Fascioloides magna in white-tailed deer (Odocoileus virginianus): observations on the pairing tendency.

Fascioloides magna (Bassi 1875) was recovered from 227 of 312 (73%) white-tailed deer (Odocoileus virginianus) in southern Texas between 1971 and 1975. Deer from age classes more than 1 year old had infection rates of from 64 to 84%. Few dead flukes were found. Flukes occurred exclusively in the livers of infected animals and were paired in 256 of 301 (85%) fibrous hepatic capsules. The prevalence of immature flukes with an average of one immature per infected liver was similar in all age classes, suggesting a relationship between fluke pairing and maturation.