Haemonchus contortus: Immunodiffusion patterns of antigens from phenotypically different females

Immunodiffusion patterns of the different morphological types of female Haemonchus contortus (Rudolphi, 1803) indicate that the three phenotypes—smooth, linguiform, and knobbed—differ from each other serologically. Linguiform antigens gave five precipitin lines, knobbed gave four lines, and smooth gave three precipitin lines with rabbit antisera. Also, lines unite in a manner indicating marked antigenic differences between the three types. Since serological studies are considered to be sensitive tools in taxonomy, the present work indicates that taxonomic importance should be attached to the vulvar configurations in female H. contortus.