In this chapter you learn how to differentiate intestinal protozoa, helminth ova, plasmodia and microfilariae by using specific morphological criteria. The diagnostic keys presented here are those of the Diagnostic Centre of the Swiss Tropical and Public Health Institute (Swiss TPH) in Basel. Of course, each laboratory has created its own keys and you should also consult diagnostic text books or keys provided by WHO to find out which keys suite you best for your daily work.

  • Under “Key Diagnostic Features” you find a list of important diagnostic criteria and pencil drawings of the parasites
  • Under “Diagnostic-Keys” you find printable versions of our keys
  • Under “Exercises” you get photo-micrographs in a random order and you have the opportunity to work with the keys

Diagnostic keys

Instruction on how to work with our four diagnostic keys

First choose one of the given keys for amoebae and flagellates, for plasmodia, for helminth ova or for microfilariae. You are provided with images of parasites in a random order and the first question of a decision tree with a series of answers. On “mouse-over” you are given pencil drawings showing the diagnostic features. You choose the answer and you get the next question and so on. At the end of the decision tree, you are given the image of the parasite you identified and the answer whether this is right or wrong. You can display the right diagnostic path by clicking (right answers in green) and you can see where you made a mistake (wrong answer is in red). With the “again key” you can restart the decision tree; with the “next key” you get a new diagnostic task.