vpg logo Parasitology
Lab Keys

Ruminant
Parasite Diagnostic Key

1. Angular egg (triangular, square) with a gray grainy, rough shell
                                                          .......... Moniezia sp.
2. Oval to ellipsoidal egg with a smooth shell ........ Go to: 3 & 4

3. Egg withOUT an operculum, micropyle, or plugs .......... Go to: 5 & 6
4. Egg WITH an operculum, micropyle, or plugs .......... Go to: 9 & 10

5. Small oval to ellipsoid embryonated or larvated egg
                                                          .......... Strongyloides sp.
6. Moderate or very large egg containing a morula .......... Go to: 7 & 8


7. Moderate size egg with morula that fills most of the shell
                                                          .......... Strongyle-type Egg
8. Very large football-shaped egg with morula that does NOT fill shell
                                                          .......... Nematodirus sp.

9. Egg with bi-polar plugs .......... Trichuris sp.
10. Egg or oocyst w/ single operculum or micropyle .......... Go to: 11 & 12

11. Oocyst with micropyle & single-celled embryo .......... Eimeria sp.
12. Large operculated egg with a morula .......... Fasciola sp.

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NC State College of Veterinary Medicine
1060 William Moore Drive
Raleigh, NC 27607