Classification of Parasites

Classification Hierarchy

In biological classification, organisms are organized into a hierarchical system that reflects evolutionary relationships. The system used for parasites follows the same general zoological classification but is often highly detailed due to their diversity.

I. Major Ranks in the Classification Hierarchy

Organisms, including parasites, are classified into progressively smaller groups:

Level	Description
Kingdom	Broadest major category (e.g., Animalia for parasites).
Subkingdom	Subdivision within a kingdom based on fundamental differences (e.g., Protozoa).
Phylum	Organisms with basic structural similarities (e.g., Platyhelminthes – flatworms).
Subphylum	Further division of a phylum (e.g., Vertebrata under Chordata).
Class	Groups sharing similar major features (e.g., Trematoda – flukes).
Subclass	Smaller group within a class (e.g., Digenea within Trematoda).
Order	Related families grouped together (e.g., Strongylida – hookworms).
Suborder	Subdivision of an order (e.g., Trichostrongylina).
Superfamily	A group of closely related families (e.g., Ancylostomatoidea).
Family	Organisms with major traits in common (e.g., Ancylostomatidae).
Subfamily	Subdivision within a family (e.g., Ancylostomatinae).
Genus	Closely related species grouped together (e.g., Ancylostoma).
Subgenus	Further division within a genus if necessary.
Species	Basic unit of biological classification (e.g., Ancylostoma caninum).
Subspecies	Varieties within a species showing minor differences.

II. Important Notes

• As you move from kingdom to species, the classification becomes more specific.
• Each level is nested inside the one above.
• Scientific names for genus, species, and subspecies follow nomenclature rules (Latinized, italicized, author citation if needed).

I. Introduction to SNOPAD

• Full Form:
  Standardized Nomenclature of Animal Parasitic Diseases.
• History:
  • First published as SNOAPAD in 1988.
  • Later revised and officially termed SNOPAD.
• Objective:
  • To standardize the terminology used for naming parasitic diseases.
  • Avoid confusing and inconsistent disease names.
  • Provide clarity in communication among parasitologists, veterinarians, and physicians.

II. Guidelines for Disease Naming Using SNOPAD

1. Addition of the Suffix “-osis”

• Rule:
  Add “-osis” (plural: “-oses”) to the stem of the parasite’s taxonomic name (genus or higher).
• Method:
  • Omit the last one or two letters of the taxonomic name stem before adding “-osis”.
  • This provides a consistent disease name linked to the parasite.

2. Special Rule for Names Ending in “-x”

• Rule:
  If the parasite taxon ends in “-x”,
  • Convert “-x” to the genitive case (typically “-cis”),
  • Then add “-osis”.

3. Disease Naming from Full Generic Name

• Rule:
  You can directly add “-osis” to the full genus name without modifying it if needed for clarity.

III. Examples of SNOPAD Application

Parasite Name	Disease Name	Explanation
Taenia	Taeniosis	Dropping “-a”, adding “-osis”
Toxoplasma	Toxoplasmosis	Directly adding “-osis”
Trypanosoma	Trypanosomosis	Dropping “-a”, adding “-osis”
Fasciola	Fasciolosis	Dropping “-a”, adding “-osis”
Ancylostoma	Ancylostomosis	Dropping “-a”, adding “-osis”
Pulex	Pulicosis	“x” becomes “c”, then add “-osis”