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Fossil evidence of insect pathogens
George Poinar1, Roberta Poinar
1Department of Zoology, Oregon State University, Corvallis, OR 97331, USA. poinarg@bcc.orst.edu
Journal of Invertebrate Pathology
|July 13, 2005
Summary
Fossil insect pathogens, including viruses and fungi, discovered in 100-million-year-old amber provide insights into ancient ecosystems and potential origins of modern diseases.
Area of Science:
- Paleontology
- Entomology
- Virology
- Microbiology
Background:
- Fossil evidence of insect pathogens is rare.
- Insect-borne diseases and their evolutionary origins are of significant interest.
Purpose of the Study:
- To report novel fossil evidence of insect pathogens from ancient amber samples.
- To investigate the evolutionary history of insect viruses and their potential links to vertebrate arboviruses.
Main Methods:
- Analysis of six amber samples (15-100 million years old) for fossilized pathogens.
- Microscopic examination and identification of viral, bacterial, and fungal inclusions within fossil insects.
Main Results:
- Identified cytoplasmic polyhedrosis virus and trypanosomatid infection in a Cretaceous biting midge.
- Discovered nuclear polyhedrosis virus in a Cretaceous sand fly.
- Found fungal infections on mosquito and fungus gnat cuticles, and tumors in a caterpillar fossil.
Conclusions:
- Insect polyhedrosis viruses existed 100 million years ago.
- Suggests a possible evolutionary link between insect cytoplasmic polyhedrosis viruses and vertebrate arboviruses (Reoviridae).
- Represents the first fossil record of monogenetic trypanosomatid infections in arthropods.