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Category B - Organisms

Indexing Principles

Category B contains the terms for living organisms. The coverage of organisms is extensive particularly for organisms that are of medical importance.

The organisms are treed taxonomically based on the three domain system - Eukaryota, Bacteria, and Archaea. The viruses are also treed taxonomically. If a particular organism is not a MeSH term, index that organism with the next higher taxonomic group that is a MeSH term. For example, rhinoceros is not a MeSH term. The rhinoceros belongs to the order Perissodactyla, which is a MeSH heading. The correct indexing term for rhinoceros is PERISSODACTYLA.

To determine the next higher taxonomic group for an organism, use one of the available reference tools such as the NCBI Taxonomy Browser or the Integrated Taxonomic Information System. Additional reference texts include Bergey's Manual of Systemic Bacteriology and the Ninth Report of the International Committee on Taxonomy of Viruses.

Category B01 Eukaryota

Organisms in the domain Eukaryota are characterized by having cells that are enclosed in a membrane and by the presence of a cell nucleus. Animals, plants, fungi and organisms that were formerly classified as protozoa belong to the domain Eukaryota.

The term ANIMALS (METAZOA) is only used as the check tag and not as an IM heading.

Invertebrates [B01.050.500]

Invertebrates include insects and helminths. Many are of medical importance and many are common research animals. When used as research animals they are indexed NIM.

Do not make human related terms IM with invertebrates; instead index the invertebrate IM and the other term NIM. MeSH is annotated regarding this policy at many of these terms.

Reproduction in snails
ANIMAL (check tag)

The presence of a helminth or other parasitic organism is indexed with the term where the helminth or other parasite is found with the subheading /parasitol not /microbiol.

Isolation of Echinococcus granulosus from the lung
ANIMAL (check tag)

There are many pre-coordinated headings in other trees used frequently with these terms such as ANTIGENS, HELMINTH; HELMINTH PROTEINS; GENES, HELMINTH.

Vertebrates [B01.050.150.900]

Vertebrates used in experimental studies are indexed NIM with no subheading. Check tags are available for some of the most common experimental animals. Vertebrates in veterinary, or comparative anatomy or comparative physiology articles will be IM and usually with a subheading. Check the annotations under each MeSH term for guidance regarding making the term IM or NIM.

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Last Reviewed: March 18, 2016