University of Arkansas, Fayetteville Division of Agriculture


Chickens and turkeys are routinely infected with the roundworms Ascaridia galli and A. dissimilis, respectively. The current study was conducted to gather basic information on these worms and to determine whether heterologous infections (chicken worms in turkeys and turkey worms in chickens) would be successful. Chickens and turkeys were obtained at day of hatch, brooded to 7 days of age, and placed in pens (25/pen) according to infection as received at 7 days of age: homologous, heterologous and control (no infection). Bird weights, mortalities, and feed efficiencies were monitored for 3 weeks postinfection, at which time all birds were killed for parasite collection and counting. Feed efficiency, a parameter more adequately measured in large-scale studies, did not vary between experimental groups. Bird weights at necropsy varied significantly (P < 0.05) between groups only for the turkeys, with homologous infection (A. dissimilis) birds weighing less than controls. All induced, homologous, and heterologous infections were successful. Rates of establishment, however, were significantly (P < 0.05) depressed for each heterologous model. Total A. dissimilis numbers were only 55% as great as those for A. galli in chickens [geometric means (GMs) of 13.2 versus 24.2], and total A. galli numbers were only 56% as great as A. dissimilis numbers in turkeys (GMs of 5.6 versus 10.0). Given the fact that heterologous infections were successful, albeit reduced, in both types of birds (infections that included tissue-phase forms), additional studies are planned to determine whether these infections might induce interspecies (overlapping) immune competence in the host and aid in reducing natural parasitisms to levels with no economic impact.