa that comprise complex ecosystems within a defined geographic area of high biodiversity. The characterization of viruses on an ecosystem scale is a novel undertaking that will discover new viruses and elucidate aspects of viral interactions and ecology. The role of viruses in ecosystem maintainance is largely unknown, but clearly viruses can play a role in stablizing populations, and they can alter the behavior of their host.
Due to the numbers of host species
in various taxa, this project is designed to investigate the viruses of
nearly all vertebrate animal species, and of multiple selected species from
each taxonomic family or genus of plants, fungi, arthropods, other invertebrates,
archaebacteria, and eubacteria occurring within a single geographic region.
By thorough analysis of as much of the biosphere as is feasible within a
defined set of ecosystems, we expect to gain knowledge at three levels relative
to our current understanding: 1) prevalence and distribution of known viruses
in the wild; 2) identification of unknown viruses that are members of known
virus families, and ; 3) discovery of unknown viruses of families that have
never been described. The information obtained will have great relevance
to the understanding of virus evolution, epidemiology, and emerging viruses.
It is significant that many pathogens that are highly virulent for humans
have alternate hosts in which they do not cause disease. The hantaviruses,
for example, are nonpathogenic in their rodent reservoirs, despite their
virulence in man. It is also expected that some of the viruses discovered
will have important practical value as new agents for biocontrol of insects,
other agricultural pests, and undesirable weed or exotic plant species.
The project we propose is a comprehensive inventory
that will require the coordinated efforts of a great many virologists with
expertise in numerous host taxa. In this way it is similar in scale to other
large research endeavors such as the human genome sequencing project. This
is possible for the first time due to many essential factors. First, there
are conserved areas of land with biologically diverse ecosystems that are
being thoroughly inventoried. These inventories provide databases of taxonomic
and distribution information for host species, that will be the foundation
of our sampling strategies. Second, advancements in molecular technologies
such as gene sequencing, DNA amplification by the polymerase chain reaction
(PCR), and micro-array hybridization chips will allow broad scale screening
of small scale samples that would previously have been completely infeasible.
Third, the vast expansion of our genetic information infrastructure paves
the way for analyses and interpretations of the results of such a study,
using databases from organizations such as Genbank, the International Committee
for the Taxonomy of Viruses, and the Centers for Disease Control. All data
generated in this project will be electronically catalogued to produce information
databases that will be made freely available to other researchers and the
public via the world wide web.
With this project we plan to investigate the virus world that is all around us but has never been seen. Once initiated, we plan to complete this inventory within six years. Our final goal will be to generate a much more complete understanding of the viruses of the entire biosphere and to provide a catalog of public information on new biological sources for numerous practical applications.
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Virus images taken with permission from http://www.bocklabs.wisc.edu/
Last modified July 14, 1997
