In the field of medicine, the term “vector” has traditionally referred to any “organism that does not cause disease itself, but which spreads infection by conveying pathogens from one host to another.” An example would be how certain species of mosquitoes serve as vectors for dengue fever or malaria.
Therefore, vectors are agents of disease or transporters of parasites. As a conduit, the vector gets no benefit and sometimes loses fitness because of the arrangement. Studying vectors allow scientists to know more about the life cycle of parasitic and infectious diseases, helping us in controlling and ultimately preventing them from spreading.
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Distinguishing the biological vector from the mechanical one is important. While the former works on the host animal by having pathogenic organisms develop and multiply before being transmitted to the next host, a mechanical vector is an animal vector not essential to the life cycle of the parasite.
When used in gene therapy, a virus itself may serve as a vector if it has been re-engineered and used to deliver a gene to its target cell. In this sense, it is better known as the “cloning vector,” as it becomes the vehicle for delivering genetic material such as DNA to a cell.
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Captain Martin Lloyd Sanders, Ph.D., is an officer in the Commissioned Corps of the U.S. Public Health Service. He has rendered more than 12 years of service in occupational safety and health. For more on Captain Sanders’ work and interests, visit this page.