• E-mail
• Print
• Comment
• Font Size
• Digg
• del.icio.us
• Discuss article

Link Between Ancient Blood-Sucking Bug and Disease-Causing Parasite Reported in Vector-Borne and Zoonotic Diseases

Posted on: Wednesday, 13 April 2005, 12:00 CDT

A sample of Dominican amber, around 20 million years old, has provided the first fossil evidence that Triatoma dominicana, a large blood-sucking bug, was a vector for the transmission of Trypanosma antiquus, a disease-causing protozoan parasite related to the microorganism that causes Chagas disease, as reported in the Spring 2005 issue (Volume 5, Number 1) of Vector Borne and Zoonotic Diseases, a peer-reviewed journal published by Mary Ann Liebert, Inc. and the only medical journal specifically devoted to such diseases. The paper is available free online at www.liebertpub.com/vbz.

George Poinar, Jr., Ph.D., Research Fellow in the Department of Zoology at Oregon State University in Corvallis, identified a fifth instar nymph of T. dominicana in a piece of amber that also contained T. antiquus present in two adjacent fecal droplets. The juxtaposition of these findings suggests that the bug excreted the protozoa in its feces prior to fossilization.

Based on similar fossil characteristics, Poinar proposes that T. antiquus may be a progenitor of T. cruzi, the infectious agent responsible for Chagas disease, a parasitic infection that affects millions of people in South and Central America.

Located near the fecal droplets were mammalian hairs, identified as bat hairs, suggesting that both the bug and the parasite relied on the bat as the vertebrate host needed to support their lifecycles. T. dominicana requires the blood of a mammal to complete its development.

"This is an extraordinary discovery and a landmark publication in research on triatomine bugs and Trypanosoma cruzi," says Michael Miles, Professor of Medical Protozoology at the London School of Hygiene and Tropical Medicine. "The evolutionary age of blood-sucking triatomines has been a controversial and debated topic, primarily due to the lack of any fossil evidence. One school of thought suggests that triatomines are very recently evolved from predatory Reduviidae, another, in part based on molecular phylogenetics, that triatomines and the blood sucking life style are older. With this first fossil record triatomines have at last come of age, although they may of course be more ancient than this specimen indicates. The finding of fecal droplets adjacent to the specimen and containing fossil Trypanosoma cruzi-like trypomastigotes is beyond all expectation and lends circumstantial support to the notion that bat Schizotrypanum might pre-date T. cruzi. Scrutiny of amber specimens proves to be a fascinating and productive endeavor, worthy of encouragement."

Vector-Borne and Zoonotic Diseases, led by Editor-in-Chief Stephen Higgs, B.Sc, Ph.D., from the Department of Pathology, University of Texas Medical Branch, in Galveston, is an authoritative peer-reviewed journal published quarterly in print and online. The Journal focuses on diseases transmitted to humans by insects or animals. It covers both vector- and zoonotic-borne diseases such as Lyme disease, ehrlichiosis, West Nile, hantavirus pulmonary syndrome, dengue, and Ebola. The Journal also features entomology, ecology, wildlife biology, and other field-related disciplines that are essential to the understanding of the geography, seasonality, and other risk factors for human disease.

Mary Ann Liebert, Inc., is a privately held, fully integrated media company known for establishing authoritative peer-reviewed journals in many promising areas of science and biomedical research, including Foodborne Pathogens and Disease, AIDS Research and Human Retroviruses, and Microbial Drug Resistance. Its biotechnology trade magazine, Genetic Engineering News (GEN), was the first in its field and is today the industry's most widely read publication worldwide. A complete list of the firm's 60 journals, books, and newsmagazines is available at www.liebertpub.com.

Source: Business Wire

More News in this Category