BACKGROUND

 An identification key (Figure 1) is a sequence of questions, typically dichotomous in nature, that are designed to help the user identify a particular object or structure. Identification keys are used throughout biology – in botany, for identifying plants; in entomology, for identifying insects; and in parasitology, for identifying immature and adult parasites and vectors. However, even though detailed keys are available to aid in the identification of various parasites, using them correctly can be difficult for a variety of reasons:

1.       “There is only one way to reach a correct identification. Mistakes or misinterpretations at any node will result in incorrect identifications.

2.       Figures are sometimes diagrammatic in nature and require interpretation in order to apply them to actual specimens.

3.       A high level of understanding of nomenclature, morphology, anatomy, and distribution of the organisms under study is usually required for successful identification.

4.       Accuracy is directly related to the user's skill at interpreting morphological characters and variation. These keys are generally not designed for novices.

5.       Not all taxa, especially at the species level, can be identified in this way. Some species are morphologically indistinguishable. These cryptic species can only be separated by more detailed methods.” [1]

Further, since the available keys are typically paper-based, non-interactive, and linear in structure, there is no functionality to diminish the cognitive load on the user. An interactive identification key that allows the user to link out to photographs, line drawings, and definitions would aid the user in reaching the correct identification and reduce the need to seek assistance from others or having to search through reference books. Dallwitz et al. list several advantages of interactive keys over conventional ones. A few of the most notable features include the ability to use any characteristic in any order, illustrations of characteristics, and inclusion of glossaries, explanatory notes, and terms for assistance in interpreting characteristics. [2] In fact, the International Consortium on Ticks and Tick-Borne Diseases decided in July 2000 that due to the difficulty of using standard keys for livestock tick identification, a computerized key should be developed. [3] Finally, such an identification key could allow for an unlimited number of photographs for a given parasite, eliminating the space limitations in standard reference texts, and a web-enabled key could be kept up-to-date more easily and with less cost than publication of a manual.

 PROJECT DESCRIPTION

Proper identification of parasites is important as certain parasites require specific methods of control, others have an impact on human health, and still others can have a profound economic impact to the production animal industry due to the impact on animal health and the cost of parasite control. While a variety of interactive identification key programs are available for other domains, such as botany, their design and functionality appears to vary widely and a review of the literature and as well as the Internet does not locate any interactive keys for veterinary parasitology. Therefore, the goal of this project is to create a prototype of an interactive identification key that helps the user identify parasites. In order to do this, we will perform the following primary tasks:

1.       Review existing interactive keys in other domains, such as botany and entomology

2.       Obtain representative veterinary parasitology identification keys

3.       Create a prototype, preferably one that is web-based

 SCOPE

Veterinary parasitology is a vast subject, because of the matrix of host species and parasites that infect those hosts. To restrict this project to a manageable level, we will focus specifically on parasites of ruminants (cattle, sheep, goats) and further restrict the scope to those commonly found in the southeastern United States.

 METHOD

 User analysis. A preliminary user analysis, shown in Table 1, identifies two target groups of people who may be responsible for identification of parasites in the context of this project: veterinarians and veterinary students.

Task analysis.  We will also perform a simple task analysis for routine parasite identification. If possible, this would be done via a talk-aloud protocol; however, obtaining veterinary student participation at this point may not be feasible.

 Functions. Using the user analysis and task analysis as a guide, we will determine the main functions to be incorporated into our design. Some possibilities include:

·         Display photographs of the suspect parasite to aid in identification

·         Provide a basic synopsis of the identified parasite. This will help the user determine if the identification is reasonable or possibly erroneous.

·         Provide the ability to click on terms and then display additional information such as definitions, line drawings, and photographs to aid the user in understanding terminology and vocabulary

Prototype Development.  There are several possible approaches to the development of a working prototype. Several products exist on the market for development of taxonomic identification keys; such products range in cost from freeware to approximately $400. Examples are DELTA (Description Language for Taxonomy), which is widely used for botanical identification and freely available from http://biodiversity.uno.edu/delta/, and Lucid, which may be purchased from http://www.lucidcentral.com/. However, a cursory review of these products indicate that a significant learning curve exists and that programming support would be required in order to web-enable the product. Therefore, we utilized a web page approach instead.

REFERENCES

1.             What is an identification key? 2003. Retrieved January 15, 2005 from http://www.sas.org/E-Bulletin/2003-06-27/labNotes/body.html

2.             Dallwitz, M.J., T.A. Paine, and E.J. Zurcher, Principles of Interactive Keys. 2004.

3.             First Annual Report, F. Jongejan, Editor. 2000, International Consortium on Ticks and Tick-borne Diseases: Utrecht University.